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Rohit Shetty, Natasha Pahuja, Thimmarayappa Roshan, , Mathew Francis, ,
Journal of Refractive Surgery, Volume 33, pp 676-682; https://doi.org/10.3928/1081597x-20170621-07

Abstract:
When normalized to the average energy density, the ring tangential map protocol appeared to provide maximum flattening and improvement in visual acuity. Further studies with larger sample sizes are needed to validate the findings of this pilot study. [J Refract Surg. 2017;33(10):676-682.].
Journal of Refractive Surgery, Volume 33, pp 690-695; https://doi.org/10.3928/1081597x-20170721-05

Abstract:
PURPOSE: To investigate the accuracy of the measurements provided by a new optical biometer (OA-2000, Tomey Corporation, Nagoya, Japan) for calculating the intraocular lens (IOL) power and to compare the refractive outcomes to those obtained with the IOLMaster 500 (Carl Zeiss Meditec, Jena, Germany). METHODS: In this interventional multicenter study, consecutive patients having cataract surgery were enrolled. Only the IOL model used in the largest sample of patients was selected and the eyes implanted with that IOL were subsequently analyzed. The OA-2000, an optical biometer based on swept-source optical coherence tomography (SS-OCT), was used to measure axial length and corneal power in all eyes. IOL power was calculated with the Hoffer Q, Holladay 1, and SRK/T formulas. In a subsample of eyes, the IOL power was also calculated with measurements obtained by partial coherence interferometry (IOLMaster 500). The median absolute error and percentage of eyes with a prediction error of ±0.50 diopters (D) or less were calculated. RESULTS: Two hundred forty-nine eyes were analyzed. Using SS-OCT, the median absolute error ranged between 0.33 (Holladay 1) and 0.35 (SRK/T) D. The rate of eyes with a prediction error of ±0.50 D or less ranged between 71.5% (Hoffer Q) and 67.1% (SRK/T). In the subsample of 87 eyes with measurements by both devices, the median absolute error was lower with the OA-2000 (Hoffer Q: P = .0377; Holladay 1: P = .0191; SRK/T: P = .0087). CONCLUSIONS: The SS-OCT–based optical biometer investigated in the current study provides accurate measurements for IOL power calculation and seems to offer more predictable refractive results compared to the partial coherence interferometry IOLMaster. [J Refract Surg. 2017;33(10):690–695.]
Xu Shao, Kai-Jing Zhou, An-Peng Pan, Xue-Ying Cheng, , , A-Yong Yu
Journal of Refractive Surgery, Volume 33, pp 696-703; https://doi.org/10.3928/1081597x-20170718-04

Abstract:
The rate of change of total corneal astigmatism showed a non-linear trend toward against-the-rule astigmatism, which was low at young and old age, high at middle age, and should be taken into account when performing surgery to correct astigmatism. [J Refract Surg. 2017;33(10):696-703.].
Fritz H. Hengerer, , Martin-Leo Hansmann, , Ina Conrad-Hengerer
Journal of Refractive Surgery, Volume 33, pp 670-675; https://doi.org/10.3928/1081597x-20170718-01

Abstract:
The use of less energy and larger spot separation led to smaller collateral damaged tissue areas along the cutting edges. The aberrant laser spots along the cutting edge may result in weakening of the remaining tissue, thereby enhancing the risk for capsular ruptures during surgery. [J Refract Surg. 2017;33(10):670-675.].
Stefano Guglielmetti, Amy Kirton, , Glenn I. Carp,
Journal of Refractive Surgery, Volume 33, pp 714-719; https://doi.org/10.3928/1081597x-20170721-04

Abstract:
Transepithelial PTK was effective in treating these cases of localized irregularly irregular astigmatism, achieving both objective and subjective improvement in vision. Compensatory epithelial remodeling over the irregularities enabled the transepithelial PTK approach to target the stromal surface irregularities. [J Refract Surg. 2017;33(10):714-719.].
Hakan Kaymak, Detlev Breyer, , Beatrice Cochener
Journal of Refractive Surgery, Volume 33, pp 655-662; https://doi.org/10.3928/1081597x-20170504-04

Abstract:
To evaluate and compare quality of vision and reading performance outcomes after implantation of bifocal refractive-diffractive, bifocal apodized diffractive, or trifocal diffractive-refractive intraocular lenses (IOLs). This randomized, prospective, three-armed multicenter (Spain, Germany, and France) trial included 104 eyes of 52 patients (mean age: 63.2 ± 7.7 years). Patients underwent cataract surgery with bilateral implantation of either AT LISA 809M (Carl Zeiss Meditec, Jena, Germany: AT LISA group, 38 eyes), AT LISA tri 839MP (Carl Zeiss Meditec: AT LISA tri group, 32 eyes), or ReSTOR SN6AD1 (Alcon Laboratories, Inc., Fort Worth, TX: ReSTOR group, 34 eyes) IOLs. Visual and refractive outcomes, depth of focus, and reading performance were evaluated at 1, 6, and 12 months postoperatively. The AT LISA tri group showed significantly better 12-month uncorrected (UIVA) and binocular distance-corrected (DCIVA) intermediate visual acuity (P ≤ .016) than the AT LISA group. The AT LISA tri group showed a significantly better 3-month UIVA compared to the ReSTOR group (P = .042). Binocular uncorrected and corrected distance visual acuities were not significantly different among groups (P ≥ .092) at the 12-month follow-up. A total of 85.3%, 90.0%, and 78.1% of eyes had a spherical equivalent within ±0.50 D in the AT LISA, AT LISA tri, and ReSTOR groups, respectively, at 12 months (P = .038). No statistically significant differences between the trifocal and bifocal groups were detected for reading performance (P ≥ .055). The trifocal diffractive-refractive IOL provides enhanced intermediate visual restoration compared to bifocal diffractive-refractive or apodized diffractive IOLs. The addition of an intermediate focal point did not deteriorate far or near vision. A comparable reading performance was maintained with the trifocal lens. [J Refract Surg. 2017;33(10):655-662.].
, Daya Papalkar Sharma, , Onurcan Sahin, , Ioannis Pallikaris
Journal of Refractive Surgery, Volume 33, pp 683-689; https://doi.org/10.3928/1081597x-20170807-01

Abstract:
This four-stage procedure appears to be an effective and safe approach for corneal stabilization and improvement of functional vision in patients with keratoconus. Larger case series with a longer follow-up are required to thoroughly evaluate the efficacy, safety, and stability of this combined approach. [J Refract Surg. 2017;33(10):683-689.].
Mary S. A. Attia, , Florian T. A. Kretz, , Tanja M. Rabsilber, Mike P. Holzer,
Journal of Refractive Surgery, Volume 33, pp 664-669; https://doi.org/10.3928/1081597x-20170621-08

Abstract:
The EDOF IOL design provided a wide range of improved visual and reading function between far and intermediate distances and also improved near visual acuity. Patients reported a high rate of satisfaction and spectacle independence at the various distances. [J Refract Surg. 2017;33(10):664-669.].
Zaina Al-Mohtaseb, Xu He, , Daniel Waren,
Journal of Refractive Surgery, Volume 33, pp 708-712; https://doi.org/10.3928/1081597x-20170731-01

Abstract:
FLACS pretreatment resulted in a decrease in CDE and less endothelial cell loss when compared to standard phacoemulsification. The decrease in endothelial cell loss was more prominent in the denser cataract group; thus, FLACS may be most beneficial in those cases. There was no significant difference in results between the two laser platforms. [J Refract Surg. 2017;33(10):708-712.].
, Hitoshi Ishikawa, , Nobuyuki Shoji, Kimiya Shimizu
Journal of Refractive Surgery, Volume 33, pp 704-707; https://doi.org/10.3928/1081597x-20170721-06

Abstract:
PURPOSE: To assess the light reflex of the pupil after Implantable Collamer Lens (ICL) (KS-aquaPORT; STAAR Surgical, Nidau, Switzerland) implantation to determine whether the ICL implantation might affect the pupil dynamics. METHODS: This study examined 28 eyes of 28 consecutive patients who underwent implantation of the posterior phakic ICL for the correction of myopia and astigmatism. Patient age at the time of surgery was 31.1 ± 6.8 years (range: 25 to 42 years). Preoperative refraction was −7.38 ± 2.26 diopters (D) (range: −3.25 to −11.80 D). Light reflex was evaluated using the infrared pupillometer Iriscorder C7364 (Hamamatsu Photonics, Hamamatsu, Japan). Measured parameters included pupil diameter (D1), constriction ratio, maximum constriction velocity, maximum dilation velocity, and the time required to recover 63% of the pupil diameter (T5). At 6 months postoperatively, the authors also investigated the relationship with the amount of vault using the Pentacam (Oculus Optikgeräte, Wetzlar, Germany). Evaluations with the instrument were performed before and at 1, 3, and 6 months after surgery. RESULTS: There was no significant association found between any of the parameters (analysis of variance, D1: P = .99, constriction ratio: P = .59, maximum constriction velocity: P = .87, maximum dilation velocity: P = .13, T5: P =.57). The vault of the ICL at 6 months postoperatively was 382.1 ± 176.5 μm. There were no significant associations between the maximum constriction velocity, maximum dilation velocity, and amount of vaulting (Spearman correlation coefficient maximum constriction velocity: r = 0.07, P = .71, maximum dilation velocity: r = 0.26, P = .28). CONCLUSIONS: The light reflex of the pupillary dynamics continued to be maintained at 6 months after ICL implantation. Current findings also verified that ICL implantation had little influence on the postoperative function of the iris. [J Refract Surg. 2017;33(10):704–707.]
Zoltan Z. Nagy
Published: 1 December 2012
Journal of Refractive Surgery, Volume 28, pp 855-857; https://doi.org/10.3928/1081597x-20121120-01

Abstract:
Guest Editorial Zoltan Z. Nagy, MD, DSc Femtosecond laser use in cataract surgery is a rapidly evolving technology and is attracting great attention worldwide because cataract procedures are the most frequently performed surgery within ophthalmology. Our group published the first clinical studies in 20091; since then a number of publications,2–8 including the article by Conrad-Hengerer et al8 in this issue of the Journal of Refractive Surgery, have appeared in the peer-reviewed literature, and an abundance of nonpeer-reviewed “information” has become available for surgeon and patient alike. In the past 30 years more development has occurred in ophthalmology than during the previous 1000 years, from intracapsular cataract extraction to the extracapsular cataract technique to the eventual acceptance of phacoemulsification as the standard technique for cataract surgery. The description of central continuous circular capsulotomy (CCC) by Neuhann and Gimbel9 provided surgeons with a good, safe, and reasonably reproducible method for safer cataract surgery. However, CCC is executed manually and its accuracy and reproducibility are inherently limited by surgeon variability. As patient demands have increased, the importance of effective lens position (ELP) has increased dramatically. New technology intraocular lenses (IOLs), including aspheric, toric, and multifocal IOLs, have also driven this need for improved ELP. A reproducible central and circular capsulorrhexis is a prerequisite for good postoperative ELP. Irregular capsulotomy might cause refractive surprises such as myopic or hyperopic shifts, unwanted surgically induced astigmatism (SIA), posterior chamber lens tilt, increase in higher order aberrations, and glare and halo phenomena as well. Once the problem of optically and efficiently delivering the femtobeam into the eye was solved, a successful central and guaranteed capsulorrhexis diameter became available. Moreover, effective fragmentation of the crystalline lens up to cataract grade +4.0, liquefaction of softer lenses with or without cataract, and corneal wound creation together with arcuate keratotomy for preoperative corneal astigmatism have been developed and recognized by official authorities such as the United States Food and Drug Administration, CE mark in Europe, and ophthalmologists worldwide. The femtosecond laser has made its great entrance into cataract surgery and is rapidly becoming an accepted, if not yet fully established, surgical technique. Based on more than 4 years of personal experience and having performed more than 1000 femtosecond laser cataract cases, I would like to share my personal thoughts, experiences, and concerns about this new technology as we move forward. Femtosecond laser–assisted cataract surgery is a rapidly developing and changing technology, but it is still in its infancy. Large, devoted teams are working on more efficient capsulotomies and lens fragmentation processes, including optimal geometrical fragmentation patterns and liquefaction to reduce the energy needed for phacoemulsification, to reduce SIA and to develop better nomograms to increase the predictability of arcuate keratotomy. None of these elements of the procedure are yet perfected. Large volumes of scientific and promotional articles in this field will be disseminated in the near future; read them carefully, filter out suspiciously perfect results if they are not based on a high number of eyes and longer follow-ups, and if they are not stringently peer-reviewed. If an article reports an ideal outcome was achieved in at least 95% to 100% of eyes studied, doubts should arise in the reader’s mind, especially if/when other manufacturers/companies have published lower success rates. In a developing technology, results exclusively above 95% success rate are possible, but usually not realistic. For all surgeries and all surgeons, a certain learning curve exists for any new technique. Everyone should acknowledge and respect stricter adherence to particular standards and rules during the learning curve, which in my experience appears to be approximately 30 to 50 eyes, depending on the dexterity of the surgeon and type of femtosecond laser utilized. After overcoming this initial learning process, some variations in surgical technique may be implemented successfully. Before operating, patients should be screened for ocular surface issues that could complicate the laser docking and use. The corneal surface needs frequent wetting, especially in cases where the docking is tried multiple times, as can happen for the less experienced surgeon. Patients with recurrent epithelial erosions are not good candidates for initial femtosecond laser–assisted treatments due to the risk of epithelial sloughing, and severe diabetic patients might also have less healthy epithelium. In these cases, special attention is needed to insert the patient interface quickly and efficiently to minimize the risk of epithelial trauma. Corneal wounds should be well designed before surgery to avoid tension and rupture intraoperatively, which could result in increased SIA and wound leak. Wounds created with the femtosecond laser seem to be tighter compared to ones created with blades. Beginning surgeons should check wound edges during opening of the wound with the specific blunt tipped spatula to ensure full opening prior to proceeding. I recommend following the contour of the capsulotomy created by the femtosecond laser until it is clear that the anterior capsule is fully detached and freefloating in the anterior chamber. Small tags or bridges may not be apparent to the inexperienced surgeon, and an anterior tear might occur with resulting unwanted complications if this is not recognized, including capsular blockage syndrome with posterior capsular tear, which can arise from issues with anterior capsule removal or abrupt hydrodissection with a large cannula as opposed to smooth hydrodissection with a small diameter cannula. The “rock-and-roll” technique is also useful to avoid this complication: following smooth hydrodissection, the nucleus is gently pressed down and rolled, allowing intralenticular gas bubbles to escape toward the anterior chamber. In the future, eyes with cataract grading <3.0 may not require hydrodissection; however, hydrodissection, even with soft lenses, remains mandatory at the present time. Femto-fragmentation might use a laser beam cross pattern or multiple cuts within the lens (6, 8, or more) referred to as a “cake-pattern” or “pizza-pattern.”10 Cubicles might also be formed within the nucleus. The diameter of lens fragmentation is important because of the biconvex shape of the lens to avoid posterior capsular damage. Two main planes are recommended, as surgeons should divide the lens into quadrants to facilitate phacoemulsification. In cubicle formation, if the lens is not fragmented, a nuclear or an epinuclear “bowl” might be the consequence, which can be difficult to remove. Presently, I prefer a “hybrid” pattern, with a central 3.0-mm diameter liquefaction and a cross or pizza-pattern fragmentation at the periphery. This fragmentation model helps reduce phacoemulsification energy and makes chopping of the crystalline lens easier. Femtosecond lasers should create wounds that do not need hydration at the end of surgery. However, this must be checked and not assumed for the beginning surgeon, and all surgeons should thoroughly check the integrity of the corneal wounds to avoid wound leakage or other possible complications. Femtosecond laser–assisted cataract surgery is a quickly developing technology. Many sources of potentially useful information have been made available during this process of development, including industry user meetings and scientific and promotional publications. However, the information presented in these forums should be continually checked and confirmed by other authors and surgeons to assure the validity of the information disseminated. Multicenter studies would be ideal, with many surgeons and potentially even many distinct laser platforms, to maximize the information concerning results and possible advantages of this technology. Femtosecond laser–assisted cataract surgery appears destined for continued market growth and utilization; it is imperative that we do our job as clinicians and surgeons to thoroughly scrutinize the data that become available to guarantee the best outcomes for our patients. 10.3928/1081597X-20121120-01 Healio is intended for health care provider use and all comments will be posted at the discretion of the editors. We reserve the right not to post any comments with unsolicited information about medical devices or other products. At no time will Healio be used for medical advice to patients.
Ina Conrad-Hengerer, Fritz H. Hengerer, Tim Schultz, H. Burkhard Dick
Published: 1 December 2012
Journal of Refractive Surgery, Volume 28, pp 879-884; https://doi.org/10.3928/1081597x-20121116-02

Abstract:
Original Article Ina Conrad-Hengerer, MD; Fritz H. Hengerer, MD; Tim Schultz, MD; H. Burkhard Dick, MD To compare the effect of femtosecond laser–assisted cataract surgery on effective phacoemulsification time (EPT) with standard cataract surgery. This prospective clinical trial evaluated the feasibility of using a femtosecond laser system (Catalys Precision Laser System, OptiMedica) to perform capsulotomy and lens fragmentation in the treatment of patients with senile cataract. Patients were evaluated preoperatively with the Lens Opacities Classification System III (LOCS III). Fifty-two patients underwent standard cataract surgery and 57 patients underwent femtosecond laser–assisted cataract surgery in December 2011. Both groups underwent phacoemulsification using pulsed ultrasound energy and EPT was evaluated. Preoperative LOCS III grades were 3.4±0.9 in the femtosecond laser–assisted cataract surgery group and 3.1±0.9 in the standard group. In the femtosecond laser–assisted cataract surgery group, mean laser treatment time was 54.9 seconds and EPT was 0.16±0.21 seconds compared to 4.07±3.14 seconds in the standard group. The use of the femtosecond laser–assisted system in cataract surgery led to a lower EPT compared to the standard procedure. From Center for Vision Science, Ruhr University Eye Clinic, Bochum, Germany. Dr Dick is a member of the medical advisory board of OptiMedica. The remaining authors have no financial interest in the materials presented herein. The paper was presented in part at the European Society of Cataract & Refractive Surgeons winter meeting; February 3–5, 2012; Prague, Czech Republic. AUTHOR CONTRIBUTIONS Study concept and design (I.C-.H., F.H.H., H.B.D.); data collection (T.S.); analysis and interpretation of data (I.C-.H., F.H.H.); drafting of the manuscript (I.C-.H.); critical revision of the manuscript (F.H.H., T.S., H.B.D.); statistical expertise (F.H.H.); supervision (H.B.D.) Correspondence: Ina Conrad-Hengerer, MD, Center for Vision Science, Ruhr University Eye Hospital, In der Schornau 23 – 25, 44892 Bochum, Germany. Tel: 49 234 299 3101; Fax: 49 234 299 3109; E-mail: [email protected] 10.3928/1081597X-20121116-02 Healio is intended for health care provider use and all comments will be posted at the discretion of the editors. We reserve the right not to post any comments with unsolicited information about medical devices or other products. At no time will Healio be used for medical advice to patients.
, Vardhaman P. Kankariya, Argyro D. Plaka, Dan Z. Reinstein
Published: 1 December 2012
Journal of Refractive Surgery, Volume 28, pp 912-920; https://doi.org/10.3928/1081597x-20121116-01

Abstract:
Review George D. Kymionis, MD, PhD; Vardhaman P. Kankariya, MD; Argyro D. Plaka, MD; Dan Z. Reinstein, MD, MA(Cantab), FRCSC, FRCOphth, FEBO To discuss current applications and advantages of femtosecond laser technology over traditional manual techniques and related unique complications in corneal refractive surgical procedures, including LASIK flap creation, intracorneal ring segment implantation, astigmatic keratotomy, presbyopic treatments, and intrastromal lenticule procedures. Literature review. From its first clinical use in 2001 for LASIK flap creation, femtosecond lasers have steadily made a place as the dominant flap-making technology worldwide. Newer applications are being evaluated and are increasing in their frequency of use. Femtosecond laser technology is rapidly becoming a heavily utilized tool in corneal refractive surgical procedures due to its reproducibility, safety, precision, and versatility. From the Department of Ophthalmology, University of Crete, Medical School, Heraklion, Greece (Kymionis, Kankariya, Plaka); London Vision Clinic, London, United Kingdom (Reinstein); and the Department of Ophthalmology, Columbia University Medical Center, New York, New York (Reinstein). Dr Reinstein is a consultant for Carl Zeiss Meditec, has a proprietary interest in the Artemis technology (ArcScan Inc), and is an author of patents related to VHF digital ultrasound administered by the Cornell Center for Technology Enterprise and Commercialization, Ithaca, New York. The remaining authors have no financial or proprietary interest in the materials presented herein. AUTHOR CONTRIBUTIONS Study concept and design (G.D.K., D.Z.R.); data collection (G.D.K., V.P.K., A.D.P.); analysis and interpretation of data (G.D.K., V.P.K., A.D.P.); drafting of the manuscript (G.D.K., V.P.K., A.D.P., D.Z.R.); critical revision of the manuscript (G.D.K., V.P.K., D.Z.R.); supervision (G.D.K.) Correspondence: George D. Kymionis, MD, PhD, University of Crete, Medical School, 71003 Heraklion, Crete, Greece. Tel: 30 28 1039 4656; Fax: 30 28 1039 4653; E-mail: [email protected] 10.3928/1081597X-20121116-01 Healio is intended for health care provider use and all comments will be posted at the discretion of the editors. We reserve the right not to post any comments with unsolicited information about medical devices or other products. At no time will Healio be used for medical advice to patients.
Huiying Liu, Wenqing Zhu, Alice C. Jiang, Alicia J. Sprecher,
Published: 1 December 2012
Journal of Refractive Surgery, Volume 28, pp 907-911; https://doi.org/10.3928/1081597x-20121115-05

Abstract:
Translational Science HuiYing Liu, MD; WenQing Zhu, MD; Alice C. Jiang, BS; Alicia J. Sprecher, BS; Xingtao Zhou, MD To evaluate the feasibility of femtosecond laser–induced lenticule transplantation in the rabbit cornea and to observe the relative histologic characteristics of corneal tissue and nerve repair after transplantation. Eight healthy, purebred, New Zealand white rabbits underwent femtosecond laser small-incision lenticule extraction (SMILE) surgery in the right eye. Lenticules were inserted into a femtosecond laser–created corneal stromal pocket in the left eye, which was defined as femtosecond laser corneal lenticule transplantation. Postoperative observation and examination were completed to evaluate the surgery. In the early postoperative period, inflammation of the cornea was noted, tissue around the lenticule was edematous, and cells were activated. Tissue edema remained at postoperative day 10. By 1 month, edema had resolved, activated cells gradually became quiescent, and nerve fiber regeneration was observed. By 3 months, the lenticule integrated into the recipient cornea, extracellular matrix gradually cleared, and thicker nerve fibers were noted. By 6 months postoperative, morphology and distribution of the corneal stromal fibers were close to normal, and the number of nerve fibers was reduced. Femtosecond laser corneal lenticule transplantation in rabbits is feasible, as the lenticule was shown to thrive and integrate with the recipient stroma. Nerve regeneration begins after 1 month. From the Department of Ophthalmology & Vision Science, Eye & ENT Hospital, Fudan University, Shanghai, China (Liu, Zhu, Zhou); and the Department of Surgery, Division of Otolaryngology - Head and Neck Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin (Jiang, Sprecher). The authors have no financial or proprietary interest in the materials presented herein. AUTHOR CONTRIBUTIONS Study concept and design (H.L., X.Z.); data collection (H.L., W.Z.); analysis and interpretation of data (H.L., W.Z., A.C.J., A.J.S.); drafting of the manuscript (H.L., W.Z., A.J.S.); critical revision of the manuscript (A.C.J., X.Z.); administrative, technical, or material support (A.J.S.) Correspondence: XingTao Zhou, MD, Dept of Ophthalmology & Vision Science, Eye & ENT Hospital, Fudan University, No. 83 Fenyang Rd, Shanghai, China, 200031. E-mail: [email protected] 10.3928/1081597X-20121115-05 Healio is intended for health care provider use and all comments will be posted at the discretion of the editors. We reserve the right not to post any comments with unsolicited information about medical devices or other products. At no time will Healio be used for medical advice to patients.
Robert L. Epstein, Yi-Lin Chiu, Greg L. Epstein
Published: 1 December 2012
Journal of Refractive Surgery, Volume 28, pp 890-894; https://doi.org/10.3928/1081597x-20121115-04

Abstract:
Original Article Robert L. Epstein, MD, MSEE; Yi-Lin Chiu, PhD; Greg L. Epstein, BS Click here to read Letter to the Editor about this article PURPOSE: To determine criteria for keratoconus or postoperative LASIK ectasia progression or improvement based on Pentacam HR (Oculus Optikgeräte GmbH) measured steepest corneal curvature. Sixty-one eyes from 41 patients with keratoconus or postoperative LASIK ectasia were evaluated. Each eye was measured 5 times with the Pentacam HR during the same clinic visit and the random measurement variations of Rmin(back) and maximal keratometry (Kmax; mathematically linked to Rmin[front]) were statistically analyzed. Confidence levels for diagnosing true curvature change were determined for 3 typical clinical situations differing by the number of available Pentacam measurements. With a single past and single present Pentacam HR measurement available (situation 1+1), the 95% confidence levels of true change for ΔKmax, ΔRmin(front), and ΔRmin(back) were 1.51 diopters (D), 0.162 mm, and 0.290 mm, respectively. With one prior and the average of five present Pentacam measurements (situation 5+1), the 95% confidence levels of true change for ΔKmax, ΔRmin(front), and ΔRmin(back) were 1.17 D, 0.126 mm, and 0.225 mm, respectively. With the average of five past and five present measurements (situation 5+5), the 95% confidence levels of true change for ΔKmax, ΔRmin(front), and ΔRmin(back) were 0.68 D, 0.072 mm, and 0.130 mm, respectively. Steepest corneal curvature changed with 95% confidence if the difference between single past and present Kmax exceeded 1.51 D. With the advantage of five past and five present measurements, 95% confidence of real Kmax change occurs at a 0.68-D difference. From Mercy Health System, McHenry, Illinois. The authors have no financial or proprietary interest in the materials presented herein. AUTHOR CONTRIBUTIONSStudy concept and design (R.L.E.); data collection (R.L.E., G.L.E.); analysis and interpretation of data (R.L.E., Y-.L.C.); drafting of the manuscript (R.L.E., Y-.L.C.); critical revision of the manuscript (R.L.E., G.L.E.); statistical expertise (Y-.L.C.); administrative, technical, or material support (G.L.E.) Correspondence: Robert L. Epstein, MD, MSEE, Mercy Health System, 5400 W Elm St, Ste 120, McHenry, IL 60050. E-mail: [email protected] 10.3928/1081597X-20121115-04 Healio is intended for health care provider use and all comments will be posted at the discretion of the editors. We reserve the right not to post any comments with unsolicited information about medical devices or other products. At no time will Healio be used for medical advice to patients.
Bettina C. Thomas, Anna Fitting, ,
Published: 1 December 2012
Journal of Refractive Surgery, Volume 28, pp 872-878; https://doi.org/10.3928/1081597x-20121115-03

Abstract:
Original Article Bettina C. Thomas, MD; Anna Fitting, MSc; Gerd U. Auffarth, MD, FEBO; Mike P. Holzer, MD, FEBO To evaluate functional results and corneal changes after femtosecond laser correction of presbyopia (INTRACOR, Technolas Perfect Vision GmbH) in emmetropes using a modified treatment pattern over a 12-month period. Twenty eyes from 20 emmetropic patients were treated with a modified intrastromal INTRACOR pattern consisting of 5 central rings and 8 radial cuts in a prospective, nonrandomized, uncontrolled, open, single-center, clinical study. Refraction, visual acuity, endothelial cell density, corneal pachymetry, total corneal power, and stray light were evaluated preoperatively and 1 (except endothelial cell density and stray light), 3, 6, and 12 months postoperatively. Patients filled out a subjective questionnaire at 12 months postoperatively. Comparison of preoperative versus 12-month postoperative median values revealed a significant improvement in uncorrected near visual acuity (UNVA) from 0.60 (20/80) to 0.10 logMAR (20/25) (P<.0001) and a significant decrease in corrected distance visual acuity (CDVA) from −0.10 (20/16) to 0.00 logMAR (20/20), which equals a median loss of one line (P=.0005). Fifteen percent of patients lost two lines of CDVA in the treated eye. Subjective spherical equivalent refraction remained unchanged at 0.00 diopters (D) (P=.194). After INTRACOR treatment, significant corneal steepening of 1.40 D and midperipheral flattening of 0.50 D occurred (both P<.0001). Corneal pachymetry at the thinnest point and endothelial cell density did not change significantly (P=.829 and P=.058, respectively). After 12 months, the modified INTRACOR pattern improved UNVA in emmetropic patients without inducing a myopic shift or significant changes in endothelial cell density or pachymetry. From the International Vision Correction Research Centre (IVCRC), Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany. Dr Holzer received consulting and lecture fees, travel and grant support; Dr Auffarth received lecture fees, travel and grant support; and Dr Thomas and Ms Fitting received travel and grant support from Technolas Perfect Vision, Munich, Germany. AUTHOR CONTRIBUTIONS Study concept and design (M.P.H.); data collection (B.C.T., A.F., M.P.H.); analysis and interpretation of data (B.C.T., A.F., G.U.A., M.P.H.); drafting of the manuscript (B.C.T., A.F.); critical revision of the manuscript (G.U.A., M.P.H.); statistical expertise (M.P.H.); obtained funding (M.P.H.); supervision (M.P.H.) Correspondence: Mike P. Holzer, MD, FEBO, International Vision Correction Research Centre (IVCRC), Dept of Ophthalmology, University of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany. Tel: 49 6221 56 6695; Fax: 49 6221 56 6607; E-mail: [email protected] 10.3928/1081597X-20121115-03 Healio is intended for health care provider use and all comments will be posted at the discretion of the editors. We reserve the right not to post any comments with unsolicited information about medical devices or other products. At no time will Healio be used for medical advice to patients.
, Shveta Jindal Bali, Chris Hodge, Timothy V. Roberts, Colin Chan,
Published: 1 December 2012
Journal of Refractive Surgery, Volume 28, pp 859-864; https://doi.org/10.3928/1081597x-20121115-02

Abstract:
Original Articles Michael Lawless, MBBS, FRANZCO, FRACS; Shveta Jindal Bali, MBBS, MD; Chris Hodge, BAppSc(Orth); Timothy V. Roberts, MBBS, MMed, FRANZCO, FRACS; Colin Chan, MBBS, FRANZCO; Gerard Sutton, MBBS, MD, FRANZCO, FRACS To report the visual and refractive outcomes in an initial series of eyes undergoing femtosecond laser cataract surgery with implantation of a diffractive multi-focal intraocular lens (IOL). The first 61 consecutive eyes undergoing femtosecond laser cataract surgery and ReSTOR (Alcon Laboratories Inc) +3.00-diopter (D) add IOL implantation between May and July 2011 were enrolled in the study (LCS group). The control group consisted of a retrospective consecutive cohort of 29 eyes that underwent manual phacoemulsification cataract surgery and ReSTOR +3.00-D add IOL implantation (MCS group) between December 2010 and April 2011. Visual and refractive parameters were collected pre- and postoperatively at 1 and 3 months. Mean postoperative spherical equivalent refraction was −0.01±0.35 D and −0.06±0.30 D in the LCS and MCS groups, respectively (P=.492). Mean absolute refractive prediction error (PE) was 0.26±0.25 D for the LCS group and 0.23±0.16 D for the MCS group (P=.489). Mean arithmetic refractive PE was 0.06±0.44 D and −0.02±0.30 D for the LCS and MCS groups, respectively (P=.388). No significant difference was noted in mean postoperative uncorrected distance visual acuity or uncorrected near visual acuity between groups. No eyes in either group had surgical complications or loss of corrected distance visual acuity in the follow-up period. Mean spherical equivalent refraction and visual acuity of our initial group of patients undergoing laser cataract surgery are comparable to the manual phacoemulsification cohort for the AcrySof ReSTOR +3.00-D add IOL. From Vision Eye Institute, Chatswood (Lawless, Bali, Hodge, Roberts, Chan, Sutton); and Save Sight Institute, Discipline of Ophthalmology, Sydney Medical School, University of Sydney, Sydney (Roberts, Sutton), Australia. Dr Lawless is a member of the medical advisory board of Alcon LenSx Inc. The remaining authors have no financial interest in the materials presented herein. AUTHOR CONTRIBUTIONS Study concept and design (M.L., T.V.R., G.S.); data collection (C.H.); analysis and interpretation of data (M.L., S.J.B., C.H., C.C.); drafting of the manuscript (S.J.B., C.H.); critical revision of the manuscript (M.L., C.H., T.V.R., C.C., G.S.); supervision (M.L., T.V.R., C.C., G.S.) Correspondence: Michael Lawless, MBBS, FRANZCO, FRACS, Vision Eye Institute, Chatswood, Australia, 2067. Tel: 61 2 94249999; Fax: 61 2 94103000; E-mail: [email protected] 10.3928/1081597X-20121115-02 Healio is intended for health care provider use and all comments will be posted at the discretion of the editors. We reserve the right not to post any comments with unsolicited information about medical devices or other products. At no time will Healio be used for medical advice to patients.
Published: 1 December 2012
Journal of Refractive Surgery, Volume 28, pp 865-871; https://doi.org/10.3928/1081597x-20121115-01

Abstract:
Original Article Jesper Ø. Hjortdal, MD, DrMedSci, PhD; Anders H. Vestergaard, MD; Anders Ivarsen, MD, PhD; Suganiah Ragunathan, MD; Sven Asp, MD, DrMedSci Click here to read the Letter to the Editor about this article PURPOSE: To study the influence of patient- and surgery-related parameters on the predictability, efficacy, and safety of small-incision lenticule extraction (SMILE) for treatment of myopia. This prospective, clinical quality, control study comprised 670 eyes from 335 patients with myopia up to −10.00 diopters (D) (spherical equivalent refraction) and astigmatism up to 2.00 D treated with SMILE in both eyes and followed for 3 months. Preoperative mean spherical equivalent refraction was −7.19±1.30 D. In eyes with emmetropia as the target refraction, 84% obtained uncorrected distance visual acuity ⩽0.10 logMAR (20/25 or better Snellen equivalent) at 3 months. Mean corrected distance visual acuity (CDVA) improved from −0.03 to −0.05 logMAR (P<.01). Two or more lines of CDVA were lost in 2.4% (16 eyes). The achieved refraction was 0.25±0.44 D less than attempted after 3 months, and 80% (537 eyes) and 94% (631 eyes) were within ±0.50 and ±1.00 D of attempted correction, respectively. Multiple linear regression analyses revealed that spherical equivalent refraction undercorrection was predicted by increasing patient age (0.10 D per decade; P<.01) and steeper corneal curvature (0.04 D per D; P<.01). Safety and efficacy of the procedure were minimally affected by age, gender, and simultaneous cylinder correction. Undercorrection of 0.25 D and small effects of patient age and corneal curvature suggest that the standard nomogram for SMILE need only minor adjustments. This study suggests that safety and efficacy are not influenced to any clinically significant degree by easily discernible patient factors. From the Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark. Drs Hjortdal and Asp receive travel reimbursement from Carl Zeiss Meditec, Jena, Germany. The remaining authors have no financial interest in the materials presented herein. Preliminary results were presented at the Carl Zeiss Meditec European user meeting, Cyprus, Greece, and the Asian-Pacific user meeting, Hangzhou, China, June 2012. Presented as a free paper at the Refractive Surgery Subspecialty Day Meeting of the International Society of Refractive Surgery, Chicago, Illinois, November 2012. AUTHOR CONTRIBUTIONSStudy concept and design (J.Ø.H.); data collection (J.Ø.H., A.I., S.R., S.A.); analysis and interpretation of data (J.Ø.H., A.H.V.); drafting of the manuscript (J.Ø.H., S.R.); critical revision of the manuscript (J.Ø.H., A.H.V., A.I., S.A.) Correspondence: Jesper Ø. Hjortdal, MD, DrMedSci, PhD, Dept of Ophthalmology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark. Tel: 45 78463221; Fax: 45 86121653; E-mail: [email protected] 10.3928/1081597X-20121115-01 Healio is intended for health care provider use and all comments will be posted at the discretion of the editors. We reserve the right not to post any comments with unsolicited information about medical devices or other products. At no time will Healio be used for medical advice to patients.
Youssef Abdelmassih, , Elias Chelala, Elise Slim, Carole G. Cherfan,
Published: 1 September 2017
Journal of Refractive Surgery, Volume 33, pp 610-616; https://doi.org/10.3928/1081597x-20170621-02

Abstract:
PURPOSE: To evaluate 6-month and 2-year safety and clinical outcomes of Visian toric Implantable Collamer Lens (toric ICL) (STAAR Surgical, Monrovia, CA) implantation for the treatment of residual refractive errors after sequential intracorneal ring segments (ICRS) insertion and cross-linking (CXL) in keratoconus. METHODS: This consecutive case series included the results of a three-step ICRS–CXL–toric ICL procedure in 16 eyes of 13 patients with moderate to severe keratoconus (stages II and III of Amsler–Krumeich classification). The ICRS and CXL procedures were performed sequentially with an interval of 4 weeks and the toric ICL implantation was performed at least 6 months after CXL. Data were collected preoperatively, at 6 months after sequential ICRS–CXL, and at 6 and 24 months following toric ICL implantation. All 16 eyes were evaluated at the 2-year follow-up. RESULTS: There was a significant decrease in keratometry (steep, flat, and maximum) and refraction (sphere and spherical equivalence, but not cylinder) and a significant increase in both uncorrected (UDVA) (from 1.06 to 0.76 logMAR, P = .004) and corrected (CDVA) (from 0.42 to 0.26 logMAR; P = .002) distance visual acuity 6 months following sequential ICRS–CXL, whereas UDVA and refraction significantly improved 6 months after ICL insertion (UDVA reached 0.33 logMAR, P = .001). At the 24-month follow-up, UDVA and keratometric readings were stable, whereas CDVA, sphere, and cylinder showed a significant improvement. CONCLUSIONS: Implantation of Visian toric ICL following sequential ICRS insertion and CXL is an effective and safe option for correcting high residual refractive error and improving visual acuity in patients with moderate to severe keratoconus in the long term.
Efekan Coskunseven, , Onurcan Sahin, Belma Kayhan, Ioannis Pallikaris
Published: 1 September 2017
Journal of Refractive Surgery, Volume 33, pp 604-609; https://doi.org/10.3928/1081597x-20170504-06

Abstract:
ICL hyperopic toric implantation is a safe method and provides stable refractive outcomes in patients with high hyperopia (up to 10.00 D) and astigmatism (up to 6.00 D). [J Refract Surg. 2017;33(9):604-609.].
, Akihito Igarashi, , , Masaki Sato, , Survey Working Group of the Japanese Society of Cataract and Refractive Surgery
Published: 1 September 2017
Journal of Refractive Surgery, Volume 33, pp 598-602; https://doi.org/10.3928/1081597x-20170621-01

Abstract:
PURPOSE: To retrospectively evaluate the current practice, trends, and outcomes of refractive surgery in Japan. METHODS: This multicenter survey comprised 78,248 eyes of 39,727 consecutive patients who underwent refractive surgery at 45 major institutions in Japan. The corresponding ophthalmologists responded to a selfadministered questionnaire. The authors especially evaluated the safety, efficacy, predictability, stability, and adverse events of LASIK and phakic intraocular lens (IOL) implantation 3 months postoperatively. RESULTS: The most common refractive surgery was LASIK (90.9%), followed by corneal inlay (5.0%), posterior chamber phakic IOL implantation (1.3%), laser-assisted subepithelial keratomileusis (1.0%), refractive lens exchange (0.9%), photorefractive keratectomy (0.3%), and refractive lenticule extraction (0.2%). For subgroup analysis, 69,987 eyes (99.5%) and 67,512 eyes (95.9%) achieved corrected and uncorrected distance visual acuity of 20/20 or better, respectively, after LASIK, and 935 eyes (98.8%) and 890 eyes (94.1%), respectively, after phakic IOL implantation. There were 69,176 eyes (98.3%) and 908 eyes (96.0%) within ±1.00 diopter (D) of the attempted correction after LASIK and phakic IOL implantation, respectively. There were 1,926 eyes (2.7%) and 1 eye (0.1%) with changes in refraction of 1.00 D or less from 1 week to 3 months after LASIK and phakic IOL implantation, respectively. No vision-threatening complications occurred in any case. CONCLUSIONS: According to this survey, LASIK remains the most prevalent surgical technique in Japan. Both LASIK and phakic IOL implantation offered good safety and efficacy outcomes, yielding predictable and stable results. [J Refract Surg. 2017;33(9):598–602.]
Asaf Achiron, Zvi Gur, Uri Aviv, Assaf Hilely, , Lily Karmona, Lior Rokach,
Published: 1 September 2017
Journal of Refractive Surgery, Volume 33, pp 592-597; https://doi.org/10.3928/1081597x-20170616-03

Abstract:
This model could support clinical decision making and may lead to better individual risk assessment. Expanding the role of machine learning in analyzing big data from refractive surgeries may be of interest. [J Refract Surg. 2017;33(9):592-597.].
, Minseo Kim, David Sung Yong Kang, , , Jin Young Choi, , , ,
Published: 1 September 2017
Journal of Refractive Surgery, Volume 33, pp 617-624; https://doi.org/10.3928/1081597x-20170620-02

Abstract:
To determine the effect of lowering femtosecond laser energy on the surface quality of the intrastromal interface during small incision lenticule extraction (SMILE). Forty age- and diopter-matched female patients (40 eyes) with moderate myopia received SMILE with different energy levels (100 to 150 nJ) and fixed spot separation (4.5 μm). Five human corneal lenticules from each energy group were evaluated by atomic force microscopy and scanning electron microscopy (SEM). Both anterior and posterior surface characteristics of the lenticules were assessed. All measurements of surface roughness were approximately three times higher and in the anterior and posterior surface of the lenticules with the energy level of 150 nJ than with 100 nJ (P < .001). Furthermore, atomic force microscopy analysis found that energy differences of 15 nJ or more made a significant difference in surface roughness at energy levels of 115 nJ or higher. Interestingly, there was no significant difference in all roughness values of both surfaces among the 100, 105, and 110 nJ groups. In addition, all values of surface roughness were significantly positively correlated with laser energy for both anterior and posterior surfaces of the lenticule (P < .001). Consistent with atomic force microscopy results, SEM also showed that the SMILE lenticules in the higher laser energy group had more irregular surfaces. Lowering laser energy levels can improve surface quality of the lenticule of SMILE. To achieve better visual outcomes with faster recovery after the procedure, it is recommended to reduce the laser energy to less than 115 nJ at a spot separation of 4.5 μm. [J Refract Surg. 2017;33(9):617-624.].
, Adi Einan-Lifshitz, Tanguy Boutin, Mahmood Showail, Armand Borovik, Clara C. Chan, David S. Rootman
Published: 1 September 2017
Journal of Refractive Surgery, Volume 33, pp 639-644; https://doi.org/10.3928/1081597x-20170718-03

Abstract:
The use of TG-PRK for corneal scarring may improve visual acuity in selected cases, obviate the need for keratoplasty in some cases, and facilitate toric IOL implantation in some cases. [J Refract Surg. 2017;33(9):639-644.].
Published: 1 September 2017
Journal of Refractive Surgery, Volume 33, pp 632-638; https://doi.org/10.3928/1081597x-20170621-09

Abstract:
The current study showed the feasibility of use of non-tomographical parameters obtained from the Corvis ST for differentiating normal eyes and those with forme fruste keratoconus and keratoconus. The diagnostic ability of the Corvis ST was comparable to that of the Pentacam for differentiating normal eyes and eyes with forme fruste keratoconus. [J Refract Surg. 2017;33(9):632-638.].
Ningling Wu, Joseph G. Christenbury, Jon G. Dishler, Tahir Kansu Bozkurt, Daniel Duel, Lijun Zhang, D. Rex Hamilton
Published: 1 September 2017
Journal of Refractive Surgery, Volume 33, pp 584-590; https://doi.org/10.3928/1081597x-20170621-06

Abstract:
To identify risk factors for opaque bubble layer (OBL) formation and compare the incidence of OBL using a cone modification technique versus the original technique for LASIK flap creation using the VisuMax laser (Carl Zeiss Meditec, Jena, Germany). This retrospective study examined videos of flap creation using the VisuMax laser to identify OBL occurrence. Eyes were divided into three groups: eyes where OBL occurred using the original technique (OBL group), eyes where OBL did not occur using the original technique (no OBL group), and eyes in which the cone modification technique was used for LASIK flap creation (larger flap diameter) (cone modification technique group). Preoperative measurements including simulated keratometry (flat and steep) values, white-to-white distance (WTW), pachymetry, patient age and gender, amount of correction, flap parameters, energy setting, corneal hysteresis, and corneal resistance factor were analyzed to identify parameters with statistical difference between the OBL and no OBL groups. Incidence of OBL was compared between the original and cone modification techniques. OBL incidence was significantly lower with the cone modification technique (7.6%; 7 of 92 eyes) than with the original technique (28.8%; 34 of 118 eyes) (Fisher's exact test, P = .0009). Factors identified with a significant difference between eyes with and without OBL using the original technique were: corneal thickness (OBL: 561.2 μm, no OBL: 549.6 μm, P = .0132), WTW diameter (OBL: 11.6 mm, no OBL: 11.9 mm, P = .0048), corneal resistance factor (OBL: 10.4 mm Hg, no OBL: 9.6 mm Hg, P = 0.0329), and corneal astigmatism (OBL: 0.80 diopter, no OBL: 1.00 diopter, P = .0472) CONCLUSIONS: Less astigmatic, thicker, denser, and smaller corneas increased the risk of OBL using the original technique for flap creation. The cone modification technique was associated with lower risk of OBL formation, even in eyes with significant risk factors for OBL using the original technique. [J Refract Surg. 2017;33(9):584-590.].
Ryan Mercer, George O. Waring, Cynthia J. Roberts, Vishal Jhanji, , Joao S. Filho, Richard A. Hemings, Karolinne M. Rocha
Published: 1 September 2017
Journal of Refractive Surgery, Volume 33, pp 625-631; https://doi.org/10.3928/1081597x-20170621-03

Abstract:
To evaluate and compare biomechanical properties in normal and keratoconic eyes using a dynamic ultra-high-speed Scheimpflug camera equipped with a non-contact tonometer (Corvis ST; Oculus Optikgeräte GmbH, Wetzlar, Germany). This retrospective study evaluated 89 eyes (47 normal, 42 keratoconic) and a validation arm of 72 eyes (33 normal, 39 keratoconic) using the Corvis ST. A diagnosis of keratoconus was established by clinical findings confirmed by topography and tomography. Dynamic corneal response parameters collected by the Corvis ST (A1 velocity, deformation amplitude [DA], DA Ratio Max 1mm, and Max Inverse Radius) and a stiffness parameter at first applanation (SP-A1) were incorporated into a novel logistic regression equation (DCR index). Area under the receiver operating curve (AUC) was used to assess the sensitivity and specificity of the DCR index. DA, DA Ratio Max 1mm, Max Inverse Radius, and SP-A1 were each found to be statistically significantly different between normal and keratoconic eyes (Mann-Whitney test [independent samples]; P = .0077, < .0001, < .0001, and < .0001, respectively; significance level: P < .05). DCR index demonstrated high sensitivity, specificity, and overall correct detection rate (92.9%, 95.7%, and 94.4%, respectively; AUC = 98.5). The sensitivity and overall correct detection rate improved when eyes with Topographical Keratoconus Classification grades (TKC) greater than 0 were reevaluated (from 92.9% to 96.6% and from 94.4% to 96.1%, respectively). Combining multiple biomechanical parameters (A1 velocity, DA, DA Ratio Max 1mm, Max Inverse Radius, and SP-A1) into a logistic regression equation allows for high sensitivity and specificity for distinguishing keratoconic from normal eyes. [J Refract Surg. 2017;33(9):625-631.].
Luca Gualdi, Federica Gualdi, , , , Bernardo Lopes, Veronica Cappello, Tatiana Fintina, Massimo Gualdi
Published: 1 September 2017
Journal of Refractive Surgery, Volume 33, pp 578-583; https://doi.org/10.3928/1081597x-20170621-05

Abstract:
To report short-term results of pulsed ciliary muscle electrostimulation to improve near vision, likely through restoring accommodation in patients with emmetropic presbyopia. In a prospective non-randomized trial, 27 patients from 40 to 51 years old were treated and 13 age- and refraction-matched individuals served as untreated controls. All patients had emmetropia and needed near sphere add between +0.75 and +1.50 diopters. The protocol included four sessions (one every 2 weeks within a 2-month period) of bilateral pulsed (2 sec on; 6 sec off) micro-electrostimulation with 26 mA for 8 minutes, using a commercially available medical device. The uncorrected distance visual acuity (UDVA) (logMAR) for each eye, uncorrected near (40 cm) visual acuity in each eye (UNVA) and with both eyes (UNVA OU) (logMAR), and reading speed (number of words read per minute at 40 cm) were measured preoperatively and 2 weeks after each session. Overall satisfaction (0 to 4 scale) was assessed 2 weeks after the last session. UDVA did not change and no adverse events were noted in either group. Bilateral and monocular UNVA and reading speed were stable in the control group, whereas they continuously improved in the treated group (Friedman, P < .00001). Post-hoc significant differences were found for monocular and binocular UNVA after the second treatment and after the first treatment considering words read per minute (P < .001). One patient (3.7%) was not satisfied and 18 patients (66.7%) were very satisfied (score of 4). Average satisfaction score was 3 (satisfied). Ciliary muscle contraction to restore accommodation was safe and improved the short-term accommodative ability of patients with early emmetropic presbyopia. [J Refract Surg. 2017;33(9):578-583.].
, Boris E. Malyugin, Lisa B. Arbisser, Nikolay P. Sobolev, , Alvi A. Nazirov, Ilya Popov
Published: 1 September 2017
Journal of Refractive Surgery, Volume 33, pp 646-648; https://doi.org/10.3928/1081597x-20170721-02

Abstract:
This case illustrates a novel and effective clinical application of the femtosecond laser. [J Refract Surg. 2017;33(9):646-648.].
, James K. Y. Ong, George Stamatelatos
Journal of Refractive Surgery, Volume 33, pp 545-551; https://doi.org/10.3928/1081597x-20170616-01

Abstract:
Bitoric mixed astigmatism ablative treatments may display non-trivial coupling effects. Historical coupling adjustments should be taken into consideration when planning mixed astigmatism treatments to improve surgical outcomes. [J Refract Surg. 2017;33(8):545-551.].
Meng-Ying Qi, Qian Chen, Qing-Yan Zeng
Journal of Refractive Surgery, Volume 33, pp 519-523; https://doi.org/10.3928/1081597x-20170602-02

Abstract:
The crystalline lens could have an important influence on postoperative vault. Eyes with a shallower anterior chamber and a forward lens position will have lower vaults. [J Refract Surg. 2017;33(8):519-523.].
Jakob Siedlecki, Nikolaus Luft, Daniel Kook, , Wolfgang J. Mayer, Martin Bechmann, Rainer Wiltfang, Siegfried G. Priglinger, Walter Sekundo, Martin Dirisamer
Published: 1 August 2017
Journal of Refractive Surgery, Volume 33, pp 513-518; https://doi.org/10.3928/1081597x-20170602-01

Abstract:
To report the feasibility and outcomes of surface ablation after small incision lenticule extraction (SMILE). In this retrospective evaluation of 1,963 SMILE procedures, 43 eyes (2.2%) were re-treated at three separate clinics. Of these, 40 eyes of 28 patients with a follow-up of at least 3 months were included in the analysis. During surface ablation, mitomycin C was applied for haze prevention. Spherical equivalent was -6.35 ± 1.31 diopters (D) before SMILE and -0.86 ± 0.43 D before surface ablation. Surface ablation was performed after a mean of 9.82 ± 5.27 months and resulted in a spherical equivalent of 0.03 ± 0.57 D at 3 months (P < .0001). The number of patients within ±0.50 and ±1.00 D of target refraction increased from 22.5% to 80% and from 72.5% to 92.5%, respectively. Mean uncorrected distance visual acuity (UDVA) improved from 0.23 ± 0.20 to 0.08 ± 0.15 logMAR (P < .0001); 65% of patients gained at least one line. Corrected distance visual acuity (CDVA) remained unchanged with 0.01 ± 0.07 logMAR before versus -0.01 ± 0.05 logMAR after re-treatment (P = .99). Six eyes (15.0%) lost one line of CDVA, but final CDVA was 0.00 logMAR in four and 0.10 logMAR in two of these cases. The safety and efficacy indices were 1.06 and 0.90 at 3 months, respectively. Three of the four surface ablation profiles (Triple-A, tissue-saving algorithm, and topography-guided) resulted in equally good results, whereas enhancement with the aspherically optimized profile (ASA), used in two eyes, resulted in overcorrection (+1.38 and +1.75 D). Combined with the intraoperative application of mitomycin C, surface ablation seems to be a safe and effective method of secondary enhancement after SMILE. Due to the usually low residual myopia, the ASA profile is not recommended in these cases. [J Refract Surg. 2017;33(8):513-518.].
Mauro C. Tiveron, , Newton Kara-Junior, Ana Belén Plaza-Puche, Sabat K. Abu-Mustafa, Ghassan Zein,
Published: 1 August 2017
Journal of Refractive Surgery, Volume 33, pp 538-544; https://doi.org/10.3928/1081597x-20170616-02

Abstract:
PURPOSE: To assess visual and refractive outcomes of toric iris-claw phakic intraocular lens (IOL) implantation in patients who had previously undergone deep anterior lamellar keratoplasty (DALK). METHODS: Retrospective case series including 24 eyes of 24 patients implanted with toric Artiflex or Artisan (Ophtec BV, Groningen, Holland) phakic IOL following DALK for keratoconus. During a 12-month follow-up, the main outcome measures were uncorrected and corrected distance visual acuities (UDVA and CDVA), refractive error components, topographic parameters, and endothelial cell count. Alpins vectorial analysis was performed. RESULTS: At the last follow-up, the spherical equivalent (SE) was within ±0.50 diopters (D) in 71% of eyes and within ±1.00 D in 92% of eyes. Mean refractive astigmatism was reduced from −4.92 ± 1.55 D (range: −2.50 to −8.00 D) preoperatively to −0.66 ± 0.61 D (range: −2.00 to 0.00 D) after treatment, and 76.5% of cases were within ±1.00 D. No significant differences (P = .123) were detected in spherical equivalent values between 3- and 12-month follow-up visits. No eyes lost lines in CDVA, and 54% of eyes gained one or more lines. Postoperative UDVA was 20/40 or better in 88% of eyes. Efficacy and safety indexes at 12 months were 0.93 and 1.00, respectively. Mean endothelial cell loss was 6.10% at 12 months postoperatively. No intraoperative or postoperative complications were noted over the follow-up period. CONCLUSIONS: The implantation of a toric iris-claw phakic IOL has shown high efficacy and safety in this series and may be considered as a reasonable option for the management of refractive errors after DALK. [J Refract Surg. 2017;33(8):538–544.]
Comment
Theo G. Seiler, Beatrice E. Frueh
Journal of Refractive Surgery, Volume 33, pp 571-571; https://doi.org/10.3928/1081597x-20170705-01

Fangjun Bao, , Bao Shu, Senmiao Zhu, Rongrong Gao, Guanxin Dang, Ayong Yu, Qinmei Wang,
Journal of Refractive Surgery, Volume 33, pp 524-530; https://doi.org/10.3928/1081597x-20170606-01

Abstract:
Both Scheimpflug-Placido systems show high repeatability and reproducibility for posterior corneal surface measurement. A high concordance between the two devices suggests interchangeable use in normal eyes. [J Refract Surg. 2017;33(8):524-530.].
Sri Ganesh, Sheetal Brar
Published: 1 August 2017
Journal of Refractive Surgery, Volume 33, pp 563-566; https://doi.org/10.3928/1081597x-20170504-09

Abstract:
To describe a "no dissection" technique of lenticule removal in small incision lenticule extraction (SMILE). After docking and laser delivery, a microforceps is used to grasp and gently peel off the lenticule from the underlying stromal bed, without performing any dissection of the upper and lower planes of the lenticule. Prerequisites are a surgeon experienced in the conventional SMILE technique, optimized laser energy settings, and a minimum peripheral lenticule thickness of 25 to 30 µm. The interface as assessed in postoperative dilated clinical photographs was seen to be clearer with less roughness compared to the conventional dissection technique. This may potentially result in better first postoperative visual acuity and quality of vision due to less corneal tissue trauma and minimal tissue handling, thus potentially resulting in faster visual recovery. No dissection lenticule removal is a feasible and reproducible technique that may result in better immediate visual quality compared to the conventional SMILE technique. [J Refract Surg. 2017;33(8):563-566.].
Merita Schojai, Tim Schultz, H. Burkhard Dick
Journal of Refractive Surgery, Volume 33, pp 568-570; https://doi.org/10.3928/1081597x-20170620-01

Abstract:
To describe a new technique for implantation of capsule-fixated intraocular lenses (IOLs) (FEMTIS; Oculentis, Berlin, Germany) in patients with small pupils. In 4 eyes with small pupils, an anterior capsule-fixated IOL was implanted into the capsular bag after femtosecond laser treatment. The two large and two small flaps of the IOL were elevated to the front of the iris and the anterior capsule. Finally, the iris was flipped over the flaps to ensure a fixation of the capsule inside of the capsulotomy. In all cases, the implantation of anterior capsule-fixated IOLs was possible. No complications occurred during surgery or within the first months after surgery. With the described technique, capsulefixated IOLs can be implanted in eyes with small pupil easily and safely. This type of IOL has great potential to improve the refractive outcome by better prediction of the postoperative IOL position and eliminating IOL rotation after cataract surgery. [J Refract Surg. 2017;33(8):568-570.].
Journal of Refractive Surgery, Volume 33, pp 532-537; https://doi.org/10.3928/1081597x-20170606-02

Abstract:
To assess Visian Implantable Collamer Lens (ICL) (STAAR Surgical, Monrovia, CA) implantation in the ciliary sulcus to correct pseudophakic ametropia in patients who are not candidates for a keratorefractive procedure. The authors performed a prospective non-comparative case series study of 18 patients (age: 48 to 61 years) with refractive surprise after phacoemulsification. Patients underwent implantation of a piggyback collagen copolymer lens: V4C design in 16 myopic eyes and V4B design in 2 hyperopic eyes. The position and vault of the ICLs were documented at all control visits clinically and with Pentacam (Oculus Optikgeräte, Wetzlar, Germany). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), intraocular pressure (IOP), and endothelial cell count were recorded at baseline and 1 week and 1, 6, 12, and 18 months postoperatively. The MRSE improved from -3.08 ± 2.37 diopters (D) preoperatively to -0.44 ± -0.23 D postoperatively, corrected with a mean ICL power of -3.20 ± 2.90 D. The mean UDVA improved from 1.03 ± 0.12 logMAR preoperatively to 0.05 ± 0.06 logMAR postoperatively (P = .00), whereas CDVA improved from 0.47 ± 0.03 logMAR preoperatively to -0.006 ± 0.02 logMAR (P = .001) postoperatively. None of the cases developed interlenticular opacification throughout the 18-month follow-up. The mean ICL vault measured by Scheimpflug tomography was 451.27 ± 178.5 µm. Acute IOP elevation with anterior uveitis developed in 2 eyes and was controlled by topical steroids and a beta-blocker. Sulcus implantation of the secondary ICL to correct pseudophakic refractive error was safe, predictable, and well tolerated in all studied eyes. [J Refract Surg. 2017;33(8):532-537.].
Hassan Hashemi, Soheila Asgari, Shiva Mehravaran, Mohammad Miraftab, Reza Ghaffari,
Published: 1 August 2017
Journal of Refractive Surgery, Volume 33, pp 558-562; https://doi.org/10.3928/1081597x-20170621-04

Abstract:
At 1 year after cross-linking in cases of mild and moderate keratoconus, corneal biomechanics appeared stable or stronger than baseline with both 5- and 10-minute protocols. However, mild cases who had the 5-minute protocol showed better improvement based on Corvis ST indices. [J Refract Surg. 2017;33(8):558-562.].
Sri Ganesh, Sheetal Brar, Archana Pawar
Journal of Refractive Surgery, Volume 33, pp 506-512; https://doi.org/10.3928/1081597x-20170328-01

Abstract:
Manual compensation may be a safe, feasible, and effective approach to refine the results of astigmatism with SMILE, especially in higher degrees of cylinders. [J Refract Surg. 2017;33(8):506-512.].
Imène Salah-Mabed, Alain Saad, Damien Gatinel
Published: 1 August 2017
Journal of Refractive Surgery, Volume 33, pp 552-557; https://doi.org/10.3928/01913913-20170619-03

Abstract:
In all groups, the Topolyzer Vario showed excellent repeatability when measuring pupil dynamic parameters except when measuring pupil center shift and distance between the pupil center and the corneal vertex along the vertical axis. [J Refract Surg. 2017;33(8):552-557.].
Anastasios John Kanellopoulos
Journal of Refractive Surgery, Volume 33, pp 306-312; https://doi.org/10.3928/1081597x-20170221-01

Abstract:
To compare safety and efficacy of topography-guided LASIK and contralateral eye SMILE for myopia and myopic astigmatism correction. This prospective, randomized contralateral eye study included 44 eyes of 22 patients with bilateral myopia or myopic astigmatism. Treated eyes were divided into two groups: 22 eyes were treated with topography-guided LASIK and the fellow eye of each patient was treated with SMILE. The following parameters were evaluated preoperatively and up to 3 months postoperatively: uncorrected distance vision acuity (UDVA), corrected distance vision acuity (CDVA), refractive error, corneal keratometry, contrast sensitivity, and Objective Scatter Index. At 3 months, 86.4% of the LASIK group and 68.2% of the SMILE group had UDVA of 20/20 (P < .002) and 59.1% and 31.8%, respectively, had UDVA of 20/16 (P < .002). Spherical equivalent refraction (±0.50 D) was 95.5% for the LASIK group and 77.3% for the SMILE group (P < .002). Residual refraction cylinder (≤ 0.25 D) was 81.8% for the LASIK group and 50% for the SMILE group (P < .001). Contrast sensitivity (6 cycles/degree) was 7.2 ± 1.01 in the LASIK group and 6.20 ± 1.52 in the SMILE group. Objective Scatter Index measurements at 3 months were 1.35 in the LASIK group and 1.42 in the SMILE group. Topography-guided LASIK was superior in all visual performance parameters studied, both subjective and objective. The main difference between the two techniques likely derives from the eye tracking, cyclorotation compensation, and active centration control in the LASIK technology studied in contrast to the current technology available with SMILE-like procedures. This difference appears to affect refractive and visual aberration performance outcomes. [J Refract Surg. 2017;33(5):306-312.].
, Kévin Pierné, , Marie-Pierre Asfaux-Marfaing, ,
Journal of Refractive Surgery, Volume 33, pp 290-297; https://doi.org/10.3928/1081597x-20170201-02

Abstract:
At 1 year postoperatively, TG-CXL seems to be as safe as C-CXL with stronger flattening in Kmax and I index and better improvement in CDVA. TG-CXL induces a biological gradient between the cone and the surrounding area that facilitates nerve and cell recovery. [J Refract Surg. 2017;33(5):290-297.].
Arthur Cummings, Daniel Durrie, Michael Gordon, Ravaughn Williams, James A. Gow, Matthias Maus
Journal of Refractive Surgery, Volume 33, pp 322-328; https://doi.org/10.3928/1081597x-20160926-01

Abstract:
To evaluate outcomes in patients with myopia up to -12.00 diopters (D), with or without astigmatism up to 6.00 D, who underwent LASIK with the WaveLight Refractive Suite (Alcon Laboratories, Inc., Fort Worth, TX). This multicenter, prospective, single-arm study evaluated patients at baseline, on the day of surgery, and 1 day and 1, 3, and 6 months postoperatively. The primary outcome was comparison of 1-month postoperative binocular uncorrected distance visual acuity (UDVA) with preoperative binocular corrected distance visual acuity (CDVA). Noninferiority was defined as the upper bound of the 95% confidence interval less than 0.1 logMAR. Post-hoc analyses for superiority were conducted for monocular and binocular CDVA at 1, 3, and 6 months. Continuous variables were summarized using mean (95% confidence interval), median, quartiles, standard deviation, minimum and maximum, and categorical variables as counts and percentages. Of the 96 patients (54% female, mean age: 31 years), 5 underwent monocular and 91 binocular LASIK surgery (187 eyes). Preoperatively, mean binocular CDVA was -0.025 ± 0.126 logMAR, mean binocular UDVA was 1.148 ± 0.626 logMAR, and mean manifest spherical refraction equivalent was -3.67 ± 1.98 D. Postoperative binocular UDVA at 1 month (-0.088 ± 0.107 logMAR) was noninferior to preoperative binocular CDVA. Postoperative binocular UDVA at 1, 3 (-0.098 ± 0.107 logMAR), and 6 months (-0.105 ± 0.113 logMAR) were significantly superior to preoperative binocular CDVA (P < .0001 each). The primary study objective was exceeded; postoperative UDVA was significantly superior to preoperative CDVA in patients with myopia and myopia with astigmatism who underwent LASIK with the WaveLight Refractive Suite. [J Refract Surg. 2017;33(5):322-328.].
, Paula Martinez-Sorribes, Margarita Recuerda
Journal of Refractive Surgery, Volume 33, pp 470-474; https://doi.org/10.3928/1081597x-20170504-07

Abstract:
To study the effect on vision of induced negative and positive spherical aberration within the range of laser vision correction procedures.In 10 eyes (mean age: 35.8 years) under cyclopegic conditions, spherical aberration values from -0.75 to +0.75 µm in 0.25-µm steps were induced by an adaptive optics system. Astigmatism and spherical refraction were corrected, whereas the other natural aberrations remained untouched. Visual acuity, depth of focus defined as the interval of vision for which the target was still perceived acceptable, contrast sensitivity, and change in spherical refraction associated with the variation in pupil diameter from 6 to 2.5 mm were measured.A refractive change of 1.60 D/µm of induced spherical aberration was obtained. Emmetropic eyes became myopic when positive spherical aberration was induced and hyperopic when negative spherical aberration was induced (R(2) = 81%). There were weak correlations between spherical aberration and visual acuity or depth of focus (R(2) = 2% and 3%, respectively). Contrast sensitivity worsened with the increment of spherical aberration (R(2) = 59%). When pupil size decreased, emmetropic eyes became hyperopic when preexisting spherical aberration was positive and myopic when spherical aberration was negative, with an average refractive change of 0.60 D/µm of spherical aberration (R(2) = 54%).An inverse linear correlation exists between the refractive state of the eye and spherical aberration induced within the range of laser vision correction. Small values of spherical aberration do not worsen visual acuity or depth of focus, but positive spherical aberration may induce night myopia. In addition, the changes in spherical refraction when the pupil constricts may worsen near vision when positive spherical aberration is induced or improve it when spherical aberration is negative. [J Refract Surg. 2017;33(7):470-474.].
, Aleksandar Stojanovic, Yangyang Xu, Wen Zhou, Sten Raeder, Sam Enayati, Tor Paaske Utheim
Journal of Refractive Surgery, Volume 33, pp 488-495; https://doi.org/10.3928/1081597x-20170504-03

Abstract:
To evaluate the medium- to long-term outcomes of corneal cross-linking in treatment of keratoconus using transepithelial phototherapeutic keratectomy (PTK-CXL) for epithelial removal and partial stromal ablation to stabilize the cornea, reduce corneal irregularity, and improve corrected vision.Retrospective analysis of 46 keratoconic eyes that underwent PTK-CXL. Corrected distance visual acuity (CDVA), manifest refraction, steep and flat simulated keratometry (Kmax and Kmin), corneal irregularity index (IRI), corneal higher order aberrations (HOAs), epithelial thickness profile, and corneal biomechanical characteristics were evaluated preoperatively and postoperatively.At a mean follow-up time of 21.0 ± 7.6 months (range: 10 to 43 months) postoperatively, CDVA improved from 0.25 ± 0.24 to 0.18 ± 0.22 logMAR (P = .002). CDVA remained unchanged in 32.6% (15 eyes) and 56.5% (26 eyes) gained up to five Snellen lines of CDVA, whereas 6.5% (3 eyes) lost two or more lines of CDVA, respectively. Postoperatively, flattening of Kmax from 50.58 ± 5.26 to 48.96 ± 4.00 diopters (D) and Kmin from 45.80 ± 3.11 to 44.77 ± 2.63 D (P < .001), reduction of IRI from 49.7 ± 24.5 to 43.4 ± 21.4 µm (P = .002), decrease of root mean square HOAs (at 5-mm diameter) from 2.66 ± 1.31 to 2.37 ± 1.37 µm (P = .037), and slight thickening of corneal epithelium were registered, whereas most of the corneal biomechanical measurements did not show statistically significant change. Two eyes demonstrated slight topographic regression.PTK-CXL seems to be effective in arresting the progression of keratoconus, improving CDVA, flattening the cornea, regularizing corneal surface, and reducing corneal HOAs. [J Refract Surg. 2017;33(7):488-495.].
Ibrahim Seven, , Iben Bach Pedersen, , Jesper Hjortdal, Cynthia J. Roberts,
Published: 1 July 2017
Journal of Refractive Surgery, Volume 33, pp 444-453; https://doi.org/10.3928/1081597x-20170504-01

Abstract:
PURPOSE: Computational analyses were performed to quantify and directly compare the biomechanical impact of flapless and flap-based procedures in a series of patients undergoing small incision lenticule extraction (SMILE) in one eye and flap-based femtosecond lenticule extraction in the other. METHODS: Tomographic data from 10 eyes of 5 patients undergoing femtosecond laser refractive lenticule extraction for myopic astigmatism with or without a stromal flap (femtosecond lenticule extraction in one eye, SMILE in the contralateral eye) were used to generate computational models. Inverse finite element analyses were performed at physiologic intraocular pressure followed by forward analyses at elevated intraocular pressure to assess corneal displacement and stress under differential loading. Case-specific treatment settings were incorporated. Preoperative material constants were obtained through inverse finite element analyses, and the surgically induced change in fiber stiffness within each flap was determined by minimization of the error between the simulated and actual 6-month topographic outcomes. RESULTS: Flap-based procedures produced a 49% (range: 2% to 87%) greater mean reduction in effective stromal collagen fiber stiffness within the flap region than contralateral SMILE cases. Lower stresses and deformations were observed within the residual stromal bed in SMILE cases than in flap-based cases. Stromal bed displacements and stresses were more affected by a loading increase in flap-based eyes than flapless eyes. CONCLUSIONS: Intrastromal flapless procedures had less impact on anterior stromal collagen mechanics and resulted in lower stromal bed displacements and stresses than flap-based procedures in contralateral eyes. However, biomechanical impact varied widely between individuals and this reinforces the need for individualized assessment of ectasia risk. [J Refract Surg. 2017;33(7):444–453].
Tae Gi Kim, Sung Rae Noh, Kyung Hyun Jin
Journal of Refractive Surgery, Volume 33, pp 460-468; https://doi.org/10.3928/1081597x-20170531-01

Abstract:
To compare the effects of the distance from the inner and outer corneal incision wounds to the corneal apex on the changes in corneal astigmatism after cataract surgery.Seventy-two eyes with anterior corneal astigmatism less than 2.50 diopters (D) were evaluated. The distance between the incision wound and the corneal apex was measured using the Pentacam (Oculus Optikgeräte, Wetzlar, Germany) Scheimpflug image and the Image J program (National Institutes of Health, Bethesda, MD). Patients were subgrouped into the inner incision distance close (less than 4,816.44 µm) and far (4,816.44 µm or greater) groups based on the median value of inner incision distance and the outer incision distance close (less than 6,131.77 µm) and far (6,131.77 µm or greater) groups based on the median value of outer incision distance.In the inner incision distance group, the mean change in anterior, posterior, and total corneal astigmatism at 1 week and anterior astigmatism at 1 month were statistically significantly greater in the inner incision close group than in the inner incision far group. In the outer incision distance group, the mean change in anterior corneal astigmatism at 1 week was statistically significantly greater in the close group than in the far group. Surgically induced astigmatism (SIA) of the posterior cornea showed a statistically significant increase in the inner incision close group compared to the inner incision far group 1 month postoperatively, whereas there were no significant differences in the outer incision distance groups. Inner incision distance significantly correlated with the mean change in anterior and posterior corneal astigmatism and posterior SIA at 1 week postoperatively.Corneal astigmatism was affected more by inner incision distance than outer incision distance, and a larger change in the posterior SIA was noted with decreasing inner incision distance. During cataract surgery, the position of the inner corneal incision should be considered rather than the outer incision. [J Refract Surg. 2017;33(7):460-468.].
Renato Ambrósio, , , Marcella Q. Salomão, Jens Bühren, Cynthia J. Roberts, , ,
Journal of Refractive Surgery, Volume 33, pp 434-443; https://doi.org/10.3928/1081597x-20170426-02

Abstract:
To present the Tomographic and Biomechanical Index (TBI), which combines Scheimpflugbased corneal tomography and biomechanics for enhancing ectasia detection.Patients from different continents were retrospectively studied. The normal group included 1 eye randomly selected from 480 patients with normal corneas and the keratoconus group included 1 eye randomly selected from 204 patients with keratoconus. There were two groups: 72 ectatic eyes with no surgery from 94 patients with very asymmetric ectasia (VAE-E group) and the fellow eyes of these patients with normal topography (VAE-NT group). Pentacam HR and Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) parameters were analyzed and combined using different artificial intelligence methods. The accuracies for detecting ectasia of the Belin/Ambrósio Deviation (BAD-D) and Corvis Biomechanical Index (CBI) were compared to the TBI, considering the areas under receiver operating characteristic curves (AUROCs).The random forest method with leave-one-out cross-validation (RF/LOOCV) provided the best artificial intelligence model. The AUROC for detecting ectasia (keratoconus, VAE-E, and VAE-NT groups) of the TBI was 0.996, which was statistically higher (DeLong et al., P < .001) than the BAD-D (0.956) and CBI (0.936). The TBI cut-off value of 0.79 provided 100% sensitivity for detecting clinical ectasia (keratoconus and VAE-E groups) with 100% specificity. The AUROCs for the TBI, BAD-D, and CBI were 0.985, 0.839, and 0.822 in the VAE-NT group (DeLong et al., P < .001). An optimized TBI cut-off value of 0.29 provided 90.4% sensitivity with 96% specificity in the VAE-NT group.The TBI generated by the RF/LOOCV provided greater accuracy for detecting ectasia than other techniques. The TBI was sensitive for detecting subclinical (fruste) ectasia among eyes with normal topography in very asymmetric patients. The TBI may also confirm unilateral ectasia, potentially characterizing the inherent ectasia susceptibility of the cornea, which should be the subject of future studies. [J Refract Surg. 2017;33(7):434-443.].
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