High magnifications of the outer retina, RPE, Batch's membrane, and choroid. The only visibly significant difference between young (A, 23 years old) and old (B, 65 years old) is the thickening of Batch's membrane with age. In retinas with hard drusen (C, 49 years old), deposits form underneath the RPE monolayer within the inner collagenous layer of Batch's membrane, and decreasing intact CC. In retinas with soft drusen (D, 73 years old), significant displacement of the flattened RPE from the CC is observed, likely contributing to loss of homeostasis in the eye. The appearance of the photoreceptors in C and D is a post-mortem artifact unrelated to the finding of drusen. INL: inner nuclear layer, OPL: outer plexiform layer, ONL: outer nuclear layer, IS/OS: inner/outer segments of photoreceptors, RPE: retinal pigment epithelium, BrM: Batch's membrane. The black arrow indicates Batch's membrane. The red arrowhead indicates drusen. Panels depict PAS staining. Scale bar, 50 μm. Paraffin sections cut at 4-6 μm.