This affection occurs in various forms, the most familiar of which is Albuminuric retinitis This affection consists of a chronic inflammation, apparently commencing in the arteries and accompanied by haemorrhages and degenerations of the retinal and choroid tissue. The affection of the arteries consists in an inflammatory thickening or sclerosis of their wall, with diminution in their calibre. The haemorrhages are mostly in the superficial fibrous layer of the retina. Pale white spots and streaks in the region of the macula are very characteristic of the condition, and these arise chiefly by fatty degeneration. The hemorrhagic spots may become white, but many spots are white from the first and not hemorrhagic.

The affection of the retina occurs in cases of chronic Bright's disease. Diabetes, lead poisoning, etc., sometimes induce a retinitis essentially similar to the albuminuric form. It would seem that a grave alteration of the blood is the cause of the affection of the retina.

Pigmentary retinitis (Retinitis pigmentosa) is a form in which the choroid is involved along with the retina. It is a chronic inflammation or sclerosis, and the pigment cells seem to undergo local enlargement and increase so as to project into the retina and form dark patches. These patches follow the lines of the vessels.