[Exudation of indocyanine green from subretinal neovascularization and its significance]

Owing to its tight binding to protein, exudation of indocyanine green from subretinal new vessels would not normally be expected, but it has been demonstrated. We investigated 102 subretinal new vessels to find out how often exudation develops and to understand the reason for it. Exudation was found in 29 (28.4%) of the cases examined; 37 (36.6%) were stained, which means that these membranes became hyperfluorescent but not lighter than other, definitively non-exuding, structures on the fundus. In 26 (25.5%) no hyperfluorescence was seen in the late phase, and in 10, or 9.8%, neovascularization remained occult. The correlation of indocyanine green exudation with retinal blood or lipid deposits was significant (r = 0.77, p = 0.0001). Histological examinations showed a correlation of lipid deposits with a severe disintegration of retinal vessels. This finding, in combination with others, indicates that the exudation of indocyanine green reflects severe destruction of vessel walls, which does not seem to occur consistently in all neovascular membranes. The exudation of indocyanine green might be of prognostic value.