Controlling Age-Related Eye Disorders: Presbyopia and Cataracts

Presbyopia - Age-related need for reading glasses
Aging is inevitable and with it the efficiency of bodily functions decline. However certain losses of functionality can have severe effects on quality of life right at a time when we are at our most vulnerable. Of these, loss of vision is probably one of the most debilitating disorders affecting the capacity for independent living and enjoyment of life in general. Studies have shown that most people require visual assistance, if only for reading, by the age of 45.

Onset of aging causes presbyopia, a reduction in the flexibility of the lens and subsequent decline in close up focusing ability. Apart from aging, there are no other known causes of presbyopia and therefore nothing much we can do at present to prevent this degenerative process. However an absence of research data on possible links between lifestyle and presbyopia does not necessarily mean that we cannot prevent or delay the onset of the condition.

Cataract - Age and lifestyle related degeneration of the lens
Cataracts cause blurred vision through clumping of the proteins in the lens. These clumps of protein impede the passage of light through to the retina. Once formed, cataracts usually grow in size, gradually obstructing vision. Three types of cataract are possible. The most common type is the nuclear cataract which occurs in the center of the lens. Cortical cataracts grow from the edge to the centre of the lens, and subcapsular cataracts are associated with the capsule of the lens.

The risk of developing cataracts increases as we age. Approximately 12% of the population can expect to develop cataracts by the age of 65. Life expectancy in countries like Australia has risen to an extent that suggests most people will live long enough to need a cataract operation eventually. Although surgery for cataracts has a very high success rate, there are advantages to delaying the need for surgery. Onset of cataract formation is influenced largely by genetics; however several lifestyle factors are also related to their formation.

Causes of the development of cataracts
Diabetes, type 1 and 2, is a known cause of cataracts. Adequate treatment to control diabetes may prevent the development of cataracts. Where cataracts have already formed, attention to diet may reverse the damage to the lens.

Certain drugs and chemicals may initiate the development of cataracts. Research suggests that an association exists between inhaled corticosteroids and cataracts.

Protecting the eyes from bright sunlight and devices which emit UV radiation, in particular UVB light, may reduce or delay the development of cortical cataracts.

Evidence exists to suggest that cataracts may also be caused by eye infections such as conjunctivitis and toxoplasmosis.

Alcohol consumption increases the risk of all forms of cataract. Two studies, the Blue Mountains Eye Study and the Beaver Dam Study, agree that 4 or more standard alcoholic drinks per day corresponding to 280g ethanol a week is linked to the development of cataracts.

A strong association between smoking and the development of nuclear cataracts, with the risk increasing with smoking load. The risk is reduced upon quitting smoking long term. Smoking may also increase the risk of developing other types of cataract.

Diet and vision: considerations for prevention of cataracts
Diets high in antioxidants, in particular lutein, may have a preventative effect against development of cataracts. Spinach and kale are rich sources of lutein, and the best sources of antioxidants in general are most fresh fruit and vegetables.

Riboflavin (vitamin B2) and niacin (vitamin B3) may also be preventative against the development of all types of cataract. Riboflavin is found in offal, eggs, dairy, green leafy vegetables, oily fish, and whole grains. Niacin in its most bioavailable form is present in highest quantities in beans and liver and fortified products such as breads. These B vitamins are water soluble and therefore high intake will not lead to toxic build up in the body.

Conclusion
Protect your eyes from the sun, quit smoking, reduce alcohol intake, increase dietary intake of fresh fruit and vegetables, oily fish, eggs, green leafy vegetables and wholegrain products fortified with B group vitamins in order to maximize prevention of cataracts. One of the strongest links to the development of cataracts is diabetes. This link can work both ways. Paying attention to diet and vision may also have a preventative effect against developing diabetes.

National Health and Medical Research Council, 2009, Risk Factors for Eye Disease and Injury, Australian Government Department of Health and Aging, viewed 14 June 2010,
http://www.health.gov.au/internet/main/publishing.nsf/content/71FBCE0AF8F09F2ECA25755C0000B2EE/$File/EYECompiledReport.pdf