Comparison Of Cup-To-Disc Ratios As Measured Using Ocular Coherence Tomography And Stereoscopic Fundus Photography.

Background: The purpose of this research project is to compare cup-to-disc (C/D) ratios as measured with the Cirrus (Zeiss) ocular coherence tomography (OCT) and stereoscopic fundus photography of the same subject.
Methods: At the University Eye Center in Big Rapids, MI, subjects will have each eye photographed stereoscopically using a fundus camera. Subjects will have each of their eyes analyzed using the OCT and the report, containing the instruments optic
nerve head measurements, will be obtained. The subjective measurements will then be
compared to the calculated values as measured with the OCT. The subject activities will be limited to aforementioned and are expected to take approximately five minutes. Results: Interclass correlation coefficients for the group of average C/Ds and vertical C/Ds shows good agreement with the clinician’s average assessment (CAA) However, when the C/Ds are divided into subgroups based on size, there appears to be little agreement. The mean of the clinician’s ICC also appears to be low for subgroups. Conclusions: Inter-observer variability can have an effect on the clinical care of a patient so the widespread use of instrumentation when assessing the C/D ratio can be useful. This study demonstrates that inconsistency exists when relying solely on objective measurement techniques, such as the Cirrus HD-OCT, compared to the fundoscopic assessment of the C/D.