Palo Alto, CA – What is myopic degeneration?
Myopia, or nearsightedness, is the most common eye condition in people under 40. It is characterized by blurry central vision due to a gradual increase in the distance between the cornea and the retina. In most cases, this elongation poses no risk to eye health and can be corrected with eyeglasses, contact lenses, or refractive surgery.
However, in a small number of cases, the elongation of the eye can occur rapidly and become so progressive and severe that it causes myopic degeneration. In this state, the sclera, the white part of the eye, stretches beyond the length of the retina, the layer of light-sensitive cells that lines the back of the eye. This can result in a blind spot in the central vision due to degeneration of retinal cells. There can also be vitreous floaters, vitreous detachment, retinal tears, retinal detachment, and abnormal blood vessel growth. Earlier formation of cataracts and glaucoma may be associated with this condition.
What causes myopic degeneration?
Researchers have not found the root cause of myopic degeneration, but they are looking at both biomechanical abnormalities and hereditary factors. The myopic eye is biomechanically different from a healthy eye in that the myopic eye is longer, causing the retina to stretch over a larger than normal area. The Mahajan lab is studying the role of genetics in determining eye shape.
Often a family history of myopic degeneration exits, leading researchers to look for a genetic cause for the retinal changes.
Who is at risk of myopic degeneration?
People with severe nearsightedness, also known as high myopia, are at greater risk for myopic degeneration in young adulthood, as well as people who have a family history of the disease.
Researchers are finding that Chinese Americans are experiencing myopic degeneration at a higher rate than other ethnicities and that the rates of the disease are higher in Asia than in other areas of the world.
How is myopic degeneration diagnosed?
Because myopic degeneration can be diagnosed during a regular eye exam, it is crucial for patients with high myopia, especially children, to be examined regularly by an ophthalmologist. Myopic Degeneration is sometimes diagnosed during childhood. It is critical for young children with myopia to be examined for glasses or contacts, since vision may be permanently impaired.
Severe nearsightedness is one indication of myopic degeneration, but so are any signs of myopic macular degeneration, macular stretching or splitting, glaucoma, cataracts, or growth and leakage of blood vessels under the retina.
Dilation, widening of the pupil using eye drops, allows an eye surgeon to examine the back of the eye and look for any retinal abnormalities such as retinal tears and retinal detachments along with other complications that are associated with the disease.
How should people with myopia monitor their conditon to detect myopic degeneration?
Between eye appointments, patients should use an Amsler grid to monitor vision at home for early disease detection. If you see blurred, distorted, or wavy lines, mismatched boxes, missing areas, or missing edges while looking at the point in the middle of the grid, report these findings to your doctor right away. Click here to view an amsler_grid.pdf.
Also, immediately report new flashes of light, floaters, curtains or veils, or loss of vision. These are possible signs of a retinal tear or detachment and may require surgery.
What are the treatments for Myopic Degeneration?
Vision loss from myopic degeneration can be mitigated in part by using glasses and contact lenses.
One sign of myopic degeneration is a thinning retina, which can make it necessary to protect the retina from damage by wearing protective lenses while doing certain activities. Talk to your eye doctor about eye protection if you are involved in contact sports or sports played with a ball.
If there is bleeding beneath the retina, it is due in part to VEGF, a protein made by the diseased retina that causes the growth and leakage of abnormal blood vessels. Injections of anti-VEGF medications into the affected eye can help control this condition. The use of VEGF inhibitors has made laser treatment less common.
What research is being done to find a cure for Myopic Degeneration?
The prevalence of myopic degeneration is growing, and researchers are actively searching for a cure. Breakthroughs in gene therapy, drug design, and non-gene therapies are changing the way researchers and physicians are diagnosing and treating their myopic degeneration patients. Dr. Mahajan and his collaborators are working to identify the genes that control eye shape, identify human eye proteins linked to myopic degeneration, and create molecular therapies to limit retinal damage. They have been successful in using gene therapy to correct the eye shape in a mouse model.
To support our research click here.