Those who wear contact lenses probably have experienced some ongoing and persistent problems, especially if they work all day at a computer. Lenses dry out, feel scratchy, and vision is blurred. Eyes become red and uncomfortable, and lenses aren't worn as long as before. Repeated attempts to clean the lenses don't help.
These kinds of problems don't need to occur if wearers understand proper care and maintenance for contact lenses, and adhere to recommended schedules.
Soft contact lenses are soft and comfortable because they are hydrophilic, meaning they absorb and retain water in their matrix-like structures. Most contact lenses are from 38 to 55 per cent water by weight. This allows water to permeate through the structure, and to transport oxygen to the cornea at the same time it makes the lens soft and pliable. The cornea has no blood vessels, and gets needed oxygen and some nutrients from the tear film. The soft lens allows oxygen and soluble nutrients to permeate through its meshwork.
Some newer lens designs incorporate Silicone in their structures to increase oxygen transmission. These lenses are referred to as "Silicone-Hydrogel" lenses and indeed they do transmit much higher levels of oxygen without relying as much on water moving through the lens. Newer silicone-hydrogel lenses also stay hydrated better.
|Replacing the contact lenses with new ones at fixed time intervals avoids the problems caused by a lens with accumulated deposits.
The density of the protein coating increases in direct proportion to the time the lens has been in use. No wonder that at the end of a planned wearing cycle, the lens's comfort and the clarity of vision have decreased. This is more true if wearing time has been extended beyond recommended replacement. Two ways to limit the onset of these problems exist.
First, follow the recommended replacement cycle for the lenses as directed by an eye care professional. Replacing the lenses with new ones at fixed time intervals avoids the problems caused by a lens with accumulated deposits.
|For those who wear lenses overnight, replacing them on schedule becomes especially critical.
Second, for those who wear lenses overnight, replacing them on schedule becomes especially critical. Reconsider whether wearing the lenses overnight is good idea. According to Mitchell H. Friedlander, M.D., director of the Cornea Service at the Scripps Clinic and Research Foundation in La Jolla, California, wearing a contact lens while you sleep is never a good idea.
Research studies at the Massachusetts Eye and Ear infirmary and Harvard Medical School in Boston confirm that with each consecutive overnight wearing cycle, the probability of lens related difficulty increases by about 5%. Contact lens over-wear and misuse have caused permanent eye damage and irrecoverable vision loss, with no one impervious to this kind of damage.
Those who wait until they experience discomfort and cloudy vision cause unneeded changes in eye health, including excessive redness and persistent discomfort, and the risk of corneal ulceration and a potential for serious and sight-threatening infection.
Treat the lenses regularly to remove protein deposits. Every night is best. There are several effective protein removers available in the contact lens products aisle in most pharmacies. Avoid tap water or any bottled water. They are not preserved with appropriate disinfectants, and often harbor organisms that are potentially very difficult to defeat and can cause catastrophic scarring of the cornea.
|Avoid the use of tap water or any bottled water.
Be careful to avoid mixing contact lens care products from different manufacturers. The solutions are formulated to work together, and because formulations differ, they can be incompatible across product lines. There are many suitable products available. If a solution or product line is unfamiliar, be sure to read the directions. Long time contact lens wearers develop habits with solutions that may not be safe or effective in combination.
After soaking the lenses overnight as directed, the loosened protein must be removed by gently scrubbing and rinsing the lens with a preserved saline storage solution. No-rub techniques are not as effective, however appealing they may be for their perceived convenience.
While cleaning the lenses, don't forget the case. After putting the lenses on, dump the old solution and wash the insides of the cases and screw caps with soap and warm water (unless you're using a peroxide system) and leave the case open to air dry.
For peroxide disinfecting systems, be sure to follow directions carefully. This sometimes involves replacing the catalytic disc in the bottom of the case that deactivates the peroxide. In the evening when the lenses are removed for storage, always use fresh solution in the clean case no matter which system is used.
The advent of disposable contact lenses has brought with it some significant advantages for contact lens wearers. Different replacement cycles apply to different lens designs, varying from a day to a month. If replacement schedules are followed as recommended, the lens is less likely to have a significant accumulation of protein and lipid deposits, and much less likely to provoke problems with comfort and wearability.
Disposable contacts are manufactured by highly automated and accurate computer-controlled machines, and are very repeatable. This assures that each lens will behave as the one before it did.
Many contact lens wearers use daily disposables. These lenses are discarded after each daily use, eliminating the need for any maintenance, and eliminating the cost of contact lens solutions. This makes them very convenient and very healthy.
Two weeks is a very popular replacement cycle, but numerous studies and clinical experience show that less than half the people using contact lenses actually adhere to the schedule. Industry insiders suggest that only about 30% of contact lens wearers replace lenses on recommended schedules.
Patients admit that they ignore the recommended replacement times to economize on lens costs, but we know that deviating from the recommended schedules is the major reason for the persistent and annoying symptoms that nearly always result.
Replacement of lenses on a calendar based schedule, and routine removal of protein and lipid deposits, are the best ways to assure a comfortable and problem-free contact lens experience, and protect the all-important health of the eyes, and the clarity of vision we all depend on.
Dr. Phillip G. Hanson is the director of Benbrook Family Vision Care, in Benbrook, Texas.
Dr. Hanson forgot to mention that people should avoid products containing Thimersol. Thimersol is the toxic, mercury-containing compound found inside vaccines that is causing so many problems. It is highly aggravating, and will absorb straight into brain tissues through the eyes.
-- The Staff