Hyperopia Treatment Study 1 (HTS1) - Glasses vs Observation

Moderate and high hyperopia are associated with the development of strabismus and amblyopia. The primary aims of treatment for asymptomatic moderate and high hyperopia in preschool children are to facilitate the development of normal visual acuity and to prevent the development of esotropia and amblyopia. Treatment consists of optical correction, typically using glasses. For children with high hyperopia (\>+5.00D) and without strabismus or amblyopia, there is general consensus that a correction should be prescribed. Nevertheless, for children with moderate hyperopia (+3.00D to +5.00D) without strabismus or amblyopia, there is less consensus among pediatric eye care professionals. A survey by Lyons et al found that for a 2-year-old child with hyperopia greater than +3.00D, 65% of optometrists would prescribe glasses compared to 25% of ophthalmologists; for a 4-year old with hyperopia greater than +3.00D, 67% of optometrists would prescribe compared with 42% of ophthalmologists. The American Association for Pediatric Ophthalmology and Strabismus (AAPOS) recommends correcting +4.00D or more in 2 to 7 year olds and the American Academy of Ophthalmology recommends a threshold of +4.50D for correction in 2-to 3-year olds. Unlike ophthalmology, optometry does not provide specific recommendations based on age and level of refractive error. Such variation in practice highlights the lack of rigorously collected scientific evidence for the management of this condition. Across all levels of hyperopia, most ophthalmologists and optometrists usually prescribe less than the full cycloplegic refraction (71% in the Lyons survey) when no strabismus or amblyopia is present. The rationale for proactively correcting moderate hyperopia in an asymptomatic child is the prevention of esotropia, amblyopia, or asthenopia. The argument against correcting moderate hyperopia in an asymptomatic child is the expense and inconvenience of glasses that might be unnecessary and the potential disruption of emmetropization in infants and toddlers. At present, it remains uncertain whether correction of moderate hyperopia is beneficial in terms of visual acuity outcomes or strabismus development. There is some evidence that using partial correction of hyperopia allows emmetropization to take place. If refractive correction of moderate hyperopia does not reduce the incidence of amblyopia and/or esotropia compared to no refractive correction, then glasses can be avoided. However, if correcting moderate hyperopia does reduce the development of amblyopia and/or esotropia, then the benefits of preemptive refractive correction will have been identified.