Novel autofluorescence and optical coherence tomography findings in birdshot chorioretinopathy

Abstract

 

Purpose

 

Birdshot chorioretinopathy (BSCR) has been characterized by choroidal lesions with central vision loss secondary to cystoid macular edema (CME). Some patients, however, have insidious central vision loss without CME. Recently, retinal pigment epithelium (RPE) atrophy observed on autofluorescence (AF) imaging has been described as a feature of BSCR contributing to central vision loss. We describe AF and optical coherence tomography (OCT) imaging findings of patients with outer retinal and RPE atrophy, and a patient with hyperautofluorescent central macula changes later evolving into hypoautofluorescence corresponding to RPE atrophy.

 

Methods

 

Wide-field AF (Optos) and OCT images (Heidelberg Spectralis) of 16 patients (32 eyes) with BSCR were examined.

 

Results

 

Patient age ranged from 45 to 71 years (mean 58 years). Hypoautofluorescent lesions were noted in 15 of 32 eyes (47%). In 7 of the 15 eyes (47%), these areas corresponded to classic birdshot lesions. However in the other 8 eyes (53%), the area of hypoautofluorescence corresponded to focal lesions in the macula. Disruption of the ellipsoid zone (EZ) and interdigitating zone (IZ) was noted on OCT in 7 of these 8 eyes (88%). The lesions on OCT frequently corresponded to the areas of hypoautofluorescence and were most commonly found surrounding the optic nerve and in the posterior pole. In one patient, focal macular lesions of hypoautofluorescence surrounded by rings of hyperautofluorescence were noted to evolve into uniformly hypoautofluorescent lesions in both eyes over a period of 9 months, and corresponded to a steroid-responsive area of EZ/IZ hyperreflectivity on OCT. Over time these areas resulted in EZ/IZ disruption suggestive of atrophy. None of the patients had CME.

 

Conclusions

 

Hypoautofluorescent focal lesions in the macula of patients with BSCR suggest a mechanism of central vision loss in these patients distinct from CME. These lesions appear to affect the outer retina and RPE on OCT and result in RPE atrophy. To our knowledge, the finding of a hyperautofluorescent halo surrounding a focal macular lesion that eventually evolves into uniform hypoautofluorescence has not been described in BSCR. It may signify pathologic activity, and autofluorescence imaging may offer an additional modality with which to follow disease activity in BSCR.

 

 

AF and OCT images showing active disease.

 

 

AF and OCT images 9 months later showing atrophy.

 

Keywords: 451 chorioretinitis • 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 746 uveitis-clinical/animal model