Hypo-accommodation Responses in Hypermetropic Infants and Children
Horwood,A, Riddell,P. Brit J Ophthalmol 2011 vol 95 (2), pp 231-237 bjo.2009.177378Published Online First: 5 July 2010 doi:10.1136/bjo.2009.177378
- Hypermetropic children rarely “make up the difference” without glasses or when undercorrected and under-accommodate more for near than distance
- Hypermetropic infants destined to emmetropise accommodate a little better for near than distance
Accommodation to overcome hypermetropia is implicated in emmetropisation. This study recorded accommodation responses in a wide range of emmetropising infants and older children with clinically significant hypermetropia to assess common characteristics and differences.
A PlusoptiXSO4 photorefractor in a laboratory setting was used to collect binocular accommodation data from participants viewing a detailed picture target moving between 33cm and 2m. 38 typically developing infants were studied between 6-26 weeks of age and were compared with cross-sectional recordings from children 5-9 years of age with clinically significant hypermetropia (n=15), corrected fully accommodative strabismus (n=14) and 27 age-matched controls.
Hypermetropes of all ages under-accommodated compared to controls at all distances, whether corrected or not (p<0.00001) and lag related to manifest refraction. Emmetropising infants accommodated better for near than distance, while the hypermetropic patient groups under-accommodated most for near.
Steep accommodation response slopes are typical of emmetropising hypermetropia in infants. Hypermetropic children referred for treatment for reduced visual acuity are not likely to habitually accommodate to overcome residual hypermetropia left by an under-correction.