The choroidal circulation was studied in 27 eyes with choroidal neovascular diseases by means of fluorescein and indocyanine green (ICG) angiography. In 10 of the cases the disciform response was seen to be associated with either watershed zones of the choroidal circulation or with areas of choroidal circulatory disturbance. This is consistent with the theory that hypoxic regions of the choroid are the underlying cause of macular disciform response.