What Is a Diabetes Eye Exam?

A diabetes eye exam, also called a diabetic eye exam, helps to check the eyes for problems such as diabetic retinopathy that may develop before you notice a change in your vision. It is not the same as a regular vision exam. Learn more about what a diabetes eye exam is and what it reveals about your eyes.

Purpose of Test

The purpose of a diabetes eye exam is to identify problems in the retina (a light-sensitive tissue in the back of the eye) or the optic nerve (a nerve that connects the brain to the eyes) before you notice any vision loss. Or, the exam can monitor the progression of eye problems that an eye doctor has already identified.

When you have diabetes, you are more likely to develop certain eye problems, including:

• Diabetic retinopathy: Causes damage to blood vessels in the retina
• Diabetic macular edema: A swelling of a part of the retina called the macula
• Glaucoma
• Cataracts: A clouding of the lens in your eye
• Optic neuropathy: Damage to the optic nerve
• Ocular muscle palsies

Eye problems like diabetic retinopathy and glaucoma often have no symptoms until they are more advanced. This is why eye doctors recommend that people with diabetes get an eye exam once a year.

A major part of the diabetes eye exam is the comprehensive dilated eye exam. During this type of exam, the eye doctor will use special drops to make your pupils (the black part of your eye) appear wider. This is called dilation.

These drops allow the eye doctor to see the back of your eyes using special equipment. Eye doctors can check for age-related macular degeneration, diabetic retinopathy, diabetic macular edema, glaucoma, and other problems by using a dilated eye exam.

People without diabetes also should get regular comprehensive dilated eye exams. An eye doctor can provide guidance on how often to get this type of exam. Problems like age-related macular degeneration and glaucoma can occur in anyone, not just those with diabetes.

However, when you have diabetes, you should get this type of exam more often because of the higher risk for eye problems. Sometimes an eye doctor may perform a dilated eye exam in a person who does not know they have diabetes and identify diabetes-related eye disease.

Risks and Contraindications

There are no major risks from a dilated eye exam, including during pregnancy. Although little is known about the risks of drugs to the fetus during the first three months of pregnancy, any risk would be very small.

The drops used to dilate eyes can cause a few temporary side effects, including:

• Blurry vision
• Glare
• Sensitivity to bright light
• Trouble judging depth of things around you

These side effects may last four to six hours. You may want to have someone drive you home after a dilated eye exam due to the effects on your vision. You also may want to schedule the exam for a time when you will not have to read for a few hours afterward.

In rare cases, dilating eye drops can cause:

• Allergic reactions
• An angle-closure glaucoma attack
• Dizziness
• Nausea and vomiting

Before the Test

You don't need to do anything special to prepare for a dilated eye exam, but make sure you have an ample amount of time for your appointment. It can take the eye drops up to 20 minutes or so to dilate your eyes adequately. If you normally drive, you may want to ask someone in advance if they can drive you home after the exam.

Timing

A diabetes eye exam may take up to an hour. This includes some time to speak with the eye doctor and staff, complete the parts of the exam that do not require dilation, receive the drops to dilate the eyes, and then complete the dilated eye exam. The eye doctor will speak with you during the exam about any findings.

Location

A diabetes eye exam typically takes place at an eye doctor's office in an exam room. The exam room will have special equipment such as a slit-lamp, which is a special microscope to examine the eyes. The room is usually darkened.

What to Wear

You don't need to wear anything special for a diabetes eye exam. If you wear contact lenses, the eye doctor's staff will have you remove them in advance. You can wear glasses when the eye doctor is not actively examining your eyes.

Food and Drink

There are no restrictions on what you eat or drink before a diabetes eye exam.

Cost and Health Insurance

Many health insurance plans will cover the cost of a diabetes eye exam. It may not be included under a vision care plan, but instead under medical insurance.

If you have health insurance, ask in advance to find out if this is something they will cover. Medicare—the federal health insurance plan for those age 65 and over—will cover one diabetes eye exam a year.

What to Bring

Bring your health insurance card or information to your appointment. Although you could bring something to read while your eyes are dilating, it may be difficult to read or look at your phone as your eyes undergo dilation.

It's helpful to have sunglasses with you, as many people feel more sensitive to light after a dilated eye exam.

During the Test

Here is what to expect before, during, and after a diabetes eye exam.

Pre-Test

Once in the eye doctor's office, you may need to complete some paperwork, especially if you have not been to their office before or in a long time. You also will need to provide proof of insurance if you have insurance. When ready, someone will take you to an exam room.

Before dilating your eyes, the eye doctor or technicians in the office may speak with you about your eye concerns and conduct some other eye tests that do not require dilation. These tests may include:

• Eye muscle function test: The eye doctor will move an object and ask you to follow it using your eyes.
• Pupil response test: During this test, the doctor will use a small flashlight to see how the pupils in your eyes respond to light.
• Tonometry test: This measures your eye pressure. Goldman tonometry, using a small probe placed on the eye with an anesthetic drop and a yellow color dye called fluorescein, is the gold standard method for testing people with diabetes.
• Visual field test: This helps check your side vision
• Visual acuity test: This is the traditional vision test you may have done before. This involves reading letters that are at a distance and close up.

When it is time to dilate your eyes, the room will usually be darkened. Someone will instill dilating drops into your eyes, and the drops may sting or burn a little.

The eye doctor or other staff will instruct you on where to wait while your eyes become dilated. You may be able to wait in that same exam room, or you may have to go to another part of the office, such as the waiting room.

Throughout the Test

A dilated eye exam only takes a few minutes. However, the full exam, including the other tests done and the wait time while your eyes are dilated, may take about an hour.

During the dilated eye exam, the eye doctor will examine the back of your eye using the slit-lamp. You will need to rest your head on the slit-lamp as indicated by your eye doctor and look in the direction indicated by the doctor.

The eye doctor will examine your optic nerve, retina, and blood vessels in the back of your eye to check for any signs of disease.

The doctor will also look at the periphery of your retina with an instrument called a binocular indirect ophthalmoscope (BIO) which the doctor wears on their head.

The BIO shines a light in the eye and the doctor looks through the magnifying lens to see peripheral areas of the retina. They look for any signs of diabetic eye disease and retinal tears, holes, or detachments. Freckles and other abnormalities can be seen in the retina this way.

Post-Test

The eye doctor will typically talk about their findings while the exam is going on. If they see signs of disease, such as diabetic retinopathy or diabetic macular edema, they will let you know the next steps. This could include additional tests, such as fluorescein angiography. Or, it could involve treatment to help preserve your vision.

Once you check out of the eye doctor's office, you can leave and return home.

After the Test

It will take several hours for your eyes to see normally again after a dilated eye exam. You should plan on doing tasks that will not tax your eyes.

Serious side effects from the drops used for eye dilation are not common. However, let your eye doctor know if any of the following potential side effects happen once you get back home:

• Nausea
• Severe eye or head pain
• Vomiting

Seek emergency care for these symptoms, do not wait.

A Word From Verywell

Regular diabetes eye exams can help identify eye problems early on so you can receive treatment before they get worse. Work with your healthcare providers, including your eye doctor, to schedule annual diabetes eye exams for better eye health.