Abstract
Purpose:
To evaluate changes in anterior segment morphology before, immediately after, and five years after laser peripheral iridotomy (LPI) in primary angle-closure suspects (PACS) and control patients using anterior segment optical coherence tomography (ASOCT).
Methods:
In this prospective observational study, ASOCT images using Zeiss CIRRUS HD-OCT were analyzed of patients who underwent LPI in the intervention group, and patients who underwent panretinal photocoagulation (PRP) in the control group. Anterior chamber angle (ACA) and anterior chamber depth (ACD) were measured before, immediately after, and five years after the laser procedure. Differences between the two patient groups were compared by paired Student’s t-tests.
Results:
8 patients who received LPI and 16 control patients who received PRP were included in this study. In the LPI group, there was a statistically significant increase in ACA (9.71 degrees, p=0.008) and ACD (276.3 μm, p=0.001) immediately post- compared to pre-LPI. Both parameters remained significantly increased at five year follow-up compared to pre-LPI (p=0.022 and p=0.003, respectively). In the control group, ACD did not significantly change throughout the three time periods. However, ACA significantly changed at five year post- compared to pre- and immediately post-PRP, with ACA becoming more narrow by 15.00 degrees (p<0.001).
Conclusions:
To our knowledge, this was the first study to analyze quantitative morphologic changes of the anterior segment in PACS and control subjects over a relatively long period of time using ASOCT. This study confirms that LPI results in a significant increase in ACA and ACD early post-PI, and increased ACD and ACA are maintained long-term. Control group’s ACA at five years significantly narrowed. ACA narrowing over long follow-up period might be induced by a change of lens vault due to aging. LPI should be a baseline treatment modality for angle closure. At the same time, the lens and anterior segment parameters change continuously as one gets older. Therefore, careful longitudinal observation of lens status as well as other anterior segment parameters is integral in the management of angle-closure glaucoma.