Morphometric Markers of the Effectiveness of Micropulse Cyclophotocoagulation

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.

Inclusion criteria

• Decision to treat by MP-CPC Laser
• Patients diagnosed with Glaucoma
• Patients aged 18 years old and above
• Glaucoma that is inadequately controlled on medical therapy

Exclusion criteria

• Patients age less than 18 years
• Patients unable or unwilling to provide informed consent to participate in the study
• Patients potentially unavailable for follow up visits
• Patients with significant scleral thinning
• Patients with ocular infection, inflammation or intraocular surgery in the study eye 2 months prior to enrollment in the study
• Albino patients that have no iris pigmentation