Monisha E Nongpiur1, Sushma Verma2, Tin A Tun2, Tina T Wong1, Shamira A Perera3, Tin Aung4. 1. Singapore Eye Research Institute, Singapore; Singapore National Eye Centre, Singapore; Duke-National University of Singapore Medical School, Singapore. 2. Singapore Eye Research Institute, Singapore. 3. Singapore National Eye Centre, Singapore; Duke-National University of Singapore Medical School, Singapore. 4. Singapore Eye Research Institute, Singapore; Singapore National Eye Centre, Singapore; Duke-National University of Singapore Medical School, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. Electronic address: aung.tin@singhealth.com.sg.
Abstract
PURPOSE: To compare the distribution of plateau iris in eyes across varying severity of primary angle closure glaucoma (PACG) using standardized ultrasound biomicroscopy (UBM) criteria. DESIGN: Cross-sectional study. METHODS: UBM was performed on 210 patients with PACG who had previously undergone laser peripheral iridotomy. Plateau iris was defined as the presence of all the following UBM criteria in ≥2 quadrants of the angle: anteriorly directed ciliary body, absent ciliary sulcus, iris angulation, flat iris plane, and iridotrabecular contact. Disease severity was based on the visual field mean deviation (MD) and classified as early-to-moderate (MD ≥ -12 dB), advanced (-12.01 dB to -20 dB), and severe (MD < -20 dB). RESULTS: Of 210 subjects recruited, 23 were excluded because of poor quality UBM images. The remaining 187 patients were categorized as having early-to-moderate (n = 103), advanced (n = 38), and severe PACG (n = 46). Of these subjects, 48.1% were male, and 90.9% were of Chinese ethnicity. The overall proportion of plateau iris was 36.9%, with 32.0% (33/103) in early-to-moderate, 34.2% (13/38) in advanced, and 50% (23/46) in severe PACG (P = .03, comparing severe PACG with early-to-moderate groups). Among the severe PACG group, those with plateau iris configuration had significantly smaller anterior chamber area (P = .03) and volume (P = .01) compared with those without plateau iris. CONCLUSION: The higher proportion of plateau iris configuration in eyes with severe PACG compared with early-to-moderate PACG suggest that this may be a contributory factor for disease severity.
PURPOSE: To compare the distribution of plateau iris in eyes across varying severity of primary angle closure glaucoma (PACG) using standardized ultrasound biomicroscopy (UBM) criteria. DESIGN: Cross-sectional study. METHODS: UBM was performed on 210 patients with PACG who had previously undergone laser peripheral iridotomy. Plateau iris was defined as the presence of all the following UBM criteria in ≥2 quadrants of the angle: anteriorly directed ciliary body, absent ciliary sulcus, iris angulation, flat iris plane, and iridotrabecular contact. Disease severity was based on the visual field mean deviation (MD) and classified as early-to-moderate (MD ≥ -12 dB), advanced (-12.01 dB to -20 dB), and severe (MD < -20 dB). RESULTS: Of 210 subjects recruited, 23 were excluded because of poor quality UBM images. The remaining 187 patients were categorized as having early-to-moderate (n = 103), advanced (n = 38), and severe PACG (n = 46). Of these subjects, 48.1% were male, and 90.9% were of Chinese ethnicity. The overall proportion of plateau iris was 36.9%, with 32.0% (33/103) in early-to-moderate, 34.2% (13/38) in advanced, and 50% (23/46) in severe PACG (P = .03, comparing severe PACG with early-to-moderate groups). Among the severe PACG group, those with plateau iris configuration had significantly smaller anterior chamber area (P = .03) and volume (P = .01) compared with those without plateau iris. CONCLUSION: The higher proportion of plateau iris configuration in eyes with severe PACG compared with early-to-moderate PACG suggest that this may be a contributory factor for disease severity.