Objectives: To study the prevalence of glaucoma in first-generation relatives (FGRs) of patients with primary open angle glaucoma (POAG), and to identify the likelihood of family history as a risk factor for the presence of POAG. Methods: In this case control study, 290 FGRs of 99 patients who were diagnosed
with POAG in West China Hospital from February 2012 to October 2013 were enrolled (POAG-related group). FGRs (n=355) of 105 cataract patients were also enrolled (control group). Both groups were matched for sex and age (40 years or older). All participants were asked to complete a questionnaireand undergo a comprehensive eye examination. A chi-square test, t-test, and multiple logistic regression analysis were used to analyze the data. Results: The FGRs of patients with POAG had a greater prevalence of glaucoma than the controls (10.7% vs. 1.4%, χ 2=26.090, P<0.001). There was a greater prevalence of glaucoma in females (11.7% vs. 1.6%, χ 2=15.203, P<0.001) and in males (9.8% vs. 1.2%, χ 2=11.098, P<0.001) in the FGRs of patients with POAG compared with the controls. For three different age groups, <50,50-59, and ≥ 70 years of age, the FGRs of patients with POAG had a greater prevalence of glaucoma than did the controls (χ 2=14.328, 4.919, 6.959, P<0.05). The calculated odds ratio (OR) for the characteristics associated with glaucoma were strong when adjusted for age and gender [OR=8.45 (95% confidence interval: 3.24-22.06)], and offspring [OR=11.53 (95% confidence interval: 2.45-54.26)] had an obvious association with POAG. Most of the FGRs of patients with POAG, 92.1%, had no awareness of the need for glaucoma screening. Conclusions: Our study shows that the FGRs of patients with POAG are at high risk for having POAG, and a family history of glaucoma is associated with the presence of glaucoma. The FGRsof patients with POAG should be made more aware of the need for glaucoma screening.