SOFT CONTACT LENS CARE
CLAO
Introduction
Today, more than 35 million Americans wear contact lenses. For the vast majority, contact lenses provide a safe, effective, and attractive means of vision correction.
The factors most important in assuring safe contact lens wear are:
- An eye that is basically healthy
- A lens that fits properly
- A wearer who adheres to recommended lens care routines
As a contact lens wearer, how important is your role in ensuring the safety of your contact lenses? Very! It has been estimated that up to 80% of all soft contact lens complications are the result of the wearer's failure to follow lens care instructions. Perhaps the greatest danger to contact lens wearers comes from infection. But faithful adherence to your eyecare practitioner's instructions for contact lens cleaning and disinfection will go a long way toward reducing this risk. The following guidelines are presented to help make your contact lens wearing experience safe and problem-tree.
Soft Lens Care
Unless specifically designed for extended wear, all soft lenses (and the soft/rigid combination lens) require daily removal, cleaning and disinfection. Because different lenses are often made of different plastics, it is important to use the recommended solutions. Your practitioner will make sure that the solutions you use are compatible with the lenses you wear.
Cleaning: The daily cleaner may contain either a surfactant (detergent) or a mild abrasive. Before cleaning your lenses, wash your hands with a deodorant-free, coldcream-free soap. With the lens in the palm of one hand, apply the daily cleaner to the lens and rub the lens in a to and fro fashion for 20 or 30 seconds. Take care that the lens is not scratched or torn by your fingernails. After cleaning, the lens is rinsed thoroughly with a commercial contact lens saline solution. (Never use home-made saline or tap water for rinsing!) Because bacteria can grow in the lens case, keeping it clean is important. Rinse the case with hot water each day and allow it to air dry. Once a week the case should be cleaned with detergent, boiled, and allowed to air dry. The case must be replaced periodically.
Disinfection: Disinfection is a very important part of soft lens care. Cleaning and disinfecting are not the same thing. Cleaning removes coatings and deposits from the lens but does not kill all of the microorganisms that can contaminate a lens. So you must always disinfect your lenses before putting them back in your eyes. There are three ways to disinfect soft lenses: 1) heat, 2) hydrogen peroxide, and 3) "cold" chemical disinfection. Commercially available heating units are effective in killing bacteria and fungi. Heat disinfection is also effective against Acanthamoeba, an organism that can cause great harm to the eyes. While Acanthamoeba infection is rare, it is very serious and hard to treat; so prevention-by careful attention to contact lens hygiene and by using a disinfection system effective against Acanthamoeba-is the best defense. But heat disinfection may not be appropriate for all lenses. Long-term use of heat can damage lenses with high water content; and heat can shorten the life of a lens.
Like other electrical products, heating units can malfunction. A damaged unit will not properly disinfect lenses and so must be repaired or replaced before being returned to use. It is advisable to replace units every 1-2 years--before they break. Periodically check your heating unit for malfunction. (If it malfunctions, you may still be able to get it repaired under the manufacturer's warranty.) Hydrogen peroxide is an effective disinfectant and safe for all contact lenses. To be effective against Acanthamoeba, the lens should remain in the hydrogen peroxide solution for at least two hours. Lenses
disinfected with hydrogen peroxide require neutralization prior to being put back in the eye. Never use a neutralizing solution intended for a different brand of hydrogen peroxide, since different brands may be incompatible. After removal from the neutralizing solution, the lenses may be rinsed with sterile commercial saline, (never use tap water), and then inserted. The used solutions (both the hydrogen peroxide and the neutralizing solution) should be discarded. Cold chemical disinfection systems ate effective against most bacteria and fungi but vary in their effectiveness against Acanthamoeba. Older chemical disinfecting solutions containing the preservative thimerosal were responsible for a number of cases of eye irritation and allergic reaction. Newer, non-thimerosal-based products are much better tolerated. Cold chemical disinfection is often the simplest of the three methods of lens disinfection and can prolong the life of the contact lens. As research progresses, disinfection systems are continually being improved. Your practitioner will be happy to discuss disinfection with you and recommend a system that will provide maximum safety for both your eyes and your lenses.
Enzyme Cleaning: Soft lenses require enzyme cleaning to remove protein build up. Used weekly (or as prescribed by your practitioner, enzyme cleaners come as either pre-mixed solutions or as tablets that can be dissolved with commercial saline. (Never use distilled or tap water with your lenses.) Clean your lenses with daily cleaner before using enzyme. High water content lenses should be exposed to the enzyme solution for up to 2 hours. Low water content lenses can undergo enzyme treatment for as long as 12 to 24 hours. After enzyme treatment, once again clean your lenses with daily cleaner, and then disinfect before returning the lenses to your eyes. Some enzyme cleaners are designed to save steps. One enzyme cleaner works in hydrogen peroxide, allowing lenses to be enzyme treated and disinfected in a single step. Other enzyme cleaners can be used directly in the heat disinfecting unit, saving heat users a step in lens care. Some enzyme systems are incompatible with some lenses. Your practitioner will recommend an enzyme cleaner that can be used safely with your lenses. By the same token, some enzyme cleaners are incompatible with some disinfecting systems-be certain to check the manufacturers' guidelines for compatibility.
Ongoing Care: Should you require a wetting solution to ensure lens comfort, either the unit-dose type or a solution with a preservative should be selected. Solutions that Use thimerosal as a preservative should generally be avoided, as thimerosal causes allergic reactions in many people. (For this reason, it might be a good idea to avoid any solution with thimerosal.) Distilled water, tap water, and home-made saline should never be used with contact lenses. Since all of these are hon-sterile, their use with contact lenses represents a serious infection risk. Sterile commercial saline, which is made for use with contact lenses, is safe and readily available. Soft lenses tend to deteriorate with age. In time, soft lenses may pick up both a thin film that covers the entire surface, as well as larger, more lumpy deposits. Careful attention to daily clean-
ing and enzyme cleaning will slow the process, but eventually all lenses reach a point where they must be replaced. Deposits, lens discoloration, and decreased comfort are all signs that the lens has reached the end of its useful life. Lenses age more quickly in some people's eyes than in others, probably due to differences in the makeup of their tears. Ordinarily, a year is the limit to the life of a soft lens. In recent years, disposable and planned replacement lenses have been introduced and these have all but eliminated the deposits, lens coloration and other problems associated with soft contact lens aging. Their replacement cycle depends on the type of soft lens prescribed, and thus it is important to follow your practitioner's instructions on their replacement. But no matter their condition, your lenses should be checked at least once a year by your eyecare practitioner while they are on your eyes.
Extended Wear
Some soft lenses can be worn for a number of days in a row without removal at night. Keeping lenses in overnight is known as extended wear (as opposed to daily wear in which the lenses are removed each night before sleep). While extended wear does offer convenience, studies have found that extended wear can increase the risk of serious contact lens complications. The decision to try extended wear should only be made after careful discussion of its risks and benefits with your practitioner .In addition, extended wear requires special lenses. Under no circumstances should you simply try extended wear with your old lenses! The U.S. Food and Drug Administration now advises that extended wear not exceed six nights (seven days). A recent development is that of Continuous Wear Contact Lenses, which the FDA has approved, i.e., extended wear for up to 30 days. This has been made possible by the advent of silicon-hydrogel lens materials. These lenses have exceptionally high oxygen permeability. However, because some eyes are better able to adapt to extended wear than other eyes, an appropriate extended wear schedule can only be determined by your practitioner. Because of its greater risk, extended wear requires more frequent practitioner visits and for this reason is likely to cost more than daily wear.
Disposable and Planned Replacement Lenses
Disposable replacement lenses are available for both extended wear and daily wear. Disposable replacement lenses that are approved for extended wear may be worn for at least 1 and up to 6 overnight periods of wear. When removed from the the eye, they are discarded, and therefore require no care (i.e., cleaning and disinfection) .Daily disposable replacement lenses are disposed of prior to sleep each night, and therefore require no care.
Planned replacement lenses, which are sometimes referred to as frequent replacement lenses, may also be worn on either an extended wear or daily wear basis. These lenses are replaced on a fixed schedule that varies from a few days to a few months. They are reused and therefore require proper contact lens care. The current continuous wear contact lenses are planned replacement lenses based on a 30-day replacement schedule. Always follow your practitioner's instructions for their replacement and care. It is important to remember that any time any contact lens is removed from the eye, it must be cleaned and disinfected before being placed back on the eye.
Guidelines
The following guidelines are de signed to maximize the safety of your contact lens wear. They apply to all contact lenses: rigid, soft, and rigid/ soft combination lenses.
- Always wash hands (with cold cream-free, deodorant-free soap) before handling contact lenses.
- Remember, different solutions are used for RGP and soft contact lenses. Your eyecare practitioner can inform you about which solutions can be used with your lenses.
- Any time you remove your lenses, always clean and disinfect them before reinserting
- Follow your practitioner's lens care recommendations exactly. They are specifically designed to meet the needs of your eyes and your specific lenses.
- Use only sterile, commercially prepared contact lens solutions
- Clean and air-dry the contact lens case every day. Wash and boil the lens case once a week.
- Replace lens cases periodically.
- Always check with your practitioner before changing solutions.
- Avoid using solution bottles for long periods after they have been opened - check with your practitioner for a recommended time to use opened solution bottles-typically 30 to 60 days after opening.
- Never reuse solutions. Discard used solutions immediately.
- Never wear contact lenses in a hot tub or while swimming.
- Avoid sleeping in lenses unless they are designed for such use and your practitioner has prescribed overnight wear for you.
- Never use saliva to moisten a contact lens; never put a contact lens into your mouth.
- Never use home-made saline.
- Never store contact lenses in nonsterile fluids such as distilled water, tap water, bottled water, or home-purified water.
- Never wear an overaged or damaged contact lens.
- Even if all seems well, contact lenses should be checked on your eyes at least once a year by your eyecare practitioner. In addition, periodic eye examinations without the contact lenses are advisable.
- Warning Signs: If an eye becomes red or uncomfortable while a contact lens is in place, remove the lens immediately. If the problem continues after the lens has been removed, see your eyecare practitioner immediately. Make an emergency appointment if needed.
CLAO
The above information is taken, with some revision, from the CLAO Patient Information Pamphlet entitled SOFT CONTACT LENS CARE. Pamphlet Advisor was Peter C. Donshik, MD. Copyright 1996-2004, Contact Lens Association of Ophthalmologists, Inc.