Original article
Long-term Changes in Anterior Segment Characteristics of Eyes With Different Primary Angle-Closure Mechanisms

https://doi.org/10.1016/j.ajo.2018.04.005Get rights and content

Purpose

To assess long-term changes in the anterior segment (AS) of eyes with different angle-closure mechanisms.

Methods

In total, 133 eyes (from 75 participants) with angle closure were enrolled. All eyes received laser iridotomy (LI) during the follow-up period. Serial anterior segment optical coherence tomography (AS-OCT) imaging was performed during a mean follow-up of 4 years. Participants were categorized into 4 groups according to angle-closure mechanisms, based on baseline AS-OCT images: pupillary block (PB), plateau iris configuration (PIC), thick peripheral iris roll (TPIR), and exaggerated lens vault (ELV). Linear mixed-effect models were applied to evaluate the longitudinal changes in AS-OCT parameters (anterior chamber depth [ACD], lens vault [LV], and angle opening distance [AOD]).

Results

Forty-six eyes (35%) were classified as PB, 30 (23%) as PIC, 34 (26%) as TPIR, and 23 (17%) as ELV. The follow-up period was 41-54 months. At baseline, ACD was shallowest in ELV, followed by PB, TPIR, and PIC, in order. The PIC group showed significantly wider AOD than the other groups at baseline. ACD decreased and LV increased over time in all groups, especially in the PIC group. After LI, the angle widened in the PB and TPIR groups, but not in the PIC and ELV groups.

Conclusions

AS parameters changed differently in the 4 groups. The effects of LI on AOD also differed among groups. Identification of the angle-closure mechanism may help predict progressive changes in AS parameters in eyes with angle closure.

Section snippets

Subjects

We consecutively reviewed the medical records of patients with eyes having the entire spectrum of angle closure (including PACS/PAC/PACG) who initially visited the glaucoma clinic of Asan Medical Center, Seoul, South Korea, between January 1, 2008 and December 31, 2015, and met the inclusion criteria listed below. This retrospective, longitudinal, observational study was approved by the Institutional Review Board of Asan Medical Center and followed the tenets of the Declaration of Helsinki.

All

Results

One hundred sixty-eight eyes (from 88 participants) met the initial inclusion criteria. Among them, 16 eyes (9.5%) were excluded owing to undetectable or ambiguous SS, similar to a previous study.13 Among the 152 remaining eyes, 19 eyes were excluded owing to discrepancies between the 2 graders regarding the angle-closure mechanisms. For 10 eyes, 1 grader classified the mechanism as PB and the other grader as ELV. For 4 eyes, 1 grader classified the mechanism as PIC and the other grader as

Discussion

In our cohort of eyes with angle closure, PB was the most common mechanism of angle closure, accounting for about 35%, followed by TPIR (26%), PIC (23%), and ELV (17%). However, we should not overlook the possibility that multiple angle-closure mechanisms can simultaneously contribute to angle closure, as proven before.19, 20 According to our previous studies, in which we divided angle-closure eyes into 2 categories,2, 8, 16 the PB group had shallower ACD, higher LV, and relatively narrower

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