Definition: Choroidal effusion is a buildup of fluid between the choroid (the blood vessel layer that nourishes the overlying retina) and the sclera, the white outer covering of the eye.
A choroidal effusion can cause a choroidal detachment, which may lead to a retinal detachment. A choroidal effusion is most often associated with eye surgery in which the pressure within the eye is extremely low, often to the point where it is difficult to measure. It is also associated with a build-up of fluid in the sinuses in the brain, as well as tumors and inflammatory disorders.
