Detachment of the vitreous

Abstract 1.(1) The vitreous has some structure and is not homogeneous, and this structure is one of concentric lamellation as described by Hanover. 2.(2) That there is a limiting membrane to the vitreous, i.e., the hyaloid, is not a myth. 3.(3) Under certain conditions degeneration of the vitreous may occur, and both the hyaloid and all other structure of the vitreous may disappear. 4.(4) Clinical cases are seen which can be explained only by supposing that such a hyaloid membrane has been thrown into folds. 5.(5) Thickening in the hyaloid may take place as the result of inflammatory processes occurring in the adjacent retina, which have caused adherence of the vitreous to the retina, so that if subsequent detachment of the vitreous occurs, this limiting membrane may tear round the edge of the adherent area, and a hole in the membrane may result, which is visible with the ophthalmoscope. 6.(6) Detachment of the vitreous is common during life, and its presence in pathologic specimens is not the result of the fixing reagent, at any rate when formalin has been used. 7.(7) If from any cause the vitreous has become adherent to the retina, from injury, haemorrhage or inflammation, then on detachment the vitreous becomes as it were pegged out at certain spots, and traction is exerted on the retina which may cause either flashes of light on movement of the eye, folding, detachment or even holes in the retina. 8.(8) Detachment of the vitreous is a necessary precursor to certain pathologic conditions, e. g., punctate deposits on the retina, and the peculiar fan formations of pus or fibrous tissue, which are sometimes found extending from the optic disc.