Purpose:
To use "enhanced depth" optical coherence tomography (OCT), both at the macula and more peripherally, for the characterization of chorioretinal structural changes in patients with Birdshot chorioretinopathy.
Methods:
Spectral domain OCT images (Spectralis, Heidelberg Engineering, Germany) were prospectively collected from patients with known Birdshot chorioretinopathy. Images were acquired both from the macula and from four peripheral locations: 1) superior to the superior temporal vascular arcade, 2) inferior to the inferior temporal vascular arcade, 3) nasal to the optic disc, 4) temporal to the macula. All images were obtained using standard and "enhanced depth" scanning protocols. Qualitative assessment was performed for each case and comparison was made with age-matched controls (Figure 1).
Results:
Images from five subjects with Birdshot chorioretinopathy, and five "normal" controls, were evaluated. Retinal atrophic changes were seen as generalized thinning with loss of normal retinal architecture, accompanied by almost complete disruption of the photoreceptor inner segment - outer segment junctions; in some patients clumps of discrete hyperreflective material were seen in the outer nuclear layer which may correspond to clusters of degenerating photoreceptors. Images from the macula often appeared normal, despite widespread atrophic changes visible on peripheral scans.
Conclusions:
In patients with uveitis, OCT has typically been limited to the use of macular scans for the evaluation of features such as cystoid macular edema. Use of extramacular scanning may extend the range of applications for OCT and allow improved phenotyping of uveitic disorders. Similarly, use of "enhanced depth" OCT, allowing improved visualization of the choroid, may be of particular use in patients with choroidal inflammatory conditions.
Keywords: uveitis-clinical/animal model • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina