Two-year efficacy after first transscleral controlled cyclophotocoagulation in patients with and without pseudoexfoliation

Abstract

Purpose: Transscleral controlled cyclophotocoagulation (COCO) is a transscleral 810-nm diode laser cyclophotocoagulation that automatically adjusts the applied laser energy utilizing an optical feedback loop. The present study investigates the influence of pseudoexfoliation (PEX) on the efficacy of COCO in a Caucasian study population.

Methods: Retrospective data from 130 consecutive eyes were analyzed during a 2-year follow-up. Baseline characteristics, intraocular pressure (IOP), number of IOP-lowering medications, visual field, best-corrected visual acuity (BCVA), and secondary surgical interventions (SSI) were analyzed. The primary endpoint was IOP reduction at M24 compared to baseline, and the secondary endpoints were IOP course, reduction of IOP-lowering medications, surgical success, and IOP-lowering SSIs stratified by PEX and baseline IOP.

Results: IOP reductions of -35, -39, -25, -25, -23, -34, and -36% could be achieved from baseline to D1, W1, M1, M3, M6, M12, and M24 (all p < 0.001), respectively, while there was a significant overall reduction over time (p < 0.001) in the number of topical IOP-lowering medications postoperatively. The proportion of eyes requiring additional systemic IOP-lowering medication reduced from 31 to 0% at M24 (p = 0.025). Eyes without PEX and IOP < 30 mmHg at baseline had the lowest risk for IOP-lowering SSIs (p < 0.03). BCVA dropped at M12 (0.25 [95% CI: 0.12-0.38]), and the drop persisted during the following 12 months.

Conclusion: The present study demonstrates a midterm IOP-lowering effect after COCO while reducing the burden for topical and systemic IOP-lowering medications. Patients without PEX and IOP < 30 mmHg have a lower risk of SSI. The procedure per se cannot be excluded as causative for the decreased postoperative BCVA. Further prospective investigations are suggested.

Keywords: COCO; CPC; Controlled transscleral cyclophotocoagulation; Efficacy; PEX.

Fig. 1

Transscleral controlled cyclophotocoagulation (COCO). Controlled cyclophotocoagulation is a newer transscleral 810-nm diode laser cyclophotocoagulation method to lower intraocular pressure in glaucoma treatment. The machine consists of a stationary box (a) with integrated laser, computer and touch displays, and a solid handpiece (b). The laser energy is delivered through a glass fiber probe (small extension) while touching the conjunctiva and measured with the inbuilt sensor (big extension) anterior the cornea. It automatically adjusts the applied laser energy by an optical feedback loop

Fig. 2

Intraocular pressure (IOP) course in the first 24 months after transscleral controlled cyclophotocoagulation. Each postoperative visit showed a statistically significant reduction of intraocular pressure of −35, −39, −25, −25, −23, −34, and −36% (all p < 0.001) compared to baseline (BL)

Fig. 3

Course of a number of topical intraocular pressure (IOP)-lowering medications in the first 24 months after transscleral controlled cyclophotocoagulation. There was an overall reduction of topical IOP-lowering medications after transscleral controlled cyclophotocoagulation (p < 0.001). Further, the proportion of patients requiring additional systemic IOP-lowering medications reduced from 31 to 0% at 24 months (p = 0.025)

Fig. 4

Course of best-corrected visual acuity (BCVA, a) and median deviation of visual field examination (MDVF, b) of patients receiving transscleral controlled cyclophotocoagulation. Significant changes of median BCVA (a; baseline 0.40 [25th quartile: 0.20, 75th quartile 0.60], M12 0.49 [25th quartile: 0.30, 75th quartile 0.66; p < 0.001], and BCVA drop persisted at M24 0.49 [25th quartile: 0.40, 75th quartile 0.89; p = 0.76]). MDVF (b) did not change significantly over time (p = 0.17)

Fig. 5

Kaplan–Meier curves for IOP-lowering secondary surgical intervention (IOP–SSI) after transscleral controlled cyclophotocoagulation (COCO) in a Caucasian study population (a) and stratified by intraocular baseline pressure and PEX (b). a Cumulative proportion of eyes without IOP–SSI after COCO. b Results with taking pseudoexfoliation (PEX) and intraocular pressure (IOP) into account (Cox proportional hazard model)