What to know about diabetic retinopathy

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Diabetic retinopathy is an eye condition that occurs due to diabetes.

It can arise as a result of the high blood sugar levels that diabetes causes. Over time, having too much sugar in the blood can damage blood vessels throughout the body, including in the retina.

The retina is the membrane covering the back of the eye. It detects light and sends signals to the brain through the optic nerve.

If sugar blocks the tiny blood vessels that go into the retina, it can cause them to leak or bleed. The eye may then grow new blood vessels that are weaker and leak or bleed more easily.

If the eye starts to grow new blood vessels, this is known as proliferative diabetic retinopathy, which experts consider a more advanced stage. The early stage is known as nonproliferative diabetic retinopathy.

The eye may accumulate fluid during long periods of high blood sugar. This fluid accumulation changes the shape and curve of the lens, causing changes in vision.

Once a person gets their blood sugar levels under control, the lens will usually return to its original shape, and vision will improve.

More than 2 in 5 people with diabetes in the United States have some stage of diabetic retinopathy.

Diabetes also increases a person’s risk of developing other eye problems, including cataracts and open-angle glaucoma.

Diabetic retinopathy does not usually produce symptoms during the early stages. Symptoms typically become noticeable when the condition is more advanced.

Diabetic retinopathy tends to affect both eyes. The signs and symptoms of this condition may include:

• blurred vision
• impaired color vision
• eye floaters, or transparent spots and dark strings that float in the person’s field of vision and move in the direction that the person looks
• patches or streaks that block the person’s vision
• poor night vision
• a dark or empty spot in the center of the vision
• a sudden and total loss of vision

Without treatment, diabetic retinopathy can lead to various complications.

When blood vessels bleed into the main jelly that fills the eye, known as the vitreous, this is called vitreous hemorrhage. In mild cases, the symptoms include floaters, but more severe cases can involve vision loss, as the blood in the vitreous blocks light from entering the eye.

If the retina remains undamaged, bleeding in the vitreous can resolve itself.

In some cases, diabetic retinopathy can lead to a detached retina. This complication can happen if scar tissue pulls the retina away from the back of the eye.

It usually causes the appearance of floating spots in the individual’s field of vision, flashes of light, and severe vision loss. A detached retina presents a significant risk of total vision loss if a person does not get treatment.

The normal flow of fluid in the eye may become blocked as new blood vessels form, leading to glaucoma. The blockage causes a buildup of pressure in the eye, increasing the risk of optic nerve damage and vision loss.

Anybody with diabetes is at risk of developing diabetic retinopathy. However, the risk is higher if the person:

• has uncontrolled blood sugar levels
• has high blood pressure
• has high cholesterol
• is pregnant
• smokes regularly
• has had diabetes for a long time

Diabetic retinopathy generally starts without any noticeable change in the vision. However, an eye specialist, called an ophthalmologist, can detect the signs.

It is important that people with diabetes have an eye examination at least once a year or when a doctor recommends that they do.

The following methods can help eye doctors diagnose diabetic retinopathy:

Dilated eye exam

For a dilated eye exam, an eye doctor places drops into the person’s eyes. These drops dilate the pupils and allow the doctor to view the inside of the eye.

They will take photographs of the eye’s interior to look for the presence of:

• abnormalities in the blood vessels, optic nerve, or retina
• cataracts
• changes in eye pressure
• new blood vessels
• retinal detachment
• scar tissue

These eye drops and the bright lights of the photographs can feel uncomfortable. In high risk individuals, the eye drops may cause an increase in ocular pressure.

Fluorescein angiography

To perform fluorescein angiography, an eye doctor uses drops to dilate the pupils, and they inject a dye called fluorescein into a vein in the person’s arm.

They will then take pictures as the dye circulates the eyes. The dye may leak into the retina or stain the blood vessels if the blood vessels are abnormal.

This test can help the doctor determine which blood vessels are leaking fluid or have broken down or become blocked.

This information provides accurate guidance for any laser treatments. It may sometimes indicate the need for the injection of medicine into the eye.

As the dye exits the body, people may notice that they have yellowish skin or dark orange urine for a day or so.

Optical coherence tomography

Optical coherence tomography (OCT) is a noninvasive imaging scan that provides high resolution cross-sectional images of the retina, revealing its thickness and allowing eye doctors to look for cysts or swelling.

Doctors can perform scans before and after treatments to check how effective treatment has been.

OCT is similar to ultrasound testing, but it uses light rather than sound to produce images. The scan can also aid the detection of diseases of the optic nerve.

Treating diabetic retinopathy depends on several factors, including the severity of the condition and how it has responded to previous treatments.

In the early stages, a doctor may decide to monitor the person’s eyes closely without intervening. This approach is known as watchful waiting.

In some cases, a person may need a comprehensive dilated eye exam as often as every 2–4 months.

Individuals will need to work with their doctor to control diabetes. Good blood sugar control can significantly slow the development of diabetic retinopathy.

In most cases of advanced diabetic retinopathy, the person will require surgical treatment.

The following options are available:

Laser treatment

Scatter laser surgery, or panretinal photocoagulation, takes place in a doctor’s office or an eye clinic. A doctor uses targeted lasers to shrink blood vessels in the eye and seal the leaks from abnormal blood vessels.

This treatment can either stop or slow down the leakage of blood and the buildup of fluid in the eye. People may need more than one session.

The procedure involves the doctor placing numbing medicine in the eye and then aiming a strong beam of light into the eye using a special lens.

The bright light can sting or feel uncomfortable, and it is common to experience blurry vision for the rest of the day. Small spots may appear in the visual field for a few weeks after the procedure.

Laser treatment comes with certain risks, such as a loss of peripheral vision, color vision, and night vision. A person can talk to their doctor about the relative benefits and risks of this treatment.

Injections

Certain medicines can reduce swelling and minimize leakage from blood vessels in the eyes. Medicines may include anti-VEGF drugs and corticosteroids.

Eye injections involve the doctor taking the following steps:

• placing numbing medicine on the eye
• cleaning the eye to help prevent infections
• placing the medicine in the eye using a very small needle

People may need to get regular injections, but over time, they usually require injections less frequently.

Eye surgery

If a person has problems with the retina or vitreous, they may benefit from a vitrectomy. This procedure is the removal of some of the vitreous from the eye.

A surgeon will perform this procedure in a hospital under general or monitored anesthesia.

The aim is to replace cloudy vitreous or blood to improve vision and to help the doctor find and repair any sources of retinal bleeding.

After removing the cloudy or bloody vitreous, the surgeon will insert a clear liquid or gas in its place. The body will absorb the liquid or gas over time and create new vitreous in its place.

After the surgery, the person will usually need to wear an eye patch for about a day and use eye drops to reduce swelling and prevent infections.

If the doctor puts a gas bubble in the eye, the person will need to hold their head in a certain position for a few days or weeks to make sure that the bubble stays in the right place. They will also need to avoid flying and visiting places at high altitudes until the bubble goes away.

Surgery is not a cure for diabetic retinopathy, but it may stop or slow the progression of symptoms. Diabetes is a long-term condition, and subsequent retinal damage and vision loss may still occur despite treatment.

The successful management of blood sugar levels will help prevent diabetic retinopathy.

Early detection of symptoms increases the effectiveness of the treatment.

High blood pressure, or hypertension, is another contributing factor. People with diabetes can take steps to control their blood pressure, such as:

• eating a healthful and balanced diet
• exercising regularly
• reaching or maintaining a moderate body weight
• quitting smoking
• moderating their alcohol intake
• taking any antihypertensive measures that the doctor recommends
• attending regular screenings

Diabetic retinopathy is an eye condition that affects people with diabetes. Without treatment, it can cause complications that include vision loss.

Having a comprehensive dilated eye exam at least once a year can help a person catch the condition early to prevent complications.