Vision loss can be caused by eye problems that are present from birth, by conditions that appear later in life, or by infections or environmental factors.
In this section, you'll find information about some common eye problems as well as the main causes of vision loss in children and adults.
Combining simple diagrams and easy-to-understand facts, this section is an excellent resource for anyone wanting to understand more about eye conditions in general, or needing further clarification of an eye care specialist's diagnosis.
Age-Related Macular Degeneration (AMD)
One million Canadians have some form of AMD, the leading cause of vision loss in Canada. More Canadians have AMD than breast cancer, prostate cancer, Parkinson's or Alzheimer's disease combined. Yet few of us even know that it affects the eyes.
AMD is a progressive condition that attacks central vision. People who have AMD may no longer be able to read, drive, or see the faces of their family members. The personal, societal, and economic costs of AMD can be devastating. And with an aging population, the number of people with the disease is expected to double in the next 25 years.
Fortunately, there is lots of information available about preventing AMD, and living a satisfying life even if you have the disease. At the same time, promising new treatments are on the horizon.
A Leading Cause of Vision Loss
More than 2.5 million Canadians have cataracts. They are painless, develop within the existing lenses in your eyes, and are usually detected during routine eye exams.
As you age, your lenses naturally harden and may also turn cloudy. A cloudy lens blocks light from reaching the retina and interferes with vision - the effect is similar to looking through a dirty car windshield. Cataracts may form in one or both eyes, at the same time or at different times.
Fortunately, cataracts can be removed and your vision can be restored. Surgery is usually recommended once a person feels their vision interferes with daily activities such as driving, reading or watching TV.
Cataract surgery is among the most highly perfected, safe and successful procedures in medicine - more than 95 per cent of patients have improved vision after surgery. It removes the cloudy lens and replaces it with an artificial one.
- Sensitivity to bright light or experiencing glares and haloes around lights
- Difficulty seeing details and poor central vision
- An inability to distinguish colours
- Difficulty seeing at night
- Double vision
- Family History
- Other health problems - complications such as diabetes
- Drinking Alcohol
- Excessive sun exposure
- Eye injury (puncture, cut, intense heat or chemical burn to the eye)
A Leading Cause of Vision Loss
It is estimated that half a million Canadians have diabetic retinopathy. Many people who have diabetes have some form of this eye condition.
Diabetes can affect many parts of the body, including blood vessels, nerves, kidneys and the heart - and people with diabetes are at a high risk of developing vision problems. Diabetes occurs when the body is unable to control the level of sugar (glucose) in the blood because it cannot produce a hormone called insulin.
Often there are no symptoms in early stages and your vision is not affected. Without treatment, diabetic retinopathy can advance to uncorrectable vision loss or even blindness, usually in both of your eyes.
With routine eye examinations, diabetic retinopathy can be detected and treated.
- Type of Diabetes (Type 1)
- High blood sugar
- High blood pressure
- Ethnicity (aboriginal Canadians are 3-5 times more likely than the general population to develop diabetes)
Lost vision from diabetic retinopathy cannot be restored, but with early detection, treatment is often very successful and can prevent your vision from getting worse.
During the first three stages, a person's vision is monitored carefully. In the fourth stage laser treatment and injections and surgery can be used.
Controlling your blood sugar can help reduce the risk of developing vision loss due to retinopathy. Regular follow up with your family doctor regarding control of your blood sugars. Be proactive.
Glaucoma is the second most common cause of vision loss in seniors in Canada. More than 250,000 Canadians have chronic open-angle glaucoma, the most common form of the disease.
Glaucoma involves damage to the optic nerve most often caused by high pressure inside the eye due to a build up of excess fluid. High eye pressure is not always a sign that you have glaucoma but may be an indication you are at risk of developing it.
Over time the disease develops into a loss of peripheral (side) vision. If glaucoma is untreated it could advance to later stages where central vision narrows to "tunnel" vision, or it may result in complete loss of vision. Early detection and treatment is essential to prevent severe vision loss or blindness.
Types of Glaucoma
Open-angle glaucoma accounts for 90 per cent of all cases in Canada - Initially you can perform all normal daily activities such as driving and reading and vision loss is not obvious until it is too late and permanent.
Primary acute closed-angle glaucoma results from a buildup of fluid in the eye because the distance between the iris and the drainage system has been closed, stopping fluid from draining from the eye. Occurs very suddenly and is an emergency.
Secondary Glaucoma can result from a variety of other conditions such as an eye injury or inflammation, eye surgery complications, diabetes and the use of certain medications.
- Elevated pressure in the eye
- Family history
- Age - after age 40 and after age 60
What is Retinitis Pigmentosa?
Retinitis pigmentosa (RP) refers to a group of diseases which tend to run in families and cause slow, but progressive loss of vision. The retina is the tissue which lines the inside of the eye and sends visual images to the brain. In RP, there is gradual destruction of some of the light sensing cells in the retina.
Causes and Symptoms
The cause of retinitis pigmentosa has not been clearly identified. About fifty percent of RP cases are sporadic with the remaining cases being hereditary. Learning more about the history of people with RP may help predict how the disease will progress for the affected person, although variations can exist even from person to person within a family.
The first symptoms usually start during young adulthood, although it may be seen first at any age. The two most common symptoms are night blindness (where adjusting to the dark happens very slowly) and the loss of side vision. Loss of side or peripheral vision makes mobility very difficult. Once this occurs, a person is left with only central vision (as if looking down a tunnel).
While developments are on the horizon--particularly in the area of genetic research--as yet, there is no cure for retinitis pigmentosa. The retina is attached to the optic nerve and transplants are not yet an option.
Unfortunately, there is no scientific evidence to demonstrate benefits from any treatment methods--including vitamin supplements--currently available.
One controversial treatment, currently available in Cuba, consists of a combination of ozone therapy (removing a small amount of blood from the eye, adding ozone, and replacing it a short while later), electrical stimulation, dietary supplements and so-called "oligoelements", and eye surgery under a local anesthetic. The rationale behind these procedures is to improve the supply of oxygen and nutrients to the affected parts of the eye.
As yet, this procedure has not been subject to critical review and, as such, remains outside the medical mainstream. The Cuban clinic where it has been performed has repeatedly refused to show the procedure to anyone outside of the clinic. As such, critical review is very difficult. There have been reports of physical damage to some patients including detached retinas, crossed eyes, and sensitivity to light.
Because of this, the RP Research Foundation in Canada and the RP Foundation Fighting Blindness in the U.S. have called the procedure into question.
For the latest treatments, please see your ophthalmologist.