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Qinyun Wang, Yen C Hsia, Claudio Ignacio Perez, Max Feinstein, Marisse Masis, Marta Mora, Shan C Lin; Post-phacoemulsification iris changes in glaucomatous and nonglaucomatous eyes.. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5885.
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© ARVO (1962-2015); The Authors (2016-present)
Anterior segment optical coherence tomography (AS-OCT) has become an increasingly useful imaging tool in glaucoma research, particularly in the investigation of how phacoemulsification impacts anterior segment parameters. In this prospective study, AS-OCT was used to determine how phacoemulsification changes various iris parameters in eyes with and without glaucoma.
Using a Visante AS-OCT device (Carl Zeiss Meditec AG), the following iris parameters were measured at baseline and at post-operative month 6: IT750 = iris thickness measured 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; and IAREA = iris area. Only high-quality images with an identifiable scleral spur were included, and only the nasal quadrant was analyzed, as the other quadrants may have been distorted by eyelid manipulation or phacoemulsification trauma. A single glaucoma specialist analyzed the iris parameters according to established protocols using the Zhongshan Angle Assessment Program (ZAAP, Guangzhou, China). Multivariate analysis was subsequently performed using mixed effects regression correcting for age, gender, and ethnicity. Of note, phacoemulsification was performed by the same surgeon using standard techniques, with placement of a standard single piece intraocular lens (IOL, Acrysof SN60AT, Alcon Laboratories, Inc).
67 eyes of 66 patients were enrolled. The mean age of the patients was 76.05 ± 9.17 years old. Diagnoses included normal tension glaucoma (NTG), primary angle closure glaucoma (PACG), primary open angle glaucoma (POAG), pseudoexfoliation glaucoma (PXG), and glaucoma suspect; glaucoma suspects accounted for 57.41% of patients. In multivariate analysis of post-operative month 6 iris parameters compared to pre-operative values, changes in IT750 (β=1.05; 95% CI = 0.79, 1.31; p-value < 0.005), IT2000 (β=1.36; 95% CI = 1.01, 1.71; p-value < 0.005), ITCM (β=0.87; 95% CI = 0.72, 1.04; p-value = < 0.005), and IAREA (β=0.70; 95% CI = 0.50, 0.90; p-value < 0.005) were found to be statistically significant in all eyes (Table 1).
After phacoemulsification, eyes with and without glaucoma undergo statistically significant decreases in iris thickness and iris area as measured by AS-OCT.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
Multivariate analysis of pre and post-operative iris changes.
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