The effect of optic neuritis attacks on choroidal vascularity index in patients with multiple sclerosis

Purpose To investigate the changes in the choroidal vascularity index (CVI) of patients with multiple sclerosis (MS) using binarization on enhanced depth imaging optical coherence tomography (EDI-OCT) images and to evaluate the effect of optic neuritis (ON) attacks on these measurements. Method Three groups were created by including forty eyes of 20 patients diagnosed with relapsing-remitting MS and had a unilateral history of ON attack and the randomly selected eyes of 30 healthy age- and sex-matched control subjects. Group 1 (n = 20) consisted of the ON-affected eyes of the MS patients (MSON); group 2 (n = 20) included their fellow healthy eyes (MSNON); group 3 (n = 30) included the eyes of healthy controls. Results The mean age was 33.3 +/- 9.4 years in the MS group and 33.4 +/- 11.1 years in the healthy control group. Mean choroidal vascularity index (CVI) was significantly lower in the MSON group than the MSNON group (59.6 +/- 3.72 % vs 61.7 +/- 3.16 %, p = 0.007). The CVI values of both the MSON and MSNON groups were significantly lower when compared to the controls (63.9 +/- 2.76) (p < 0.001, p = 0.030). Compared to controls, the subfoveal total choroidal area and luminal area values were significantly greater in the MSON (p = 0.009, p = 0.009, respectively) and MSNON groups (p = 0.031, p = 0.013, respectively). Conclusion The presented study demonstrates that, compared to healthy subjects, CVI values are lower in the affected and unaffected eyes of patients who had a history of ON in relation with their MS diagnosis. The presence of significant anatomical changes, especially in the luminal area, may suggest that ON causes vascular disorganization which contributes to MS pathophysiology.