Birdshot Retinochoroiditis: Long Term Follow-up of a Chronically Progressive Disease

Purpose: To determine the long-term course of birdshot retinochoroiditis by reviewing patient records from The University of Iowa Hospitals and Clinics.

Design: A descriptive case series.

Methods: We conducted a retrospective review of 19 patients seen at The University of Iowa for birdshot retinochoroiditis. Inclusion criteria were set before review. Goldmann perimetry isopters were converted to an area measurement in steradians and the I2e and I4e isopters were evaluated at each time point. The visual acuity, electroretinography (ERG), and visual field findings were compared to the clinical appearance of the fundus.

Results: Follow-up ranged from one visit to 220 months. Of the 14 patients who were tested, all were HLA-A29-positive. Seven patients were followed for >or=60 months. Eleven patients were followed for >or=30 months. The initial visual acuity was 20/50 or better in 36 of 38 eyes and 20/60 and 20/80 in the remaining two. Visual acuity was worse than 20/50 in three of 22 eyes followed for more than 30 months. Visual field data demonstrated progressive loss of area for either the I4e or I2e isopters in six of seven patients who were followed for >or=60 months. Multiple ERGs were performed over time on eight of 19 patients; seven of eight patients demonstrated progressive loss of electrophysiologic indices.

Conclusion: Retinal function in birdshot retinochoroiditis deteriorated progressively over a period of years despite stable visual acuity. Late in the course of disease, visual acuity may be lost due to chorioretinal atrophy in the posterior pole. Visual acuity alone is not an adequate parameter with which to monitor disease activity and may falsely suggest that a patient is stable or doing well. Intermittent treatment of the inflammatory exacerbations did not prevent progressive visual loss. Other treatment strategies such as prolonged corticosteroid or immunosuppressive treatment should be investigated for patients with birdshot retinochoroiditis.