CHOROIDAL ABNORMALITIES IN BIRDSHOT CHORIORETINOPATHY - AN INDOCYANINE GREEN ANGIOGRAPHY STUDY

Birdshot chorioretinopathy is a rare inflammatory disorder with an ins idious onset that can slowly progress to severe visual loss, The patho genesis is unknown. This study used indocyanine green (ICG) angiograph y to investigate the degree of choroidal vascular involvement with pro gression of disease and to determine the nature of the birdshot lesion s. Seven patients with birdshot chorioretinopathy had ICG angiography performed with a scanning laser ophthalmoscope at various stages of cl inical disease, Results were compared with fluorescein fundal angiogra phy (FFA), All large choroidal vessels appeared normal. The birdshot l esions were demonstrated with ICG but not with FFA and were represente d by dark areas on ICG angiography, Typically these areas were bordere d by large or medium-sized choroidal vessels and their appearance sugg ested small choroidal vessel hypoperfusion. In disease of recent onset , some lesions masked fluorescence from large underlying choroidal ves sels possibly due to inflammatory choroidal infiltrates. In long-stand ing disease, the choroidal angioarchitecture was relatively normal wit hin the birdshot lesions. This study of birdshot chorioretinopathy dem onstrates abnormalities in the small choroidal vessels within the bird shot lesions. ICG angiography detects the birdshot lesions more readil y than FFA and may be of benefit in assessing disease activity.