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Smoking and eye damage

Macular degeneration is the result of damage inside the eye that can lead to irreversible blindness. It can occur in one or both eyes and cause a permanent 'blind spot' directly in the line of sight (the opposite effect of tunnel vision). Macular degeneration is the leading cause of blindness in Australia and affects people over the age of fifty. It has a direct effect on peoples' daily lives, severely limiting their ability to carry out everyday tasks such as driving, reading, writing or even recognising faces.

Smoking leads to oxidative or other damage to the macula (this is the part of the retina at the back of the eye that we use when we look directly at someone or when reading). It may also constrict blood vessels to this area. There are two types of macular degeneration.. In the first, critical parts of the macula then may die (atrophy) or, in the second type (which is more common), critical parts of the macula are weakened, allowing abnormal new blood vessels to break through and bleed.  This second type of macular degeneration leads to scarring of the macula and severe loss of the central area of vision. People may initially notice distortion of straight lines and then a dark or greyish patch develops in the centre of vision, completely obscuring what they are looking at.

Smoking may cause both types of macular degeneration and the resulting blindness is irreversible. The process can be stopped using laser treatment only if the condition is caught in its early stages.

Some interesting facts on smoking and macular degeneration:

• Macular degeneration is the leading cause of blindness in Australia and smoking is the major preventable cause of this condition.
• The chemicals in cigarette smoke (around 4000 of them) get into the bloodstream of smokers and may induce the damage to the macula, at the back of the eye. This damage results in macular degeneration and blindness over time.
• The damage from macular degeneration limits the ability of a person to see what they are looking directly at (such as the face of someone they are talking to).
• Macular degeneration also limits colour vision.
• Laser surgery cannot reverse the damage resulting from macular degeneration (except in a minority of cases detected in the very early stages). However, laser surgery may retard and or prevent the progression of the disease and reduce the visual loss. Recurrence of the condition occurs in about half of those who have initial successful laser treatment. For people who continue to smoke, almost all develop a recurrence.
• An estimated 20,000 Australians have macular degeneration that can be attributed to their smoking and around 8,000 of these people develop legal blindness in both eyes that is likely to have been caused by their smoking.
• In Australia you are legally blind if you cannot read the top letters on an eye chart with either eye from six metres.
• Many people with macular degeneration do not realise that they have the condition until their second eye starts to deteriorate, as one eye can compensate for the other.
• Up to two thirds of people with macular degeneration in one eye will ultimately lose sight in both eyes from this condition.
• When a smoker quits, the recovery process in some other parts of the body can begin almost immediately. Although it is not known whether stopping smoking reduces the risk to the second eye, it seems likely given evidence that links current smoking to development of macular condition.
• Providing they live long enough, one in four people will lose vision because of macular degeneration. Smoking increases this risk dramatically and may cause the loss of vision at an earlier age than it might otherwise occur

Smoking and eye damage - questions and answers

How does smoking damage my eyes?

When you inhale cigarette smoke thousands of chemicals get into your bloodstream and can travel throughout your body. These chemicals cause damage to the macula (the most sensitive part of the retina, at the back of your eye). Tiny blood vessels can burst through the macula, leading to irreversible damage, or alternatively, the cells of the macula slowly die. Both ultimately lead to loss of vision.

Can this damage be reversed?

No. Laser treatment can sometimes kill the new blood vessels before they hit the macula. However, most people are not able to be helped this way because the blood vessel has already involved the very centre of the macula, and even after treatment, the condition recurs in half the cases and in almost all those who continue to smoke. A new treatment, photodynamic therapy (PDT) may be able to help some to reduce the severity of vision loss, but the majority of people with macular degeneration will still not be able to be treated.

How long does it take for my eyes to become damaged?

At this stage, there is no research to confirm at what point the damage occurs, however it is known that the process of macular degeneration is the result of progressive damage over many years. The condition is not usually detected until people are in their fifties or are older.

If I quit smoking will my eyes recover?

Your risk of macular degeneration will be reduced if you quit smoking, however existing damage to the eyes cannot be repaired, particularly once vision is affected.

Is there a test to tell if my eyes are damaged?

Your general practitioner or optometrist may be able to perform a simple test to indicate if your eyes are damaged. An ophthalmologist (eye specialist) will be able to determine the extent of the damage. You need to be seen urgently by an ophthalmologist if you suddenly become aware of distorted vision in one eye or if you notice a dark or greyish patch near the centre of your vision in one eye.

Chemicals in cigarette smoke get into the bloodstream and cause damage to the macula (part of the retina in the eye).  There is no cure for macular degeneration and not smoking or stopping smoking is one way to decrease the chances of developing this eye disease.