Refraction
REFRACTION IN CHILDREN
Infant’s eyes tend towards the hypermetropic side of normal. The incidence of myopia is low in preschool children but increases in childhood. Click for causes of myopia
Astigmatic refractive errors are common in neonates but frequently resolve within the first six months of life.
Refraction of children of all ages is possible. This is performed following the instillation of drops (atropine or cyclopentolate) to paralyse the ciliary muscle. This enables a measurement of the ocular refractive state to be made objectively using the retinoscope. Subjective refraction becomes practicable from the age of 7 years. (click on pictures below for enlargement)
Hypermetropia Myopia Astigmatism
click pictures to enlargeCorrection Of Refractive Errors
Spectacles can be prescribed from an early age if high myopia is present or if hypermetropia precipitates an accommodative squint. Small refractive errors do not require spectacle correction. Children are not assisted in any way by the prescription of weak spectacles.
Where the refraction is different in each eye amblyopia may occur (anisometropic amblyopia), requiring the prescription of spectacles.
Contact lenses
Daily wear soft contact lenses are well tolerated by older children and can be prescribed for recreational or cosmetic purposes.
Extended wear soft contact lenses are suitable for the correction of gross refractive errors in infancy (see Congenital Cataract). They require removal for cleansing on a regular basis.
Pinhole Vision
In older children the best corrected vision may be determined by testing visual acuity through a pinhole. If vision is not improved in this manner the visual loss is not due to refractive error.
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