Dynamic And Static Vessel Analysis In Patients With Retinitis Pigmentosa: A Pilot Study of Vascular Diameters and Functionality.

To evaluate in vivo the vascular anatomy and functionality of early manifestation retinitis pigmentosa (RP) by means of a dynamic and static vessel analyzer. Fourteen patients with early RP and 14 normal subjects were consecutively enrolled in this observational, prospective study. Each patient underwent a complete ophthalmologic examination, including dynamic and static retinal vessel analysis using the Dynamic Vessel Analyzer. The patients with RP and the control group were well matched in age and sex. Patients with RP had a mean best-corrected visual acuity of 20/25 (range: 20/40-20/20). Dynamic vessel analysis performed in patients with RP showed an arterial and venous dilation during flicker stimulation of 5.28 ± 1.7% and 4.07 ± 1.78%, respectively. Only arterial dilation was statistically different compared with control subjects (3.33 ± 0.99%, P = 0.0062). Static retinal vessel analysis in patients with RP showed a decreased mean central retinal artery equivalent (P < 0.001) and central retinal vein equivalent (P < 0.001) compared with control subjects. By contrast, the arterial-to-venous ratio was similar in both groups (RP: 0.79 ± 0.11, control group 0.86 ± 0.04, P = 0.072). Our data confirm that retinal arterial and venous narrowing is present at an early stage in patients affected by RP. However, dynamic vessel analysis shows how the retina of patients with RP with no best-corrected visual acuity loss presents an augmented artery dilation response compared with normal subjects and retained neurovascular coupling.