Reduced Central Retinal Artery Blood Flow is Related to Decreased Central Visual Function in Retinitis Pigmentosa Patients

Abstract

Purpose : A previous study described how patients with retinitis pigmentosa (RP) exhibited significantly reduced systolic and diastolic blood flow velocities in the central retinal artery (CRA) compared to normal controls using color Doppler imaging (CDI). We explored whether such vascular abnormalities are related to level of vision loss across RP patients with a wide range of disease severity.

Methods : We measured the CRA peak systolic velocity (PSV) and end diastolic velocity (EDV) in 22 RP patients using CDI (GE Logiq 7 ultrasound) twice in each eye at each of two visits within a month. At each of these two visits, ETDRS visual acuity (VA), Goldmann visual fields (GVF), and 10-2 Humphrey visual fields (HVF) were completed. PSV and EDV were used to calculate mean flow velocity (MFV); correlations with visual function 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 >0.3 logMAR, MFV was significantly lower on average than in eyes with better VA (p=0.037). Reduced MFV was also significantly associated with lower HVF mean deviation scores using size III target (p=0.007). Subjects with worse vision who completed the HVF with the size V target had significantly reduced MFV that was significantly correlated with decreased mean sensitivity at the 4 most central test locations around fixation (p=0.004). GVF log retinal areas (V4e and III4e) were not significantly related to MFV (p=0.79; p=0.78).

Conclusions : The PSV and EDV measures in the CRA of RP patients were reliable and appeared reduced in cases of impaired central but not peripheral visual function loss. These measures of retrobulbar ocular blood flow are a promising outcome measure to determine the potential physiological basis for visual function changes in clinical trials for RP.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.