Abstract
Purpose:
To compare the impact of laser iridotomy on anterior chamber configuration in patients with: (1) suspect primary angle closure (PACS), and (2) either primary angle closure or primary angle closure glaucoma (PAC/PACG).
Methods:
Patients with PACS or PAC/PACG were recruited from the Aravind Eye Hospital in Pondicherry, India. All patients underwent baseline anterior segment OCT (AS-OCT) analysis, and AS-OCT was repeated immediately after laser iridotomy (LPI). Scleral spur location was marked by a masked grader, and markings were used to calculate anterior chamber parameters including anterior chamber volume, lens vault, angle opening distance at 500 microns (AOD), trabecular iris space area at 500 microns (TISA), and anterior chamber depth. Changes in anterior chambers resulting from LPI were compared in the PACS and PAC/PACG groups.
Results:
A total of 321 eyes from 321 patients were evaluated, including 204 PACS and 117 PAC/PACG eyes. LPI was associated with increases in anterior chamber volume in both PACS eyes (+5.4 mm3, p<0.001) and PAC/PACG eyes (+5.8 mm3, p<0.001). Lens vault was observed to increase in PACS eyes (+31 microns, 95% CI = +1 to +51 microns, p=0.002), but not in PAC/PACG eyes (-21 microns, 95% CI = -68 to +27 microns, p=0.4). No significant LPI-associated changes were observed in either the PACS or PAC/PACG group with respect to anterior chamber depth, AOD, and TISA (p>0.05 for all). The magnitude of LPI-induced changes in anterior chamber depth, anterior chamber volume, AOD, and TISA did not differ between PACS and PAC/PACG eyes (p>0.1 for all). Differences were noted in the magnitude of LPI-induced change in lens vault observed for PACS and PAC/PACG eyes (p<0.001).
Conclusions:
Suspect angle closure (PACS) eyes and eyes with either PAC or PACG both demonstrate increases in anterior chamber volume with LPI, though only PACS eyes demonstrate increased lens vault with LPI. Further work, including detailed examination of iris configuration, is necessary to understand the mechanism behind these LPI-induced changes, and to understand why these changes differ with the stage of angle closure glaucoma.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
421 anterior segment