Late effect of external eye irradiation on choroidal circulation

To report two cases of atypical late onset radiation chorioretinopathy occurring 15 and 25 years post exposure and the indocyanine green (ICG) angiographic findings in these patients.

Clinical examination and imaging including fluorescein and ICG angiography were performed.

Fundus examination of the first patient revealed microangiopathy with intraretinal hemorrhages, lipid exudation, telangiectatic and aneurysmal capillary changes. Indocyanine green angiography showed an apparent chorioretinal anastomosis and delayed perfusion of the choriocapillaris. Fundus examination of the second patient revealed a pigment epithelial detachment and retinal pigment epithelial changes. Indocyanine green angiography showed atypical, tortuous, dilated, choroidal vessels as well as areas of hypoperfusion. Both patients had multiple dot-like hyperfluorescent spots in the midphase of the ICG angiogram.

External radiation exposure may lead to both retinal and choroidal alterations which may be independent events and which may manifest after a long period of quiescence. Furthermore, ICG angiography appears to be a useful diagnostic tool to study the alterations of the choroid following external eye irradiation.