Choroidal assessment in idiopathic panuveitis using optical coherence tomography

BACKGROUND: Idiopathic panuveitis is a diagnosis of exclusion that lacks distinguishing features on fluorescein and indocyanine green angiography. Choroidal hypoperfusion or ischaemia has been implicated in panuveitis of different aetiologies. In this study, we use enhanced depth imaging optical coherence tomography (OCT) to examine the choroid and its vasculature in patients with this disease. METHODS: In this retrospective, cross-sectional study, OCT-derived measurements of retinal and choroidal thickness were obtained after manual segmentation using custom software. Choroidal measurements were further subdivided into Haller's large vessel layer (HLVL) and Sattler's medium vessel layer (SMVL), and correlated with clinical parameters. RESULTS: Twenty-one eyes from 21 patients were included. A reduction in hypo-reflective spaces, corresponding to vascular lumens, was observed in HLVL. The mean thickness of both the choroid (233.7 ± 73.3 μm), and HLVL (167.8 ± 53.7 μm), was less than that previously reported for normal eyes. Choroidal thickness expressed as a ratio to retina thickness showed significant correlation to visual acuity (r = 0.58, p = 0.006). This correlation was maintained in the ratio between HLVL and retinal thickness (r = 0.56, p = 0.009), but not in SMVL to retinal thickness (r = 0.352, p = 0.12). CONCLUSIONS: This study reports novel OCT-derived parameters in patients with idiopathic panuveitis. We noted loss of hyporeflectivity in HLVL, and thinning of both HLVL and the choroid as a whole. The observed correlation between visual acuity and the ratio of choroidal to retinal thickness is a strong enhanced depth imaging (EDI)-OCT derived candidate for prospective validation in future studies.