Diabetes and Blindness: Understanding the Link and Preventative Measures

Post updated: 6th May 2023

Diabetes damages the body’s small blood vessels. Diabetic blindness occurs when the blood vessels in the retina are damaged due to high blood sugar. The retina is the part of the eye responsible for sending images to the brain. You can lower your risk of diabetic retinopathy by keeping your blood sugar levels within your target range.

It is essential to keep in mind that diabetic retinopathy can cause poor vision or even blindness. However, it often gets worse over several years.

The small blood vessels of the eye get weak at first and this leads to blood seeping into the retina. This is known as nonproliferative retinopathy and is the most common form of retinopathy.

If your blood sugar stays high, retinopathy keeps getting worse. Moreover, new blood vessels growing in the retina will be weak and can easily break open. Once they break open, fluid leaks into the middle of the eye just in front of the retina and alter your vision.

Bleeding can also lead to the formation of scar tissue. Scar tissue in the eye can pull on your retina and cause it to move from the wall of your eye. This is known as retinal detachment. Some people with proliferative retinopathy may have no symptoms at all until it is too late for effective treatment. That’s why it’s very important to have regular eye exams.

Diabetic retinopathy can also lead to swelling of the macula of your eye (macular edema). When this happens, it can worsen your vision and even lead to blindness.

Diabetic retinopathy risk factors

Anyone with diabetes (type 1 diabetes, type 2 diabetes, or gestational diabetes) can develop eye complications, including diabetic retinopathy. Having uncontrolled diabetes for long increases your risk of developing diabetic retinopathy. Other factors that increase your risk include:

Poor control of blood sugar levels
Tobacco use
Pregnancy
High cholesterol
High blood pressure
Being Black, Native American, or Hispanic

Types of diabetic retinopathy

There are two main stages of diabetic retinopathy:

1. Early diabetic retinopathy (non-proliferative)

Early-stage retinopathy occurs when the small blood vessels in the retina weaken and form tiny pockets. While you may not be able to detect the tiny pouches, your eye doctor can. These tiny pockets can leak fluid, which can cause the macula in the retina to swell (macular edema), leading to vision distortion.

Macular edema is the leading cause of vision loss in people with diabetes. About 50% of diabetes patients with retinopathy develop macular edema at some point.

2. Advanced diabetic retinopathy (proliferative)

New blood vessels begin to grow in the retina but these vessels are often weak and leak blood and other fluids into the vitreous (the gel between the retina and the lens). Minor bleeding may cause you to see dark spots floating in your vision. However, if the bleeding increases you may go blind.

The symptoms of diabetic retinopathy can be noticed in the early stage. This is the main reason why you should undergo annual eye exams to catch any problems early enough when treatment is most effective.

Advanced-stage symptoms can include:

Floaters (dark shapes or spots in your vision)
Blurry vision
Trouble seeing colors
Empty or dark spots in your vision
Blindness (vision loss)

Complications

Complications of diabetic retinopathy (growth of weak small blood vessels in the retina):

1. Vitreous hemorrhage

The new small blood vessels bleed into the jellylike substance filling the center of the eye. A small amount of bleeding might only lead to a few small floaters (dark spots). However, in severe cases, fluid fills the vitreous cavity, leading to blindness (complete loss of vision).

Vitreous damage does not cause permanent blindness by itself. The fluid (including blood) clears from your eyes within a few days, weeks, or months. If your retina is not damaged, your vision will return to its previous state.

2. Retinal detachment

The weak small blood vessels associated with retinopathy can stimulate the development of scar tissue, which pulls the retina further away from the back of your eye. This often causes flashes of light, floaters in your vision, or even blindness (severe vision loss).

3. Glaucoma

New small blood vessels can develop in the iris (the front part of the eye) and obstruct the normal flow of blood and other fluid out of your eye, causing a build-up of pressure in the eye. This pressure damages the optic nerve (the nerve responsible for carrying images from the eye to the brain).

4. Blindness

Glaucoma, macular edema, diabetic retinopathy, or a combination of these eye conditions can cause diabetes blindness, especially if they are poorly managed.

Prevention

While diabetic retinopathy can’t always be prevented, good management of your blood pressure and blood sugar levels, regular eye exams, and early detection and intervention can help prevent blindness.

If you have diabetes, you can reduce the risk of developing diabetic retinopathy by taking the following measures:

· Controlling your diabetes

Make physical activity and healthy eating part of your routine. It is recommended that you get 20 – 30 minutes of aerobic activity, such as swimming or walking, each day. Take insulin or medications as directed by your physician.

· Keep track of your blood sugar levels

Monitor and record your blood sugar levels as directed. You may need to do this several times a day if you are stressed or ill.

· Ask your doctor about a hemoglobin A1C test

A hemoglobin A1C test, or glycosylated hemoglobin test, indicates your average blood sugar for the last 2 -3 months before the test. The goal for most diabetes patients is to be 7%.

· If you use tobacco, try to quit

Tobacco use increases your risk of diabetes complications, such as diabetic retinopathy.

· Keep your cholesterol and blood pressure under control

Exercising regularly, losing excess weight, and eating well can help. Some people with diabetes may also need medication.

· Pay attention to changes in your vision

Seek immediate medical attention if you notice any sudden changes in your vision or if it becomes hazy, spotty, or blurry.

Keep in mind that diabetes does not necessarily lead to blindness. Proper diabetes management can help prevent or delay complications.

The Facts about Diabetic Retinopathy

Diabetic retinopathy is a complication of diabetes that mainly affects the eyes and it is the leading cause of blindness especially among diabetic (both type 1 and 2) adults aged between 20 and 74 years. It occurs when elevated blood sugar levels damage the tiny light sensitive blood vessels and tissue inside the retina (at the back of the eye).

Stages of diabetic retinopathy

1. Mild non-proliferative retinopathy: This is the earliest stage that occurs when diabetes affects the circulatory system of the retina thus weakening the walls of retinal capillaries forming microaneurysms. Microaneurysms are small outpunches of the small blood vessels which can leak blood and fluid leading to edema and swelling in the retina which result in small dot-like hemorrhages.

2. Moderate non-proliferative retinopathy: As the disease worsens or progresses the nourishing small blood vessels of the retina are blocked.

3. Severe non-proliferative retinopathy: As many more tiny blood vessels in the retina are blocked, several areas of the retina are deprived off blood and oxygen supply. In an attempt to maintain adequate blood supply, sends signals to the body to stimulate the growth of new fragile blood vessels in order to bring in nourishment.

4. Proliferative retinopathy: Once neovascularization (formation of new blood vessels in the retina) occurs the condition becomes worse. Proliferative retinopathy is mainly characterized by the growth of fragile abnormal tiny blood vessels both on the retinal surface and also on the vitreous gel inside the eye. If left untreated, these fragile and delicate blood vessels leak blood leading to severe vision loss or even blindness resulting from retinal detachment.

Signs and Symptoms of Diabetic Retinopathy

Patients are normally asymptomatic in the early phases of diabetic retinopathy. However, in the more advanced stages, complications may start developing and the patient may experience several symptoms including blurred vision, distortion, floaters, and acute progressive loss of vision. There are also other signs and symptoms of diabetic retinopathy which include;

Microaneurysms: This is the earliest clinical symptom of diabetic retinopathy. They occur secondary to outpunch of capillary walls due to pericyte loss. They primarily appear as small red dots mainly in the superficial retinal layers.
Dot and blot hemorrhages: If they are very small, they appear similar to microaneurysms. They occur as a result of rupturing of the microaneurysms in the deep layers of the retina such as the outer pexiform and the inner nuclear layers.
Flame-shaped hemorrhages: These are splinter hemorrhages that mainly occur in the superficial nerve fiber layer.
Hard exudates and retinal edema: These are caused by breakdown of the retina-blood barrier. This allows leakage of allowing leakage of lipids, serum proteins, and protein from the tiny blood vessels.
Macular edema causes visual impairment.
Complexity reading due to blurred or distorted vision.
Pain in the eyes.
Distorted central vision.
Abnormal patterns or floaters in the field of vision.

Who is at risk of Diabetic Retinopathy?

Diabetics (both type 1 and type 2) are at risk of developing this and other eye diseases which can result in severe loss of vision and/or blindness. This can occur much earlier and is likely to be more severe is a person’s diabetes is poorly managed or left untreated. Additionally, pregnant women who are diabetic should guard their vision by having a comprehensive dilated eye examination.

Treatment of Diabetic Retinopathy

· Glucose control: Intensive glucose control especially in patients with IDDM (insulin dependent diabetes mellitus) decreases the progression and incidence of diabetic retinopathy.

· Laser photocoagulation: This entails the use of a high focused beam of light (energy) to stimulate a coagulative response.

· Pan-retinal photocoagulation: This procedure involves the application small laser burns over the retina in order to spark the central muscular area. This can eliminates the blood vessels completely and stop the leaking.

· Vitrectomy: This procedure is very effective in case of tractional retinal detachment, long standing vitreous hemorrhage, and combined rhegmatogenous and tractional retinal detachment. Treatment of diabetic retinopathy is often very successful especially in preventing, delaying or reducing loss of vision. However, all these procedures do not eliminate the disease entirely.

Prevention

Diabetic retinopathy can be prevented or slowed down by keeping all systemic parameters under control. Such systemic parameters include kidney function, blood sugar levels, lipid profile (triglycerides and cholesterol), hemoglobin levels, and blood pressure. Meditation practice is very effective in reducing and preventing stress. This helps prevent a rise in blood sugars. Moreover, mindful and responsible food choices supports healthy blood sugar level. Yoga and exercise are essential in the management of the blood sugar levels mainly because it helps move glucose into the muscle. On the other hand, yoga postures can be modified to accommodate diabetic people.

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