Background Haas first described what is now acknowledged as being X linked retinoschisis (XLRS) nearly a century ago in a paper entitled'Ueber das Zusammenvorkommen von Veranderungen der Retina und Choroidea'. I Accompanying his description of the disease in two males was a beautiful drawing of the typical radiatingcystic mac-ulopathy. The fact that subsequent authors failed to observe these macular changes and instead described the peripheral retinal features of the disease2-4 is testimony perhaps to his shrewd powers of observation. Although Haas believed the retinal and choroidal changes were inflammatory in origin, Pagenstecher published a pedigree some 15 years later which showed an X linked pattern of inheritance. 5 The variable clinical manifestations of the disease are exemplified by the wide variety of names that have been ascribed to XLRS in the past.'Anterior retinal dialysis', 6'neuroretinal disease in males', 7'congenital cystic detachment of the retina', 2 and'congenital vascular veils'8 were variously used to describe the condition before Jager coined the term X linked retinoschisis. 9 There areno other systemic associations and experience does not support Jager's assertion that all affected patients were'from their early youth very difficult and extremely irritable persons'!

Clinical features XLRS has been described worldwidein white,'0 black," I 12 and Asian people.'3 Although considered a rare condition it is much underdiagnosed and is among the commonest causes of juvenile macular degeneration.'0 The largest series of patients has been described in Finland where