Abstract
Purpose: :
To assess the reproducibility and variability of the retinal arterial and venous response to flicker light in healthy patients using commercially available Retinal Vessel Analyser (RVA).
Methods: :
Ten healthy subjects (mean age:36.4 years, range:25–48 years) were examined. The diameter of the retinal arteries and veins was measured using RVA (Imedos, Weimar, Germany). Each examination consisted of three 20–second periods of flicker stimulation (530–600 nm, 12.5 Hz), each followed by an 80–second observation period. Arterial and venous flicker response was calculated using 3 different formulae, to assess the most reproducible. Intraobserver, interobserver, and intervisit reproducibility of flicker response measured at the same location, and variability of flicker response between different locations on the same vessel, different vessels of the same eye, and between right and left eye were studied. Intersubject variability was also analyzed. Results were assessed by their repeatability and intraclass correlation coefficients.
Results: :
All patients showed retinal arterial and venous dilation to flicker light at all examinations. Intraobserver, interobserver, and intervisit reproducibility of flicker response measured at the same location was very good (intraclass correlation coefficients were between 0.710 and 0.956 for arteries and between 0.868 et 0.956 for veins, with the optimal formula). The variability of flicker response between different locations on the same vessel, and different vessels of the same eye, and between right and left eye was higher (intraclass correlation coefficients were between 0.525 and 0.657 for arteries and between 0.294 et 0.639 for veins). Intersubject variability of flicker response was +/– 21.6% in retinal arteries and +/– 29.6% in retinal veins.
Conclusions: :
Reproducibility of the retinal arterial and venous response to flicker light in healthy patients using RVA was very good at the same location. Variability of flicker response between different vessels of the same eye, between right and left eye, and between subjects was higher. Measurement of the flicker response at the same location and with the optimal formula should be recommend for further interventional studies using RVA.
Keywords: clinical (human) or epidemiologic studies: systems/equipment/techniques • vascular cells • retinal connections, networks, circuitry