Morphometric Markers of the Effectiveness of Micropulse Cyclophotocoagulation: The Influence of Choroidal Thickness on the Extent and Duration of the Hypotensive Effect

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.