Overwear of Contact Lenses
Overwear of Contact Lenses

Author - Jessica Ding (Optometrist) 

Why you should never overwear your contact lenses

If you’re a contact lens wearer, chances are you’ve been guilty of thinking to yourself at some point “It’s okay if I wear my monthly lenses for one extra week, they still feel pretty comfortable” or “I’m exhausted tonight, I’ll take my contacts out tomorrow”. Well, let me tell you why you should always ignore those tempting little voices.

Your contact lenses rest on the part of your eye called the cornea, it is a clear dome of tissue above the iris and its clarity is essential for good vision. Unlike the rest of the body, it receives the majority of its oxygen from the atmosphere. The contact lens acts as a barrier that limits the amount of atmospheric oxygen getting to your cornea. As they age, the amount of oxygen able to pass through decreases to the point where it’s no longer adequate for the maintenance of healthy tissue. If your cornea is deprived of oxygen for long enough, it can begin to swell up and cause your vision to be blurry, compromise its immune defences and make you more susceptible to infections. If that’s not enough to convince you, maybe you should consider the proteins, bacteria and debris that collect on your contacts over time. They can bind and react with the material of the lens causing a buildup of gunk which makes your eyes irritated, itchy, scratchy, or worse, infected. I mean, you probably would not wear the same pair of underwear for months at a time... Eww! Gross. 

So maybe I have persuaded you to replace your lenses regularly, but it is okay to wear them for 16 hours a day, seven days a week right? Not so! Just like you, your eyes need periods of rest. Most people don’t work seven days a week, so why should their eyes? Overwear of contact lenses will lead to the same detrimental effects of oxygen deprivation mentioned above. I generally recommend my patients to wear their lenses up to five days a week and only eight hours a day. Once you get home from work or study, take your contacts out and pop on your glasses. Your eyes will thank you for it in the long run. 

Now, what happens when you sleep in your contact lenses? Unfortunately, the prognosis is even worse. Once the eyes close at night, it vastly decreases the amount of oxygen filtered to your eyes, add in a contact lens and it’s even less. Research suggests that people who wear their lenses to bed have a 10 to 15 times higher risk of developing an eye infection compared to those who only wear them during the day. But before you panic, there are contact lenses which are specifically designed for ‘extended-wear’, contacts that you can wear for several days or more at a time. In the case of wearing daily disposable contact lenses, you must avoid wearing it while you sleep and even the next day. So if you often find yourself tempted to sleep in your lenses, talk to your optometrist and so he or she can assess your suitability and advise on the option for you. 

Contact lenses are an amazing technology which can sometimes be life changing, however, they are considered a medical device and proper care must be taken when using them. You only have one set of eyes, give them the care that they deserve. If in doubt, don’t be shy, talk to your optometrist!


By Jessica Ding.  

Optometrist at 1001 Optical. 

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