Macular Degeneration

Structure of the Eye

Structure of the Eye

The macula is the central most part of the retina that is responsible for detailed sharp vision. It is used for reading, driving, recognizing people’s faces and fine work. Macular Degeneration is a condition that causes the centre of your vision to blur while the side or peripheral vision is unaffected. It is generally related to the aging process, and is also commonly referred to as Age-related Macular Degeneration (AMD). It is the leading cause of blindness in North America in adults over the age of 55.

There are two types of AMD: dry and wet. The most common is the dry form. This is the milder form where there is a gradual degeneration of the tissue cells that make up the macula and symptoms generally develop slowly over time. The wet form is a severe leakage, or even bleeding, from weak blood vessels under the macula and symptoms progress rapidly. Wet AMD accounts for approximately 10 percent of all cases, but the dry form can develop into the wet form over time.

Initially, the most common symptom is slightly blurred vision when performing tasks that require seeing detail. A blurred spot or sense that there is dirt in the way of clear vision may develop. Over time, the blurred spot may increase in size and interfere with reading and recognizing faces. Wet AMD causes a straight line to look wavy or distorted, and dark spots may blank out portions of the central vision. There is no pain with AMD.

The risk of developing AMD increases with age. High risk groups include smokers and people who have had extensive UV exposure. AMD is also associated with conditions such as high blood-pressure, arteriosclerosis, and those with a family history of AMD.

Lifelong UV protection and general nutrition are believed to play a key role in preventing AMD. Living a healthy lifestyle by keeping your blood pressure down, reducing your intake of fatty foods and not smoking are all recommended. A diet high in antioxidants such as beta-carotene (a form of vitamin A), vitamins C and E, zinc, lutein, zeaxanthin and selenium can also help prevent AMD. Most of these antioxidants are found in fruits and leafy green vegetables. Regular eye examinations are also important in the early detection of AMD. Early stages of AMD may be found during an eye examination even if no symptoms are noticed. Your optometrist can discuss ways to minimize the possibility of vision loss due to AMD.

Currently, dry AMD has no treatment. There are older types of treatment for wet AMD that involve using lasers. One such treatment is known as Photodynamic Therapy (PDT). Recently, a new treatment for wet AMD has been used which involves injecting a drug into the eye which stops the growth of new, leaky blood vessels. Early detection and prompt intervention are crucial to the success of treatment for wet AMD. Certain vitamins can assist in slowing down the progression of AMD. It is important to realize that the use of vitamins will not reverse any vision loss that has already occurred, nor will it stop the progression of AMD completely.