Residual anterior chamber angle closure in narrow-angle eyes following laser peripheral iridotomy: anterior segment optical coherence tomography quantitative study

Abstract

Overall, ACA parameters changed significantly after LPI; however, when assessed by AS-OCT, ACA remained unchanged in some narrow-angle eyes despite LPI. Our findings suggest that multiple causes other than pupillary block may contribute to narrow-angle closure following LPI.

A Hierarchical Cluster Analysis of Primary Angle Closure Classification Using Anterior Segment Optical Coherence Tomography Parameters

“…Hence, some studies have reported that LPI might not be effective in treating all narrow angles. [8][9][10][11][12] Therefore, other pathogenic mechanisms, such as forward movement of the lens or a plateau iris configuration, have also been suggested to contribute to PAC. [13][14][15][16] Those outcomes suggest that PAC is not a single disease entity caused by single mechanism and thus may be classifiable into several categories with differing features.…”

“…Image acquisition procedure and analysis method are described in detail elsewhere. 12,19,20 ACD was defined as the distance from the corneal endothelium to the anterior surface of the lens. The scleral spur was defined as the point at which a change in curvature of the inner surface of the angle wall became apparent, and often presented as an inward protrusion of the sclera.…”

Longitudinal Changes in Anterior Segment Parameters After Laser Peripheral Iridotomy Assessed by Anterior Segment Optical Coherence Tomography

“…1,2 However, in previous studies, the AC angles of some ACG eyes that underwent LPI remained closed. [3][4][5] Furthermore, some eyes that underwent LPI showed progression of peripheral anterior synechiae (PAS). [6][7][8] These observations raise the questions whether pupillary block is the only mechanism of ACG, and whether LPI is suitable for treating all types of ACG.…”

“…13,14 Recent studies using AS OCT showed that LPI substantially increased the AC angle width in ACG eyes. 5,[15][16][17][18][19] Lee et al found that approximately two-thirds of patients with a narrow angle showed opening of the AC angle after LPI. 5 However, these results were obtained early post-LPI, with post-LPI imaging performed at 1 week to 1 month.…”

“…5,[15][16][17][18][19] Lee et al found that approximately two-thirds of patients with a narrow angle showed opening of the AC angle after LPI. 5 However, these results were obtained early post-LPI, with post-LPI imaging performed at 1 week to 1 month. Anterior segment structures change according to aging 14 ; thus the anterior segment and AC angle may undergo further changes from those observed early post-LPI.…”