Refine Search

New Search

Results: 24

(searched for: doi:10.3928/1081597x-20090515-05)
Save to Scifeed
Page of 1
Articles per Page
by
Show export options
  Select all
Therapeutics and Clinical Risk Management, pp 1125-1137; https://doi.org/10.2147/tcrm.s279065

Abstract:
Purpose: To assess the functional and refractive outcomes in hyperopia and presbyopia correction by clear lens exchange with the intraocular trifocal artificial lens (IOL) Acrysof IQ Panoptix implant at 1 year. Materials and Methods: A number of 128 eyes (64 patients) underwent clear lens exchange with placement of the trifocal IOL Acrysof IQ Panoptix implant for hyperopia and presbyopia. Prior to the surgery the patients had a complete ocular examination. In all cases the artificial lens was implanted in the bag without any intraoperative complications. Visual acuity (VA) at distance, intermediate and near and ocular refraction were evaluated at 4 weeks, 6 and 12 months postoperatively. Results: The mean age was 53.49 ± 7.377 years old (range 40– 73 years). As high as 51.57% of the patients were males and 48.43% were females. The mean achieved refraction was 0.26 ± 0.73D. Almost 60.93% of patients were within ± 0.25D of the target refraction, with 82.03% eyes within ± 0.50D of the planned correction. At 1 year after surgery, 96.45% of eyes had a stable refraction (p > 0.05). At 1 year, a total of 92.25%, 89.92% and 91.47% achieved a monocular uncorrected distance, intermediate and near visual acuity of 0.2 logarithm of the minimum angle of resolution or better, respectively. At the same time point, a total of 95.35%, 91.47% and 93.80% achieved a binocular uncorrected distance, intermediate and near visual acuity of 0.2 logarithm of the minimum angle of resolution or better, respectively. There was no statistically significant difference (p> 0.05) between the postoperative uncorrected and best corrected VA (distance, intermediate, near) at 6 months and postoperative uncorrected and best corrected VA (distance, intermediate, near) at 12 months. None of our patients had any intraoperative complications. Two cases (1.56%) developed posterior capsule opacification. Twelve patients (18.75%) complained about photic phenomena such as glare and haloes, but this symptom disappeared after 6 months postoperatively. As high as93.56% of patients had a high satisfaction with the outcomes of the surgery. Spectacle independence was obtained in 97.65% eyes. Conclusion: The Acrysof Panoptix trifocal artificial lens offers a good vision at distance, intermediate and near, with a good quality of vision and refraction.
Hassan Hashemi, Mohammad Saatchi, AbbasAli Yekta, Marzieh Nojomi, Soheila Asgari, Mehdi Khabazkhoob
Published: 16 April 2020
Abstract:
Purpose. The aim of the present study was to compare the trend of excimer laser refractive surgery in different provinces of Iran. Methods. This cross-sectional study was performed in 12 provinces of Iran in 2015 using the data of 2010 to 2014. A total of 28 surgical centers were selected. For each center, one week per season was randomly selected, giving a total of 20 weeks for all seasons of the study years. Then, to estimate the surgical rate in the selected provinces, since 4 weeks were selected each year, the number of operations on the 4 weeks was multiplied by 12.5 to generalize the results to 50 weeks (= 1 year). After applying the weight of each center, the number of refractive operations on each year was divided by the population of the province on that year, and reported per million population. Results. On average, Kermanshah (35.8%, P<0.001) and Tehran (3.1%, P<0.001) had the highest and lowest annual increase and Qom (11.8%, P<0.001) had the highest annual decrease in the rate of excimer laser refractive surgery, respectively. The highest rate was seen in Tehran in 2012 (8885 operations per million population) and the lowest rate was seen in Gilan in 2010 (142 operations per million population). Moreover, the concentration index was 0.25 in 2012, indicating a socioeconomic inequality in the rate of excimer laser refractive surgery. Conclusion. The results of the present study showed an increasing trend in the rate of the excimer laser refractive surgery in 9 Iranian provinces for the first time. Moreover, concerning the inequalities and the higher surgical rate in provinces with a better economic status, it is necessary to expand an insurance coverage and equip more public centers with the instruments and devices required for laser refractive surgery.
Published: 1 January 2020
Indian Journal of Ophthalmology, Volume 68, pp 3002-3005; https://doi.org/10.4103/ijo.ijo_1307_20

Abstract:
Purpose: The purpose of this study is to establish the safety of clear lens extraction (CLE) for the correction of high myopia in patients unfit for implantable contact lenses (ICLs) and laser in situ keratomileusis in the central Indian population. Methods: In this retrospective observational study performed at a tertiary care centre, medical records of the patients who had undergone CLE with implantation of intraocular lens (IOL) to treat high myopia were retrieved. Details of the demographic profile, surgical procedure, complications, power, and type of IOLs implanted were recorded. Results: The average postoperative follow-up period was 64.1 ± 4.2 months. The average postoperative spherical power was −1.4 ± 0.6 D, which was much lower than the preoperative spectacle power -15 ± 4.4 D. There was improvement in the postoperative visual acuity (0.4 ± 0.2 logMAR) from the preoperative distant uncorrected visual acuity (0.8 ± 0.2 logMAR). No significant change in intraocular pressure (IOP) was observed. The postoperative average anterior chamber depth (ACD) (2.66 ± 0.1 mm) was significantly deeper than the preoperative ACD (2.61 ± 0.1 mm) P = 0.00. Barrage laser was required for lattice degeneration in one patient before CLE and in two patients during follow-up. Two patients (8.7%) required Nd:YAG capsulotomy for posterior capsular opacification. None of the patients had corneal decompensation, retinal detachment, or endophthalmitis. Conclusion: CLE with implantation of IOL is the safe procedure for correcting high myopia in patients who are unfit for ICL. None of the patient had eye loss in the follow-up period of 5 years. The low incidence of complications can be attributable to the closed chamber lens removal and implantation of IOL and prophylactic retinal treatment.
E. N. Batkov, N. P. Pashtayev, V. I. Mikhaylova, Н. П. Паштаев, В. И. Михайлова
Published: 1 January 2019
Vestnik oftal'mologii, Volume 135, pp 21-27; https://doi.org/10.17116/oftalma201913501121

Abstract:
Accuracy of calculation of the intraocular lens (IOL) power in eyes with short axial length is inferior to one in emmetropic eyes. Most studies focus on relatively standard eyes. To assess the accuracy of power calculation for IOL used to correct extreme hyperopia and to compare available formulas based on their predictive capacity. Results of 13 implantations involving IOLs of at least 40 Diopters (D) in power were retrospectively evaluated. IOL power was calculated using five formulas: Haigis, Hoffer Q, HolladayI, SRKII, SRK/T. Mean numerical refractive prediction error (RPE) and mean absolute refractive prediction error (ARPE) were calculated. Mean and median ARPE were computed after optimizing the A0 constant. Proportions of eyes within certain RPE limits were compared between the formulas. Mean RPE ranged from 1.43 to 11.71 D before adjustment and from 1.08 to 5.34 D after adjustment (p<0.0001). Haigis formula produced the least RPE, and SRKII - the most. Pairwise comparison by mean ARPE after adjustment revealed no statistically significant difference between Haigis and Hoffer Q formulas. Comparison of formulas by percentage of eyes with minimal RPE identified Haigis and Hoffer Q as the most accurate, while the difference between the two was not statistically significant. The difference between the most accurate formulas (Haigis and Hoffer Q) and the least accurate (SRKII) was statistically significant. In eyes with extremely short anterior-posterior axis, prediction errors in IOL power calculations are relatively frequent (only 31-46% of eyes are within ±0.5 D) and warrant reduction. Among the evaluated formulas, Haigis and Hoffer Q are the most accurate. In order to improve the accuracy of IOL power calculations, it is necessary to employ personalized constants.
, Mateja Koncarevic, Adrijana Dukic, , Vesna Cerovic, , Nikica Gabric, Sudi Patel
Optometry and Vision Science, Volume 95, pp 1064-1076; https://doi.org/10.1097/opx.0000000000001298

Abstract:
Small incision lenticule extraction (SMILE) is advanced as the most minimally invasive and least traumatic corneal procedure for correcting refractive errors using a single laser. Although SMILE obtains similar results to femtosecond laser in situ keratomileusis (LASIK) with spherical myopia, it has deficiencies in astigmatism correction. The purpose of this study was to compare refractive outcomes and high-order aberrations (HOAs) between SMILE and femtosecond LASIK corneal procedures at 1 year post-operative. Ninety-two patients (181 eyes) with myopia/myopic astigmatism underwent either SMILE (group 1) or femtosecond LASIK (group 2). The refractive target was to achieve emmetropia in all cases. Data were analyzed to determine significance of change in refraction and HOAs. Furthermore, astigmatism was subjected to vector analysis using the Thibos (calculation of change, Δ, in J0 and J45 values) and Alpins (calculation of difference, ΔC, between target-induced astigmatism [TIA] and surgically induced astigmatism) methods. Forty-five patients (89 eyes) from group 1 and 47 patients (92 eyes) from group 2 completed the study. The main significant (P ≤ .001) findings were as follows: (a) residual astigmatism was greater in group 1; (b) group 1, ΔJ0 = 1.015J0 + 0.040 (R = 0.861), ΔJ45 = 1.082J45 + 0.019 (R = 0.792), ΔC = 0.401TIA + 0.323 (R = 0.489), and mean spherical aberration increased from −0.003 (SD, ±0.059; 95% confidence interval [CI], −0.015 to 0.009) to 0.028 μm (SD, ±0.041; 95% CI, −0.037 to −0.020); and (c) group 2, ΔJ0 = 0.952J0 − 0.005 (R = 0.921), ΔJ45 = 0.962J45 − 0.002 (R = 0.923), ΔC = 0.187TIA + 0.101 (R = 0.272), mean coma reduced from 0.114 (SD, ±0.087; 95% CI, 0.096 to 0.132) to 0.077 μm (SD, ±0.059; 95% CI, 0.065 to 0.089), and trefoil from 0.089 (SD, ±0.049; 95% CI, 0.079 to 0.0990) to 0.056 μm (SD, ±0.047; 95% CI, 0.046 to 0.066). In comparison with SMILE, femtosecond LASIK offered better precision in the overall control of astigmatism and HOAs.
T. Pahlitzsch, M.-L. Pahlitzsch, U. Sumarni
Published: 30 October 2017
Der Ophthalmologe, Volume 115, pp 928-940; https://doi.org/10.1007/s00347-017-0598-4

Abstract:
Ziel der Studie ist es, drei refraktive Verfahren, LenSx®-Femto-Laser-in-situ-Keratomileusis (LASIK), FEMTO LDV Z4®-Femto-LASIK und photorefraktive Keratektomie (PRK), hinsichtlich visueller Ergebnisse, Astigmatismus, Komplikationen, Schmerzen und Patientenzufriedenheit zu evaluieren.
, Olfat A Hassanin
Published: 25 December 2016
Electronic Physician, Volume 8, pp 3429-3433; https://doi.org/10.19082/3429

Abstract:
The Goldmann applanation tonometer readings were noted to be markedly reduced after Lasik surgery using a thin flap technique which is widely used nowadays, to correct a wide range of myopia and astigmatism. The Ocular Response Analyzer (ORA) is considered one of the important tools for refinement of Intraocular Pressure (IOP) measurements. The aim of this study is to evaluate and refine ORA measurements for IOP changes post- M2 90 Moria microkeratome Lasik procedure for Egyptian myopic and astigmatic patients trying to aid in glaucoma diagnosis and management. Thirty-five eyes of nineteen Egyptian patients with myopia or myopic astigmatism who had undergone Lasik procedure using M2 90 Moria microkeratome were included in this consecutive case series study. All cases were subjected to full ophthalmological examination including uncorrected and best corrected visual acuity, refraction, slit lamp examination, Scheimpflug imaging and ORA (Reichert Ophthalmic Instruments, Inc., Buffalo, NY, USA). The refractive errors were measured using an auto refractometer and were confirmed by trial. For the ocular response analyzer, the Goldmann-correlated IOP measurement (IOPg) which simulates IOP measured by Goldmann tonometer and the Corneal-Compensated Intraocular Pressure (IOPcc) that takes corneal biomechanical properties into consideration were reported as well as the Corneal Hysteresis (CH) and the Corneal Resistance Factor (CRF). Cases were examined preoperatively and again about one month after Lasik, after stabilization of eye condition. The collected data were tabulated and analysed with the suitable statistical methods. The mean values and standard deviation were calculated for quantitative data. Comparison tests (t-test) and correlation tests (Pearson) were also performed. In our study, involving M2 90 Moria microkeratome Lasik procedure, a highly significant post-Lasik reduction in IOPg (t-test = 8.62 (p<0.01), and a statistically significant reduction in IOPcc (t-test = 3.37 (p<0.05) by ocular response analyzer. The average post-Lasik reduction in IOP in mmHg was 4.84±2.82 for IOPg and 2.23±3.51for IOPcc. A statistically significant correlation (p<0.05) existed between post-Lasik reduction of IOPg and ablation depth as well as preoperative spherical equivalent. A non-significant correlation existed between post-Lasik reduction of IOPcc and both of ablation depth and preoperative spherical equivalent. Following Lasik procedure using M2 90 Moria microkeratome, the IOPcc values by ORA were closer to the preoperative values than the IOPg values and the reduction of IOPcc values was not affected by ablation depth (i.e. preoperative spherical equivalent). Therefore, it is advisable to use the IOPcc values by ORA when evaluating post-Lasik patients for glaucoma diagnosis and management, but with the addition of the average value for post-Lasik reduction which in the study was 2.23±3.51mmHg.
Nader Nassiri, , Abbas Azimi, Farinaz Mahmoodi Khosravi, Javad Heravian, , , Saman Nassiri, , Nariman Nassiri
Published: 1 October 2015
Journal of Refractive Surgery, Volume 31, pp 683-690; https://doi.org/10.3928/1081597x-20150831-01

Abstract:
Original Article Supplemental Data Nader Nassiri, MD; Kourosh Sheibani, MD, MSc; Abbas Azimi, PhD; Farinaz Mahmoodi Khosravi, MSc; Javad Heravian, PhD; Abasali Yekta, PhD; Hadi Ostadi Moghaddam, PhD; Saman Nassiri, MD; Mehdi Yasseri, PhD; Nariman Nassiri, MD, MPH To compare refractive outcomes, contrast sensitivity, higher-order aberrations (HOAs), and patient satisfaction after photorefractive keratectomy for correction of moderate myopia with two methods: tissue saving versus wavefront optimized. In this prospective, comparative study, 152 eyes (80 patients) with moderate myopia with and without astigmatism were randomly divided into two groups: the tissue-saving group (Technolas 217z Zyoptix laser; Bausch & Lomb, Rochester, NY) (76 eyes of 39 patients) or the wavefront-optimized group (WaveLight Allegretto Wave Eye-Q laser; Alcon Laboratories, Inc., Fort Worth, TX) (76 eyes of 41 patients). Preoperative and 3-month postoperative refractive outcomes, contrast sensitivity, HOAs, and patient satisfaction were compared between the two groups. The mean spherical equivalent was −4.50 ± 1.02 diopters. No statistically significant differences were detected between the groups in terms of uncorrected and corrected distance visual acuity and spherical equivalent preoperatively and 3 months postoperatively. No statistically significant differences were seen in the amount of preoperative to postoperative contrast sensitivity changes between the two groups in photopic and mesopic conditions. HOAs and Q factor increased in both groups postoperatively (P = .001), with the tissue-saving method causing more increases in HOAs (P = .007) and Q factor (P = .039). Patient satisfaction was comparable between both groups. Both platforms were effective in correcting moderate myopia with or without astigmatism. No difference in refractive outcome, contrast sensitivity changes, and patient satisfaction between the groups was observed. Postoperatively, the tissue-saving method caused a higher increase in HOAs and Q factor compared to the wavefront-optimized method, which could be due to larger optical zone sizes in the tissue-saving group. [J Refract Surg. 2015;31(10):683–688.] From the Clinical Research and Development Center (KS), Imam Hossein Medical Center (Nader Nassiri, SN), Shahid Beheshti University of Medical Sciences, Tehran, Iran; Refractive Errors Research Center (AA, JH, AY, HOM), Student Research Committee (FMK), School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran; School of Public Health and Public Health Research Institute, Tehran University of Medical Sciences, Tehran, Iran (MY); Stein Eye Institute, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California (Nariman Nassiri). The authors have no financial or proprietary interest in the materials presented herein. AUTHOR CONTRIBUTIONSStudy concept and design (Nader Nassiri, KS, AA, FMK, JH, HOM, MY, Nariman Nassiri); data collection (Nader Nassiri, KS, AA, FMK, JH, AY, HOM); analysis and interpretation of data (Nader Nassiri, KS, AA, FMK, AY, SN, MY, Nariman Nassiri); writing the manuscript (Nader Nassiri, KS, AA, FMK, JH, SN, Nariman Nassiri); critical revision of the manuscript (Nader Nassiri, KS, AA, FMK, AY, HOM, SN, MY, Nariman Nassiri); statistical expertise (Nader Nassiri, FMK, SN); obtaining funding (Nader Nassiri, FMK); administrative, technical, or material support (Nader Nassiri, KS, FMK); supervision (Nader Nassiri, KS) Correspondence: Kourosh Sheibani, MD, MSc, Basir Eye Safety Research Center, Basir Eye Clinic, North Jamalzadeh St., Tehran, Iran. E-mail: [email protected] 10.3928/1081597X-20150831-01 To compare refractive outcomes, contrast sensitivity, higher-order aberrations (HOAs), and patient satisfaction after photorefractive keratectomy for correction of moderate myopia with two methods: tissue saving versus wavefront optimized. In this prospective, comparative study, 152 eyes (80 patients) with moderate myopia with and without astigmatism were randomly divided into two groups: the tissue-saving group (Technolas 217z Zyoptix laser; Bausch & Lomb, Rochester, NY) (76 eyes of 39 patients) or the wavefront-optimized group (WaveLight Allegretto Wave Eye-Q laser; Alcon Laboratories, Inc., Fort Worth, TX) (76 eyes of 41 patients). Preoperative and 3-month postoperative refractive outcomes, contrast sensitivity, HOAs, and patient satisfaction were compared between the two groups. The mean spherical equivalent was −4.50 ± 1.02 diopters. No statistically significant differences were detected between the groups in terms of uncorrected and corrected distance visual acuity and spherical equivalent preoperatively and 3 months postoperatively. No statistically significant differences were seen in the amount of preoperative to postoperative contrast sensitivity changes between the two groups in photopic and mesopic conditions. HOAs and Q factor increased in both groups postoperatively (P = .001), with the tissue-saving method causing more increases in HOAs (P = .007) and Q factor (P = .039). Patient satisfaction was comparable between both groups. Both platforms were effective in correcting moderate myopia with or without astigmatism. No difference in refractive outcome, contrast sensitivity changes, and patient satisfaction between the groups was observed. Postoperatively, the tissue-saving method caused a higher increase in HOAs and Q factor compared to the wavefront-optimized method, which could be due to larger optical zone sizes in the tissue-saving group. [J Refract Surg. 2015;31(10):683–688.] From the Clinical Research and Development Center (KS), Imam Hossein Medical Center (Nader Nassiri, SN), Shahid Beheshti University of Medical Sciences, Tehran, Iran; Refractive Errors Research Center...
Zaid Shalchi, , Robert J. McDonald, Parul Patel, Timothy J. Archer, John Marshall
Journal of Cataract and Refractive Surgery, Volume 41, pp 23-32; https://doi.org/10.1016/j.jcrs.2014.05.034

Abstract:
Purpose To evaluate the long-term efficacy of photorefractive keratectomy (PRK). Setting University Hospital, London, United Kingdom. Design Prospective case series. Methods One eye of patients who had PRK 18 years previously was examined. All had myopic corrections with a 6.0 mm optical zone. Results Forty-six patients were examined. The mean preoperative spherical equivalent (SE) refractive error was −4.86 diopters (D) (range −2.75 to −7.375 D). The mean programmed correction was −4.43 D (range −2.50 to −7.00 D). Between 1 year and 18 years, the mean change in SE was −0.31 D (P = .06) and a significant increase in variance occurred (P < .002). The mean change in SE was −0.54 D in patients younger than 40 years at the time of correction (P < .02) and −0.05 D in patients older than 40 years (P = .9). The mean SE change was −0.40 D in women (P < .04) and −0.08 D in men (P = .8). The efficacy index was 0.58. The safety index was 0.998. The corrected distance visual acuity (CDVA) improved significantly from 1 to 18 years (P < .01). Ninety-six percent of corneas were clear at 18 years, with a reduction in haze scores (P < .001). There was no evidence of ectasia. Conclusions A significant increase in myopic SE occurred between 1 year and 18 years after PRK in patients younger than 40 years and in women. Predictability decreased between 1 year and 18 years. The procedure was safe with no long-term complications. The CDVA and corneal transparency improved with time. Financial Disclosure Dr. Marshall was a consultant to Summit Technology, Inc. No author has a financial or proprietary interest in any material or method mentioned.
Published: 10 December 2014
Eye and Vision, Volume 1, pp 1-13; https://doi.org/10.1186/s40662-014-0010-2

Abstract:
Cataract surgery due to advances in small incision surgery evolved from a procedure concerned with the primary focus on the safe removal of cataractous lens to a procedure focused on the best possible postoperative refractive result. As the outcomes of cataract surgery became better, the use of lens surgery as a refractive modality in patients without cataracts has increased in interest and in popularity. Removal of the crystalline lens for refractive purposes or refractive lens exchange (RLE) presents several advantages over corneal refractive surgery. Patients with high degrees of myopia, hyperopia and astigmatism are still not good candidates for laser surgery. Moreover, presbyopia can currently only be corrected with monovision or reading spectacles. RLE supplemented with multifocal or accommodating intraocular lenses (IOLs) in combination with corneal astigmatic procedures might address all refractive errors including presbyopia, and eliminate the future need for cataract surgery.
, Zaid Shalchi, Robert J. McDonald, Parul Patel, Timothy J. Archer, John Marshall
Published: 1 October 2014
American Journal of Ophthalmology, Volume 158, pp 651-663.e1; https://doi.org/10.1016/j.ajo.2014.06.013

Abstract:
To investigate the 20-year efficacy and safety of photorefractive keratectomy (PRK). Long-term observational case series. In the setting of a university hospital, a study population of 42 patients (42 eyes) who had, as part of a randomized prospective trial, undergone PRK 20 years previously were studied. All had received -3.0 or -6.0 diopter (D) corrections with either 5.0 or 6.0 mm optical zones or a multizone treatment. The mean preoperative spherical equivalent refractive error (SEQ) was -5.13 D (range, -2.75 to -8.0 D). The outcome measures included visual acuity, refractive error, corneal topography and axial length. Between 1 and 20 years there was an increase in mean myopic SEQ of -0.54 D (P < 0.02). In patients younger than 40 years of age at time of correction, this increase was -0.92 D (P < 0.002) with an accompanying increase in variance (P < 0.02), whereas in those older than 40 it was -0.08D (P = 0.8). In female patients the change was -0.69D (P < 0.01), while in males it was -0.26D (P = 0.6). The efficacy index at 20 years was 0.49, and the safety index was 0.97. Corrected distance visual acuity improved between 1 and 20 years (P < 0.01); 93% of corneas were clear at 20 years; 3 eyes had trace haze. There was an improvement in haze scores between 1 and 20 years (P < 0.02). Cornea power remained unchanged between 6 months and 20 years (P = 0.4). Axial length increased by a mean of 0.84 mm (P < 0.0001). There was no ectasia. There was a slight but significant increase in myopic SEQ after PRK between 1 and 20 years, particularly in those under 40 at the time of treatment and in female patients. Corneal power remained unchanged, but axial length increased. The procedure was safe, with no long-term sight-threatening complications and with improvements in corrected distance visual acuity and corneal transparency with time.
Clinical and Experimental Optometry, Volume 97, pp 12-17; https://doi.org/10.1111/cxo.12061

Abstract:
The aim was to review the recently published literature on excimer laser surface ablation procedures, including photorefractive keratectomy (PRK), laser sub-epithelial keratomileusis (LASEK), microkeratome-assisted PRK (epi-LASIK) and trans-epithelial (laser-assisted) PRK, to help elucidate where and how surface ablation may best fit into current refractive surgical practice. The emphasis was on publications within the last three years and included systemic reviews, meta-analyses and randomised controlled trials. Where such evidence did not exist, selective large series cohort studies, case-controlled studies and case series with follow-up preferably greater than six months were examined and included. Refractive and visual outcomes are excellent and comparable to those after LASIK even in complex cases after previous corneal surgery. Indeed, surface ablation combined with corneal collagen cross-linking may be used in selected eyes with biomechanical instability, where LASIK is contraindicated. In addition, there is evidence to suggest that there may be less induction of higher order aberrations with surface techniques. Long-term stability and safety appear to be extremely satisfactory. The literature supports the use of modern excimer laser surface treatments, with outcomes comparable to those after LASIK and evidence of less induction of higher-order aberrations. Follow-up studies at 10 to 20 years indicate excellent stability and safety.
, Frank Wilhelm, Kathleen S Kunert, Rabea Schlueter, Ute Stuhltraeger, Thomas Hammer
Published: 1 December 2013
Clinical Ophthalmology, Volume 8, pp 61-69; https://doi.org/10.2147/opth.s51200

Abstract:
Purpose: Femtosecond lasers have become the standard for laser-assisted in situ keratomileusis (LASIK) flap creation, but advanced mechanical microkeratomes are still an alternative, more cost-effective way to create the flap. The SCHWIND Carriazo-Pendular microkeratome is one of the most commonly used microkeratomes. The influence of different cutting parameters (head-advance speeds, cutting heads) on morphology of LASIK cuts was investigated. Setting: Experimental study performed at the University Eye Hospital of the Martin Luther University Halle/Wittenberg, Halle (Saale), Germany. Methods: The Carriazo-Pendular microkeratome was used on freshly enucleated porcine eyes for lamellar keratotomy. After flap removal, the cutting edge and stromal bed were evaluated from scanning electron micrographs using an individualized scoring system. Four different settings of microkeratome parameters were compared. For each setting, eight cuts were evaluated (n=32). Results: Different oscillation frequencies and head-advance speeds did not influence the cutting qualities. A higher oscillation/feed rate ratio seemed to be advantageous for a smoother interface. Concerning different cuttings heads, a deeper keratotomy led to sharper cutting edges. The thinner the flap, the more irregularities in the stromal bed appeared. Complications did not occur. Conclusion: The Carriazo-Pendular microkeratome is a safe tool with which to create a LASIK flap and is a good alternative to a costly femtosecond laser. Deeper keratotomies, as well as the use of a higher oscillation/feed rate quotient, improve the cutting quality.
Oskar Lundqvist, Timo Koskela,
Published: 27 August 2013
Acta Ophthalmologica, Volume 92, pp 482-485; https://doi.org/10.1111/aos.12256

Abstract:
To compare the efficacy and intra-operative safety of intracameral mydriatics to topical mydriatics in patients undergoing refractive lens exchange (RLE) surgery. In a randomized intra-individually comparing study performed at Koskelas Eye Clinic, Luleå, and Department of Clinical Sciences/Ophthalmology, Umeå University Hospital, Umeå, Sweden, 56 patients undergoing same-day bilateral RLE were included. Pupils were randomly dilated with topical mydriatics in one eye and intracameral mydriatics in the fellow eye. Pupil sizes were recorded intra-operatively throughout the procedures. Perceived pain/discomfort and glare were assessed immediately postoperatively using a visual analogue scale from 0 to 10. Topical mydriatics and intracameral mydriatics both give satisfactory pupil dilation in routine RLE. However, there was noticeable iris billowing in 17 eyes dilated with topical mydriatics but only one eye with intracameral mydriatics (p < 0.001). Pupils were initially slightly larger in the topical mydriatics group but contracted during surgery. There was no perceived difference with regards to glare, pain or discomfort between the treatments. The surgeon graded intracameral mydriatics eyes as easier to operate on. Both topical mydriatics and intracameral mydriatics give satisfactory mydriasis for RLE, but pupil constriction and iris billowing are more pronounced with topical mydriatics.
, K. Hebestedt, Gernot I W Duncker, Eberhard Sporl
Published: 18 January 2013
Der Ophthalmologe, Volume 110, pp 41-47; https://doi.org/10.1007/s00347-012-2633-9

Abstract:
Laser in situ keratomileusis is a safe and accepted method for correcting myopia. The operational results in terms of accuracy as well as the subjective acceptance of patients for corrections to - 8 D are now considered to be promising (Seiler, Refraktive Chirurgie der Hornhaut, 2000); however, postoperative results show individual patient problems in long-term stability. It is believed that the preoperative condition of the cornea (e.g. thickness, biomechanical properties) could have an influence on postoperative problems such as myopic regression. This study included a total of 46 eyes from 25 patients. At 3 months postoperatively, 15 patients (19 eyes) showed a SEQ of -0.50 D or more. Within this group, 11 patients (15 eyes) developed a regression (regression group) within the first 3 postoperative months. The remainder of the total group did not show any regression (stability group). The subjects of this study were on average 33 ± 8 years (stability group) and 31 ± 7 years old (regression group). The corneal thickness was tested and refractive error, visual acuity (BCVA/UCVA) and intraocular pressure was measured. In addition, the corneal hysteresis (CH) and corneal resistance factor (CRF) were determined. The mean preoperative spherical equivalent refraction was -3.14 D ± 1.41 D (SE) in the stability group and - 6.47 D ± 1.40 D (p = 0.001)in the regression group. Also, the postoperative spherical equivalents were statistically significant different (p < 0.05). In contrast, the mean preoperative corneal thickness showed no differences in both groups (p = 0.96) (stability group 563 ± 36 µm and regression group 563 ± 28 µm). The aim of the study to detect a possible causal relationship between myopia regression after LASIK and the biomechanical properties of the cornea and corneal thickness could not be clearly identified.
Elad Moisseiev, Tzahi Sela, Liza Minkev, David Varssano
Published: 1 January 2013
Clinical Ophthalmology, Volume 7, pp 93-98; https://doi.org/10.2147/opth.s38959

Abstract:
Peer reviewed article authored by (Moisseiev E, Sela T, Minkev L, Varssano D). Read article or submit your manuscript for publishing.
, G. Duncker
Published: 24 March 2012
Der Ophthalmologe, Volume 109, pp 242-249; https://doi.org/10.1007/s00347-011-2520-9

Abstract:
Implantation of phakic intraocular lenses (pIOL) is gaining in importance. Exact measurement of the anterior chamber is important to assure safe and effective pIOL implantation. In this study six currently available diagnostic devices were tested in order to compare accuracy of measurements (anterior chamber depth and diameter) and ease of handling. In this study 100 eyes from 50 healthy patients were enrolled. All measurements were done by the same operator (L. K.) on the same day and under the same lighting conditions. The following devices were used to measure anterior chamber depth and diameter: IOLMaster 500, Visante OCT, UBM Vumax II, Galilei, Pentacam Classic und Orbscan IIz. Correlations between each method were assessed using Pearson's correlation. Bland Altman plots were composed to evaluate the range of agreement between two methods. The mean epithelial anterior chamber depth was 3.45 ± 0.38 mm with IOLMaster 500, 3.69 ± 0.33 mm with Visante OCT, 3.59 ± 0.35 mm with Pentacam, 3.67 ± 0,36 mm with Galilei, 3.48 ± 0.38 mm with Orbscan IIz and 3.52 ± 0.34 mm with UBM VumaxII. The mean white-to-white measurements were 11.98 ± 0.37 mm with IOLMaster 500 and 11.71 ± 0.36 mm with Orbscan IIz. The mean angle-to-angle distances were 11.83 ± 0. 43 mm with Visante OCT, 10.73 ± 0.38 mm with Pentacam, 12.30 ± 0.45 mm with Galilei, and 11.15 ± 0.52 mm with UBM Vumax II. In the Bland Altman plots the range of agreement was 0.5 mm between Visante OCT and IOLMaster 500, regarding anterior chamber depth as well as anterior chamber diameter. The IOLMaster 500 provides exact measurement of the anterior chamber depth and diameter and is easy to handle in the daily clinical routine.
Sebastiano Serrao, , Pietro Ducoli,
Journal of Cataract and Refractive Surgery, Volume 37, pp 1655-1666; https://doi.org/10.1016/j.jcrs.2011.03.046

Abstract:
To analyze the higher-order corneal wavefront aberration during an 8-year follow-up after photorefractive keratectomy (PRK). IRCCS Fondazione G.B. Bietti, Rome, Italy. Case series. Patients having PRK using the Technolas 217C excimer laser platform were divided into 3 groups according to the preoperative refraction as follows: low myopia, high myopia, and astigmatism. The preoperative and 1-, 4-, 6-, and 8-year postoperative root mean square (RMS) values of coma, spherical aberration, and total higher-order aberrations (HOAs) were calculated with 3.5 mm and 6.0 mm simulated pupils. The mean preoperative and postoperative higher-order corneal wavefront aberration maps, point-spread functions, and radial modulation transfer functions (MTFs) were represented to describe the impact of PRK on the optical quality of the anterior cornea. The study enrolled 33 patients (66 eyes). Corneal spherical aberration was statistically significantly higher after PRK for simple myopia with 3.5 mm and 6.0 mm pupils (P<.05). The postoperative increase in coma was statistically significant in the high-myopia group with both pupil sizes (P<.05). Total RMS HOAs increased postoperatively with a 6.0 mm pupil in all groups (P<.05). The mean radial MTF was almost stable in all groups between preoperatively and postoperatively. Higher-order corneal wavefront aberrations stabilized 1 year after PRK to treat myopia or myopic astigmatism. The effect of induced corneal HOAs tended to increase after correction of high myopia with large pupils, although without degrading the image optical quality of the cornea over the long term.
Nader Nassiri, Sare Safi, Mohammad Aghazade Amiri, Kourosh Sheibani, Hamid Safi, Nekoo Panahi, Nariman Nassiri
Journal of Cataract and Refractive Surgery, Volume 37, pp 1858-1864; https://doi.org/10.1016/j.jcrs.2011.05.023

Abstract:
To compare visual outcomes and contrast sensitivity after wavefront-optimized or conventional photorefractive keratectomy (PRK) in myopic patients with or without astigmatism. Vanak Eye Surgery Center, Tehran, Iran. Comparative case series. Patients with low to moderate myopia with or without astigmatism were allocated into 2 groups. The study group was treated with wavefront-optimized PRK (Allegretto Wave Eye-Q software version 2.020 default treatment) and the control group, with conventional PRK (Technolas 217z). In all cases, treatments were bilateral and performed with the same device. Baseline and 3-month postoperative measures were uncorrected and corrected distance visual acuities, manifest refraction, and contrast sensitivity. Each group comprised 66 eyes. The mean preoperative spherical equivalent refraction improved from −2.99 diopters (D) ± 1.02 (SD) preoperatively to −0.08 ± 0.26 D 3 months postoperatively in the study group and from −2.66 ± 0.95 D to 0.01 ± 0.30 D, respectively, in the control group. In both groups, the postoperative mesopic and photopic contrast sensitivity decreased significantly at most spatial frequencies. The postoperative decrease in contrast sensitivity in both groups was comparable except at spatial frequencies of 3 cycles per degree (cpd) under mesopic conditions and 12 cpd under photopic conditions, frequencies at which the control group had a greater reduction. Visual acuity and refractive error outcomes were similar in both treatment groups. After 3 months, mesopic and photopic contrast sensitivity were significantly decreased in both groups; the reduction in the 2 groups was almost comparable. No author has a financial or proprietary interest in any material or method mentioned.
Li-Quan Zhao, Huang Zhu
Published: 16 March 2011
Journal of Ophthalmology, Volume 2011, pp 1-6; https://doi.org/10.1155/2011/839371

Abstract:
This control-matched comparative study evaluated changes in contrast sensitivity after Zyoptix tissue-saving (TS) LASIK and Planoscan standard LASIK (Technolas 217z, Bausch & Lomb) for myopia 6 months postoperatively. 102 TS LASIK-treated eyes were matched with 102 standard LASIK-treated eyes (divided into low, moderate, and high groups). There were no significant differences in refraction outcomes between the groups postoperatively. In high group, a significant reduction in contrast sensitivity after TS LASIK was found at high spatial frequencies (P<.05) under photopic conditions and at middle to high spatial frequencies (P<.05) under mesopic conditions. And significant reduction was also found in standard LASIK at high spatial frequency (P<.05) under mesopic conditions. The reduction was significantly lower in TS LASIK than that in standard LASIK at high spatial frequencies (P<.05) under mesopic conditions. TS LASIK was prone to reduce mesopic contrast sensitivity of high myopia at high spatial frequencies.
Brian T. Fisher,
Published: 17 February 2011
Optics Express, Volume 19, pp 4231-41; https://doi.org/10.1364/oe.19.004231

Abstract:
The current popularity of excimer laser refractive surgery suggests a need for continued research and refinements to further improve clinical outcomes. A fundamental limitation of current clinical systems is the lack of real-time feedback specifically addressing the laser-tissue interactions as directly related to laser ablation rates. This paper reports data to assess the feasibility of a novel approach that holds promise as a real-time feedback scheme based on comparison of the incident and reflected laser pulse waveforms, as quantified using a cross-correlation algorithm. The approach is evaluated for ablation of bovine cornea over a range of clinically relevant laser fluences. A linear relationship was observed between several cross-correlation metrics and the directly measured corneal ablation rate, yielding an average RMS predictive error of 3.9% using a 25-shot average reflected waveform. Assessment of the cross-correlation approach for single-shot ablation data revealed a brief transient corresponding to the first few laser pulses, which is attributed to a slight hydration gradient near the surface of the de-epithelialized cornea. Clinical refractive data are necessary to assess the precision of this approach for actual refractive surgery.
Hassan Hashemi, Mohammad Saatchi, AbbasAli Yekta, Marzieh Nojomi, Soheila Asgari,
Published: unknown date
Abstract:
Purpose. The aim of the present study was to compare the trend of excimer laser refractive surgery in different provinces of Iran.
Page of 1
Articles per Page
by
Show export options
  Select all
Back to Top Top