Low-grade "benign" birdshot retinochoroiditis: prevalence and characteristics

To establish the prevalence, morphologic and functional characteristics and evolution of mild birdshot retinochoroiditis (BRC).

Retrospective review of all BRC cases treated at the Centre for Ophthalmic Specialized Care, Lausanne, Switzerland, with at least 3 years of follow-up since the initial symptoms. Sub-Tenon's injection of triamcinolone was the first line of treatment if visual field changes were unilateral, with no additional treatment if visual field returned to normal. The percentage of patients who did not need systemic therapy was established, and the following parameters were evaluated: demographic characteristics, best-corrected visual acuity (BCVA), fundus photographs, fluorescein angiography (FA) and indocyanine green (ICGA) angiography frames and perimetry evaluation from initial visit to last follow-up.

Twenty cases of BRC were included in this study. Three of these patients (15%) received only local periocular therapy and qualified as mild BRC, with a mean follow-up of 9.3 years. The BCVA was 0.89 ± 0.25 at presentation and 1.0 ± 0.39 at last follow-up. Average visual field mean defect was 5.05 ± 3.27 at presentation and 1.78 ± 0.95 at last follow-up. Depigmented fundus lesions remained stable from presentation to last follow-up. Choroidal inflammatory activity monitored by ICGA decreased from 11.66 ± 3.44 at presentation to 4.25 ± 2.87 at last follow-up. FA revealed mild retinal vasculitis (2.25 ± 3.20) which remained stable (2.00 ± 4.00).

In our setting, 15% of BRC cases had a benign course, controlled with periocular treatment. It is important to identify such cases in order not to overtreat, exposing patients needlessly to potential side effects of aggressive and prolonged immunosuppressive treatment.