Roland Y Lee1, Toshimitsu Kasuga2, Qi N Cui1, Travis C Porco1, Guofu Huang3, Mingguang He4, Shan C Lin5. 1. Department of Ophthalmology, University of California, San Francisco, California. 2. Department of Ophthalmology, University of California, San Francisco, California; Department of Ophthalmology, Juntendo University School of Medicine, Tokyo, Japan. 3. Department of Ophthalmology, University of California, San Francisco, California; Department of Ophthalmology, Nanchang University, Nanchang, Jiangxi Province, China. 4. Department of Ophthalmology, University of California, San Francisco, California; State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yatsen University, Guangzhou, China. 5. Department of Ophthalmology, University of California, San Francisco, California. Electronic address: LinS@vision.ucsf.edu.
Abstract
OBJECTIVE: To evaluate the association between baseline measurements of iris thickness at 3 positions and change in anterior segment biometric parameters after prophylactic laser peripheral iridotomy (LPI). DESIGN: Prospective clinical cohort study. PARTICIPANTS: Fifty-two eyes of 52 nonglaucomatous subjects with anatomically narrow angles. METHODS: Anterior segment optical coherence tomography (ASOCT) images captured before and after LPI were analyzed using customized software, the Zhongshan Angle Assessment Program (ZAAP) (Zhongshan Ophthalmic Centre, Guangzhou, China). Differences in preoperative and postoperative measurements for anterior segment biometric parameters were compared by paired Student t tests. Multivariate linear regression models, adjusted for age, sex, ethnicity, and preoperative pupil diameter, were used to examine the association between the baseline measurements of iris thickness at 3 positions and the change in anterior segment biometric parameters after LPI. MAIN OUTCOME MEASURES: Baseline iris thickness measured at 750 μm from the scleral spur (IT750), iris thickness measured at 2000 μm from the scleral spur (IT2000), and maximal iris thickness (ITM). Changes in iris curvature (ICURV) and trabecular-iris space area at 500 μm from the scleral spur (TISA500) and 750 μm from the scleral spur (TISA750) after LPI. RESULTS: The ICURV significantly decreased, whereas TISA500 and TISA750 significantly increased after LPI (all P < 0.0001). Lower baseline IT750 was significantly associated with greater postoperative increases in TISA500 and TISA750 (both P < 0.05). Lower baseline IT2000 and ITM were significantly associated with greater postoperative decrease in ICURV (both P < 0.05). CONCLUSIONS: Our results showed that lower baseline measurements of iris thickness are associated with greater decrease in ICURV and increases in TISA500 and TISA750 after LPI. This suggests that eyes with thinner irides undergoing LPI were more likely to exhibit greater magnitude of change in terms of flattening of the iris convexity (i.e., ICURV) and widening of the anterior chamber angle (i.e., TISA500 and TISA750).
OBJECTIVE: To evaluate the association between baseline measurements of iris thickness at 3 positions and change in anterior segment biometric parameters after prophylactic laser peripheral iridotomy (LPI). DESIGN: Prospective clinical cohort study. PARTICIPANTS: Fifty-two eyes of 52 nonglaucomatous subjects with anatomically narrow angles. METHODS: Anterior segment optical coherence tomography (ASOCT) images captured before and after LPI were analyzed using customized software, the Zhongshan Angle Assessment Program (ZAAP) (Zhongshan Ophthalmic Centre, Guangzhou, China). Differences in preoperative and postoperative measurements for anterior segment biometric parameters were compared by paired Student t tests. Multivariate linear regression models, adjusted for age, sex, ethnicity, and preoperative pupil diameter, were used to examine the association between the baseline measurements of iris thickness at 3 positions and the change in anterior segment biometric parameters after LPI. MAIN OUTCOME MEASURES: Baseline iris thickness measured at 750 μm from the scleral spur (IT750), iris thickness measured at 2000 μm from the scleral spur (IT2000), and maximal iris thickness (ITM). Changes in iris curvature (ICURV) and trabecular-iris space area at 500 μm from the scleral spur (TISA500) and 750 μm from the scleral spur (TISA750) after LPI. RESULTS: The ICURV significantly decreased, whereas TISA500 and TISA750 significantly increased after LPI (all P < 0.0001). Lower baseline IT750 was significantly associated with greater postoperative increases in TISA500 and TISA750 (both P < 0.05). Lower baseline IT2000 and ITM were significantly associated with greater postoperative decrease in ICURV (both P < 0.05). CONCLUSIONS: Our results showed that lower baseline measurements of iris thickness are associated with greater decrease in ICURV and increases in TISA500 and TISA750 after LPI. This suggests that eyes with thinner irides undergoing LPI were more likely to exhibit greater magnitude of change in terms of flattening of the iris convexity (i.e., ICURV) and widening of the anterior chamber angle (i.e., TISA500 and TISA750).
Authors: Carol Yim-lui Cheung; Shu Liu; Robert N Weinreb; Jing Liu; Haitao Li; Dexter Yu-lung Leung; Syril Dorairaj; Jeffrey Liebmann; Robert Ritch; Dennis Shun Chiu Lam; Christopher Kai-shun Leung Journal: Invest Ophthalmol Vis Sci Date: 2010-03-17 Impact factor: 4.799
Authors: Sunita Radhakrishnan; Jason Goldsmith; David Huang; Volker Westphal; David K Dueker; Andrew M Rollins; Joseph A Izatt; Scott D Smith Journal: Arch Ophthalmol Date: 2005-08
Authors: Nishani Amerasinghe; Paul J Foster; Tien Yin Wong; Hla Myint Htoon; Mingguang He; Sunny Y Shen; Han T Aung; Seang-Mei Saw; Tin Aung Journal: Invest Ophthalmol Vis Sci Date: 2009-01-31 Impact factor: 4.799
Authors: Michael I Seider; Melike Pekmezci; Ying Han; Simi Sandhu; Shiu Y Kwok; Roland Y Lee; Shan C Lin Journal: J Glaucoma Date: 2009 Oct-Nov Impact factor: 2.503
Authors: Seema Kansara; Lauren S Blieden; Alice Z Chuang; Laura A Baker; Nicholas P Bell; Kimberly A Mankiewicz; Robert M Feldman Journal: J Glaucoma Date: 2016-05 Impact factor: 2.503
Authors: Anna I Dastiridou; Xiaojing Pan; ZhouYuan Zhang; Kenneth M Marion; Brian A Francis; Srinivas R Sadda; Vikas Chopra Journal: J Ophthalmol Date: 2015-03-23 Impact factor: 1.909