Post-phacoemulsification iris changes in eyes with glaucoma or glaucoma suspect status

Abstract

Purpose This prospective study used anterior segment optical coherence tomography (AS-OCT) to determine how phacoemulsification (phaco) changes iris parameters in eyes with glaucoma or glaucoma suspect status. Methods Using Visante AS-OCT (Carl Zeiss Meditec AG), the following pre- and post-phaco parameters were measured: IT750 = iris thickness at 750 μm from the scleral spur; IT2000 = iris thickness 2000 μm from the scleral spur; ITCM = the maximum iris thickness at the middle one third of the iris; ICURV = iris curvature; IAREA = iris area; and pupil size = pupil diameter (mm). Only high-quality images with an identifiable scleral spur were included, and only the nasal quadrant was analyzed. A single glaucoma specialist analyzed the parameters according to the Zhongshan Angle Assessment Program (ZAAP, Guangzhou, China). Multivariate analysis was performed using mixed effects regression correcting for age, gender, and ethnicity. Results 89 subjects and 110 eyes were included in this study. The mean age of subjects was 74.83 {+/-} 8.69 years old. Most common diagnoses were POAG and glaucoma suspect (23% and 52%, respectively), and 16% of subjects had an LPI. In multivariate analysis of AS-OCT parameters, decreases in IT750, IT2000, ITCM, ICURV, and pupil size were statistically significant (p<0.05). Conclusions After phacoemulsification, eyes with glaucoma as well as glaucoma suspect eyes have thinner irises and smaller pupils. This may lead to less iris-mediated aqueous outflow obstruction, providing support for early phacoemulsification glaucoma treatment. Translational relevance Our AS-OCT imaging findings may guide clinical practice as iris parameters become increasingly relevant in preoperative phaco planning.