Macular Degeneration Screening & Diagnosis
If you notice a change in your central vision, you should have your eyes checked by an ophthalmologist, a doctor who specializes in eyes. The ophthalmologist will most likely perform the following series of tests to determine whether or not you have macular degeneration:
On this page, you will find the following:
Diagnosis of Macular Degeneration
To help diagnose macular degeneration, an eye care professional will perform a comprehensive eye exam which may include the following:
- Amsler grid: The patient is asked to cover one eye and to focus the other eye on a grid composed of black, straight lines running horizontally and vertically, and a black dot in the center. If any of the lines on the grid appear wavy, missing or distorted, it may be an indication of macular degeneration. You can perform a home version of the Amsler test using the grid below. Once an individual is diagnosed with macular degeneration, he or she is encouraged to perform the Amsler test every day using only one eye at a time, to make sure vision is not worsening.
- Autofluorescence: The retinal pigment epithelium (RPE) is the deepest layer of the retina. RPE cells are responsible for maintaining the function of the light-sensitive cells in the retina (the cells that allow us to see). In dry age-related macular degeneration, the RPE layer of the retina thins, eventually causing the death of light-sensitive cells, ultimately leading to visual impairment. When dry age-related macular degeneration is in the advanced stage, geographic atrophy occurs . An autofluorescence photo is used to determine the extent and/or increase in the area of geographic atrophy in patients with advanced, dry age-related macular degeneration.
- Dilated eye exam: In this test, the doctor will administer eye drops that dilate, or widen, the pupil. This provides a larger “window” to the back of the eye. Then, using a special instrument, the doctor can look into the eye and study the retina for signs of disease. The doctor will look for the presence of drusen using this type of eye exam. Dilation allows the doctor see the retina more easily to determine optic nerve damage as well.
- Fundoscopy or ophthalmoscopy: The pupil is dilated and a bright beam of light is aimed into the eye to view the retina, choroid, blood vessels and optic disk.
- Visual acuity test or eye chart test: This test measures how well an individual can see letters or numbers at different distances.
- Fundus photography: The pupil is dilated, light is focused through the cornea, pupil and lens, and a customized camera photographs the back of the eye, including the retina, macula and optic nerve.
- Fluorescein angiography: If the wet form of macular degeneration is suspected, this test may be done to detect leaking blood vessels. A dye is injected into the arm of the patient, and is traced as it courses through the blood vessels in the retina, where it can reveal leakage.
- Optical coherence tomography (OCT): OCT is a relatively new, non-invasive technique used to image the retina. Cross-sectional images of the retina are produced so the different layers and their thicknesses can be measured. When advanced dry age-related macular degeneration is suspected, this technique is used to identify regions of the retina that are thinning, indicating the presence of geographic atrophy. This technique is also routinely used to assess the retina’s response to various treatments.
- Tonometry: This test measures the pressure inside the eye. Pressure is often measured after an individual receives a numbing eye drop.
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Home Test for Macular Degeneration
The Amsler Grid can help detect early signs of retinal disease and monitor changes in vision after a diagnosis has been made. It should not in any way substitute for the advice of a qualified health care professional and it is not intended to constitute medical advice.
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Directions: |
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Wear your reading glasses or bifocals.
- Cover one eye with your hand without putting pressure on the eye.
- Look at the dot in the center of the grid.
- Do not let your eye drift from the center.
- All of the lines should appear straight and all of the boxes should appear to be the same size and shape. There should be no distortion on the grid. If any of the lines are missing, or they appear to be crooked, bent, wavy or discolored, you should contact your physician immediately for an examination.
- Do the same test with the other eye.
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Find a Doctor
It is very important to have regular eye examinations, particularly as you age, or if you have any of the risk factors associated with age-related macular degeneration. If only one eye is affected by macular degeneration, there may be no noticeable symptoms, but a doctor can still make an accurate diagnosis. Early diagnosis and treatment may help control progression of the disease, and stabilize or even restore some vision. People under age 65 should have an eye exam at least every two years; for those over age 65, one exam per year is recommended.
Many people confuse optometrists and ophthalmologists. An optometrist has a four year post-graduate degree (following a Bachelor of Science degree) and is a Doctor of Optometry. Optometrists examine patients and prescribe treatment, normally non-surgical, such as eyeglasses and contacts. An ophthalmologist has an undergraduate degree, a four-year medical degree and four years of post-graduate training in ophthalmology. An ophthalmologist is a medical doctor and can also perform eye surgery. For those with eye diseases, such as macular degeneration, an ophthalmologist is recommended.
The following websites may be helpful in finding an eye care professional:
Find an optometrist (AOA): http://www.aoa.org/x5428.xml
Find an ophthalmologist (AAO): http://www.aao.org/find_eyemd.cfm
American Medical Association: http://webapps.ama-assn.org/doctorfinder/html/patient.html
WebMD: http://doctor.webmd.com/physician_finder/home.aspx?sponsor=core
Find a Doc: http://www.findadoc.com/
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Further Information
The following publications from AHAF can provide you with more information:
- Living with Macular Degeneration
- Macular Degeneration: The Essential Facts
- Amsler Grid Eye Test
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Source: The American Health Assistance Foundation is grateful to Jeffrey H. Stern, M.D., Ph.D. at the Regenerative Research Foundation and Susan E. Yanni at Vanderbilt University for reviewing aspects and providing some of the above content.
Last Reviewed On: 12/23/09
