Background: The excess risk of bilateral visual impairment (BVI, bilateral visual acuity <0.5) among persons with amblyopia is an argument for screening for amblyopia. However, data are rare.
Methods: We estimated this risk by determining the incidence of BVI within The Rotterdam Study, a population-based cohort of subjects aged 55 years or over (n=5220), including 192 persons with amblyopia (3.7%). With a multi-state lifetable, the lifetime risk and excess period spent with BVI were determined.
Results: The relative risk of BVI for amblyopes was 2.6 (95% confidence interval 1.4-4.5). For amblyopic persons, the lifetime risk of BVI was 18% while they lived on average 7.2 years with BVI. For non-amblyopic persons, these figures were 10% and 6.7 years, respectively.
Conclusion: Amblyopia nearly doubles the life-time risk of BVI and affected persons spent an extra 6 months with BVI. This study provides data for future cost-effectiveness analyses.
- lifetime risk
- visual impairment