Movie S1.

Large-scale serial-section electron microscopy allows large areas of the retina to be examined in high-resolution throughout its entire thickness. The ability to scroll through aligned images also permits the unequivocal identification of cell processes and allows the observation of changes in subcellular structure. Variations in mitochondrial pathology and stages of degradation are seen in the proximal end of a Henle fiber near the center of the MacTel zone. Mitochondrial integrity ranges from normal to those containing nearly completely condensed cristae. A clusters of mitochondria at various stages of degradation is seen along the right edge which faces the outer plexiform layer. This includes electron-dense structures still recognizable as mitochondria as well as mitochondria fusing with phagosomes forming mitophagosomes and multi-vesicular bodies. Still images from this area are shown in Figure 4B and D.