Retinal Photographic Grading: The Orthoptic Picture

Robert Sparkes, DipAppSc (Cumb), DOBA, MOAA
Paul Mitchell, MD, FRACO, FRCS, FCOphth
Peteris Darzins, BMBS, FRACP

Signs of the major retinal causes of blindness in Australia are readily identified from stereoscopic fundus photographs. This study involved the masked grading of 922 photographic slide sets which included 400 cases of advanced Age-related Macular Degeneration (AMD) and a similar number of age and sex-matched controls.
Photographic colour slides of the retina showing AMD lesions, including drusen (size, number and confluence), focal pigment, geographic atrophy and neovascular disease, were graded individually by an ophthalmologist, orthoptist and a nurse using the protocol set by the Waterman Chesapeake Bay study. These grades were then used to define four categories of AMD severity.
Kappa statistics were generated from the data to show inter-observer variability between the ophthalmologist and Orthoptist and nurse. The resulting high level of agreement in all areas graded (between 0.45…0.83) indicated that the Orthoptist compares favourably to the ophthalmologist and the nurse in grading expertise.