Bruch's Membrane: A thin layer of fibrous proteins that separates the retinal pigmented epithelium from the choroid. It serves to support and anchor the cells of the pigmented epithelium as well as helping to regulate the exchange of materials between the retina and the blood vessels in the choroid.
Choroid: A layer of tissue rich in blood vessels that lies between Bruch's membrane and the sclera (the white part of the eye).
Cones: Photoreceptor cells that have cone-shaped outer segments and convey color information in bright light.
Drusen: Abnormal deposits that form between Bruch's membrane and the retinal pigmented epithelium that are a hallmark of AMD. Drusen are thought to cause dysfunction in pigmented epithelial cells and adjacent photoreceptor cells of the retina.
Dry AMD: The form of macular degeneration that involves drusen deposition and other abnormalities in the absence of abnormal blood vessel growth or angiogenesis. Also known as atrophic macular degeneration.
Fovea: The centermost portion of the macula where the retina is thinned to allow more direct access of light to photoreceptor cells.
Glia: Non-neuronal cells of the nervous system that perform supportive functions.
Macula: The cone-rich portion of the retina responsible for high acuity vision in the central portion of the visual field.
Neuron: A general term for a cell of the nervous system that is involved in the transmission of nerve impulses.
Optic Nerve: The nerve that conveys visual information in the form of nerve impulses from the retina to the brain.
Outer Segments: The portion of photoreceptor cells that contain light-absorbing molecules called "photopigments" (e.g. rhodopsin in rod photoreceptors).
Photoreceptors: The cells of the retina that are responsible for the capture of light. Photoreceptors are of two types: Rods and Cones that are characterized by differences in shape and function.
Pigmented Epithelium: A single layer of cells that lies between Bruch's membrane and the retina. Cells of the pigmented epithelium perform a number of supportive functions that are crucial to the survival of photoreceptor cells.
Retina: The transparent layer of neuronal tissue that lines the back of the eye. The retina is actually a direct extension of the brain, connected by the optic nerve.
Rods: Photoreceptor cells that have rod-shaped outer segments and are specialized for the detection of low level light, and do not convey color information.
Wet AMD: The form of macular degeneration that involves the invasion of the pigmented epithelium and/or retina by new blood vessel growth. Leakage from these vessels can cause massive damage to pigmented epithelial and retinal cells and lead to rapid loss of vision in the affected eye. Also known as the neovascular or exudative form of macular degeneration.