Risk factors for amblyopia in the vision in preschoolers study
Maisie Pascual1, Jiayan Huang2, Maureen G Maguire2
1School of Biomedical Sciences, College of Medicine, Drexel University, Philadelphia, Pennsylvania.
Insights
Strabismus and significant refractive errors are key risk factors for unilateral amblyopia in preschoolers. Bilateral astigmatism and hyperopia increase the risk of bilateral amblyopia, underscoring the need for early detection.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Public Health
Background:
- Amblyopia, or
Purpose of the Study:
- To identify risk factors for unilateral and bilateral amblyopia in preschool-aged children.
- To validate findings from previous pediatric eye disease studies.
Main Methods:
- A multicenter, cross-sectional study involving 3869 Head Start preschoolers (ages 3-5).
- Comprehensive eye examinations including visual acuity (VA), cover testing, and cycloplegic retinoscopy.
- Logistic regression models were used to estimate odds ratios for amblyopia risk factors.
Main Results:
- Unilateral amblyopia (7.7%) and bilateral amblyopia (3.7%) were diagnosed. Strabismus and significant refractive errors (myopia, hyperopia, astigmatism, anisometropia) were independent risk factors for unilateral amblyopia.
- Bilateral hyperopia (≥2.0D) and astigmatism (≥1.0D) were associated with unilateral amblyopia. Bilateral hyperopia (≥3.0D) and astigmatism (≥1.0D) were independent risk factors for bilateral amblyopia, present in 76% of affected children.
Conclusions:
- Strabismus and refractive errors are significant risk factors for unilateral amblyopia.
- Bilateral astigmatism and hyperopia are identified as risk factors for bilateral amblyopia.
- Study findings corroborate previous research in pediatric eye diseases.
Objective:
To evaluate risk factors for unilateral amblyopia and for bilateral amblyopia in the Vision in Preschoolers (VIP) study.
Design:
Multicenter, cross-sectional study.
Participants:
Three- to 5-year-old Head Start preschoolers from 5 clinical centers, overrepresenting children with vision disorders.
Methods:
All children underwent comprehensive eye examinations, including threshold visual acuity (VA), cover testing, and cycloplegic retinoscopy, performed by VIP-certified optometrists and ophthalmologists who were experienced in providing care to children. Monocular threshold VA was tested using a single-surround HOTV letter protocol without correction, and retested with full cycloplegic correction when retest criteria were met. Unilateral amblyopia was defined as an interocular difference in best-corrected VA of 2 lines or more. Bilateral amblyopia was defined as best-corrected VA in each eye worse than 20/50 for 3-year-olds and worse than 20/40 for 4- to 5-year-olds.
Main Outcome Measures:
Risk of amblyopia was summarized by the odds ratios and their 95% confidence intervals estimated from logistic regression models.
Results:
In this enriched sample of Head Start children (n = 3869), 296 children (7.7%) had unilateral amblyopia, and 144 children (3.7%) had bilateral amblyopia. Presence of strabismus (P<0.0001) and greater magnitude of significant refractive errors (myopia, hyperopia, astigmatism, and anisometropia; P<0.00001 for each) were associated independently with an increased risk of unilateral amblyopia. Presence of strabismus, hyperopia of 2.0 diopters (D) or more, astigmatism of 1.0 D or more, or anisometropia of 0.5 D or more were present in 91% of children with unilateral amblyopia. Greater magnitude of astigmatism (P<0.0001) and bilateral hyperopia (P<0.0001) were associated independently with increased risk of bilateral amblyopia. Bilateral hyperopia of 3.0 D or more or astigmatism of 1.0 D or more were present in 76% of children with bilateral amblyopia.
Conclusions:
Strabismus and significant refractive errors were risk factors for unilateral amblyopia. Bilateral astigmatism and bilateral hyperopia were risk factors for bilateral amblyopia. Despite differences in selection of the study population, these results validated the findings from the Multi-Ethnic Pediatric Eye Disease Study and Baltimore Pediatric Eye Disease Study.
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