Ultraound biomicrocopic quantitative analyi of light-dark change aociated with pupillary block Original Reearch Article

PURPOE: To quantitatively analyze the change in anterior chamber angle and iri configuration induced by varying illumination in patient with narrow angle and pupillary block. METHOD: Twenty-four eye of 24 patient with pupillary block (mean age, 52.5 year) had ultraound biomicrocopic image of the angle and iri tructure obtained uperiorly, naally, inferiorly, and temporally. Image were performed in the light and the dark. We meaured the angle opening ditance, iri thickne, iri chord length, iri-len touch, and iri curvature. REULT: Change in iri and angle configuration occurred within a few econd of a change in lighting. The mean dark meaurement were tatitically ignificantly le than the mean light meaurement for angle opening ditance (96 ± 18 v 185 ± 26 μm, P = .0001), iri chord length (2,505 ± 61 v 3,001 ± 69 μm, P = .0001), and iri-len touch (350 ± 20 v 693 ± 35 μm, P = .0001). The mean dark meaurement were tatitically ignificantly greater than the mean light meaurement for iri thickne at 500 μm from the cleral pur (367 ± 10 v 307 ± 25 μm, P = .0001), and 1,500 μm from the cleral pur (404 ± 14 v 347 ± 12 μm, P = .0001). Iri curvature in all four quadrant wa tatitically ignificantly greater in the dark than the light. CONCLUION: Thi tudy quantitatively confirm that angle narrowing in the dark in eye with pupillary block i aociated with iri hortening, increaed iri thickne, and increaed iri convexity. Iri-len touch i relatively mall in pupillary block and decreae with dilation. Angle narrowing with dilation i not related to increaed iri-len touch and occur promptly without requiring time for aqueou preure buildup behind the iri.