Choroidal vascular index in cystoid macular edema associated with retinitis pigmentosa

Retinitis pigmentosa (RP) is an inherited degenerative disease characterized by night blindness (nyctalopia), visual field defects, and varying degrees of vision loss. Choroid tissue has an essential role in the pathophysiology of many chorioretinal diseases. The choroidal vascularity index (CVI) is a choroidal parameter obtained as the ratio of the luminal choroidal area to the total choroidal area. The study aimed to compare the CVI of RP patients with and without CME with each other and with healthy individualsAU: Please confirm that the provided email ''ademoztel@hotmail.com" is the correct address for official communication, else provide an alternate e-mail address to replace the existing one..

A retrospective, comparative study of 76 eyes of 76 RP patients and 60 right eyes of 60 healthy subjects was conducted. The patients were divided into two groups: those with and those without cystoid macular edema (CME). The images were obtained using enhanced depth imaging optical coherence tomography (EDI-OCT). CVI was calculated by using the binarization method with ImageJ software.

The mean CVI was significantly lower in RP patients compared to the control group (0.61±0.05 and 0.65±0.02, respectively, p<0.01). The mean CVI in RP patients with CME was significantly lower than in those without CME (0.60±0.54 and 0.63±0.35, respectively, p=0.01) The CVI was positively correlated with subfoveal choroidal thickness (r=0.74, p=0.001), central macular thickness (r=0.27, p<0.001) and visual acuity (logMAR) (r=-0.23 p=0.03) in RP patients.

The CVI is lower in RP patients with CME than in patients without CME and in RP patients compared to healthy subjects, indicating an ocular vascular involvement in the pathophysiology of the disease and the pathogenesis of RP-associated cystoid macular edema.