In an intact eye, photoreceptors are unlikely to be the cells with the greatest requirement for lactate as a fuel. First, among all the structures in the retina, photoreceptor cell bodies have the most direct access to glucose. In contrast, Muller cell apical surfaces are € recessed below the photoreceptor cell bodies and essentially covered by a carpet of photoreceptors (Fig. 4; see also Fig. 4 of Tarboush et al., 2012). Based on the physical appearance of this part of the retina, Muller cells’ access to € glucose from the IPM would be limited to what is left over after photoreceptors take what they require