A-H

Age-related macular degeneration (AMD):
Disease in which the macula degenerates; the leading cause of vision loss in persons over age 55

 

Age-Related Eye Disease Study (AREDS):
NIH-sponsored study that proved antioxidants are helpful in slowing the progression of macular degeneration. Part II of this study is ongoing

 

Amsler grid:
Graph paper-like grid that is used to monitor changes in vision that may indicate age-related macular degeneration

 

Angiogenesis:
Formation of new blood vessels

 

Antiangiogenic Treatment:
Treatment that controls disease by stopping new abnormal blood vessels from forming

 

Antioxidants:
Vitamins and nutrients that can prevent cell damage and help slow the progression of macular degeneration

 

Anti-VEGF therapy:
Treatment designed to reduce the levels of function of the protein VEGF, which causes new blood vessels to form in wet AMD

 

Avastin (also Bevacizumab):
See section on  Avastin

 

Bruch’s Membrane:
Thin layer of tissue that helps provide oxygen and nutrition to the retina

 

Carotenoids:
Naturally-occurring substances found in yellow and orange-colored fruits and vegetables and green, leafy vegetables—beta-carotene and alpha-carotene are responsible for the orange color of carrots, and lycopene for the red color of tomatoes; they are antioxidants that protect against free-radical damage

 

Cataract:
Clouding of the crystalline lens which results in loss of light transmission to the retina

 

Central vision:
Images seen from the center of the eye, coming from light received at the macula

 

Choroid: 
A layer in the back of the eye containing blood vessels that nourish the retina; the only source of blood supply for the macula

 

Choroidal neovascularization (CNV):
Growth of abnormal blood vessels underneath the macula associated with diseases like wet AMD

 

Clinical trial:
Medical study with patients, to determine if a treatment is safe and effective

 

Cones:
Specialized light-sensitive cells in the retina that are responsible for sharp central vision and color perception

 

Cornea:
Clear front surface of the eye responsible for transmitting light to the retina

 

Dilate:
Temporary enlargement the pupil with special eye drops to allow an eye care specialist to better view the inside of the eye

 

Drusen:
Yellow deposits comprised of cellular debris and other biological material that accumulate underneath the retina as a person ages; an increase in the number and/or size of drusen is associated with the development and progression of Dry AMD

 

Dry AMD:
Type of macular degeneration associated with the presence of deposits called drusen that accumulate under the retina; this type of AMD can lead to wet AMD

 

Endothelial cells:
Cells that make up the lining of blood vessels

 

Endothelial progenitor cell:
Adult stem cell that resides in bone marrow, and that be called into the circulation and recruited to sites of angiogenesis in wet AMD

 

Exudative macular degeneration:
Another name for wet AMD

 

Eylea:
See section on Eylea

 

Fluorescein angiogram:
Photographic procedure: Colored dye is injected into the patient’s arm, and when the dye reaches the eye, a special camera is used to photograph the blood vessels in the retina

 

Fovea:
Central part of the macula that provides the sharpest vision

 

Geographic atrophy:
Deterioration of the light-sensing cells and surrounding tissue in the macula

 

Fundus Camera and Autofluorescence (AF):
The fundus camera is a low powered microscope with an attached camera—special filters attached to the fundus camera can detect naturally occurring fluorescence (Autofluorescence, AF) in the eye to reveal damaged retinal pigment epithelium cells (RPE); AF is noninvasive and does not require any dye injections

 

Hot laser:
Laser that is sometimes used for cauterizing the abnormal blood vessels that grow underneath the retina in wet AMD

I-P

Lens:
A clear structure in the front of the eye that bends light to a pinpoint focus on the retina

 

Low vision specialists:
Specialists who can assist patients who have lost some central vision, through training and use of vision aids

 

Lucentis:
See section on Lucentis

 

Macugen:
See section on Macugen

 

Macula:
Small central area of the retina responsible for the sharp, clear vision needed to look directly at an object

 

Ocular Coherence Tomography (OCT):
OCT uses light to scan the retina, allowing a doctor to visualize the different layers of the retina and ocular tissues, and it only takes a few minutes to perform; it is noninvasive and no instruments touch the eye, no injections or exposure to intense light is necessary—it monitors the structure of the eye, to evaluate how well different therapies are working

 

Optic nerve:
Biggest nerve in the eye that connects the retina to the brain, where light is processed into vision

 

Peripheral vision:
Ability to see objects and movements with side vision, outside the direct line of sight

 

Photodynamic therapy (PDT):
Type of treatment for wet AMD that involves injections of a light-activated drug that, when exposed to special laser light, destroys abnormal eye blood vessels

 

Photoreceptors:
Nerve cells in the retina that emit electrical signals when activated by light

 

Placental growth factor (PlGF):
A protein that stimulates angiogenesis, helps to recruit cells to stabilize newly formed vessels, and recruits bone marrow derived stem cells in wet AMD

 

Pupil:
Adjustable opening at the front of the eye (the black “hole” in the iris) that expands and contracts to regulate the amount of light entering the eye

Q-Z

Retina:
Light-sensitive lining at the back of the eye that converts light images into nerve signals relayed to the brain

 

Retinal detachment:
Serious disorder that occurs when part of the retina becomes separated from the back of the eyeball

 

Retinal pigment epithelium (RPE):
Thin layer of cells deep in the retina that supports and nourishes the light-detecting photoreceptor cells

 

Retinal Specialist:
Ophthalmologist who specializes in treating diseases of the retina; Retinal Specialists are also surgeons and have completed an additional one to two years of specialty training

 

Scotomas:
Blind spots in vision

 

Vascular endothelial growth
factor (VEGF):
Family of proteins that stimulates the growth of new blood vessels—there are four members of the VEGF family, designated -A, -B, -C, -D in humans; VEGF-A is the target for most anti-VEGF therapies, and excess levels of these factors cause new vessels to be leaky

 

Visual field:
Entire area that can be seen by the eye, including front (central) vision and side (peripheral) vision

 

Wet AMD:
Serious, advanced form of macular degeneration where new blood vessels grow under the macula and leak fluid and blood; this accumulation of fluid and bleeding causes central vision loss, and if left untreated and scar tissue develops, the vision loss is permanent