Residual Structural Differences on Anterior Segment OCT After Laser Peripheral Iridotomy in Primary Angle Closure Disease

Précis: AS-OCT parameters, especially ACD and nasal angle parameters, demonstrates persistent structural differences across the PACD disease spectrum even after LPI and may serve as a useful adjunctive tool for structural assessment and risk stratification in treated eyes. Purpose: Although laser peripheral iridotomy (LPI) alleviates pupillary block in primary angle closure disease (PACD), structural differences across the disease spectrum may persist after treatment. This study aimed to evaluate anterior segment optical coherence tomography (AS-OCT) parameters in treated primary angle closure disease (PACD) and identify features associated with severity. Patients and Methods: Retrospective analysis was performed on 160 eyes from 91 patients. AS-OCT was conducted using Tomey CASIA2 Angle Protocol. Disease severity was established prior to laser peripheral iridotomy (LPI) based on clinical gonioscopy and standard diagnostic criteria. All eyes underwent AS-OCT after LPI. One-way ANOVA with post-hoc Tukey’s HSD and ROC curve analysis evaluated intergroup differences and diagnostic cutoffs. Results: Significant differences in AS-OCT parameters were observed for ACD ( P =0.020), AOD ( P <0.001), TISA ( P <0.001), ARA ( P <0.001), ITC Index ( P =0.001), and ITC Area ( P =0.013). Acute angle closure glaucoma (AACG) had the most narrowing and highest ITC values. ROC analysis demonstrated modest discriminative performance for individual AS-OCT parameters. ACD ≤1.82 mm demonstrated high sensitivity (100%) but low specificity (21.4%), while AOD 250/500 nasal cutoffs demonstrated high specificity (100%/96.4%) with low sensitivity. Conclusion: AS-OCT demonstrates persistent structural differences across the PACD spectrum after LPI and may serve as an adjunct for structural assessment and risk stratification in treated eyes.