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The biggest problem with contact lenses is not the devices themselves, but the people who wear them. A study from the Centers for Disease Control and Prevention in the US found that nearly a million visits to the doctor each year relate to eye infections from lenses. |
The most serious eye infection is keratitis, caused by bacteria and other organisms that affect the cornea – the transparent dome-shaped structure at the front of the eye. Studies suggest that infections occur because people ignore their opticians’ advice.
Considering that eyes are so precious, it is surprising that 45% of people don’t wash their hands before putting in or taking out their lenses. Other studies show that monthly contact lenses are used for one and a half times longer than recommended. Two-weekly disposable lenses are used for more than two and half times as long as they should be.
Contact lenses are medical devices and soft contacts tend to be packaged in small sterilised containers filled with fluid, which over time (hence the expiration date) can become contaminated. The biggest cause of infection, however, is overnight wear, says Professor Roger Buckley, associate director of the Vision and Eye Research Unit at Anglia Ruskin University.
Sleeping with your lenses in raises the risk of corneal infection 20-fold. The cornea is starved of oxygen when lenses are in and eyelids closed, making it less effective as a barrier for keeping out germs. The overall risk is still small (3.5 per 10,000 people wearing daily soft lenses), but keratitis is painful, can make your eyes weep and causes blindness. So should contact lenses be treated with more respect?
Anyone who wears contacts should take care. Hands should be washed and thoroughly dried before putting in or removing lenses. Lenses should never come into contact with water of any type, including showers. This is because water can be contaminated by Acanthamoeba organisms that stick tenaciously to contact lenses and cause ulcers in the cornea.
Lenses should be removed before swimming or watertight goggles worn.
Saliva and contact lenses are a no-no as your mouth is full of bacteria that your eye isn’t meant to meet. Likewise, avoid eyeliner and apply mascara only after your lenses are in.
People who use rigid lenses should replace their cases at least every three months, use recommended contact lens solution and never mix the fresh solution with the old.
If your eyes hurt, are red or blurry or you have any doubt, take your lenses out and see your doctor. Always have glasses as a standby.
Some people do buy lenses online, but always see an optician regularly and be careful which lenses you choose and how you put them in.- Guardian News and Media
♦ Dr Luisa Dillner heads BMJ Group Research and Development.
