Macular dystrophy is a rare, genetic eye disorder that causes vision loss.
Macular dystrophy affects the retina in the back of the eye. Specifically, it leads to damage of cells in an area in the retina called the macula. The macula is responsible for central vision. When the macula is damaged, people have difficulty seeing straight ahead. This makes it difficult to read, drive, or perform other daily activities that require fine, central vision.
The iris is a circular, pigmented membrane that provides the eye its color and the opening in the center is the pupil of the eye.
The iris is made up of muscular fibers that control the amount of light entering the pupil so that you can see clearly. The iris accomplishes this task by making the pupil smaller in bright light and larger in dim light.
In some people, the iris can become inflamed. This is termed iritis.
In macular dystrophy, a pigment builds up in cells of the macula. Over time, this substance can damage cells that are critical for clear central vision. Vision often becomes blurry or distorted. Typically, people with macular dystrophy maintain side (peripheral) vision, so they are not totally blind.
Who Gets Macular Dystrophy?
There are two types of macular dystrophy. A form called "Best disease" usually appears in childhood and causes varying degrees of vision loss. The second form affects adults, usually in mid-adulthood, and tends to cause vision loss that worsens slowly over time.
People with Best disease usually have one parent with the condition. The parent passes the gene to their child.
For adult-onset macular dystrophy, it’s less clear how the condition is passed from parent to child. Many people with adult-onset macular dystrophy have no other family members with the condition.
What Causes Macular Dystrophy?
Macular dystrophy is caused by a genetic mutation. In some people, doctors have identified two specific genes that are affected.
Mutations in the BEST1 gene cause Best disease and sometimes adult-onset macular dystrophy. Mutations in the PRPH2 gene cause adult-onset macular dystrophy. However, in most people with macular dystrophy, it’s unclear which gene is affected and the exact cause is unknown.
It is not known why mutations in these genes lead to the buildup of pigment in the macula. Doctors also don’t know why only central vision is affected.
How Is Macular Dystrophy Treated?
Unfortunately, there is no effective treatment for macular dystrophy. Vision loss usually develops slowly over time. There is new ongoing research on macular dystrophy that involves stem cell placement and the possible benefits.