Iris Ischemic Changes And Visual Outcome After Acute Primary Angle Closure

Abstract

Abstract: : Purpose:Ischemic changes in the iris occur frequently after an attack of acute primary angle closure (APAC). The aim of this study was to investigate the significance of such changes with regards to visual outcome. Methods:APAC cases were treated with medical therapy followed by laser peripheral iridotomy (LPI) after resolution of the acute episode. Subjects were examined at 1, 4, 8, 12 and 16 weeks post–LPI. At each visit, visual acuity, slit–lamp examination, ophthalmoscopy, intraocular pressure (IOP) measurement and automated white–on–white threshold perimetry were performed. Affected eyes were examined specifically for signs of iris ischemic changes (IIC), defined as the presence of identifiable areas of iris whorling or stromal atrophy. Iris photographs were also taken on Week 1, 8 and 16. Results:Sixty–one subjects with APAC completed the study. The majority of subjects were female (82%) and Chinese (92%), and the mean age was 59 ± 8.8 years. More than half the subjects (52.5%) were found to have developed IIC during the study, 65% of whom already had signs of IIC by the first week. There were 13 subjects (41%) with IIC and 6 subjects (21%) without IIC who had significant glaucomatous visual field defects (p=0.09) at Week 16. There was no difference in final visual acuity between groups, the majority of subjects in both groups having visual acuity of 6/12 or better. High presenting IOP (>60 mm Hg) was found to be a risk factor for developing IIC, but duration of symptoms, the number of days from presentation to LPI and a history of hypertension or diabetes mellitus were not associated with IIC. Conclusions:After APAC, iris ischemic changes were found to develop in more than half of cases but the presence of IIC did not correlate with a poorer visual outcome.

Keywords: visual fields • imaging/image analysis: clinical