Comparison of Retinal Vessel Measurements in Digital vs Film Images

PurposeTo compare central retinal artery equivalents (CRAE) and central retinal vein equivalents (CRVE) from vessels measured from images captured with a digital camera and digitized images taken with a film camera.DesignComparison of techniques.MethodsSetting: Clinic. Patients: A total of 75 eyes of 48 adults. Observation procedures: Gradings of retinal vessel diameters from images produced by using two photographic techniques: directly from a 45° digital camera and digitized by scanning from a 30° film-based camera. Main outcome measure: Differences in CRAE and CRVE from two types of images.ResultsCRAE and CRVE were highly comparable between the two techniques with correlation coefficients of 0.88 and 0.87, respectively.ConclusionEstimates of CRAE and CRVE from measurements taken from digitally captured and digitized film-based images were highly comparable. It is likely that inferences about factors associated with retinal vessel diameters will be unbiased by the method of imaging.