The Course of the Changes in Anterior Chamber Parameters After Laser Peripheral Iridotomy: Follow-up for 6 Months With a Scheimpflug-Placido Disc Topographer.

Abstract

To evaluate the course of the changes in anterior chamber (AC) parameters using a Scheimpflug-Placido disc topographer before and through 6 months after laser peripheral iridotomy (LPI). A total of 109 eyes of 56 consecutive patients classified as primary angle closure suspect (PACS), primary angle closure (PAC), and primary angle closure glaucoma (PACG) were included in this prospective, interventional, observational case series. Anterior chamber volume (ACV), central anterior chamber depth (CACD), and anterior chamber angle (ACA) were measured by Scheimpflug photography preoperatively and at 1, 3, and 6 months after LPI. With respect to the parameters above, alterations in the measurements were assessed to determine whether the effects induced by LPI on AC morphology persisted with time. At 1 month after LPI, mean ACV, CACD, and ACA increased significantly in all groups (P<0.05). However, in eyes with PACG, significant reductions at 3 months in ACA [0.00 (-1.00 to 0.00) degrees, median (Md) [quartile 1 (Q1) to quartile 3 (Q3)], P=0.032] and at 6 months in ACV [-1.00 (-2.25 to 1.00) μL, P=0.043) and CACD (-0.01 (-0.02 to 0.00) mm, P=0.006) were shown. On analysis of all eyes together, a weak correlation was found between axial length and the change in CACD (r=0.266, P=0.007). Eyes with ACA≤25 degrees widened by 6.6±2.8 degrees versus 4.9±2.4 degrees in eyes with ACA>25 degrees at 1 month after the procedure (P=0.002). Scheimpflug-Placido disc topographer detected significant changes in the AC parameters after LPI in all groups. However, compared with PACS and PAC, the PACG showed significant alterations in the AC parameters through 6 months.