Investigation of laser peripheral iridotomy characteristics using the ImageJ program on anterior segment parameters

This study aimed to evaluate the characteristics of laser peripheral iridotomy (LPI), including area size, location, and distance from the pupil center, using ImageJ software, and to explore their correlation with changes in anterior segment parameters observed through Pentacam imaging.

This retrospective study analyzed 29 eyes of 29 patients with angle-closure who underwent LPI between April 2023 and December 2024. Patients diagnosed with primary angle-closure glaucoma, primary angle closure, and high-risk primary angle-closure suspects were included. Anterior segment parameters were assessed pre- and post-LPI using Pentacam imaging. ImageJ software was used to analyze anterior segment photographs to assess LPI characteristics, including the area size, location, and distance from the center of the pupil.

Following LPI, significant increases were observed in superior (0.93 to 1.00 mm), inferior (1.12 ± 0.20 to 1.26 ± 0.19 mm), temporal (1.23 ± 0.20 to 1.36 ± 0.17 mm), and nasal (1.0 to 1.06 mm) peripheral anterior chamber depths (ACD), anterior chamber volume (ACV) (74.1 ± 13.5 to 84.6 ± 10.8 mm³), and anterior chamber angle (20.4 ± 4.1º to 23.4 ± 4.4º) (p < 0.05, for all), while central ACD (1.92 ± 0.21 to 1.91 ± 0.20 mm) remained unchanged (p = 0.432). The mean intraocular pressure decreased significantly from 18.6 ± 4.2 mmHg to 16.6 ± 3.3 mmHg (p < 0.001). Negative correlations were found between increases in superior and temporal peripheral ACDs and the pupil-to-LPI area ratio (p < 0.05 for all). Additionally, ACV improvement was negatively correlated with the LPI distance (β=-0.531, p = 0.013).

The characteristics of the LPI, specifically the pupil-to-LPI area ratio and the LPI distance from the pupil, may significantly influence changes in anterior segment parameters. A small LPI area relative to the pupil area and excessively peripheral LPI locations may be associated with reduced treatment efficacy. These findings may highlight the importance of considering both pupil size and the precise positioning of the LPI to optimize therapeutic outcomes.