A Variant of Micro-Invasive Glaucoma Surgery: Calibrated Reverse Meridional Cyclodialysis ab interno Involving Implantation of a Non-Absorbable Collagen Implant

Abstract

Purpose. To assess safety and effectiveness of calibrated cyclodialysis ab interno involving implantation of a non-absorbable collagen implant in the suprauveal space in decreasing IOP in glaucoma patients.Methods. Forty-three patients (43 eyes; 16 male and 27 females; average age — 70.4 ± 10.0 years) were included in this pilot study. A 6 mm long and 2.0 mm wide cyclodialysis cleft was created ab interno in one of the lower quadrants of the eye using a specially designed spatula followed by insertion of a strip of implant in the cleft. In 19 eyes (44.3 %) the procedure was performed as standalone procedure and in 24 eyes (55.7 %) along with cataract surgery. Outcome measures were IOP change, use of hypotensive medication(s), complications, and need for a second surgery. Decrease in IOP by >20 % and IOP between 6 and 21 mmHg without hypotensive medication(s) constituted complete success; similar changes in IOP with medication(s) constituted partial success. Need for second surgery constituted failure.Results. At 6 months, baseline IOP decreased from 20.6 ± 7.4 mmHg to 12.9 ± 4.9 mmHg (a decrease by 37.4 %; р < 0.001) and hypotensive medication use reduced from 2.6 ± 0.8 to 1.0 ± 1.1 (a reduction by 57.7 %; р < 0.001). Complete success was achieved in 19 eyes (44.2 %), partial in — 15 eyes (34.9 %). Nine eyes had unsuccessful outcomes (20.9 %); among these, seven eyes (78 %) had severe glaucoma and five eyes (55 %) had undergone previously glaucoma surgeries. Hemorrhaging at the cleft site was the most common intraoperative complication — 18 eyes (41.9 %). Postoperative complications included hyphema, which was completely resorbed within one week.Conclusion. Calibrated cyclodialysis ab interno procedure involving implantation of a non-absorbable collagen implant in the suprauveal is safe and easy to perform. It effectively decreases IOP in patients with moderate glaucoma but is less effective in patients with severe glaucoma and in patients with previously failed glaucoma surgeries. Complications were found to be minimal.