Abstract
Purpose: :
To determine whether subfoveal choroidal blood flow (ChBF) is altered in retinitis pigmentosa (RP) patients and whether this alteration is associated with central cone-mediated dysfunction
Methods: :
Subfoveal choroidal blood flow (ChBF) by real-time, confocal laser Doppler flowmetry1 and focal macular (18 deg) cone-mediated electroretinograms (FERGs)2 were recorded in 30 patients with retinitis pigmentosa (age range 35-64 yrs) and relatively preserved visual acuity (range: 0.4-1.0). Twelve age-matched control subjects were also examined. Volume (ChBVol), velocity (ChBVel) and flow (ChBF) were determined as the average of three 60 sec recordings with changes in DC < 10% between the recordings (the DC measures the intensity of the light scattered by the tissue and red blood cells in the illuminated volume). FERGs were recorded in response to 41 Hz flickering stimuli (average of two repetitions of 600 events each). The amplitude and phase of the Fourier-isolated 1st harmonic component of the FERG were determined
Results: :
In RP patients, ChBF and ChBVel were on average reduced by 28% (p < 0.01) in patients compared to controls, while average ChBVol was similar in the two groups. FERGs were on average reduced by 60% (p < 0.01) and delayed by 50 deg (p < 0.01) in patients compared to controls. FERG phase delays in patients were correlated (r = 0.50, p < 0.01) with corresponding ChBF and ChBVel values, respectively. FERG amplitudes of patients were correlated (r = 0.49, p < 0.01) with ChBVol values
Conclusions: :
The data indicate significant alterations of ChBF hemodynamic in RP patients. Smaller ChBF values were associated with greater FERG delays and smaller amplitudes, suggesting a link between ChBF and central cone-mediated dysfunction in RP1Riva CE, Cranstoun SD, Grunwald JE, Petrig BL. Invest Ophthalmol Vis Sci. 1994.2Falsini B, Fadda A, Iarossi G et al. Invest Ophthalmol Vis Sci. 2000.
Keywords: blood supply • choroid • retinal degenerations: hereditary