Inherited retinal detachment.

Case 1 (II, 5), James W., aged 72, is bed-ridden with cardiac disease, and does not give a reliable history. Two years ago his Wassermann reaction was negative. Right eye divergent, no perception of light, no red reflex, presumably because of a total detachment of the retina. Immature amber cataract, no signs of iritis. Left eye immature central cataract, good projection of light. Fundus visible, with exception of macular area, with pupil dilated. Below there is a dark-grey, snail-shaped membrane projecting into the vitreous, with its tail attached to the retina. Temporal to it are white dendritic lines in the retina. The more temporal group are very white and have sharply defined edges, exactly like those in Case 2. The more nasal group, which have a yellowish tint and branch less, may be an earlier stage. There are two round central vitreous opacities. Case 2 (III, 25), John He., aged 41, known to have defective vision before the age of 1 year, sight has changed little for as long as he remembers, attended school for the blind at age 12, has occasional fine nystagmus. Right eye divergent, as can be seen in a snapshot taken 30 years ago, with limited adduction. Abduction of the left eye slightly limited. Visual acuity in both eyes 3/60, c. + 5.0 D.S. Pupils dilate poorly and both lenses have a small posterior polar opacity. Disks are partly atrophic and vessels narrow, especially in right eye. Macular area in each eye occupied by a slightly raised, white-speckled plaque, with a few bright cholesterol crystals and small clumps of pigment. In the right macula there is a small crater; its base is formed of a spongy red tissue, and from its upper border a white strand passes downwards, on the surface of the retina. An area of retina, temporal to the macula and extending to the periphery along a branch of the superior temporal artery, is