Choroidal atrophy. Clinical and genetic types.

In ophthalmology, as in medicine generally, there has been a rapid development of treatment to combat infections and allergic conditions, but the choice of therapy for degenerative, hereditary conditions is-admittedly-just as small as before. The proportionate role played by the genetic degenerative eye lesions as causative factors of blindness, or impaired vision, has thus greatly increased. Related to the large and not very well-defined group of degenerative eye lesions called the tapetoretinal degenerations, there is a somewhat disputed group termed choroidal sclerosis, or perhaps more correctly, choroidal atrophy. As mentioned later in this paper, there is histological evidence of choroidal atrophy rather than sclerosis. The term 'atrophy' will therefore be preferred in this article. According to Sorsby (1939), there are three clinical forms of choroidal atrophy, first, central areolar choroidal atrophy, first established by Sorsby (1939) as a clinical entity, secondly, the diffuse choroidal form, described by Morton (1893), Frost (1896), and Harman (1902), and lastly peripapillary choroidal atrophy, described by Haab (1895), Harman (1902), Cuperus (1903), and Di Marzio (1938). Central areolar choroidal atrophy is characterized by the development in both fundi of a sharply circumscribed central oval area of choroidal atrophy with disappearance of the choriocapillaris and the retinal pigment (Fig. 1). Retinal vessels can be seen traversing the atrophic zone. The size of the atrophic area is about 3 to 4 times that of the disc. The earliest ophthalmoscopic appearances are evident between the ages of 20 and 40, and are of an exudative oedematous type somewhat resembling that of macular degeneration. The development of the disease is slow and gradual. The end-stage is reached at about the age of 50-60 years. Visual acuity is then usually reduced to less than 0 1, while