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Two infant vision screening programmes: prediction and prevention of strabismus and amblyopia from photo- and
J Atkinson1, O Braddick, B Robier
1Visual Development Unit, London, UK.
Insights
Infant vision screening effectively identifies refractive errors and strabismus. Early intervention with partial spectacle correction reduces risks of strabismus and acuity deficits in hyperopic children.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Public Health Vision Screening
Background:
- Infant vision screening is crucial for early detection of strabismus and refractive errors.
- Existing screening methods require validation for accuracy and efficacy in young children.
Purpose of the Study:
- To evaluate two infant vision screening programs in Cambridge.
- To assess the effectiveness of photorefraction and videorefraction in identifying visual impairments.
- To determine the long-term outcomes of refractive errors and the impact of early intervention.
Main Methods:
- Two screening programs utilized isotropic photorefraction/videorefraction with and without cycloplegia.
- Identified infants underwent follow-up retinoscopic refractions.
- A randomized controlled trial investigated partial refractive correction for hyperopic/anisometropic children.
- Children were followed up to age 4 years.
Main Results:
- Screening methods showed good agreement with retinoscopic refractions.
- Prevalence: 5-6% hyperopia, <1% anisometropia, 0.25% myopia > -3D, <1% strabismus.
- Infants with hyperopia were significantly more likely to develop strabismus and acuity deficits by age 4.
- Partial spectacle correction reduced these risks.
Conclusions:
- Photo- and videorefraction are effective for infant ametropia screening.
- Early detection and intervention, including partial correction, can mitigate risks of strabismus and amblyopia.
- Infant vision screening programs can reduce the incidence of preschool vision problems.
Abstract:
Two infant vision screening programmes on total populations in the Cambridge Health District have been designed to identify manifest strabismus and strabismogenic and amblyogenic refractive errors at 7-9 months of age. The first, completed, programme used the isotropic photorefractor with cycloplegia together with a standard orthoptic examination. The second, current, programme uses the VRP-1 isotropic videorefractor to identify infants with accommodative lags which are followed up by refraction under cycloplegia. Both programmes show good agreement between infants identified at screening and retinoscopic refractions at follow-up, showing that photo- and videorefraction (with or without cycloplegia) can be effective methods for screening for ametropia in infants and young children. In each programme 5-6% of infants showed abnormal levels of hyperopia (> or = 3.5 D in any meridian), less than 1% showed anisometropia > or = 1.5 D; very few infants (0.25%) showed -3D myopia or greater. Less than 1% showed manifest strabismus. Hyperopic and anisometropic children entered a randomised controlled trial of partial refractive correction. All children identified at screening, alongside appropriate control groups, are extensively followed up to age 4 years. The first programme has found that children who were hyperopic in infancy were 13 times more likely to become strabismic, and 6 times more likely to show measurable acuity deficits by 4 years, compared with controls. Wearing a partial spectacle correction reduced these risk ratios to 4:1 and 2.5:1 respectively. The impaired acuity can be attributed, in part, to meridional amblyopia resulting from persisting astigmatism. Both hyperopic and myopic infants showed refractive changes in the direction of emmetropia between 9 months and 4 years. Wearing a partial spectacle correction did not affect this process of emmetropisation, but does provide the possibility of reducing the incidence of common pre-school vision problems.