Blood vessels normally provide oxygen and nutrients to the retinal pigment epithelium (RPE), a layer of tissue sandwiched between the retina and the inside of the eyeball. Abnormal blood vessel growth associated with wet age-related macular degeneration causes damage to the retina and problems with vision. Here abnormal blood vessels invade (red) the RPE. RPE cells are outlined in green and cell centers, or nuclei, are shown in blue.
Credit: National Eye Institute, National Institutes of Health (NEI/NIH)