Morphometric Markers of the Effectiveness of Micropulse Cyclophotocoagulation

Overview

This prospective study aims to evaluate morphometric markers of treatment response following micropulse transscleral cyclophotocoagulation (MP-CPC) in patients with glaucoma. The study will assess changes in choroidal thickness and the choroidal vascularity index (CVI) measured by optical coherence tomography (OCT) before treatment, 3-7 days after the procedure, and 1 month postoperatively. Intraocular pressure (IOP) will be measured at the same time points. The correlation between changes in choroidal thickness, the choroidal vascularity index (CVI) and IOP reduction will be analyzed. Additionally, the study seeks to determine the minimal baseline choroidal thickness associated with a clinically significant hypotensive effect after MP-CPC.

Glaucoma is a chronic progressive optic neuropathy characterized by irreversible visual field loss. Reduction of intraocular pressure (IOP) remains the only evidence-based strategy to slow disease progression. Micropulse transscleral cyclophotocoagulation (MP-CPC) has become an increasingly used laser modality due to its favorable safety profile compared to continuous-wave cyclophotocoagulation. Despite demonstrated efficacy, the magnitude and durability of the hypotensive effect after MP-CPC vary considerably among patients. Identification of structural ocular biomarkers associated with treatment response may improve patient selection and enable a more individualized therapeutic approach. The choroid plays a key role in ocular blood flow regulation and may influence aqueous humor dynamics, particularly uveoscleral outflow. Variations in choroidal thickness may reflect differences in vascular reactivity, tissue compliance, and structural characteristics that could modulate the biological response to laser energy. This prospective study will include patients with various types of glaucoma scheduled to undergo MP-CPC. Subfoveal choroidal thickness and the choroidal vascularity index (CVI) will be measured using enhanced depth imaging optical coherence tomography (EDI-OCT) at three time points: Preoperatively (baseline), 3-7 days after MP-CPC, 1 month after MP-CPC Intraocular pressure will be assessed at the same time points using Corvis ST tonometry. The primary objective of the study is to evaluate the correlation between changes in choroidal thickness, the choroidal vascularity index (CVI) and IOP reduction at early (3-7 days) and short-term (1 month) follow-up. Secondary objectives include: Assessment of dynamic changes in choroidal thickness after MP-CPC, Evaluation of the relationship between baseline choroidal thickness and the degree of IOP reduction, Determination of a threshold (minimal) baseline choroidal thickness associated with a clinically significant hypotensive response, Safety evaluation, including changes in visual acuity and postoperative complications Correlation and regression analyses will be performed to determine whether baseline choroidal thickness and its early postoperative changes can predict the degree and stability of IOP reduction. The identification of morphometric predictors of MP-CPC efficacy may contribute to the development of personalized treatment algorithms and improve prognostic stratification in patients undergoing laser management of glaucoma.