Purpose
To examine the effects of various cardiovascular, ocular, and lifestyle factors on retinal vessel diameters over short periods of time.
Methods
Subjects were invited to have photographs of their retina taken at each of 3 study visits. The same eye was photographed each time. The photographs were digitized and the retinal vessel diameters were measured. Measurements from the retinal photographs taken consecutively (at visit 2 and visit 3), and 1, 3, and 4 weeks apart (between visits 1 and 2, 2 and 3, and 1 and 3, respectively) were compared.
Results
There were 63 persons who participated in all study visits and had gradable vessel measurements from all 5 images used in analysis. Correlations for pairs of study visits were high, and decreased slightly with increasing length of the time interval. For photographs taken approximately 3 minutes, 1 week, 3 weeks, and 4 weeks apart, correlations were 0.95, 0.90, 0.91, and 0.86 for central retinal arteriolar equivalent (CRAE) and 0.95, 0.90, 0.91, and 0.87 respectively for central retinal venular equivalent (CRVE). We examined the associations of blood pressure levels, smoking habits, time since last eating, exercising, consuming caffeine, and taking anti-hypertensive medication, and image focus with CRAE and CRVE. We found no consistent pattern of association of any of these characteristics with short-term changes in CRAE and CRVE.
Conclusion
Retinal vessel diameters are stable over short intervals of time and none of the factors studied were consistently associated with change in the diameters of either vessel type.
