Disease-associated visual image degradation and spherical refractive errors in children.
Retrospective clinical data from 496 eyes of 256 children attending a low vision clinic were analyzed to determine the relation between disease states which involve visual image degradation and refractive error. Refractive data from 1023 normal vision children were used as a control. The low vision children were grouped according to their disease classification and the acknowledged age-of-onset of their visual disability. It was found that there was an overall inability to emmetropize and a trend towards myopia. It was also observed that the diseases which led to myopia were associated with a peripheral or peripheral plus central impairment of vision and that those conditions in which foveal vision was primarily impaired showed a mild hypermetropic trend. Eyes in which the visual impairment was not congenital but occurred before the age of 3 years tended to develop hypermetropia. The deviation from emmetropia decreased with increasing age-of-onset of the visual impairment, as did the variation about the mean refraction. The plastic period for emmetropization is estimated to end at 8 to 9 years of age.
D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D005128:Eye Diseases / Q000145:classification / Q000150:complications*; D006801:Humans; D007223:Infant; D012030:Refractive Errors / Q000150:complications*; D012189:Retrospective Studies; D014786:Vision Disorders / Q000209:etiology*