Birdshot chorioretinopathy

Birdshot chorioretinopathy is the disease with the strongest link to a human leukocyte antigen class I allele. Current research aims at understanding its immunogenetic mechanisms, focusing on the A29 allele, its subtypes, and on other loci of the human leukocyte antigen region. Research criteria can be applied to define birdshot chorioretinopathy. Its heterogeneous presentations and its multiple consequences on visual function are being delineated.

HLA-A*2902 is the most frequent subtype in Caucasians and in patients with birdshot chorioretinopathy. The condition has also been observed, however, in a few HLA-A*2901 Caucasian patients, but remains absent or extremely rare in Asia where HLA-A*2901 is the most prevalent subtype. Birdshot chorioretinopathy affects visual acuity, color vision, contrast sensitivity or visual field and pigmentation of birdshot spots could be a marker of disease severity. Electroretinography has been used to monitor the course of the disease; abnormalities may be due to altered outer retinal function or to inner retinal dysfunction. Various therapeutic regimens have been tested and most studies confirm that corticosteroids alone are not a sustainable treatment for patients with birdshot chorioretinopathy.

Progress has been made in understanding the spectrum of manifestations of birdshot chorioretinopathy. The disease remains of unknown cause and many decisions regarding the management of patients are still empirical.