Risk factors for tube exposure following Baerveldt glaucoma implantation and overlying tissue thickness assessed by anterior segment optical coherence tomography

PURPOSE: We identified clinical factors associated with tube exposure following Baerveldt glaucoma implantation (BGI) and used anterior segment optical coherence tomography (AS-OCT) to assess postoperative tissue thickness over the tube. STUDY DESIGN: Retrospective, single-center cohort study. METHODS: In this single-center retrospective cohort study, 405 eyes underwent BGI (BG101-350) with preserved scleral patch grafts between October 2014 and December 2022. Tube exposure was documented through clinical records and slit-lamp examination. Risk factors were evaluated using Firth's penalized logistic regression. Overlying tissue thickness at 1 year postoperatively was measured via AS-OCT, and its association with clinical variables was analyzed using linear regression. RESULTS: The mean follow-up was 630.7 days, and tube exposure occurred in 12 eyes (2.96%). Neovascular glaucoma (NVG) (odds ratio [OR] 5.03, p = 0.033) and anterior chamber (AC) tube insertion (OR 6.07, p = 0.017) were independently associated with exposure. Overlying tissue was significantly thinner with AC insertion compared with ciliary sulcus or pars plana placement (Kruskal-Wallis with Bonferroni-adjusted Dunn's tests; AC vs sulcus, p = 0.039; AC vs pars plana, p < 0.001). Among eyes with AC insertion, prior micropulse transscleral cyclophotocoagulation (MP-CPC) was associated with greater tissue thickness (estimate 0.173; p = 0.032). CONCLUSION: AC insertion and NVG were associated with an increased risk of tube exposure after BGI. AS-OCT revealed thinner tissue over AC-placed tubes, providing a structural basis for this risk. Avoiding AC insertion may reduce exposure; the observed association between prior MP-CPC and thicker tissue requires prospective validation.