Differential effects of various causes of deafness on the eyes, refractive errors, and vision of children.

A retrospective study of oculovisual assessment records of the population of three Ontario schools for deaf children assessed the differential effects of various causes of deafness on the prevalence of vision anomalies. Inherited deafness (ID) appears to be associated with the fewest visual anomalies. Congenital rubella (CR) had the greatest prevalence and was associated with the broadest spectrum of ocular and visual problems. It appears to have a significant effect on corneal curvature as well as being associated with anomalies of other organ systems. Children who had had CR, neonatal sepsis (NS), and Rh incompatibility (Rh) all showed higher rates of strabismus and amblyopia. Those who were deaf from meningitis (MEN) or NS showed a tendency to be more hyperopic, whereas the sample with Rh showed a trend toward myopia. The CR children had the broadest range of spherical refractive errors of all the causes of deafness. Children in schools for the deaf are generally those with substantial or profound hearing loss and thus are more likely to have an accompanying vision impairment. Knowledge of the effect on vision of the causes of deafness should aid practitioners in identifying and detecting similar effects on vision when mild or moderate deafness does not require a child's attendance at schools for the deaf.