Chorioretinal anastomoses after argon laser photocoagulation.

Communication between the retinal and the choroidal circulation occurred in one case of proliferative diabetic retinopathy and one case of Leber's disease (multiple miliary aneurysms) after argon laser photocoagulation treatment to eliminate abnormal retinal vasculature. In both instances rapid-sequence fluorescein angiography documented the choroidal origin of the anastomoses. Such anastomoses developed in areas where an excessively dense laser beam aimed at occluding retinal vessels presumably destroyed the underlying Bruch's membrane and permitted invasion of the retina by fibrovascular growth from the choriod. The occurrence of such growths is a potential complication of argon laser photocoagulation directly related to the power density used.