Variability of measurement of retinal vessel diameters.
OBJECTIVE
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 three study visits. The same eye was photographed each time. The photographs were digitized and 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 five images used in the analysis. Correlations for pairs of study visits were high, and decreased slightly with increasing length of the time interval. For consecutive photographs taken, and 1 week, 3 weeks, and 4 weeks apart, correlations were 0.95, 0.90, 0.91, and 0.86, respectively, 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.


CONCLUSIONS
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.
Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health , Madison, WI , USA.
Charles D
CD
McCanna
Chelsea E
CE
Myers
Minyoung
M
Lee
Lorraine G
LG
Danforth
Emily L
EL
Moore
Stacy M
SM
Meuer
Ronald
R
Klein
Barbara E K
BE
Klein
D000368:Aged; D000959:Antihypertensive Agents / Q000008:administration & dosage; D001794:Blood Pressure / Q000502:physiology; D002110:Caffeine / Q000008:administration & dosage; D002320:Cardiovascular Physiological Phenomena; D015444:Exercise / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012161:Retinal Artery / Q000033:anatomy & histology*; D012169:Retinal Vein / Q000033:anatomy & histology*; D012907:Smoking / Q000453:epidemiology; D014792:Visual Acuity / Q000502:physiology
D000959:Antihypertensive Agents; D002110:Caffeine