ORIGINAL STUDY
Prevalence of Angle Closure in Siblings of Patients With Primary Angle-closure Glaucoma Shahin Yazdani, MD,* Shadi Akbarian, MSc,*w Mohammad Pakravan, MD,* and Mohsen Afrouzifar, MD*
Purpose: To determine the frequency of angle closure in siblings of patients with primary angle-closure glaucoma (PACG). Methods: In this cross-sectional observational study, siblings of consecutive patients with PACG underwent a comprehensive ophthalmologic examination, including slit-lamp biomicroscopy, measurement of intraocular pressure, stereoscopic optic nerve head examination, and dynamic gonioscopy. Ultrasonic pachymetry was obtained in all subjects; peripapillary retinal nerve fiber layer thickness measurement by optical coherence tomography and standard achromatic perimetry were performed in subjects with angle closure, categorized as primary angle-closure suspect (PACS), primary angle closure (PAC), and PACG, or any suspicion of glaucoma in the presence of open angles. Results: Overall, 95 siblings from 47 families with at least 1 subject affected with PACG participated in the evaluations; 55 (57.9%) individuals were categorized within the spectrum of angle closure, including 34 (35.8%) subjects with PACS, 7 (7.4%)individuals with PAC, and 14 (14.7%) cases of PACG. Nine (9.5%) individuals with open angles demonstrated other abnormal features, these included 3 (3.2%) subjects with suspicious discs, 5 (5.3%) cases of primary open-angle glaucoma, and 1 patient (1.1%) with normal-tension glaucoma. The remaining 31 individuals (32.6%) had no evidence of glaucoma. Conclusions: Our findings indicate familial segregation of angle closure. Siblings of PACG patients are at high risk for the condition, such that two thirds of them demonstrate clinical findings related to glaucoma. These observations suggest a hereditary basis for angle closure; therefore, siblings of patients affected with angle closure should undergo targeted screening for glaucoma. Key Words: prevalence, primary angle closure glaucoma, sibling
(J Glaucoma 2015;24:149–153)
patients.2 The Nottingham family glaucoma screening study reported the prevalence of POAG in siblings of PACG patients to be 11.8% and the Barbados family study revealed it to be 19.8%.3,4 These reports have supported the notion that POAG is a familial disease with considerable risk among first-degree relatives. Although primary angle-closure glaucoma (PACG) is less prevalent than POAG globally, it more frequently leads to blindness. PACG has been more extensively studied in East Asians, Indians, Chinese, and recently in Singaporeans, demonstrating a positive family history in these geographical regions.5–11 Heritability rates of 20% and 60% have been reported in siblings of PACG patients of white descent, and in residents of Singapore, including subjects of Chinese, Malay, and Indian origin.9,11 Overall, it is believed that firstdegree relatives of subjects with PACG are at 3 to 6 times higher risk of the condition than the general population.12–16 The current study selected a group of consecutive Iranian patients with PACG, and examined their siblings to determine the frequency of angle closure among them.
METHODS Case Selection The study was conducted at Labbafinejad Medical Center, Tehran, Iran. Subjects older than 50 years of age who had been diagnosed with PACG were considered as index cases. Siblings over 40 years of age were invited to participate; to avoid overrepresentation from particular families, a maximum of 4 phakic siblings from each family with
Prevalence of Angle Closure in Siblings of Patients With Primary Angle-closure Glaucoma Shahin Yazdani, MD,* Shadi Akbarian, MSc,*w Mohammad Pakravan, MD,* and Mohsen Afrouzifar, MD*
Purpose: To determine the frequency of angle closure in siblings of patients with primary angle-closure glaucoma (PACG). Methods: In this cross-sectional observational study, siblings of consecutive patients with PACG underwent a comprehensive ophthalmologic examination, including slit-lamp biomicroscopy, measurement of intraocular pressure, stereoscopic optic nerve head examination, and dynamic gonioscopy. Ultrasonic pachymetry was obtained in all subjects; peripapillary retinal nerve fiber layer thickness measurement by optical coherence tomography and standard achromatic perimetry were performed in subjects with angle closure, categorized as primary angle-closure suspect (PACS), primary angle closure (PAC), and PACG, or any suspicion of glaucoma in the presence of open angles. Results: Overall, 95 siblings from 47 families with at least 1 subject affected with PACG participated in the evaluations; 55 (57.9%) individuals were categorized within the spectrum of angle closure, including 34 (35.8%) subjects with PACS, 7 (7.4%)individuals with PAC, and 14 (14.7%) cases of PACG. Nine (9.5%) individuals with open angles demonstrated other abnormal features, these included 3 (3.2%) subjects with suspicious discs, 5 (5.3%) cases of primary open-angle glaucoma, and 1 patient (1.1%) with normal-tension glaucoma. The remaining 31 individuals (32.6%) had no evidence of glaucoma. Conclusions: Our findings indicate familial segregation of angle closure. Siblings of PACG patients are at high risk for the condition, such that two thirds of them demonstrate clinical findings related to glaucoma. These observations suggest a hereditary basis for angle closure; therefore, siblings of patients affected with angle closure should undergo targeted screening for glaucoma. Key Words: prevalence, primary angle closure glaucoma, sibling
(J Glaucoma 2015;24:149–153)
patients.2 The Nottingham family glaucoma screening study reported the prevalence of POAG in siblings of PACG patients to be 11.8% and the Barbados family study revealed it to be 19.8%.3,4 These reports have supported the notion that POAG is a familial disease with considerable risk among first-degree relatives. Although primary angle-closure glaucoma (PACG) is less prevalent than POAG globally, it more frequently leads to blindness. PACG has been more extensively studied in East Asians, Indians, Chinese, and recently in Singaporeans, demonstrating a positive family history in these geographical regions.5–11 Heritability rates of 20% and 60% have been reported in siblings of PACG patients of white descent, and in residents of Singapore, including subjects of Chinese, Malay, and Indian origin.9,11 Overall, it is believed that firstdegree relatives of subjects with PACG are at 3 to 6 times higher risk of the condition than the general population.12–16 The current study selected a group of consecutive Iranian patients with PACG, and examined their siblings to determine the frequency of angle closure among them.
METHODS Case Selection The study was conducted at Labbafinejad Medical Center, Tehran, Iran. Subjects older than 50 years of age who had been diagnosed with PACG were considered as index cases. Siblings over 40 years of age were invited to participate; to avoid overrepresentation from particular families, a maximum of 4 phakic siblings from each family with
