Background/Aims To analyse choroidal vascular density of affected and non-affected areas in active and inactive serpiginouschoroiditis (SC) by means of optical coherence tomography angiography (OCT-A).

Methods In this cross-sectional and observational study, 22 eyes of 11 patients diagnosed with SC were included. All patients underwent blue-light fundus autofluorescence (spectralis Heidelberg retinalangiography+OCT) and swept-source OCT-A (AngioPlex Elite 9000 SS-OCT, Carl Zeiss Meditech) to analyse qualitative features and choroidal vessel density of areas considered affected, and the inner and the outer border of the lesions. Unaffected areas of otherwise healthy retina have also been studied.

Results All inactive inflammatory lesions were characterised by atrophy of choriocapillaris with an impairment of its detectable flow and greater visibility of choroidal vessels. On the other hand, all active inflammatory lesions showed an area of complete absence of decorrelation signal. The pathological border was characterised by a statistically significant lower choroidal vessel density compared with both the outer border and the unaffected area (0.650±0.113 vs 0.698±0.112, (p<0.001)). Although not statistically significant, vessel density of the outer border of inactive lesions was lower than vessel density of unaffected areas (0.650±0.113 vs 0.698±0.112, p=0.441). Active inflammatory lesions showed an area of complete absence of decorrelation signal at the level of the choriocapillaris and whole choroid.

Conclusion OCT-A represents a new imaging technique that provides useful information about the leading changes of choroidal vascular network in active and inactive lesions of SC.