Risk of Glaucoma in Children of Affected Fathers
Children of a father with primary open-angle glaucoma have approximately a 9-fold increased risk of developing glaucoma compared to the general population, though the absolute lifetime risk translates to roughly 10-20% depending on ethnicity and other risk factors. 1, 2
Quantified Familial Risk
The most robust data comes from the Rotterdam Eye Study, which physically examined all siblings and found that individuals with any first-degree relative (parent or sibling) with confirmed POAG have 9.2-fold increased odds of developing the disease. 1, 2 This represents the gold standard because family members were actually examined rather than relying on patient reports.
Other population-based studies show more modest but still significant increases:
- Baltimore Eye Survey: 1.92-fold increased odds for any first-degree relative with glaucoma 1, 2
- Los Angeles Latino Eye Study: 2.85-fold increased odds for any first-degree relative 1, 2
The variation between studies (1.92 to 9.2-fold) reflects differences in methodology—studies that physically examined relatives found higher risk than those relying on patient reports. 1
Risk Stratification by Relationship Type
The type of affected relative matters significantly:
- Having an affected parent: 2.17-fold increased odds 3
- Having an affected sibling: 3.4 to 3.7-fold increased odds 1, 2
- Having two or more affected siblings: 5-fold increased odds 1, 2
Interestingly, one older study suggested maternal family history may confer 6-7 times greater risk than paternal history, though this finding has not been consistently replicated and may reflect reporting bias. 4
Absolute Risk Translation
While the relative risk is high, the absolute lifetime risk for a child with one affected parent is approximately 10-20%, depending on ethnicity and other risk factors. 5 This is derived from the baseline population prevalence of POAG (roughly 2-3% in most populations) multiplied by the 9.2-fold increased odds. 1
African Americans and Latinos face higher absolute risk because their baseline prevalence is already elevated, and glaucoma prevalence increases dramatically with age in these populations. 1
Critical Caveats About Family History Reporting
Approximately 75% of glaucoma cases remain undiagnosed in the general population, which means many children may have affected parents who don't know they have glaucoma. 2, 6 This substantially underestimates true familial risk when relying on patient-reported family history. 7
Recall bias significantly inflates reported associations—the Blue Mountains Eye Study found that previously diagnosed glaucoma patients were more likely to report positive family history (OR 4.2) compared to newly diagnosed cases (OR 2.4), suggesting that awareness of one's own diagnosis influences family history reporting. 7
Screening Recommendations for At-Risk Children
Children with an affected parent should begin comprehensive ophthalmologic screening by age 40, with measurements of intraocular pressure, optic disc examination, and visual field testing. 2, 6
Earlier screening is recommended for African Americans and Latinos given their higher baseline prevalence and earlier age of onset. 2
Screening accompanying first-degree relatives during clinic visits is cost-effective—one study found that examining relatives who accompanied POAG patients to appointments identified glaucoma in 8.2% and glaucoma suspects in 23% of screened individuals. 5
Additional Risk Factors That Modify Familial Risk
Beyond family history alone, age is the most important modifier—prevalence increases dramatically after age 60, particularly in African Americans and Latinos. 1
Other risk factors that compound familial risk include: