Figure 2. Spectral domain optical coherence tomography shows damage to the photoreceptors in the nasal retina of the left eye.

Each cross-section corresponds to the green line in the adjacent fundus image. In the left eye, it passes through the blood vessel (white arrow) visible in Fig. 3, marking the eccentricity at which the density of cone outer segments plummets and the absolute scotoma begins. Between the white arrow and the optic disc (red bracket), the outer nuclear layer in the left eye appears slightly thinner than at the corresponding location in the right eye (red bracket). In the left eye, the dim line representing the external limiting membrane (long yellow arrow) is preserved, but the bright line marking the junction of the inner and outer segments (short yellow arrow) becomes disrupted. Critically, there is substantial volume loss in the layer containing outer segments, which is normally seen as a gray band just to the scleral side of the inner/outer segment junction. F = fovea.