Purpose: Progressive glaucomatous optic neuropathy is an asymptomatic process with an insidious onset. Patients who are aware of glaucomatous signs and who suspect that they may have the disease may present earlier. If a person has glaucoma, this may alert his or her other family members to seek assessment and thereby permit earlier diagnosis. The authors sought to determine whether glaucoma patients with a family history of the disease were younger and showed less evidence of glaucomatous optic neuropathy at diagnosis than glaucoma patients without a family history of the disease. Patients and Methods: Family history of glaucoma, age at diagnosis, and visual field mean defect within 2 years after diagnosis were recorded in 292 patients with primary open-angle glaucoma. Results were analyzed to compare visual field loss with age and family history. Results: At diagnosis, patients with a family history of glaucoma were younger than those without such a history (mean ± SD, 58 ± 12.7 years versus 63 ± 10.8 years; t = 3.68, P<0.001). Patients who were younger than 50 years at the time of diagnosis and had a positive family history were significantly less likely to have a worse visual field than those with a negative family history (OR = 0.3; 95% CI, 0.1-0.6; P<0.001), whereas those aged 50 years or older showed no such correlation (OR = 0.9; 95% CI, 0.7-1.3; P = 0.6). Conclusion: A family history of glaucoma was associated with a better visual field at diagnosis in patients younger than 50 years, but not in patients 50 years or older.