*Department of Ophthalmology, University of California, San Francisco School of Medicine, San Francisco, CA †State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China ‡Department of Ophthalmology, Cathay General Hospital, Taipei, Taiwan.
J Glaucoma. 2013 Dec;22(9):673-8. doi: 10.1097/IJG.0b013e318264ba68.
To evaluate the capability of iris thickness parameters to explain the difference in primary angle-closure glaucoma prevalence among the different racial groups.
In this prospective study, 436 patients with open and narrow angles that met inclusion criteria were consecutively recruited from the UCSF general ophthalmology and glaucoma clinics to receive anterior segment optical coherence tomography imaging under standardized dark conditions. Images from 11 patients were removed due to poor visibility of the scleral spurs and the remaining images were analyzed using the Zhongshan Angle Assessment Program to assess the following measurements for the nasal and temporal angle of the anterior chamber: iris thickness at 750 and 2000 μm from the scleral spurs and the maximum iris thickness at middle one third of the iris. Iris thickness parameters were compared among and within the following 5 different racial groups: African Americans, Caucasian Americans, Hispanic Americans, Chinese Americans, and Filipino-Americans.
In comparing iris parameters among the open-angle racial groups, significant differences were found for nasal iris thickness at 750 and 2000 μm from the scleral spurs in which Chinese Americans displayed the highest mean value (P=0.01, P<0.0001). Among the narrow-angle racial groups, significant difference was found for nasal iris thickness at 2000 μm from the scleral in which Chinese Americans showed the highest mean value (P<0.0001). Significant difference was also found for temporal maximum iris thickness at middle one third of the iris in which African Americans exhibited the highest mean value (P=0.021). Iris thickness was modeled as a function of angle status using linear mixed-effects regression, adjusting for age, sex, pupil diameter, spherical equivalent, ethnicity, and the use of both eyes in patients. The iris thickness difference between the narrow-angle and open-angle groups was significant (P=0.0007).
Racial groups that historically showed higher prevalence of primary angle-closure glaucoma possess thicker irides.
评估虹膜厚度参数解释不同种族原发性闭角型青光眼患病率差异的能力。
在这项前瞻性研究中，连续招募了来自 UCSF 普通眼科和青光眼诊所的 436 名具有开放和狭窄角度且符合纳入标准的患者，在标准化暗室条件下接受眼前节光学相干断层扫描成像。由于巩膜刺的可视性差，11 名患者的图像被删除，其余图像使用中山角评估程序进行分析，以评估前房鼻侧和颞侧的以下测量值：巩膜刺 750μm 和 2000μm 处的虹膜厚度以及虹膜中部三分之一处的最大虹膜厚度。在以下 5 个不同种族组（非裔美国人、白种人、西班牙裔美国人、美籍华人、菲律宾裔美国人）之间和内部比较虹膜厚度参数。
在比较开放角种族组的虹膜参数时，发现巩膜刺 750μm 和 2000μm 处的鼻侧虹膜厚度存在显著差异，其中美籍华人的平均值最高（P=0.01，P<0.0001）。在窄角种族组中，发现巩膜刺 2000μm 处的鼻侧虹膜厚度存在显著差异，其中美籍华人的平均值最高（P<0.0001）。在虹膜中部三分之一处的颞侧最大虹膜厚度也存在显著差异，其中非裔美国人的平均值最高（P=0.021）。使用线性混合效应回归，根据年龄、性别、瞳孔直径、等效球镜、种族以及患者双眼的使用情况，将虹膜厚度建模为角度状态的函数。窄角组和开角组之间的虹膜厚度差异具有统计学意义（P=0.0007）。
历史上原发性闭角型青光眼患病率较高的种族群体拥有更厚的虹膜。
