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Diabetic Retinopathy

Diabetic retinopathy refers to an eye condition that occurs in people with type 1 or type 2 diabetes. Damage to the retina, an essential section of the eye responsible for vision, causes this condition.

Although some might start by experiencing minor eyesight issues, others can completely lose their vision in the end. Luckily, vision impairment due to diabetic retinopathy is usually preventable.

The layer of tissue lining the rear of the eye is the retina. Signals transmitted to the brain from the retina enable one to see. However, high levels of blood sugar in diabetes damage blood vessels in the retina, causing diabetic retinopathy.

As per the American Diabetes Association, diabetic retinopathy is the leading cause of blindness that is preventable in the US. Also, it's the most prevalent eye problem among individuals with diabetes.

Therefore, regular eye examination is essential for people who are diabetic. Early detection and treatment are most likely to prevent complications from happening.

By Able Health I Medically reviewed by Dr. Alireza Estedlal

Page last reviewed: February 2024 I Next review due: February 2026

What are the stages of diabetic retinopathy?

Diabetic retinopathy comprises four phases:

Phase 1 to 3: Nonproliferative diabetic retinopathy

The first three stages are collectively referred to as nonproliferative diabetic retinopathy (NPDR). It is termed 'nonproliferative' since, in the early stages of the condition, the eye does not create new blood vessels. Another name for nonproliferative retinopathy is background retinopathy.

During the initial stages of diabetic retinopathy, you may not have any problems with your eyesight. However, the eye specialist often notices changes in the retina.

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The three nonproliferative phases of retinopathy are:

Phase 1: This is mild nonproliferative retinopathy whereby the small blood vessels within the retina swell while some begin leaking.

Phase 2: This is moderate nonproliferative retinopathy in which blockages start forming within some blood vessels. Leakages often occur from these vessels.

Phase 3: This is severe nonproliferative retinopathy whereby blockages become more widespread and cut off areas of the retina from the blood supply. These parts of the retina may be damaged due to loss of blood flow.

Phase 4: This is proliferative diabetic retinopathy (PDR), also called advanced retinopathy, which arises when new, abnormal blood vessels start growing in the eye. Loss of nourishment in the retina signals the body to create new blood vessels. The abnormal blood vessels might as well develop in the eye's centre, and such changes could lead to vision loss in various ways, including:

  • Leakage of the new, abnormal blood vessels. This reduces the retina's nourishment as the leaking vessels outdo the healthy ones.

  • Blood leakage into the eye, making it difficult to see well. This can sometimes cause a total blockage of the vision.

  • Scar tissue formation on the retina.

Mild bleeding may lead to symptoms such as lines and dark spots in the eyesight. On the other hand, severe bleeding can result in major vision loss, including blindness or complete loss of sight.

You should, therefore, seek medical attention if you are diabetic and notice any eye changes, such as floaters or cobwebs. Even when the issues seem to resolve on their own, getting treatment is still important to prevent further severe vision loss.

What are The Symptoms of Diabetic Retinopathy?

In the early stages of diabetic retinopathy, symptoms are usually uncommon. This condition often goes unnoticed till damage has occurred in the eye. Monitoring eye health through regular eye tests and management of blood sugar levels is important in preventing undetected damage.

For cases where symptoms appear, they might include the following:

  • Seeing dark spots or floaters

  • Blurry vision

  • Difficulty seeing at night

  • Vision loss

  • Difficulty differentiating colours

Usually, diabetic retinopathy affects both eyes.

What Causes Diabetic Retinopathy?

Diabetic retinopathy is primarily caused by prolonged high blood sugar levels. Too much sugar leads to damage to the blood vessels supplying blood to the retina. Another risk factor of the condition is high blood pressure.

The retina is a light-sensitive tissue layer found behind the eye. Whenever light gets into the eye, nerve signals are sent to the brain, which are then translated into the images we see.

Damage to the blood vessels in the retina can cause them to block, cutting off some of the blood flow. This can trigger the growth of weaker vessels, which could leak and form scar tissue, leading to vision loss.

Determining the number of diabetic people who develop retinopathy is somewhat hard to tell. However, according to a 2016 research, 44% of individuals with diabetes suffered from retinopathy, whereas the study conducted in 2017 indicated 24.5%.

Generally, the possibility of getting diabetic retinopathy increases with the duration of diabetes. Therefore, effective management of diabetes can minimize the progression of the condition.

Individuals with existing diabetes, especially pregnant women or those planning to conceive, require a comprehensive eye test to assess if they have retinopathy signs. This is crucial since pregnancy can accelerate retinopathy progression.

How is Diabetic Retinopathy Diagnosed?

To diagnose diabetic retinopathy, the practitioner will perform a dilated eye examination. The procedure is done using eye drops to dilate or widen the pupils, enabling the doctor to thoroughly examine the inside of the eye.

During the examination, they will also look for signs such as:

  • Swelling

  • Abnormal blood vessels

  • Scarring

  • Optic nerve damage

Alternatively, the doctor may recommend one of these tests for a more detailed evaluation of the eye:

  • Fluorescein angiography: This test involves injecting dye into the arm, which enables the doctor to track blood movement in the eye. As the pupils are widened, pictures of the dye flowing inside the eye will be taken to assess the vessels that are leaking, blocked, or damaged.
  • Optical coherence tomography (OCT): This imaging test utilizes light waves to create pictures of the retina, which enables the doctor to assess the thickness of the retina. OCT examination also helps in determining the amount of fluid accumulation in the retina if any.

It's important for type 1 or 2 diabetes patients to regularly visit an eye specialist at least once every 1 to 2 years. In case the doctor detects any sign of diabetic retinopathy, additional frequent examination may be recommended.

How is Diabetic Retinopathy Treated?

Early diabetic retinopathy treatment focuses on diabetes management and monitoring eye health. To detect retina changes earlier, routine eye test may be recommended. The endocrinologist or primary care provider may as well assist in slowing down the changes by providing tips on controlling blood sugar levels and overall health.

For advanced diabetic retinopathy cases, the treatment will be determined by the severity of the condition and the form of damage.

The treatment options may include the following:


Anti-VEGF are injectable drugs that block the protein, causing the development of new, leaking blood vessels. They can also help ease eye swelling, which might improve overall eyesight.

Examples of anti-VEGF drugs are:

  • Aflibercept (Eylea)
  • Bevacizumab (Avastin)

  • Ranibizumab (Lucentis)

The physician usually injects these drugs after numbing the eye to lessen discomfort. Typically, injections are required each month, but the frequency may decrease with time.

Laser treatment

Also referred to as photocoagulation, laser treatment may prevent loss of eyesight. The procedure involves using a laser to seal or constrict blood vessels.

During the procedure, local anaesthesia will first be administered to make one comfortable while receiving treatment. Medicine to dilate the pupil will also be used. Next, the physician will shine light into the eye using laser equipment.

The two forms of laser treatment for treating diabetic retinopathy are:

  • Scatter laser treatment: Helps constrict the blood vessels.

  • Focal laser treatment: Stops or regulate leakage of fluid and blood.

Sometimes, several laser treatment sessions may be required for it to be effective.


Vitrectomy is a surgical procedure doctors use to remove gel known as vitreous fluid in the eye. This clears off the cloudy fluid affecting eyesight and also gives them access to the retina to remove scar tissue and repair blood vessels.

Discuss with your physician the best ways to make you feel comfortable while undergoing surgery. General anaesthesia or medicine that numbs the eye are the available options that may be used to make you unconscious.

How is Diabetic Retinopathy Prevented?

For people with diabetes, diabetic retinopathy can be prevented by following these necessary steps to maintain healthy blood vessels:

  • Keeping blood sugar at the recommended level as possible as you can.

  • Keeping cholesterol and blood pressure levels within a healthy range.

Other preventive or managing approaches of diabetic retinopathy are:

  • Undergoing annual eye test

  • Striving to quit smoking if you are a smoker

Engaging in routine, moderate exercises a few times every week. You can consult your doctor if you have retinopathy to help determine the right exercises for your condition.

Complications of Diabetic Retinopathy

Diabetic retinopathy is associated with several severe eye conditions such as:

Diabetic macular oedema (DME)

This condition occurs when the middle part of the retina (macula) starts swelling. Since the macula is responsible for central eyesight, DME causes blurry vision. This is a prevalent complication in diabetic people, which affects around 1 out of 15 persons with the disorder.

Neovascular glaucoma

Sometimes, the development of abnormal blood vessels obstructs fluid drainage out of the eye, especially in advanced cases of diabetic retinopathy. This leads to neovascular glaucoma, which causes symptoms like pain and pressure in the eye.

Retinal detachment

Scar tissue formation on the retina can sometimes pull it away from the rear of the eye. This is usually a medical emergency, which could lead to permanent loss of vision.

Retinal detachment warning signs are:

  • Blurred vision

  • Sudden and multiple floaters

  • Dimmed or darkened eyesight

  • Flashing lights in the vision side

You should seek immediate medical attention if you think you have retinal detachment. Call emergency services or have someone take you to the emergency department near you.


What to expect from your doctor

Your physician may ask questions such as:

  • Are you experiencing eye symptoms like blurry vision or floaters?

  • How long have you had your symptoms?

  • How well are you managing your diabetes in general?

  • What was your previous haemoglobin A1C reading?

  • Do you have other medical problems like high cholesterol or high blood pressure?

  • Have you undergone an eye surgery?


Overall, diabetic retinopathy is a severe eye problem that could cause diminished vision or sometimes blindness in people with diabetes. But the good news is that there are several approaches to preventing and slowing down progression.

If you are diagnosed with diabetes, you should consider the following measures:

  • Getting regular eye tests and physical check-ups.

  • Keeping your blood pressure, blood sugar and cholesterol levels at a healthy range.

  • Being aware of any vision changes you notice and promptly discussing them with your physician.