The Importance of Contact Lens Compliance
When a new lens is placed on the cornea the level of oxygen getting through to the cornea is at its peak. Thanks to recent advances in contact lens technology new lens materials and care systems can provide unbelievable comfort throughout the day. But contact lens use is not without risk and the potential for vision-threatening problems is present especially in those who abuse the use of contacts. Those who overextend contact lens wearing time or don’t replace their lenses as instructed run the risk of developing problems.
Contact lens complications: It’s mostly about oxygen!
When you think of contact lens-related complications you must think in terms of oxygen. Simply stated even the best-fitting contact lens causes a compromise of the oxygen supply to the cornea. When a contact lens is in the eye not as much atmospheric oxygen gets through to the cornea as compared to when there is no contact lens on the eye. Over a long period too little oxygen is not good.
What can happen?
If you were to continue using a disposable razor you’d eventually knick your skin by the dulled blade. Disposable razor blades are meant to be thrown away after a period of time. It’s similar with disposable contact lenses. They are meant to be discarded after a designated period of time.
It’s important to understand that overwearing your contact lenses – whether it’s too many hours a day or too many weeks before discarding – may not cause you to experience any symptoms and herein lies the danger. If the cornea doesn’t receive enough oxygen it actually becomes somewhat anesthetized being less able to experience pain or discomfort. All eye doctors have seen patients with various degrees of contact lens-related corneal abrasions often without any symptoms. Several things can happen when the cornea is deprived of sufficient oxygen. The term “deprive” does not mean completely cutting off the oxygen supply but instead refers to a subtle reduction in oxygen supply over a long period of time. Slow starvation if you will.
Abnormal blood vessel growth
In the normal eye the cornea is perfectly transparent tissue with no blood vessels. If the cornea is deprived of enough oxygen over a period of time blood vessels from the surrounding tissues can grow into the cornea. This is a response of the cornea “calling out” for oxygen; it’s the body’s natural reaction to send in blood vessels. The aim of these new blood vessels is to deliver fresh oxygen to the starved corneal tissue. If left untreated these vessels can continue to grow into the cornea and can interfere with vision. These vessels are permanent and remain even if a person ceases wearing contact lenses. So prevention of their growth is key.
Surface cell problems
Another adverse effect of reduced oxygen supply involves the single layer of cells on the surface of the cornea. These epithelial cells are very sensitive to reduced oxygen supply. Over time they can swell and become loosened from their firm attachment to the cornea leaving openings in the cornea’s protective surface. These openings in the surface are opportunities for bacteria to cause infection. If too many epithelial cells slough off an abrasion or worse a corneal ulcer can form.
We now know that reduced oxygen supply to the cornea causes various bacteria to be able to bind to the epithelial cells. Healthy well-oxygenated epithelial cells tend to resist bacterial binding. Obviously when bacteria bind to the surface cells they are in a position to cause an infection.
All these complications are highly preventable through the use of common sense. Don’t wear your contact lenses all the time. It’s important to give your corneas a regular “oxygen break”. If you are just hanging around the house it’s a nice opportunity to give your eyes a rest by wearing your glasses. Avoid wearing your contacts for all your waking hours.
Disposing of your lenses
Timely disposal of your contact lenses after a designated wearing period whether it s daily two weeks or one month again has to do with oxygen. When a new lens is placed on the cornea the level of oxygen getting through to the cornea is at its peak. Over time as the lens is worn and becomes layered with tear proteins as well as other debris and makeup corneal oxygen levels begin to diminish. Unfortunately some patients continue to wear their lenses far beyond the safety point. Since they frequently have no symptoms they mistakenly believe that nothing is wrong. Don’t be deceived into this way of thinking. A fresh lens will give your corneas the oxygen they need.
The big picture
One must think in terms of the long haul when wearing contact lenses. It’s important to maintain optimal corneal health throughout life. You’re not doing yourself any favors by wearing lenses too many hours each day or wearing your lenses past their designated life span. Remember the key is to keep as much oxygen flowing to the cornea as possible.
Stay in close touch with your doctor
Your doctor will examine your corneas to make sure none of the problems we’ve talked about are taking place. Adhere to the lens replacement and appointment schedule you are given by your doctor. If you suspect that you do have a problem if your eye is painful gets red or if your vision is blurred stop wearing your contact lenses and call your doctor’s office.
Giving your eyes a reasonable oxygen break each day and replacing your lenses when you’re supposed to will help ensure that your corneas remain healthy and that you have many years of problem-free clear vision with your contact lenses.