Structural changes of the choroid in sarcoid- and tuberculosis-related granulomatous uveitis

The aim of this study is to characterise the choroidal features of patients diagnosed with sarcoid- and tuberculosis (TB)-associated granulomatous uveitis using spectral domain optical coherence tomography (OCT).

Twenty-seven patients (27 eyes) diagnosed with sarcoid- (13 eyes) and TB (14 eyes)-related uveitis were included in this retrospective, cross-sectional study. Over a six-month period, patients diagnosed with sarcoid and TB granulomatous uveitis were scanned using enhanced depth imaging OCT. Clinical and demographical characteristics were recorded, including the method of diagnosis, disease activity, site of inflammation (anterior or posterior), treatments, and visual acuity (VA). Manual segmentation of the choroidal layers was performed using custom image analysis software.

The main outcome measure was OCT-derived thickness measurements of the choroid and choroidal sublayers (Haller's large vessel and Sattler's medium vessel layers) at the macula region. The ratio of Haller's large vessel to Sattler's medium vessel layer was significantly different at the total macula circle in eyes diagnosed with TB uveitis (1.47 (=140.71/95.72 microm)) compared with sarcoid uveitis (1.07 (=137.70/128.69 microm)) (P=0.001). A thinner choroid was observed in eyes with a VA ≥0.3 LogMAR (Snellen 6/12; 198.1 microm (interquartile range (IQR)=147.0-253.4 microm) compared with those with VA <0.3 LogMAR (292.4 microm (IQR=240.1-347.6 microm)) at the total macula circle (P=0.004). At the foveal central subfield, the median choroidal thickness was 336.8 microm (IQR=272.3-375.4 microm) in active compared with 239.3 microm (IQR=195.3-330.9 microm) in quiescent disease (P=0.04).

A disproportionately enlarged Sattler's layer may indicate a diagnosis of sarcoid-related uveitis, and choroidal thickening may be a feature of active granulomatous uveitis.