Risk of Glaucoma with Parental History
If you have one parent with glaucoma, your risk of developing primary open-angle glaucoma (POAG) is approximately 9 times higher than someone without an affected first-degree relative, and this risk increases substantially if both parents or multiple family members are affected. 1
Quantified Familial Risk
The most robust evidence comes from the Rotterdam Eye Study, which physically examined all siblings and family members rather than relying on patient reports:
- 9.2-fold increased odds of having POAG if you have a first-degree relative (parent or sibling) with confirmed POAG 1
Additional population-based studies provide supporting evidence with slightly lower but still significant risk estimates:
- Baltimore Eye Survey: 1.92-fold increased odds for any first-degree relative with glaucoma 1
- Los Angeles Latino Eye Study (LALES): 2.85-fold increased odds for any first-degree relative with glaucoma 1
Risk Stratification by Number of Affected Relatives
The risk escalates dramatically with multiple affected family members:
- One sibling affected: 3.4-3.7 times higher odds 1
- Two or more siblings affected: 5-fold higher odds 1
- Multiple affected siblings (≥2): Standardized incidence ratio exceeding 20 2
Type-Specific Familial Risks
Different glaucoma subtypes carry varying familial risks:
- Primary open-angle glaucoma: Standardized incidence ratio of 3.25 2
- Primary angle-closure glaucoma: Standardized incidence ratio of 9.93 2
Important Clinical Caveats
Family history reporting is notoriously unreliable because approximately 75% of glaucoma cases remain undiagnosed in the general population. 1, 3 A "negative" family history should be documented as "no known family history" rather than definitively stating no family history exists. 3
Maternal inheritance patterns appear more significant than paternal in POAG—offspring are 6-7 times more likely to develop POAG when the maternal side has the disease compared to the paternal side. 4 This suggests possible cytoplasmic or mitochondrial factors in disease transmission. 4
Clinical Implications for Screening
Given these substantial risks, individuals with one or both parents affected by glaucoma should:
- Begin comprehensive ophthalmologic screening by age 40 (earlier for African Americans or Latinos) 1, 5
- Undergo regular IOP measurement, optic disc examination, and visual field testing 5
- Recognize that other modifiable risk factors (elevated IOP, thin central corneal thickness, diabetes, myopia) compound the familial risk 1, 5
The combination of family history with other risk factors creates multiplicative rather than additive risk, making vigilant screening essential for preventing irreversible vision loss. 5, 2