Visual Acuity Outcomes After Trans Scleral Cyclophotocoagulation: A Systematic Review and Meta-analysis.

Topic: The aim of this systematic review and meta-analysis is to evaluate best-corrected visual acuity (VA) outcomes following transscleral cyclophotocoagulation (TSCPC) in patients with refractory glaucoma.

Clinical Relevance: TSCPC is typically reserved for cases of refractory glaucoma, due to apprehension of negative affects on VA. Prior studies have reported the VA outcomes from TSCPC, but no comprehensive review of the literature has yet been conducted.

Methods: The full protocol was registered on PROSPERO (42023485891). The electronic databases OVID MEDLINE, and EMBASE were searched using keywords related to TSCPC and visual acuity outcomes (start date to February 7, 2025). Meta-analysis was completed using random effects models and risk ratios to calculate pooled estimates.

Results: In total, 90 studies with 6331 eyes were included. Weighted mean patient age was 61.8 (SD 9.8) years, with 53.3% males (n=3374). Follow-up periods of the studies consisted of 19.8% with less than 1 year follow-up, 38.4% with between 1-2 years, and 40.7% with more than 2 year follow-up. Among 19 studies and 1,246 eyes, the weighted mean pre-operative VA was 1.11 LogMAR (SE 0.02)(20/258 Snellen), and 1.12 LogMAR (SE 0.02)(20/264 Snellen) post-procedure. Meta-analysis of 19 studies and 1,246 eyes did not show a statistically significant difference between VA before TSCPC and at last follow-up (Mean Difference: -0.10 LogMAR, 95% confidence interval: -0.22 to 0.01, I=78.9%, p=0.077). In 59 studies and 3,855 eyes, 50.0% (SE 0.3) of patients maintained their VA at final follow-up, with 6.8% (SE 0.2) showing a 1-line improvement, 9.0% (SE 0.2) improving by 2 or more lines, 17.6% (SE 0.2) decreasing by 1 line, and 16.9% (SE 0.3) decreasing 2 lines or more. In 84 studies and 5,941 eyes, the mean pre-operative IOP was 34.2 (SE 0.09) mmHg, which dropped to 18.3 (SE 0.05) mmHg, with 79.3% of patients achieving an IOP below 22 mmHg. Meta-analysis of 42 studies and 2,393 eyes showed a mean reduction of 1.1 glaucoma medications pre-procedure to last follow-up (95%CI: 0.89-1.31, I:91.76, p<0.0001). There was a significant negative linear relationship between total energy (Joules) administered with logMAR BCVA outcome (correlation coefficient: -0.008, I:77.7%, p=0.038). There was no significant correlation between BCVA with duration (milliseconds) of TSCPC application (correlation coefficient: -7.4 × 10, I: 21.5%, p=0.876).

Conclusion: This meta-analysis suggests no significant decrease in VA after TSCPC, with a moderate degree of certainty. Larger amounts of total energy during TSCPC was found to be correlated with worse BCVA. However, given the substantial heterogeneity and observational nature of most studies, these findings should be interpreted with caution.