Sasan Moghimi1, Rebecca Chen2, Mohammadkarim Johari3, Faezeh Bijani3, Massood Mohammadi3, Alireza Khodabandeh3, Mingguang He4, Shan C Lin5. 1. Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran; Koret Vision Center, University of California, San Francisco Medical School, San Francisco, California. 2. Koret Vision Center, University of California, San Francisco Medical School, San Francisco, California. 3. Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. 4. Department of Ophthalmology, University of Melbourne, Melbourne, Australia. 5. Koret Vision Center, University of California, San Francisco Medical School, San Francisco, California. Electronic address: lins@vision.ucsf.edu.
Abstract
PURPOSE: To evaluate the anterior segment biometric changes measured by anterior segment optical coherence tomography (AS-OCT) in acute primary angle closure (APAC) after laser peripheral iridotomy (LPI). DESIGN: Prospective interventional study. METHODS: In this clinic-based study, 52 eyes of 52 patients with resolved APAC attack who underwent LPI were enrolled. Subjects underwent complete ophthalmic examination and AS-OCT imaging before and 6 weeks after LPI. Anterior chamber depth (ACD), anterior chamber area (ACA), iris thickness (IT), iris area, iris curvature, lens vault (LV), anterior vault, angle opening distance (AOD500, AOD750), and trabecular iris space area (TISA500, TISA750) were measured in qualified images and compared before and after LPI. A linear mixed-model analysis was performed for potential predictors of change in AOD750. Main outcome measure was change in AOD750 after LPI. RESULTS: The mean age of participants was 60.7 ± 9.2 years. Mean angle width (Shaffer grade) changed from 0.25 ± 0.34 at baseline to 1.22 ± 0.86 after LPI (P < .001). However, 25 nasal angles (48.0%) and 28 temporal angles (53%) had iridotrabecular contact after LPI. All angle parameters (AOD500, AOD750, TISA500, TISA750; P ≤ .03), ACD (P = .001), and ACA (P < .001) increased significantly after LPI. Iris curvature and LV were reduced (P = .01 for both) after LPI, but there was no significant change in IT and iris area. After multivariate analysis, pre-LPI AOD750 was the only factor associated with change in AOD750 (β = -0.992, P = .02). Exaggerated LV, defined as LV greater than one-third of the anterior vault (sum of LV and ACD), was present in 61.5% of the cases (32 eyes). The extent of change in angle parameters was not significantly different between groups with and without exaggerated LV after LPI. CONCLUSION: This study confirms that LPI results in a significant increase in the angle width, ACD, and ACA as well as flattening of the iris in APAC eyes. The extent of angle deepening is inversely related to baseline angle width. The lens shifts posteriorly after resolution of attack, especially in those with greater lens vault.
PURPOSE: To evaluate the anterior segment biometric changes measured by anterior segment optical coherence tomography (AS-OCT) in acute primary angle closure (APAC) after laser peripheral iridotomy (LPI). DESIGN: Prospective interventional study. METHODS: In this clinic-based study, 52 eyes of 52 patients with resolved APAC attack who underwent LPI were enrolled. Subjects underwent complete ophthalmic examination and AS-OCT imaging before and 6 weeks after LPI. Anterior chamber depth (ACD), anterior chamber area (ACA), iris thickness (IT), iris area, iris curvature, lens vault (LV), anterior vault, angle opening distance (AOD500, AOD750), and trabecular iris space area (TISA500, TISA750) were measured in qualified images and compared before and after LPI. A linear mixed-model analysis was performed for potential predictors of change in AOD750. Main outcome measure was change in AOD750 after LPI. RESULTS: The mean age of participants was 60.7 ± 9.2 years. Mean angle width (Shaffer grade) changed from 0.25 ± 0.34 at baseline to 1.22 ± 0.86 after LPI (P < .001). However, 25 nasal angles (48.0%) and 28 temporal angles (53%) had iridotrabecular contact after LPI. All angle parameters (AOD500, AOD750, TISA500, TISA750; P ≤ .03), ACD (P = .001), and ACA (P < .001) increased significantly after LPI. Iris curvature and LV were reduced (P = .01 for both) after LPI, but there was no significant change in IT and iris area. After multivariate analysis, pre-LPI AOD750 was the only factor associated with change in AOD750 (β = -0.992, P = .02). Exaggerated LV, defined as LV greater than one-third of the anterior vault (sum of LV and ACD), was present in 61.5% of the cases (32 eyes). The extent of change in angle parameters was not significantly different between groups with and without exaggerated LV after LPI. CONCLUSION: This study confirms that LPI results in a significant increase in the angle width, ACD, and ACA as well as flattening of the iris in APAC eyes. The extent of angle deepening is inversely related to baseline angle width. The lens shifts posteriorly after resolution of attack, especially in those with greater lens vault.
Authors: Sasan Moghimi; Ali Torkashvand; Massood Mohammadi; Mehdi Yaseri; Luke J Saunders; Shan C Lin; Robert N Weinreb Journal: PLoS One Date: 2018-07-23 Impact factor: 3.240
Authors: Anmol A Pardeshi; Abe E Song; Naim Lazkani; Xiaobin Xie; Alex Huang; Benjamin Y Xu Journal: Transl Vis Sci Technol Date: 2020-08-07 Impact factor: 3.283