It's never too early: Take steps to prevent vision loss from wet macular degeneration

Wet macular degeneration causes rapid loss of clear, sharp vision.¹ It is a leading preventable cause of vision loss and blindness in Australia and other developed countries. There is no cure for macular degeneration, so it's important to take steps to prevent the condition.²

There's a hole in my vision

The macula is the area of the eye responsible for 'high acuity vision' – the clear, sharp vision needed to focus on objects, for example when reading and driving. Macular degeneration is a condition in which high acuity vision is lost. An affected person may eventually see nothing but a blank spot in the centre of their visual field.¹

Although peripheral (side) vision remains unaffected, a person with macular degeneration can experience such serious vision loss that they meet the official criteria for blindness.¹Approximately half the people considered legally blind in Australia have lost vision because of macular degeneration.²

How long do I have, Doc?

There are two types of macular degeneration which may affect healthy individuals. Dry macular degeneration (also called early macular degeneration) causes gradual vision loss.¹ It is the most common type of macular degeneration and occurs in 90% of cases.⁵

The 'wet' type is more serious. It causes rapid vision loss and accounts for the majority of blindness associated with macular degeneration.⁵ It's variously called 'wet', 'exudative' 'late' and 'neovascular' macular degeneration, and is caused by the abnormal growth of tiny blood vessels in the eye.¹

In wet macular degeneration, blood vessels grow abnormally under the macula of the eye. If the blood vessels burst or leak, blood or fluid can spill out, cause the macula to shift, and disturb the individual's vision.² Individuals with wet macular degeneration require urgent treatment to prevent vision loss.³

Symptoms to watch out for include:³

Distorted vision where straight lines may appear wavy;
Blind spots or holes in the vision; or
Difficulty reading smaller print.

Don't wait: What you lose today won't come back tomorrow

Despite considerable improvements in the last decade,⁴ treatment for wet macular degeneration can only prevent further vision loss.² It has limited ability to restore vision loss that has already occurred.¹ So preventing the condition before it affects vision,² or limiting progression once the disease has been diagnosed,³ is much better than treating it once vision loss has already occurred.²

Macular degeneration is, to some extent, a natural part of ageing and many individuals can expect their vision to deteriorate over the years. However, some older people are more likely to experience macular degeneration than others. An individual's likelihood of experiencing macular degeneration is largely determined by modifiable risk factors. Modifiable risk factors are the aspects of an individual's lifestyle which affect the risk of experiencing macular degeneration and which can be changed.²

Smoking is the key modifiable risk factor for macular degeneration.² Individuals who smoke are three times more likely to experience the condition,⁶ and the more they smoke the greater the risk that their macular degeneration will progress more quickly.²

There is also evidence that modifiable risk factors relating to a person's diet and physical activity influence their risk of macular degeneration. For example, a diet high in fat (especially animal fat) appears to increase the risk, while a diet high in antioxidants (found mainly in fruit and vegetables) is thought to reduce the risk of macular degeneration.²

Having a high body mass index (BMI) and high blood pressure also make macular degeneration more likely,² while regular exercise is associated with a lower risk of macular degeneration.⁷ For example, one study reported that individuals who perform 30 minutes of moderate exercise three times a week are 70% less likely to experience macular degeneration than those who don't.⁷

Treatment to protect the vision you have

The most promising treatment option is injecting an anti-vascular endothelial growth factor (anti-VEGF) such as ranibizumab (Lucentis) into the eye. Another drug, bevacizumab (Avastin) is cheaper if unsubsidised prices are compared, but is not approved for the treatment of macular degeneration in Australia.⁴

Laser eye surgery to close leaking blood vessels can also be used to prevent vision loss in wet macular degeneration. However, the treatment is rarely effective in maintaining the necessary vision for reading or driving.⁴

Prevent or seek urgent treatment

So don't wait: make some changes that could save your sight. Eating a healthy diet, exercising regularly and avoiding smoking will improve your health in general and also reduce the chance you'll develop macular degeneration later in life.

If symptoms of wet macular degeneration do occur, urgent medical assessment is required to ensure treatment is given to prevent vision loss. Go to your GP and ask for a referral to an ophthalmologist (eye specialist).

For more information about macular degeneration, see Macular Degeneration.

References

Chakravarthy U, Evans J, Rosefield PJ. Age related macular degeneration. BMJ. 2010;340:c981. [Abstract]
Guymer RH, Chong EW. Modifiable risk factors for age-related macular degeneration. Med J Aust. 2006;184(9):455-8. [Full text]
Morris B, Imrie F, Armbrecht AM, Dhillon B. Age-related macular degeneration and recent developments: New hope for old eyes? Postgrad Med J. 2007;83(979):301-7. [Abstract]
Guymer RH. Managing neovascular age-related macular degeneration: A step into the light. Med J Aust. 2007;186(6):276-7. [Full text]
Oliff HS. Adult macular degeneration [online]. New York, NY: Langome Medical Centre, New York University; September 2010 [cited 4 May 2011]. Available from: URL link
Smith W, Assink J, Klein R, et al. Risk factors for age-related macular degeneration: Pooled findings from three continents. Ophthalmology. 2001;108(4):697-704. [Abstract]
Knudtson MD, Klein R, Klein BE. Physical activity and the 15-year cumulative incidence of age-related macular degeneration: The Beaver Dam Eye Study. Br J Ophthalmol. 2006;90(12):1461-3. [Abstract]