Fig. 1.

OCT images from the right eye of a 55-year-old male with diabetic retinopathy and without macular edema. Images a and c are copies of the same image that was the first of the two taken in this eye. The copies were marked separately with the calipers to measure the thickness, respectively, of the total photoreceptor layer (image a) and the photoreceptor outer segment layer (image c). The second OCT image taken in this eye is shown in b and d, which are likewise copies that were separately marked for measurement of the layers. The central measurements were taken from the foveal center; the other two measurements are taken from 750 μm away from the central fovea.