Reduced Central Retinal Artery Blood Flow Is Related to Impaired Central Visual Function in Retinitis Pigmentosa Patients

Abstract

Purpose We evaluated the test-retest repeatability of blood flow velocities in the retrobulbar central retinal artery (CRA) and explored whether reduced blood flow is related to the degree of visual function loss in retinitis pigmentosa (RP) patients with wide range of disease severity. Materials and Methods We measured CRA peak systolic velocity (PSV) and end diastolic velocity (EDV) to calculate mean flow velocity (MFV) in 18 RP patients using color Doppler imaging with spectral flow Doppler (GE Logiq7 ultrasound) twice in each eye at each of two visits within a month. At each of these two visits, we measured ETDRS visual acuity (VA), quick Contrast Sensitivity Function (qCSF), Goldmann visual fields (GVF), 10–2 Humphrey visual fields (HVF), and dark-adaptation at 5° from fixation with the AdaptDx; multifocal electroretinography (mfERG) was obtained at a single visit. Results Mean coefficients of variation for PSV, EDV and MFV were 16.1–19.2% for within-visit measurements and 20.1–22.4% for between-visit measures. Across patients, greater visual function loss assessed with VA (p = 0.04), extinguished versus measurable amplitude in ring 1 for mfERG (p = 0.001), and cone-only versus rod function with the AdaptDx (p = 0.002) were statistically significantly correlated with reduced MFV in the CRA when included a multilevel multivariate regression model along with the qCSF and HVF results, which all together accounted for 47% of the total variance in MFV. GVF log retinal areas (V4e and III4e; p = 0.30 and p = 0.95, respectively) and measurable far peripheral vision during GVF testing (p = 0.66) were not significantly related to MFV. Conclusions MFV in the CRA decreased with impaired central vision due to loss of both rod and cone function, had good test-retest repeatability, and may serve as a biomarker outcome to determine the potential physiological basis for improvements in RP clinical trials of therapies with indirect effects on blood flow to the retina.

Randomized controlled trial of electro‐stimulation therapies to modulate retinal blood flow and visual function in retinitis pigmentosa

“…Retrobulbar ocular hemodynamics in the CRA were measured with color Doppler imaging and spectral flow Doppler using the GE Logiq 7 according to previously published guidelines (Stalmans et al 2011) and procedures. (Kayser et al 2017) by trained sonographers (DM, PV, JH) who were masked to the subjects’ intervention group. Mean peak systolic velocity (PSV) and end diastolic velocity (EDV) were used to calculate mean flow velocity (MFV) using the equation: MFV=((PSV)+(2×EDV))/3.…”

Role of ICAM-1 in impaired retinal circulation in rhegmatogenous retinal detachment

“…Retinal circulation in eyes with macula-off RRD did not recover to the levels observed in fellow eyes until at least 6 months after 25G MIVS. Accumulating evidence suggests that retinal circulation is severely impaired in retinal degenerative diseases such as retinitis pigmentosa and other inherited retinal diseases 16 – 18 . Macula-off RRD led to thinning of the macula and degeneration of photoreceptors.…”

Vascular dysfunction in retinitis pigmentosa

“…Recently, reduced CRA blood flow was shown to be related to impaired central visual function in RP patients (Kayser et al. ). The authors concluded that reductions in CRA flow may occur prior to RP diagnosis or shortly thereafter, as impairment was present in RP subjects who had normal central visual function and greater than 4 years of self‐reported visual field loss (Kayser et al.…”

“…The authors concluded that reductions in CRA flow may occur prior to RP diagnosis or shortly thereafter, as impairment was present in RP subjects who had normal central visual function and greater than 4 years of self‐reported visual field loss (Kayser et al. ). These results indicate that vascular abnormalities in RP are not merely confined to the peripheral retina, but may also exacerbate the loss of central visual function.…”