Hereditary sex-linked retinoschisis.

The management of retinoschisis still presents a complex clinical problem, and a survey of the current literature suggests that opinion remains divided regarding the most suitable form of treatment. It has been suggested that the results of surgery are poor and that operative treatment should be undertaken only with reluctance (Balian and Falls, I960; Shea, Schepens, and von Pirquet, I960; Duke-Elder, I964). Pischel (I963), however, claimed good results from surgical treatment and in selected cases photocoagulation has been advocated (Okun and Cibis, I964; Harris, I968). Hereditary sex-linked retinoschisis is a rare familial form of the condition, first described in detail by Mann and Macrae (1938). Subsequent authors have contributed a variety of additional information (Sheehan, 1952; Jager, 1953; Goodside, I960; Gieser and Falls, 196I; Duke-Elder, I964; Cibis, I965; Falls, I966; Keith, I966). The clinical appearance is variable. Mild cases present as a localized, cystic macular degeneration associated with haemorrhages and radial streaks caused by 'creasing' of the superficial retinal layers. More severe forms show advanced macular changes, vascular sheathing, optic atrophy, chorio-retinal degeneration, and semi-translucent veils which may become detached to float free in the vitreous (Jager, 1953; Balian and Falls, 1960; Duke-Elder, I964; Sabates, I966; Bengtsson and Linder, I967; Vainio-Mattila, Eriksson, and Forsius, I969). A high incidence of retinal detachment has been a consistent observation (Jager, 1953; Ricci, 196I; Sabates, I966; Bengtsson and Linder, I967; Harris, I968; Ewing and Ives, I969; Vainio-Mattila and others, I969) and some authors have reported degenerative changes in the vitreous (Ewing and Ives, I969; Vainio-Mattila and others, I969). The electroretinogram has consistently been reduced or absent (Ricci, I961; Forsius, Eriksson, and Vainio-Mattila, I963; Vainio-Mattila and others, I969), and dark adaptation has been reported to be either within normal limits (Ricci, I 96 I) or impaired (VainioMattila and others, I969). Colour discrimination has been recorded as reduced (Forsius and others, I963; Vainio-Mattila and others, I969) or unaffected (Levy, 1952; Ricci, I96I). No haematological or chromosomal abnormalities have been recorded (Bengtsson and Linder, I967). Pathological examination reveals that cleavage occurs in the nerve fibre layer, unlike senile retinoschisis in which splitting is observed in the outer plexiform layer (Yanoff, Rahn, and Zimmerman, I968; Vainio-Mattila and others, I969). The retinal vessels may lift off with the separated inner leaf which may undergo progressive hole formation. The pathogenesis of the intraretinal fluid is uncertain, but is variously ascribed to vitreous traction, microscopic holes in the inner lamina, ischaemic autolysis, or osmosis with the inner leaf acting as a semi-permeable membrane. Alternative theories suggest