Effect of High Myopia on Dynamic Changes of Anterior Angle After Pharmacologic Mydriasis in Cataract Patients: A SS-ASOCT Study

PURPOSE: The purpose of this study was to evaluate the effect of high myopia on anterior angle change after pharmacologic mydriasis in patients with cataract using swept-source anterior segment optical coherence tomography (SS-ASOCT). METHODS: This prospective cross-sectional study continuously recruited patients with cataract aged 40 years and older during the period August 2019 to August 2020. The anterior segment parameters, including central corneal thickness (CCT), anterior chamber depth (ACD), angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular-iris angle (TIA), angle to angle width (ATA), and anterior chamber volume (ACV), were obtained using SS-ASOCT at baseline and 30 minutes after mydriasis. Regression analyses were performed to identify the factors related to the relative change of AOD500 (ΔAOD500). RESULTS: A total of 938 patients (938 eyes) were included. The AOD500 decreased from 0.46 ± 0.22 mm to 0.40 ± 0.19 mm, with percent ΔAOD500 of −13.59% ± 37.73% (P = 0.005). The patients with high myopia had a smaller reduction of anterior angle parameters, with a percent ΔAOD500 of −22.74% ± 58.09%% in non-high myopic eyes and −0.84% ± 45.47% in high myopic eyes (P < 0.001). The stepwise multivariate regression demonstrated that the smaller reduction of AOD500 were independently associated with younger age (coefficient = −2.11, 95% confidence interval [CI] = −2.59 to −1.64, P < 0.001), presence of high myopia (coefficient = 15.35, 95% CI = 3.63 to 27.07, P = 0.010), greater baseline TISA500 (coefficient = 60.78, 95% CI = 8.75 to 112.82, P = 0.022), and ATA (coefficient = 11.21, 95% CI = 4.53 to 17.89, P = 0.001). CONCLUSIONS: The anterior chamber angle decreased after pharmacologic mydriasis in these patients with cataract. Angle shallowing after pharmacologic mydriasis was significantly less pronounced in high myopic eyes than in non-high myopic eyes. TRANSLATIONAL RELEVANCE: These findings are informative for the relative less risk of angle-closure glaucoma in highly myopic eyes.