The rate and route of fluid resorption from the subretinal space of the rabbit.

Small nonrhegmatogenous detachments were formed in living rabbit eyes by injecting a few microliters of fluid into the subretinal space. The change in volume of these detachments was followed by sequential photogrammetric measurements. Detachments of 1 to 3 mm diameter filled with a balanced salt and glucose solution (Ames' solution) resorbed at a constant rate over approximately 80 min of observation and appeared to be totally resorbed within 2 to 6 hr. The rate at which fluid resorbed per unit area of pigment epithelium was consistent with the rate of resorption in other transporting epithelia as well as with clinical observations in humans. Detachments filled with isotonic sucrose resorbed much more slowly than those filled with saline solutions, suggesting that fluid resorption requires the passage of ions through cell membranes. Hypoxia markedly and reversibly reduced the rate of resorption, suggesting that active transport is involved in the removal of the saline solutions from the subretinal space Anatomical and physiological evidence indicate that the site of active transport is the pigment epithelium. Active resorption of subretinal fluid is probably a factor in the maintenance of normal retinal adhesion.