Overview of Diabetic Vision Loss
Diabetes can cause a number of complications, including cardiovascular disease, skin conditions, nerve or kidney damage, and diabetic vision loss. In fact, the risk of blindness is 25 times higher for someone with diabetes than for someone without the disease.
People with diabetes are at risk for developing diabetic eye disease, which is a group of eye problems that can negatively affect vision. These conditions include diabetic retinopathy, cataracts, glaucoma, and diabetic macular edema.
How Diabetes Affects the Eyes
Eyes are complex organs. Carrying visual information about the outside world, light enters the eye through the pupil and lens, and strikes the light-sensitive tissue lining the back of the eye. This tissue, known as the retina, contains thousands of photosensitive cells that absorb the light.
The retina converts the information from the light it absorbs into electrical impulses, which travel to the brain via the optic nerve. The brain then translates the impulses into the images we perceive.
High Blood Sugar
Diabetes is a condition characterized by high blood sugar levels. Blood delivers oxygen, nutrients, and other substances to body cells, which then use the substances to function. Blood also carries sugar, also known as glucose, which body cells use as energy.
After you eat, your digestive system converts carbohydrates into glucose and delivers the sugar through the bloodstream. As body cells absorb the sugar, glucose levels drop. However, diabetes is a condition in which the body cells cannot absorb or use the glucose properly, which causes the sugar to remain in the bloodstream.
Three Main Types of Diabetes
Type 1 diabetes: Present at birth; develops when the pancreas does not produce enough insulin, which is a hormone that helps “unlock” cells so they can absorb glucose
Type 2 diabetes: Most common type of diabetes; occurs when body cells becomes resistant to insulin
Gestational diabetes: Occurs in pregnant women and usually resolves after delivery of the baby
High blood sugar levels, a condition known as hyperglycemia, can damage the tiny blood vessels in the back of the eye. These damaged blood vessels can leak fluid and cause swelling. New, abnormal blood vessels may also grow where they can bleed into interior of the eye, contribute to tissue scarring, or cause dangerously high pressure inside the eye.
Eye damage associated with hyperglycemia can occur during prediabetes, which is a condition in which blood glucose levels are higher than normal but not high enough to be considered diabetes. In fact, up to 21 percent of patients with type 2 diabetes have diabetic retinopathy when they receive their diabetes diagnosis.
Short and infrequent bouts of hyperglycemia will probably not cause diabetic vision loss, although they may cause temporary blurry vision for days or weeks after the episode. High glucose levels can cause fluids to seep into the lens of the eye, which makes the lens swell and change shape. This type of vision loss is temporary; vision returns as glucose drops to normal levels.
Diabetic Eye Diseases that Cause Vision Loss
Diabetic retinopathy is a progressive condition, which means it gets worse in time. The condition may not produce symptoms in its early stages. Later, symptoms of diabetic retinopathy may develop and include:
- Blurry vision
- Floaters, which are spots that “float” in your vision
- Halos around lights
- Loss of central vision, which is what you see in the center of your vision when staring straight ahead
- Loss of colour vision
Cataracts are cloudy areas in the lens of the eye. The lens focuses the light entering the eye so that it strikes the correct spot on the retina or macula. Clouding of the lens associated with cataracts cause cloudy or fuzzy vision. Cataracts can also cause sensitivity to glare.
Fluid inside the eye, known as aqueous humor, provides oxygen and nutrients that nourish the lens and other structures inside the eye. Aqueous humor also contains glucose. The lens turns some of the glucose into sorbitol, which can affect cells and other proteins in such a way as to turn the lens opaque. High levels of glucose in aqueous humor can cause the lens to produce even more sorbitol, thereby clouding the lens further.
Cataracts are quite common in people with diabetes. In fact, the results of a recent study show that, among adults aged 45 and over with diagnosed diabetes, more than 32 percent had cataracts, and more than 9 percent had vision loss due to cataracts.
People with diabetes are twice as likely to develop glaucoma as are people without diabetes. Glaucoma is a group of eye diseases that damage the optic nerve. Damage is usually the result of high pressure within the eye. Warning signs for glaucoma include eye pain, watery eyes, blurred vision, halos around lights, and headaches.
One rare type of glaucoma, known as neovascular glaucoma, can develop in people with diabetes. It can occur after diabetic retinopathy has damaged blood vessels on the retina; the retina responds to the damage by manufacturing new, abnormal blood vessels. If the new blood vessels grow on the iris, which is the coloured part of the eye, they can close off the flow of fluid through the eye and raise pressure inside the eye.
Diabetic Macular Edema
This complication of diabetes causes swelling of the retina due to leaking blood vessels. Specifically, the condition causes swelling of the macula, which sits at the center of the retina. The macula is responsible for sharp central vision used for reading, driving, seeing faces, and other details. In order to develop diabetic macular edema, someone must first have diabetic retinopathy.
Blurry or wavy vision near or at the center of vision is the primary symptom of diabetic macular edema. Colours might appear washed out or faded. The severity of symptoms of diabetic macular edema can range from vision that is slightly blurry to noticeable vision loss.
Diabetic Vision Loss Treatment
Treatment for vision loss associated with diabetes depends largely on the condition causing the vision loss and its severity. Treatment for mild cases of diabetic retinopathy usually involves controlling blood sugar levels, for example, while advanced cases require laser treatment or surgery. Corticosteroid treatments in the form of pills, eye drops, or injections can reduce inflammation associated with macular edema.
Treatment for cataracts involves surgical removal of the eye’s lens and replacement with a clear artificial lens. Neovascular glaucoma is difficult to treat. Laser surgery can reduce abnormal blood vessels on the iris and on the surface of the retina.
Available Assistive Technology for Diabetic Vision Loss
For those who are going through diabetic vision loss, eSight glasses are an option. eSight is a low vision eyewear device that stimulates synaptic activity from the remaining photoreceptor function of its users’ eyes. Many successful eSight users live with diabetic vision loss. Eye conditions like diabetic retinopathy can damage the blood vessels and tissues in the back of the eye, which can prevent the photoreceptors and retina from working well which often results in cloudy or blurred vision.
Fortunately, eSight can stimulate synaptic activity from the remaining photoreceptor function of the user’s eyes. As a result, eSight makes clearer vision possible, resulting in enhanced vision of up to seven lines on a doctor’s eye chart. It uses a cutting edge camera, smart algorithms and high resolution screens, and provides the flexibility to read books up close with the same ease as seeing a crosswalk sign from a distance.
eSight Users with Diabetic Vision Loss
Long-time eSight user Jason Smetters lives with cataracts, and he has been able to use his eSight to enjoy watching live stadium baseball games again. He no longer requires someone else to read the board to him, as he can now identify the score and the players on his own. Jason especially loves watching games at night, due to eSight’s sharpened contrast between the glistening green field and the dark blue sky.
Jason is looking forward to using his eSight on his Alaskan cruise in 2021, to enjoy whale watching from the comfort of his own cabin.
How many people have diabetes?
Does diabetes cause vision loss?
Yes. The abnormally high blood sugar levels associated with diabetes can damage the eyes to cause vision loss. The longer someone has diabetes, the higher the risk for vision loss.
How does diabetes cause vision loss?
Diabetes causes vision loss by damaging the blood vessels that serve the eyes, or by causing the growth of abnormal blood vessels within the eyes. The high glucose levels associated with diabetes can also cause clouding of the lens of the eye.
Can eye doctors detect eye diseases in people with diabetes?
Yes. Eye doctors can detect diabetic eye issues during routine eye exams, in which they test visual acuity, measure the pressure inside the eyeball, assess nerve damage, and look at the blood vessels in the retina.
Can I prevent diabetic vision loss?
In many cases, yes. Maintaining healthy blood glucose levels can prevent many types of diabetic eye diseases. Early detection and treatment can help slow the progression of diabetic eye diseases.
Can vision loss from diabetes be reversed?
Yes, if detected and treated early enough.