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Glossary – Macular Degeneration Terms

A

Age-related macular degeneration

Also known as AMD, this is a leading cause of vision loss in older people. It is a condition that causes damage to the macula, the middle of the retina. The macula is vital for sharp central vision and when damaged, results in black spots, blurriness, or blind spots in vision.1

Anti-VEGF therapy

Medication that is injected into the eye and inhibits the molecule VEGF, or vascular endothelial growth factor. VEGF is a protein that promotes the growth of abnormal blood vessels; when this protein is in the eyes at abnormally high levels, it can lead to wet AMD and severe vision loss.1

Amsler grid

A test you can do at home that helps alert you to any changes in your vision, or any progression of macular degeneration, particularly wet AMD. Similar to graph paper, this black and white grid can be used to spot any changes in your condition if you see any wavy or broken lines, dark spots, or missing areas.2

Angiogram

For an eye angiogram, sodium fluorescein dye is injected into the arm, where it then travels through the body to get to the blood vessels in the eye. A special camera tracks the dye’s progress through the blood vessels and takes pictures throughout the dye’s journey to see if it leaks anywhere, seeping into surrounding tissues.3

AREDS

The 2001 Age-Related Eye Disease Study that found that a supplement can reduce the risk of developing advanced AMD. The original formulation contained vitamin C, vitamin E, beta-carotene, zinc as zinc oxide, and copper as cupric oxide.4

AREDS2

The same research group that did the AREDS conducted a second study in 2006, called AREDS2, in which they investigated whether adding antioxidants and omega-3 fatty acids, removing beta-carotene, and lowering the amount of zinc had any effect on the progression of AMD. The formulation that came about as a result of both AREDS and AREDS2 contains: vitamins C and E, zinc as zinc oxide, copper as cupric oxide, and lutein and zeaxanthin.4 Before you take any supplements, make sure to talk with your health care professionals to make sure it’s right for you.

B

Bruch’s membrane

Located between the retinal pigment epithelium (RPE) and the choroidal capillaries, this membrane regulates the reciprocal exchange of nutrients, oxygen, fluid, and metabolic waste between the retina and the general circulation.5

C

Choroid

A layer of tissue between the retina and the sclera; it contains blood vessels that provide nourishment to the retina.6

Choroidal neovascularization

Growth of new, abnormal blood vessels originating from the choroid through Bruch’s membrane and growing into the sub-RPE space.7 This is seen with wet AMD and in some cases of myopic macular degeneration.

Cornea

The clear front part of the eye on which you may place contact lenses. It helps focus light onto the retina.6

D

Dilated eye exam

Also known as a comprehensive dilated eye exam, these are recommended to be done every year after the age of 60; for African-Americans, after the age of 40, because of the increased risk of glaucoma. Drops are put into the eyes to dilate the pupils, allowing the eye doctor to better see the inside of the eye. Other aspects of the exam include tonometry, visual field testing, and visual acuity testing.8

Diopter

A unit of measurement used to measure the power of lens needed to correct vision.9

Drusen

Yellow deposits underneath the retina made up of lipids and other waste products.1

Dry AMD

This type of AMD involves the slow breakdown of light-sensitive cells in the macula and the underlying supporting tissue.1

I

Iris

The colored part of the eye; it also includes the pupil, which is a hole in the middle of the iris that constricts and dilates to allow varying amounts of light into the eye.6

L

Lens

Located right behind the pupil, the lens further focuses light that comes in through the cornea, to help focus it onto the retina. It also changes shape to help the eye focus on near or far objects, a reflex called accomodation.6

Low-vision

When even with contacts, glasses, medicine, or surgery, everyday activities are challenging because of your impaired vision.1

M

Macula

Part of the retina responsible for central vision.6

Myopia

Nearsightedness, or the ability to see close objects clearly, but trouble seeing objects that are far away.9 This is because light entering the eye isn’t focused properly onto the retina; often the eye is too long relative to its focusing power.

Myopic macular degeneration

In myopia, the eyeball is not a sphere but rather more shaped like an egg. Therefore, light entering the eye is not focused properly onto the retina. Severe, or high myopia increases the risk of myopic macular degeneration, which is similar to AMD, but can present at a younger age. The eyeball becomes so stretched and the walls of the eyeball become very thin, thinning the layers of tissue in the eye, causing retinal cells to die. Abnormal leaky blood vessels may also develop similar to those seen in wet AMD.10

O

Occupational therapist

Trained professional who helps individuals do the things they want and need to do through therapeutic use of regular daily activities. They help provide support for those with physical or cognitive impairments, those who are recovering from injuries, those with disabilities, and more.11 With macular degeneration, an occupational therapist can help you rearrange your house so that it’s easier to get around, help you learn how to use assistive devices, or help you modify your routine to take your low vision into account.

Ophthalmologist

A medical or osteopathic doctor (MD or DO) specializing in eye and vision care. They have completed college, medical school and specialized training, and are licensed in both medicine and surgery. They can diagnose and treat eye disorders, perform surgery, and prescribe and fit glasses and contacts. Some also conduct research.12

Optic chiasm

Place in the brain where the two optic nerves come together.6

Optic nerve

A structure that connects each eye to the brain; it also sends the pictures the eye sees to the brain for processing.6

Optical coherence tomography (OCT)

This is a non-invasive imaging test performed with a machine that scans your eyes (which may or may not be dilated) to take cross-sectional pictures of your retina using light waves. These images allow the doctor (and patient) to see the fluid building up between the tissues as well as other fine abnormalities and can be an important tool to see if treatment for wet AMD is working.13

Optician

Technicians who have gone through training to properly fit glasses frames and lenses, and contact lenses. They do not perform eye exams nor write prescriptions for corrective vision devices; they use prescriptions given from ophthalmologists or optometrists.12

Optometrist

Practitioners who specialize in primary vision care. They have a doctor of optometry degree (OD) but did not go to medical school; instead, after college, they completed 4 years of optometry school. They provide vision testing and eye exams, prescriptions for glasses and corrective lenses, and can prescribe some medications for certain eye diseases.12

P

Photoreceptors

Specialized light-sensing cells that include rods and cones; rods are mostly used with night vision and perceive black and white, whereas cones perceive color and are used in central vision.6

R

Retina

A thin, see-through structure covering the inner wall of the eye, containing 10 layers of specialized cells. When you look at something, the images are projected first onto the retina before traveling through the optic nerve to the brain.6

Retinal pigment epithelium (RPE)

This is a layer of pigmented cells underneath the retina that helps the photoreceptor cells in the retina maintain their functioning; it helps process vitamin A products, absorbs light, and transports nutrients in and out of the photoreceptor cells.6

Risk factor

Any characteristic of an individual that increases the likelihood of a disease, occurrence, or injury.14

S

Stargardt disease

An inherited disorder of the retina that usually causes vision loss in childhood or adolescence, usually slowly. There is progressive degeneration of the macula, and though it is rare for an affected individual to go completely blind, there is severe vision loss.15

T

Tonometry

Part of the comprehensive dilated eye exam where eye pressure is measured. This is helpful in checking for glaucoma.16

V

Visual acuity

The clarity or sharpness of vision; normal visual acuity is generally described as 20/20 vision. This means you can see clearly and easily at 20 feet what should typically be seen at that distance.17

Visual cortex

The area of the brain that receives visual information from the retina. The visual cortex helps process information about the images, and then sends the information to other parts of the brain. It is located in the back of the head.6

Visual field test

Often used to diagnose glaucoma, it can also be used to see if part of one’s visual field has been impaired. The visual field test is also called perimetry and is done with a machine that evaluates how each eye sees, one at a time, while the other eye is covered. Often times the test involves a light appearing in different places within the visual field, and then the patient presses a button when they see it.18

W

Wet AMD

Also called neovascular AMD, this is when abnormal blood vessels grow underneath the retina. These vessels tend to be weaker than typical blood vessels and prone to swelling and leaking, which can damage the macula.1

Jaime R. Herndon | February 2019
  1. National Institutes of Health: National Eye Institute. Facts About Age-Related Macular Degeneration. 2018. https://nei.nih.gov/health/maculardegen/armd_facts. Accessed December 24, 2018.
  2. The Discovery Eye Foundation. Amsler Grid Testing. 2018. https://discoveryeye.org/amsler-grid-testing. Accessed December 24, 2018.
  3. American College of Cardiology. Eye Angiogram. 2011. Accessed December 24, 2018. https://www.cardiosmart.org/healthwise/aa79/585/aa79585.
  4. National Institutes of Health: National Eye Institute. For the Public: What the AREDS Means For You. 2018. https://nei.nih.gov/areds2/PatientFAQ. Accessed December 26, 2018.
  5. Booij JC, Baas DC, Beisekeeva J, Gorgels TG, Bergen AA. The dynamic nature of Bruch’s membrane. Prog Retin Eye Res. 2010; 29(1): 1-18. Doi: 10.1016/j.preteyeres.2009.08.003. Accessed December 26, 2018.
  6. American Association for Pediatric Ophthalmology and Strabismus. Anatomy of the Eye. 2017. https://www.aapos.org/terms/conditions/22. Accessed December 27, 2018.
  7. Wu L. Choroidal Neovascularization. 2017. https://emedicine.medscape.com/article/1190818-overview. Accessed December 27, 2018.
  8. National Institutes of Health: National Eye Institute. What is a Comprehensive Dilated Eye Exam? n.d. https://nei.nih.gov/healthyeyes/yeyeexam. Accessed December 27, 2018.
  9. Dunaeif J. Myopic Macular Degeneration. BrightFocus Foundation website. 2018. https://www.brightfocus.org/macular/article/myopic-macular. Accessed February 5, 2019.
  10. Macular Society. Myopic Macular Degeneration. n.d. https://www.macularsociety.org/myopic-maculopathy. Accessed December 27, 2018.
  11. The American Occupational Therapy Association. About Occupational Therapy. 2018. https://www.aota.org/About-Occupational-Therapy.aspx. Accessed December 27, 2018.
  12. American Association for Pediatric Ophthalmology and Strabismus. Difference Between an Ophthalmologist, Optometrist, and Optician. 2011. https://aapos.org/terms/conditions/132. Accessed December 27, 2018.
  13. Rosenfeld P. Optical coherence tomography and the development of antiangiogenic therapies in neovascular age-related macular degeneration. Invest Ophthalmol Vis Sci. 2016; 57(9). Doi:  10.1167/iovs.16-19969. Accessed December 27, 2018.
  14. World Health Organization. Risk Factors. N.d. https://www.who.int/topics/risk_factors/en. Accessed December 27, 2018.
  15. National Institutes of Health: National Eye Institute. Facts About Stargardt Disease. 2015. https://nei.nih.gov/health/stargardt/star_facts. Accessed December 27, 2018.
  16. Johns Hopkins Medicine: Glaucoma Center of Excellence. Tonometry. n.d. https://www.hopkinsmedicine.org/wilmer/services/glaucoma/book/ch06s01.html. Accessed December 27, 2018.
  17. American Optometric Association. Visual Acuity: What Is 20/20 Vision? 2018. https://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/visual-acuity. Accessed December 27, 2018.
  18. Johns Hopkins Medicine: Glaucoma Center of Excellence. Visual Field Test. n.d. https://www.hopkinsmedicine.org/wilmer/services/glaucoma/book/ch06s04.html. Accessed December 27, 2018.