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PURPOSE: We studied the association between dynamic iris changes and the spectrum of primary angle closure disease (PACD), using the anterior segment optical coherence tomography (ASOCT). METHODS: Eligible primary angle closure (PAC), primary angle closure glaucoma (PACG), age, and sex comparable primary angle closure suspects (PACS) and normal subjects from the 5-year follow-up of the Handan Eye Study underwent ASOCT testing in dark and light conditions. The right eye of each subject was analyzed and biometric parameters including iris cross-sectional area (IA), lens vault (LV), pupil diameter (PD), and centroid-to-centroid distance (CCD) were calculated using the Zhongshan Angle Assessment Program. RESULTS: Totals of 31 PACS, 31 PAC/PACG, and 31 normal eyes were eligible for analysis. Loss of IA per mm PD increase in the dark compared to light was 0.18 mm in PACS, 0.13 mm in PAC/PACG, and 0.24 mm in normal (P = 0.015 between groups) groups. Diagnoses of normal (P = 0.001) and a smaller PD in light (P = 0.003) were statistically significant determinants of a larger IA loss per mm PD increase in the dark compared to light. Logistic regression analysis showed that LV (P = 0.002) and IA loss per mm PD increase (P = 0.017) were risk factors for an occludable angle. CONCLUSIONS: Significant differences in iris behavior in the dark compared to light in PACS, PACD, and normal eyes add to the evidence that dynamic iris change has a role in the pathogenesis of PAC in a rural Chinese population.
Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Lab, Beijing, China.
Full article9.3.1 Acute primary angle closure glaucoma (pupillary block) (Part of: 9 Clinical forms of glaucomas > 9.3 Primary angle closure glaucomas)
6.9.2.1 Anterior (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.2 Optical coherence tomography)
2.8 Iris (Part of: 2 Anatomical structures in glaucoma)
9.3.5 Primary angle closure (Part of: 9 Clinical forms of glaucomas > 9.3 Primary angle closure glaucomas)