Vascular Density and Retinal Function in patients with Retinitis Pigmentosa evaluated by swept-source OCT angiography and microperimetry.

PURPOSE: To determine the retinal and choroidal vessel density in the macular area with OCT angiography (SS-OCTA) in patients affected by retinitis pigmentosa (RP), to compare their data with healthy subjects, and to study a possible morphofunctional correlation by microperimetry (MP1). METHODS: 40 eyes of 40 patients affected by RP and 24 eyes of 24 healthy subjects were included in the study. Manually moving down the segmentation line of the SS-OCTA we have evaluated the vessel density for the superficial retinal plexus, deep retinal plexus, choriocapillaris and 3 levels of choroid. RESULTS: Linear regression analyses were performed of retinal structure and function. No significant correlation was detected in any case (R square = 0, p>0.05). A comparison between RP and healthy control revealed a significant reduction in SS-OCTA mean capillary density in the RP group (p=0.0011). This relationship was consistent across vascular layers (p=0.2413). A significant association between the capillary density of the various vascular complexes was detected within individual eyes (p<0.0001). CONCLUSIONS: This study represents the first study comparing MP1 and SS-OCTA data with the largest cohort of patients. RP patients showed a reduction in both the retinal and choroidal vascular network in the macular area compared to healthy subjects.