Comparison of conventional fluorescein angiography film images with a cathode ray tube display

We evaluated the effectiveness of cathode ray tube (CRT) displays in the transfer of diagnostic information to the ophthalmologist. Retinal fluorescein angiography images were used and data were taken using the receiver operating characteristic experimental paradigm. Three ophthalmologists with experience ranging from two to 12 years participated in the study. Sixty-eight images were selected from proof sheets of 800 original images. Next, these images were digitized, then each set was shown on its respective display (slide projection for the proof sheet images and CRT for the digital images). These 68 images were from a variety of patients and represented a broad range of normal and abnormal retinas (including diabetic retinopathy, hypertension independent of diabetes, and sickle-cell disease). Results show (1) that there is no difference between the systems in terms of diagnostic accuracy; (2) that certainty of diagnosis was not a function of the system; and (3) that although there was an effect due to experience of the ophthalmologist, it did not affect diagnosis accuracy. We conclude that CRT displays at conventional video resolutions can deliver the needed diagnostic information as well as film. We also hypothesize that digital enhancement techniques can increase the available diagnostic information beyond that of film.