Baseline characteristics of children in the Early Glasses Study
J S Steltman1, M Nordmann2, D Sanders2
1Dept. of Ophthalmology, Erasmus University Medical Center, Dr. Molewaterplein 40, Ee-1667, 3015 GD, Rotterdam, Netherlands. j.steltman@erasmusmc.nl.
Insights
This study found that amblyopia (lazy eye) is less common in one-year-olds than previously thought, suggesting it develops later. Early glasses may offer protection against refractive errors, but more research is needed.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Public Health
Background:
- High refractive errors are known to cause amblyopia.
- The precise relationship between early refractive error and amblyopia risk, and the protective effect of early glasses, remains unquantified in population-based studies.
- The Early Glasses Study aims to address this knowledge gap through a prospective, longitudinal, randomized controlled design.
Purpose of the Study:
- To investigate the relationship between refractive error at age 1 and the risk of developing amblyopia or accommodative esotropia.
- To assess the protective effect of early-onset glasses in a population-based cohort.
- To report baseline findings from the Early Glasses Study.
Main Methods:
- Recruitment of healthy children aged 12-18 months at Children's Healthcare Centres (CHCs).
- Initial orthoptic examination and cycloplegic retinoscopy, excluding children with amblyopia, strabismus, or significant refractive errors.
- Randomization of eligible children exceeding AAPOS 2003 Criteria for refractive error into glasses or no-glasses groups; follow-up by research orthoptists or regular CHC screening.
Main Results:
- Of 742 enrolled children, 601 completed baseline examination at approximately 14.5 months of age.
- Mean spherical equivalent (SE) was +1.73D ± 1.18D, astigmatism -0.70D ± 0.44D, and anisometropia 0.21D.
- 10.3% of children exceeded refractive error criteria, with 52 randomized; strabismus prevalence was 1.65% (10/601), and amblyopia prevalence was low at 0.33% (2/601).
Conclusions:
- The observed low prevalence of amblyopia (0.33%) at age 1 suggests that common forms of amblyopia may develop later in childhood.
- The prevalence of strabismus (1.65%) was consistent with expectations for this age group.
- Baseline data indicate a low prevalence of anisometropia (0.8%) at 14.5 months, a factor often associated with amblyopia in older children.
Purpose:
The relationship between refractive error at age 1 and the risk of developing amblyopia or accommodative esotropia, and the protection offered by early glasses, is unknown. These are determined in the Early Glasses Study, a prospective, population-based, longitudinal, randomized controlled study. We report baseline findings.
Methods:
Healthy children aged 12-18 months were recruited at Children's Healthcare Centres (CHCs) and received an entry orthoptic examination followed by cycloplegic retinoscopy. Children with amblyopia, strabismus, ophthalmic disease or very high refractive error were excluded. Those exceeding the AAPOS 2003 Criteria (> + 3.5D spherical equivalent (SE), > 1.5D astigmatism, > 1.5D anisometropia) were randomized into wearing glasses or not, and are followed-up by research orthoptists. Other children are followed-up by regular vision screening at CHCs and visual acuity is measured in all children at age 4.
Results:
Parents of 865 children were called, 123 were excluded. Of 742 children enrolled, 601 underwent the entry orthoptic examination at age 14.5 ± 1.7 months. Mean SE was + 1.73 ± 1.18D, astigmatism -0.70 ± 0.44D, anisometropia 0.21D (IQR: 0-0.25). Of 62 (10.3%) children exceeding the Criteria, 52 were randomized into wearing glasses or not. Of 539 other children, 522 are followed up at CHCs. In total, 31 were excluded: 2 had strabismus and amblyopia, 7 strabismus, 2 amblyopia suspect, 1 strabismus suspect, 1 squinting during sinusitis, 4 excessive refractive error, 9 myopia, 2 ptosis, 1 oculomotor apraxia, 1 Duane syndrome, 1 congenital nystagmus.
Conclusion:
Prevalence of strabismus (10/601) was as expected, but prevalence of amblyopia (2/601) was low, suggesting that common amblyopia develops later than generally thought.
Key Messages:
What is known High refractive errors cause amblyopia, but no study has determined the exact relationship between the kind and size of refractive error at age 1 and the risk to develop amblyopia, and assessed the protective effect of glasses in a controlled, population-based, longitudinal study. What is new At baseline, 601 children received a full orthoptic examination followed by retinoscopy in cycloplegia at the age of 14.5 ± 1.7 months; 10.3% had high refractive error exceeding spherical equivalent > + 3.5D, > 1.5D astigmatism, > 1D oblique astigmatism or > 1.5D anisometropia. The prevalence of amblyopia was lower (0.3%) than expected, suggesting that most amblyopia develops after the first year of life. The prevalence of anisometropia, associated with amblyopia in older children, was low (0.8%).
