Estimated reading time: 6 minutes
Throughout our lives, we will get a number of eye exams done. These can be as children, to check our vision to see if we need glasses. They can be as adults to look for irregularities or defects. If you have diabetes, you need regular eye exams to catch complications early. One serious condition that can develop is called diabetic macular edema (DME). This is a leading cause of vision loss in people with diabetic retinopathy, affecting about 750,000 Americans. If your doctor thinks you might have DME, your eye exam will be a little different! Here, PatientsLikeMe will break down a standard eye exam and the additional steps involved when testing for DME.
What Happens During a Routine Eye Exam?
A routine eye exam checks for common vision problems and evaluates your overall eye health. To start, your doctor will get a patient history filled out. They will ask about:
- Any vision problems or symptoms you have noticed.
- Your overall health and any medical conditions (like diabetes).
- Medications you take.
- Family history of eye diseases.
Next on the to-do list is a visual acuity test. This test measures how clearly you can see. You will read letters or symbols from an eye chart at different distances to determine your vision level (e.g., 20/20 or 20/40). When you think of eye exams this is probably the first image that pops into your head. The ratio of numbers expresses visual acuity. If you have 20/20 vision, you can see clearly at 20 feet what is meant to be seen at 20 feet. If you have 20/40 vision, you have to be 20 feet away to see what can normally be seen at 40 feet.
Follow up Tests
This will be followed by a few other preliminary tests. Your doctor may check your depth perception, test your color vision, look at how the muscles in your eye are moving, and measure your pupil's response to light. A refraction test will determine whether you need glasses or contact lenses. By sitting in a chair with a special device called a phoroptor attached to it, a specialized light will be shined into your eyes that determines how the light refracts. If there are any "refractive errors," you may need glasses to correct your vision.
Your doctor may use a slit lamp to look at the structure of your eye. This lamp focuses a high-intensity beam of light into a narrow slit. Your eye is made up of several parts, and the slit lamp lets your doctor look more closely at the cornea, iris, eyelids, conjunctiva and sclera. They often add a special yellow dye called fluorescein to help look at the cornea and tear layer. Doctors perform a tonomotry test to look for glaucoma, a group of eye problems that can damage the optic nerve. Finally, your doctor may decide to dilate your pupils to get a clearer view of the retina and optic nerve. This helps them check for signs of eye disease.
Eye Exams for DME
If you have diabetes and your doctor thinks you might have DME, your exam will include a few more specialized tests. These help figure out whether fluid is leaking into the macula of your eye. There are three standard tests to know.
Fluorescein Angiography (FA)
Doctors do a fluorescein angiography to look at blood flow in the retina. It can also find any leaking blood vessels. To start, your doctor will dilate your pupils and take some images of your eyes. They will then inject a yellow dye into a vein in your arm. This dye travels through your body and eventually gets to the blood vessels in your eyes. By looking at your eyes with a special camera, your doctor can see where fluid is (or is not) leaking. The yellow dye can temporarily turn your skin yellow and your urine a dark yellow or orange. People also occasionally report dizziness, increased heart rate, nausea and a metallic taste in their mouth. If the dye leaks during the injection you may feel a slight burning sensation, but this only lasts a few minutes and does not harm your skin.
Optical Coherence Tomography (OCT)
An OCT is a non-invasive test that uses light waves to take pictures of your retina. These cross-sectional photographs actually let your doctor see each layer of the retina and the optic nerve fiber. By seeing the different layers, they can measure thicknesses and how they change over time. In this test, you rest your chin on a support while a machine takes the images of your retina. It usually lasts between 5-10 minutes, and there are no potential side effects to be aware of. Doctors do occasionally dilate your pupils before an OCT, which will make you more sensitive to light for a few hours after.
Amsler Grid Test
The amsler grid test is a simple way to check central vision. The grid itself is just a piece of paper with vertical and horizontal lines covering it. There is a dot in the middle of the grid. With normal vision, someone looking at an amsler grid would be able to see straight vertical and horizontal lines with a dot in the center. With DME, the grid may appear wavy or broken. There could be distorted lines and blurry eyes, particularly in the center of the grid. You can actually do this test can at home! It helps evaluate change over time.
Why These Extra Tests Matter
Diabetic macular edema can cause permanent vision loss if untreated. The additional tests used in a DME exam help find fluid leaking into the retina early, can determine how severe the swelling in the macula is, and guide how doctors decide to treat and prevent damage. When it comes to your eye health, if you have diabetes you need to make sure you are getting exams annually.
Catching diabetic retinopathy early can help prevent DME and protect your vision. If you already have DME, regular follow-ups and treatment can slow its impact. If you notice any blurry vision, wavy lines, or difficulty seeing in the center of your vision, get an eye exam as soon as possible. Your eye doctor can help you take steps to protect your eyesight for the long term.
Taking control of your health has never been easier with PatientsLikeMe, a platform that empowers you to manage your wellness journey proactively. PatientsLikeMe offers tools to track your symptoms, treatments, and outcomes. Click below to join today!