Eye health goes far beyond how well one sees. What an eye doctor concerns themselves with is how long a person can see well. There are a handful of eye diseases that can affect this. Macular degeneration is one of them. Fortunately, this condition can be diagnosed early when comprehensive eye exams are the norm. Early detection is achieved via several specific tests, which we’ll outline here.
Screening for Macular Degeneration
Macular degeneration occurs at the very back of the eye. The macula is the center of the retina. The retina is the small piece of tissue that transfers rays of light through the optic nerve to the brain. To evaluate the retina and macula, the ophthalmologist must dilate the eye. Dilation does not hurt. It is achieved with eye drops that make the pupils larger. The observation of the retina through dilated pupils may show a mottled appearance that indicates changes in pigment in the macula. Drusen, tiny yellow-colored deposits beneath the retina, may also be observed during the dilated eye exam. Additional tests include:
This may seem like a vision test but it is a screening for the function of the macula. During the Amsler grid test, the patient looks at a dot in the center of the grid. One eye is tested at a time. The non-tested eye is covered with a hand or small paddle. When observing the grid, the patient notes areas where there are blank spots, blurred or wavy lines, or other visual abnormalities.
This screening is achieved by reflecting light into the eye, which passes through to the retina. An ophthalmoscope is a special instrument that consists of a light and tips of varying sizes that direct the light through a central hole. This illuminates the retina and surrounding tissue.
Fluorescein, as it sounds uses the power of fluorescence to evaluate the retina. This test injects a special dye into the bloodstream, then photographs the eye to observe how the blood is circulating through the tiny vessels near the retina. This test can identify if blood vessels are leaking.
Optical Coherence Tomography
This brief imaging screening takes 5 to 10 minutes per eye. It can capture images of all of the structures at the back of the eye, including the optic nerve, macula, and retina. OCT can detect areas of the retina in which atrophy is occurring. A thinning retina is a sign of macular degeneration.
This test is conducted to measure how much pressure exists in the eye. Some degree of pressure is necessary; it keeps the retina and other structures stable. High pressure is dangerous to the optic nerve. It can press on this part of the eye, causing irreparable damage. Tonometry is not painful and may be done without dilation. It may involve a quick burst of air directed at the eye.