Purpose:
To compare angle width in west african eyes with primary angle closure before and after laser iridotomy using slit-lamp based anterior segment optical coherence tomography (SL-OCT)
Methods:
Subjects diagnosed with appositional angle closure on gonioscopy during a population-based survey in Ghana were offered treatment with sequential Argon/YAG laser iridotomy. Anterior segment OCT images of the nasal and temporal angles were obtained in dim lighting conditions using the SL-OCT prior to and following iridotomy. The following angle parameters were measured for each angle quadrant using semi-automated software after observer identification of scleral spur on best quality scans: Anterior chamber angle and angle opening distance at 500 microns anterior to scleral spur (ACA500 and AOD500) and trabecular iris space area at 750 microns anterior to scleral spur (TISA750). The measurements for each eye pre and post-iridotomy were compared using paired t-test.
Results:
Eighteen right eyes of 18 subjects with angle closure underwent laser iridotomy. There was a significant increase in the angle width as measured by all three parameters for both nasal and temporal angles (see table)
Conclusions:
There is significant widening of the angle following iridotomy in West African subjects with primary angle closure when measured with anterior segment imaging. This suggests that pupil block plays a role in the mechanisms of angle closure in this African population.
Keywords: anterior segment • imaging/image analysis: clinical • laser