RECOGNIZING AND DIAGNOSING AMD
Although there is no cure for either form of AMD, early diagnosis is a key step in delaying disease progression and helping patients become more vigilant about eye care, since the chances of progressing from intermediate dry AMD to advanced dry or wet AMD are as high as 18 percent over a five-year period.34 Because both wet and dry AMD tend to progress, people at risk for AMD, including those over the age of 50 and those with a family history of AMD, should have their eyes examined regularly. They should make a point of knowing the symptoms of the disease and the recommendations for minimizing risk.
Symptoms
Symptoms of AMD can vary from person to person and can even be unrecognizable in the disease’s early stages. Occasionally, only one eye will develop vision loss, while the other functions normally, making symptoms harder to detect. When both eyes are affected, symptoms of central vision loss are more easily noticeable. Such symptoms can include the following:
Blurred or fuzzy vision – These symptoms are early signs of AMD that, in some cases, might become less apparent as light gets brighter. 8
Straight lines appearing wavy or crooked – This symptom is particular to wet AMD and can affect both lines seen in near vision, such as sentences on a page, and those farther away, such as telephone poles and the sides of buildings.
Decreased contrast sensitivity – People with AMD might have difficulty seeing objects that are the same color as their background, for example, facial features or black coffee in a black cup.
- A small, but growing, blind spot in the center of vision.
- Decreased ability to distinguish colors.
Diagnostic Tests
A number of tests can be performed to detect and diagnose AMD (and other conditions that can impair vision), even before symptoms might be apparent. In addition to the standard visual acuity tests to assess the eye’s ability to distinguish details and shape at varying distances and lighting situations, the following tests may be specifically performed to diagnose AMD:
Dilated eye exam – Eye care professionals use a variety of techniques and instruments to examine the retina and the optic nerve for disease characteristics of AMD after eye drops have been placed in the eye to widen or dilate the pupils.
Fluorescein angiography – This procedure involves injecting a non-toxic dye into the bloodstream through a vein in the arm to capture blood vessel growth, leakage and deposits in the retina and macula. Pictures are taken as the dye passes through the blood vessels in the retina to identify any leaking blood vessels and diagnose wet AMD. Other imaging studies may also give valuable information on the type and extent of the disease.
Optical coherence tomography (OCT) – This technique involves capturing a cross section image of the macula with a camera-like device. It may be helpful in determining the presence of fluid beneath the retina and in documenting degrees of retinal thickening. It adds information that is complementary to fluorescein angiography.
Amsler grid – This test, using a grid that resembles graph paper with a dot in the center, can be performed at home. By looking directly at a spot in the center of a grid, one eye at a time, people can determine whether they have symptoms of AMD if the lines on the grid appear blurred or wavy, or if the center spot is not visible.
Who Can Help: The Role of Optometrists, Ophthalmologists and Retina Specialists
People over the age of 50 and/or otherwise at risk for AMD are encouraged to see an eye care specialist for regular eye exams that can include one of the above-mentioned screenings. Such tests and assessments can be made at varying stages by one of the following types of eye doctors:
Optometrists – Doctors of optometry (O.D.s) are independent eye care providers. It is important to note that optometrists are licensed to practice optometry, not medicine. Their role in detecting AMD can be critical since there are no symptoms at very early stages and regularly scheduled visits to an optometrist for such routine matters as corrective lenses can include screenings to detect signs of the disease. Additionally, optometrists serve as referrals to other health care professionals, like ophthalmologists and retina specialists, who can confirm a diagnosis of AMD and recommend treatment.
Ophthalmologists – Specializing in eye and vision care, ophthalmologists are medical doctors (M.D.s) and doctors of osteopathy (D.O.s) specially trained to provide the full spectrum of eye care, including diagnosis, management and surgery of ocular diseases and disorders. In addition to four years of medical school and one year of internship, ophthalmologists spend a minimum of three years of residency during which they receive special training in all aspects of eye care. People who suspect they may be at risk of developing AMD or who notice symptoms of the disease may go directly to an ophthalmologist for diagnosis and/or treatment. Sometimes, referral to a retina specialist is made.
Retina specialists – Retina specialists are ophthalmologists who are highly trained in the diagnosis, management and treatment of macular degeneration and other retinal problems such as diabetic retinopathy, macular holes, macular puckers and retinal detachments. In addition to four years of medical school and three years of residency, they also spend an additional one to two years completing fellowship training. Because these physicians are so highly specialized in the field, ophthalmologists often refer people who show signs of AMD to a retina specialist to confirm diagnosis and, ultimately, recommend and perform treatment. 10
