Importance: Retinopathy of prematurity (ROP) can cause severe visual disability even in high-resource settings. A better understanding of the prevalence and processes leading to ROP-induced severe visual impairment may help health care professionals design preventive measures.
Objectives: To determine the prevalence of severe visual disability among children born preterm in Sweden, evaluate adherence to best practice, and determine the health system's structural capacity.
Design, setting, and participants: Population-based, nationwide cohort study of 1 310 227 children born between January 1, 2004, and December 31, 2015, in Sweden, of whom 17 588 (1.3%) were born very preterm (<32 weeks of gestation). Children born preterm with a verified diagnosis of severe visual disability had their medical records reviewed for evaluation of ROP screening, diagnosis, and treatment. In addition, a questionnaire on structural capacity was sent to all ophthalmology departments.
Exposures: Stages 4 and 5 ROP.
Main outcomes and measures: The primary outcome was prevalence of severe visual disability (visual acuity ≤20/200 for both eyes) associated with ROP stages 4 and 5. Secondary outcomes included adherence to national ROP guidelines using a predefined protocol with 15 key performance indicators for screening, diagnosis, and treatment; assessment of whether visual disability was deemed avoidable; and examination of structural capacity, including information on equipment and facilities, staffing, and patients.
Results: Seventeen children (10 boys; mean [range] birth weight, 756 [454-1900] g; mean [range] gestational age, 25 [22-33] weeks) became severely visually disabled because of ROP, corresponding to a prevalence of 1 in 1000 very preterm infants (<32 weeks of gestational age) and 1 in 77 000 for all live births. Severe visual impairment was considered potentially avoidable in 11 of 17 affected children (65%) owing to untimely or no screening, missed diagnosis, or untimely and suboptimal treatment. Large variations in infrastructure (facilities, guidelines, staffing, and annual patient numbers) were also identified as potential contributors to these findings.
Conclusions and relevance: Retinopathy of prematurity still causes severe visual disability in Sweden, resulting in 1 affected infant per 1000 very preterm births. In most of these infants, noncompliance with best practice was identified, indicating that a significant proportion could have been avoided.