Eye Health | Macular degeneration
Macular degeneration is a progressive condition where the part of the retina called the macula is damaged, which leads to loss in central vision. The retina is a light-sensitive membrane at the back of the eye which functions like the film in a camera. If the “film” is warped or damaged, the film will not record the image that is “photographed by the eye”.
There are two main types of macular degeneration: “wet” macular degeneration and “dry” macular degeneration. “Dry” macular degeneration is the more common condition. It is most common under European descendants over the age of 55.
The causes of this condition are not completely understood, but there is a genetically inherited tendency. Smoking, dietary factors and sun exposure may also play a role. The condition cannot be cured but its progress can be slowed down in some individuals if treated promptly.
The macula of the retina degenerates as a result of aging. Small yellow or white deposits called “drusen” develop under the macula in normal eyes as they age. Drusen may lead to macular degeneration. Macular degeneration occurs when the retinal pigment epithelium, the insulating layer between the retina and the layer of blood vessels behind the retina (called the choroid) stops functioning efficiently. The macula may be damaged by blood vessels growing under the retina. The blood vessels may leak fluid or bleed (wet macular degeneration), or by the retina degenerating (dry macular degeneration).
Dry macular degeneration…
This is the common form of macular degeneration. When the eye is examined, the retina appears to have degenerated in certain areas and looks healthy in other areas. Damage to the macula is permanent; it cannot heal. There are no eye drops, tablets, spectacles, operations or alternative therapies proven to restore the vision that has been lost. However, you will not go blind from this condition and will keep your secondary vision. The disease is slowly progressive, and the rate of progress may be extremely slow. The condition eventually stabilizes.
Wet macular degeneration…
Wet macular degeneration is rare. It is more rapidly progressive than dry macular degeneration, but it also doesn’t cause blindness. Secondary vision is preserved and some people can be treated to preserve some useful vision. It occurs when abnormal blood vessels develop under the retina, and leak fluid or bleed under the retina. The fluid, blood or vessels eventually disappear, but the central vision is permanently damaged, and a scar forms.
Symptoms and signs of macular degeneration
- Blurred central vision – difficulty when reading and engaging in other activities that require good fine eyesight
- Lost central vision – dark or empty spaces
- Distorted central vision – straight lines may appear wavy
How is macular degeneration monitored?
The ophthalmologist (eye specialist) will see you for regular check-ups. You can also monitor your own condition using an Amsler Grid, which allows the patient or eye specialist to pick up subtle deterioration or changes in vision. During this testing, you should wear the contact lenses or glasses you usually wear for reading. If you use bifocals, you should look through the reading portion of the glass.
Hold the grid at a comfortable reading distance (usually about 30 to 35 centimeters away) and focus on the dot at the centre of the grid. Any wavy areas, blurred areas or blank spots observed should be marked on the grid, allowing for future monitoring of the progress of the condition.
Can macular degeneration be prevented?
If you are over the age of 45 and you have a family history of macular degeneration or if you experience any visual problems, you should have regular eye examinations. This will enable early diagnosis of the disease and make the few treatments that are available more effective.
Although macular degeneration cannot be prevented, you may be able to delay the progression by:
- Avoiding cigarette smoke. Smoking is the most commonly identified factor aggravating the condition.
- Avoiding contact with ultra-violet light (UV rays) by wearing protective eye gear that blocks out 100% of UV rays.
- Proper nutrition – particularly balanced and sufficient intake of vitamins, minerals and fresh vegetables – is also believed to help prevent the condition, and at the very least will improve general health.
- Regular exercise, which improves both general and eye health.
How is macular degeneration treated?
There is currently no proven treatment for dry macular degeneration, however in some people with the condition, supplements containing vitamins, lutein or certain trace elements such as zinc or selenium may slow the progress of the disease. There are also many unproven treatments which desperate patients will spend as much as they can afford on in an attempt to regain their vision. Unfortunately these therapies are unproven and usually benefit the therapist more than the patient.
If diagnosed early, wet macular degeneration can be treated in some patients by laser treatment. A newer variation of laser treatment is photodynamic therapy (PDT). In laser photocoagulation treatment, a laser is used to seal leaky blood vessels and inhibit their growth to prevent any further deterioration.
In the case of partial blindness caused by macular degeneration, “low vision rehabilitation” can help you adjust to your condition. Rehabilitation may include:
- adjusting the lighting in your home
- visual aids and voice-activated devices
- seeking assistance from someone reliable with good eyesight in performing daily work and tasks.
What is the outcome of treatments?
Laser photocoagulation treatment, even when successful, results in a scar and a permanent blind spot in the treated area. Vision is unlikely to improve and some people might find the situation worse immediately after the surgery. However, if it halts the development of the disease in the treated areas, this therapy may result in less long-term vision loss than occurs if no treatment is given. It may also reduce visual distortion. Therapy is more successful in slowing the disease if it is detected in an early stage.
Low vision rehabilitation can allow macular degeneration sufferers with access to good public transport and assistance from family or friends to live fairly normal lives, even if they are partially blind.
When to call the doctor
If you experience any symptoms of macular degeneration it is vital that you consult your eye-care specialist as soon as possible. As a safety-precaution, you should have your eyes tested regularly. Also, consult your eye specialist before trying any treatment whatsoever, to ensure that any “miracle cures” on the market are at least not dangerous to your health.