Diabetes and the Eyes


Diabetes and the Eyes

Vision impairment is a frequent complication of diabetes.

General Overview

Right now the World Health Organization estimates that more than 150 million people worldwide have diabetes. This common condition needs special attention and constant monitoring. Generally
it is a disease in which the body does not produce or properly use insulin – a hormone needed to convert sugar starches or other food into energy. The cause of diabetes is still unknown
although genetics and environment (obesity lack of exercise) both appear to play roles. Perhaps the most dangerous aspect of the condition is that many affected people do not even realize that they have it – most are diagnosed only when serious symptoms emerge.

There are two types of diabetes:

Type I usually diagnosed in childhood or young adulthood
is when the body does not produce any insulin. This type accounts for 5-10 percent of diabetics. Type II is far more prevalent; it results from insulin resistance (the body doesn’t use insulin properly) combined with relative insulin deficiency. The number of people with Type II is increasing dramatically due to a number of factors:

  • The population is aging.
  • Obesity rates are rising.
  • Lifestyles are increasingly sedentary.
  • Native American/Canadians and African American/Canadians are three to five times more likely than the general population to develop Type II diabetes.
  • People of Hispanic, Asian,South Asian or African descent are at higher risks for developing Type II diabetes.
  • There is a growing incidence of Type II diabetes in children from high-risk populations. Recent data suggests an American child born in 2000 stands a one in three chance of being diagnosed with diabetes in his or her lifetime.

(Information courtesy of www.diabetes.ca)

High blood glucose levels over a long period of time can cause heart disease kidney problems
nerve problems and blindness. The effects on the body can be profound.

Diabetes & The Eyes

Vision impairment is a frequent complication of diabetes. Diabetes is responsible for approximately ten percent of legal blindness; it is the leading cause of new cases of blindness in adults between 20-74 years. Loss of vision in diabetes occurs largely through blood vessel damage. With high blood sugars damage can occur to blood vessels throughout the body in three ways:

Leakage – High blood sugar causes damage to individual cells which later shows up as damage to structures like capillaries the smallest of blood vessels. As damage progresses the blood vessel walls start to become porous leaking proteins and other materials.

Blood vessel blockage – High blood sugar causes partial and total blockage within existing blood vessels. Arteriolar blockage slows the delivery of oxygen and other nutrients that are required to maintain cell health.

Abnormal growth – As blood vessels become blocked and oxygen deprivation begins the body begins to promote the growth of new blood vessels. This process is called neovascularization. The newly created blood vessels are thin-walled often very fragile and not very functional.

Diabetic Retinopathy

The most common visual complication is diabetic retinopathy. Generally speaking this condition is caused by damage to the tiny blood vessels in the retina. Between 40 to 45 percent of North Americans diagnosed with diabetes have some stage of diabetic retinopathy and it often has no early warning signs. Without timely treatment damaged blood vessels can bleed cloud vision and finally destroy the retina which could lead to blindness. Management includes annual eye examinations and the possibility of laser treatment in more serious cases to control the damage. To prevent progression of this condition people with diabetes should control their levels of blood sugar blood pressure and blood cholesterol.


The lens in the eye has a unique physical structure that cannot be repaired or replaced
and it retains any damage that may occur to it over time. About 90 percent of the material in the lens consists of long stringy proteins to allow nearly perfect light transmission. Damage to this precise structure can lead to cloudiness and discoloration of the lens-also known as a cataract. Blurred vision often results. Cataracts form in a variety of types. The most common type
called a senile cataract is usually seen in people over 60 years of age. Diabetes with its environment of high blood sugars raises the risk for senile cataract by about 40 percent. People with diabetes also tend to get cataracts at a younger age and have them progress faster.

Another type of cataract called a posterior capsular cataract is often seen in diabetics. This type occurs at any age but is most common in Type I young adults who have very poor control of their diabetes. Posterior capsular cataracts can grow rapidly and loss of vision in the affected eye can occur in days.


People with diabetes are 40 percent more likely to suffer from glaucoma than people without diabetes. The longer someone has had diabetes the more common glaucoma is; risk also increases with age. Glaucoma occurs when pressure builds up in the eye. Through various mechanisms longstanding elevated pressure can cause gradual and permanent peripheral vision loss.

Refractive Changes

Diabetes may produce sudden hyperopic or myopic shifts which means your vision can abruptly become a lot worse. In fact extreme changes in vision may be the first sign of diabetes. These visual shifts occur because the lens of the eye swells thereby affecting how light enters the eye.

The key to preventing diabetes-related eye problems is to maintain good control of blood glucose levels eat a healthy diet exercise don’t smoke and make sure you visit your eye care practitioner at least once a year. Most diabetic eye diseases have no early warning symptoms. Your retina can be badly damaged before you notice any change in vision. It is therefore important to have a yearly eye examination even if it feels like nothing is wrong.

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