Electrical activity of the eye in high myopia.

IT IS generally agreed that simple myopia and degenerative myopia are separate conditions, the former being a normal chance variant in the biological series which includes emmetropia and hypermetropia (Duke-Elder, 1949) and the latter a pathological condition. Degenerative myopia in its advanced stage consists of an association of defects: a highly myopic refraction, chorio-retinal degeneration and atrophy, thinning of the posterior sclera, and an increased axial length of the eye. Additional defects, such as cupuliform cataract, glaucoma, and retinal detachment, are relatively common in patients with degenerative myopia, and a hereditary element is often present. In the investigation here reported the function of eyes with degenerative myopia has been studied using electroretinography and electro-oculography. Although degenerative myopia may be congenital, it usually takes many years to develop. In its early stages a myopic refraction, straight temporal vessels, and a temporal crescent at the optic disc may be the only physical signs, and these cannot be distinguished from cases of simple myopia (Blach, Jay, and MacFaul, 1965). It is hoped that the electrical tests described here may prove to be of some diagnostic and prognostic value, and be of some help in pointing to the primary defect in degenerative myopia.