Retinal blood flow velocity measured by retinal function imaging in retinitis pigmentosa

Background To measure the retinal blood flow velocity in patients with retinitis pigmentosa using the retinal function imaging technique. Methods The clinical observational investigation included a study group of five eyes of five patients (age: 55.7 ± 8.6 years) with retinitis pigmentosa (RP) and a control group of five eyes of five healthy subjects. We used a randomly chosen eye of the RP patients, and compared its results to the normal subjects using a mixed linear model, correcting for heart rate, age, and gender. Results The mean blood velocity in the narrow retinal veins (1.7 ± 0.35 cm/s versus 3.0 ± 0.35 cm/s; P<0.001) and wide retinal veins (1.5 ± 0.35 cm/s versus 3.1 ± 0.30 cm/s; P<0.001) was significantly lower in the study group than in the control group not correcting for heart rate, age or gender. Correspondingly, the arterial blood flow velocity was significantly lower in the study group than in the control group for the narrow arterial vessels (2.3 ± 0.55 versus 4.2 ± 0.5; P=0.006) and for the wide retinal arteries (2.5 ± 1.05 cm/s versus 4.8 ± 1.0 cm/s; P<0.001). Conclusions Using the retinal function imaging technology revealed significantly lower retinal blood flow velocities in the small and large retinal vessels in patients with retinitis pigmentosa than in healthy subjects. This corresponds with the known decrease in the retinal vessel diameters as observed upon ophthalmoscopy in patients with retinitis pigmentosa. Retinal function imaging technology may hold promise for measurements of retinal blood flow parameters.