Tests and diagnosisBy Mayo Clinic staff
You may go through testing so that your doctor can determine whether you have Fuchs' dystrophy. Testing may include:
- Visual acuity. This is a basic standard test that is used during routine eye exams. You'll be asked to look at a chart with letters and numbers on it and read the characters. This test helps determine if your vision has worsened since your last exam.
- Glare test. Similar to the vision acuity test, a bright light is directed at your eye while you read the characters on the chart. This test helps to determine if bright light reduces your ability to see. For example, if you notice you have a hard time seeing when you drive toward headlights at night, you'll probably have decreased visual acuity during the glare test.
- Grade or guttata stage. Your doctor uses an optical microscope called a slit lamp to look inside your eye. Your doctor then examines the endothelial cells in your cornea. If there are irregularities, called guttae, on the back surface of the cornea, you may have Fuchs' dystrophy. After this exam, your Fuchs' dystrophy may be assigned a "grade" or "stage" of zero through five. This number indicates the severity of dystrophy. A zero means there's no disease while a five means much of your cornea is affected.
- Corneal pressure test. Your doctor may numb your eyes with drops. Then your doctor will momentarily touch your eye with a special instrument that measures pressure within the eye.
- Corneal thickness test. For this test, your doctor uses ultrasound to determine the thickness of your cornea. If your cornea is too thick, it could be the result of excess fluid that has caused the cornea to swell. This swelling is usually seen in people with moderately advanced Fuchs' dystrophy.
- Corneal cell count. Your doctor may use a special instrument that records the size and shape of your endothelial cells. The instrument also measures the number of endothelial cells within a specific part of your cornea. A lower cell count usually correlates with advanced disease. This test is usually only done before eye surgery.
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