Effect of mydriasis on anterior segment biometric parameters of patients with age-related cataracts.

PURPOSE: To determine the risk of mydriasis-induced angle closure in patients with intumescent age-related cataracts with different anterior chamber angle widths through a comparative analysis of anterior segment biometric parameters before and after mydriasis. METHODS: A total of 195 patients with cortical intumescent cataracts were grouped into four according to the mean TIA in the four quadrants before mydriasis as follows: extremely narrow-angle group, 0° < TIA ≤ 10°; narrow-angle group, 10° < TIA ≤ 20°; wide-angle group, 20° < TIA ≤ 30°; and ultra-wide-angle group, TIA > 30°. The biological parameters obtained with UBM before and after mydriasis were compared. RESULTS: For the extremely narrow-angle group, the TIA and AOD500 values could increase or decrease after mydriasis, indicating that the anterior chamber angle could widen or narrow, and there was a slight but statistically significant increase in IOP after dilation. For the other groups, the AOD500 and TIA significantly increased after mydriasis, signifying a more open anterior chamber angle. CONCLUSION: Patients with 0° < TIA ≤ 10° have a high risk of angle closure and should undergo laser peripheral iridotomy before mydriasis to prevent acute elevation of intraocular pressure. Patients with 10° < TIA ≤ 20° have a low risk, and they can undergo routine mydriasis, but changes in their anterior chamber morphology should be closely monitored. When TIA > 20°, the risk is almost negligible, and mydriasis can be safely induced.