[Refractive errors in visually handicapped children].

Aside from hereditary juvenile macular dystrophy (Stargardt's disease), the author observed a significant increase in the incidence of spheric and astigmatic refractive errors in a further six hereditary or congenital deformities with poor vision. A shift toward myopia was seen in cases of coloboma, both of the optic nerve head as well as of the macular region, and in cases of macular aplasia and hypoplasia. A shift toward hyperopia was found in complete and ocular albinism, in retinitis pigmentosa and congenital achromatopsia. This hyperopic shift is in contradiction to the hypothesis that myopia can be deprivation-induced. It is assumed that a disturbance of visual stimulation early in life can disrupt emmetropization and thus induce the eye to become either myopic or hyperopic, in combination with a high incidence of astigmatism. This disturbance of visual stimulation may be due to clouding of the dioptric media, though equally to congenital or hereditary defects in the retina or the visual pathways of visual cortex.