Improved Ocular Blood Flow in the Central Retinal Artery during a Randomized Controlled Trial of Electrostimulation Therapies for Retinitis Pigmentosa

Title: Improved Ocular Blood Flow in the Central Retinal Artery during a Randomized Controlled Trial of Electro-Stimulation Therapies for Retinitis Pigmentosa Patricia Vargas, Deborah Mendelsohn, Jorge Han, Brennan Nelson, Alexandra Benavente, Ava K. Bittner Objective: We explored whether blood flow velocities in the central retinal artery (CRA) were repeatable and related to baseline vision loss in retinitis pigmentosa (RP), and determine any changes following transcorneal electrical stimulation (TES) or electro-acupuncture (EA). Background: A previous study found reduced blood flow velocities in the CRA of RP patients compared to normal controls using color Doppler imaging (CDI). Methods: We measured the CRA peak systolic velocity (PSV) and end diastolic velocity (EDV) in 22 RP patients using CDI twice in a month at baseline, then within 1 week and 1 month post-intervention. At each visit, visual acuity (VA) and 10-2 Humphrey visual fields (HVF) were completed. PSV and EDV were used to calculate mean flow velocity (MFV); correlations with vision were adjusted for age and gender. Results: Mean within- and between-visit coefficients of variation were 16-22% for PSV and EDV. In eyes with reduced mean VA \u3e0.3 logMAR (20/40), MFV was significantly lower (p=0.037) than in eyes with better VA. For HVFs with the size III target, reduced MFV was significantly associated with lower HVF mean deviation scores (p=0.007). Subjects with worse vision who completed the HVF with the size V target had significantly reduced MFV with decreased mean sensitivity at the 4 most central test locations (p=0.004). There were statistically significant improvements (p\u3c0.05) in the CRA blood flow (PSV and EDV) after two TES sessions or within 1 week of EA when compared to controls. Conclusions: Blood flow measures were reliable, related to visual loss, and improved following TES or EA in RP. Grants: NIH R21 EY023720 to AK