Diabetic Vision Loss
Vision Loss is a common problem that can affect individuals with diabetes, and although some vision loss is common amongst diabetics, fewer than 5% develop severe vision loss. Many people living with diabetes experience progressive eye damage, which in some cases, goes unnoticed until vision loss occurs. Diabetes can lead to multiple eye conditions, including Retinopathy, Diabetic Macular Edema, Cataracts, Glaucoma, and even blindness. In fact, the risk of blindness is 25 times higher for a person with diabetes than for a person without the disease. If you are living with diabetes, read on to gain an understanding of how diabetes can affect your vision- and most importantly, the treatments and technologies available to you to prevent vision loss and improve everyday functionality.
The term “diabetic eye diseases” covers a broad spectrum of eye conditions that can arise in people with diabetes. This is because when diabetes is not well-controlled, high levels of blood glucose, also called blood sugar, can damage blood vessels in the eye. This slowly occurs over time and can ultimately result in complete vision loss. Most serious diabetic eye diseases begin with blood vessel problems. Let’s look more closely into these conditions.
Diabetic Retinopathy is the most common cause of vision impairment and Diabetic Vision Loss in adults. This eye disease occurs when high blood sugar levels cause progressive damage to blood vessels in the retina (the tissue lining the back of the eye). Damage can cause these blood vessels to swell and leak, or even close entirely, which stops blood from reaching parts of the eye.
Diabetic Retinopathy, being a progressive condition, gets worse over time and usually affects both eyes. That said, the condition may not produce symptoms in its early stages. When symptoms do present, they include:
- Blurry vision
- Floaters (spots that“float” in your vision)
- Halos around lights
- Poor night vision
- Loss of colour vision
- Blank or dark areas in your field of vision
Every healthy eye has a clear lens that focuses the light entering the eye so that it strikes the correct spot on the retina or macula, which in turn, creates vision. Cataracts are cloudy areas in the lens of the eye that cause cloudy or fuzzy vision.
Aging is the most common cause of Cataracts. However, Cataracts can develop more quickly in people with diabetes because the higher level of glucose present in the aqueous humor (the fluid inside the eye that provides oxygen and nutrients to the lens and other structures). The lens will convert some of the glucose into sorbitol, which can turn the lens opaque. High levels of glucose in the aqueous humor itself can also cause the lens to produce even more sorbitol, thereby clouding the lens further.
Some vision changes that you may notice if you have Cataracts are:
- Blurry vision
- Seeing double
- Extra sensitive to light
- Poor night vision
- Seeing bright colours as faded or yellow instead
Glaucoma is a disease that damages your eye’s optic nerve. A damaged optic nerve can cause permanent vision loss and, in some cases, it may even lead to blindness.
Damage in the eye’s optic nerve is usually the result of high pressure within the eye. This situation could be happening because your eyes continuously produce a clear fluid known as the aqueous humor that fills the inside of your eye. New fluid constantly replaces the older fluid, which leaves your eye through a meshwork drainage field and channels. This process keeps pressure in the eye (called intraocular pressure or IOP) stable. But if something obstructs this drainage mechanism, fluid builds up. The pressure inside the eye rises, damaging the optic nerve.
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 ( the coloured part of the eye) they can reduce or block the flow of fluid through the eye, thereby raising pressure inside the eye.
Warning signs for glaucoma include:
- Eye pain
- Watery eyes
- Blurred vision
- Halos around lights
Diabetic Macular Edema
In people with diabetes, sometimes tiny bulges (microaneurysms) protrude from the vessel walls which leak or ooze fluid and blood into the retina. This fluid can cause swelling (edema) in the central part of the retina (macula). This is a serious eye complication called Diabetic Macular Edema that can cause vision problems or blindness. The severity of symptoms of Diabetic Macular Edema can range from a vision that is slightly blurry to noticeable vision loss. To develop Diabetic Macular Edema, however, someone must first have Diabetic Retinopathy.
Common symptoms of Diabetic Macular Edema are:
- Blurry or wavy vision
- Colours might appear washed out or faded.
Prevalence of Diabetic Retinopathy
According to the Centers for Disease Control and Prevention (CDC), Diabetic Retinopathy affects nearly one-third of all adults over 40 who have diabetes. Other statistics on the prevalence of this condition include:
- 4.2 million adults in the U.S. live with Diabetic Retinopathy
- 655,000 adults in the U.S. have a vision-threatening form of DR
- From 2010 to 2050, the number of Americans with diabetic eye disease is expected to double, from 7.7 million to 14.6 million
- Diabetic Retinopathy and age related eye disease are the most common cause of vision impairment and blindness among working-age adults in the U.S.
Signs and Symptoms
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 cells use as energy.
After you eat, your digestive system converts carbohydrates into glucose and delivers the sugar through the bloodstream. Thanks to insulin, body cells absorb the sugar, and 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.
Over time, high levels of sugar in the bloodstream can cause serious health problems, such as heart disease, kidney disease, and vision loss. The damage to your eyes begins when sugar blocks the tiny blood vessels that go to your retina, causing them to leak fluid or bleed. To make up for these blocked blood vessels, your eyes then grow new blood vessels that may leak or bleed easily. This, over time, will result in vision loss.
Only a physician or optometrist can diagnose eye conditions related to diabetes. A full, dilated eye exam is conducted, including using drops in your eyes to dilate your pupils. By doing so, they are able to examine a larger area at the back of each eye, using a special magnifying lens.
Your physician may suggest other tests, too, depending on your health history, your type of diabetes, and the time since you were first diagnosed.
Three Main Types of Diabetes
There are three core types of diabetes: Type 1, Type 2, and Gestational Diabetes.
Stage 1 of DR is largely asymptomatic. People with this stage might develop microaneurysms (small red dots of dilated capillaries). While microaneurysms do not affect vision, these blood vessels can leak blood into the retina and cause the macula to become swollen, a condition called macular edema.
With type 2 diabetes, your body doesn’t use insulin well and can’t keep blood sugar at normal levels. About 90-95% of people with diabetes have type 2. It develops over many years and is usually diagnosed in adults.
Gestational diabetes develops in pregnant women and usually goes away after the baby is born, however, it increases the mother’s and baby’s risk for type 2 diabetes later in life.
High Blood Sugar: Hyperglycemia
High blood sugar levels, also known as Hyperglycemia, is a condition where there is too much sugar in the blood because the body lacks enough insulin. Hyperglycemia is closely linked to diabetes and can cause vomiting, excessive hunger and thirst, rapid heartbeat, and vision problems.
Vision problems may arise from Hyperglycemia because the conditions damages the tiny blood vessels at the back of the eye, causing swelling, scar tissue, or dangerously high pressure inside the eye. Short and infrequent bouts of Hyperglycemia will probably not cause permanent vision loss, although they may cause temporary blurry vision for days or weeks.
Diabetes is a condition associated with high blood sugar levels (hyperglycemia). Excessive amounts of sugar in the bloodstream can damage blood vessels within the retina, leading to swelling and leakage. Hyperglycemia also permits sugar to accumulate in the eye’s lens, which can change the curvature of the lens and thus affect vision.
Over time, damaged blood vessels can completely prevent blood from reaching the retinal tissue. In such cases, new blood vessels may form on the surface of the retina to supply the retina with the oxygen-rich blood it needs to function. As the condition worsens, however, the new blood vessels may also leak into the back of the eye, which leads to vision loss.
To prevent diabetic eye disease, or to prevent the progression of existing disease, it’s important to manage your diabetes. Consider following the ABCDEs of staying healthy with diabetes.
The ABCDEs of staying healthy with diabetes, according to Diabetes Canada, include:
Monitoring your blood sugar levels is essential. Most people should aim for an A1C of 7% or less to retain a healthy level. A1C is a blood test, also known as a glycosylated hemoglobin test, which measures your average blood sugar level over the past 120 days.
Ideally, most people should maintain a blood pressure level of 130/80 mmHg or less.
Most people should set an LDL cholesterol target of less than 2.0 mmol/L.
There are some medications known to help with diabetes and related symptoms. Speak with your healthcare team to learn about which medications are best for you.
Exercise & Eating
Regular physical activity, healthy eating, and a healthy body weight can improve diabetes and related symptoms.
Smoking damages blood vessels in the eye, therefore increasing the risk of developing diabetic eye diseases. Smoking may also increase the severity of dry eyes and increase the risk of damage to the optic nerve and diabetic retinopathy.
Stay on top of your health. Try setting goals for your well-being. Be sure to manage any comorbidities, like depression or anxiety, and have a dilated eye exam at least once a year or more often if recommended by your eye care professional. These actions are powerful ways to protect the health of your eyes and can prevent blindness. The sooner you work to manage your diabetes and other health conditions, the better.
Treatment for diabetes-related vision loss depends largely on the condition causing the vision loss and its severity. Your doctor may recommend, along with management of your diabetes, medicine, laser treatments, surgery, assistive technology, or a combination of these options.
Your doctor may treat your eyes with anti-VEGF medicine, such as aflibercept, bevacizumab, or ranibizumab. These medicines block the growth of abnormal blood vessels in the eye. Anti-VEGF medicines can stop further vision loss and may improve vision in some people.
Cataract Lens Surgery
Surgery to correct cataracts involves your surgeon removing the cloudy lens in your eye and replacing it with a clear artificial lens. People who have cataract surgery generally have improved vision afterward.
Laser treatment creates tiny burns inside the eye with a beam of light. This method corrects leaky blood vessels and stems the production of extra fluid, called edema. Laser treatment can also prevent eye disease from getting worse, which is important to prevent vision loss or blindness.