Show Me the Science

Why? Not washing hands with soap and water prior to touching your contact lenses is a risk factor for complications related to contact lens wear ^1,2, as germs from the hands are transferred to the contact lenses and the lens case ^3,4. Because microbes that cause eye infections are found in the water ⁵, you should dry your hands first before touching your contact lenses . Washing hands with soap and water, and drying them with a clean, lint-free cloth, is essential each time that contact lenses are inserted and removed. Follow these tips for proper handwashing.

Why? Sleeping in any type of contact lens increases by 6 to 8 times the risk of getting a serious type of corneal infection called microbial keratitis ^1-4. Out of every 10,000 people who sleep overnight in their contact lenses in an average year, 18-20 infections of microbial keratitis will occur ^1,3,5-7. Several companies make contact lenses that are approved by the U.S. Food and Drug Administration to wear during the day and to sleep in (often called “extended wear,” “continuous wear,” or “overnight wear”); however, contact lens wearers who choose this type of lens should be informed that sleeping in any type of contact lenses increases the risk of serious eye infections ⁸.

Why? Contact lenses are a known risk factor for Acanthamoeba keratitis ^1-5, a severe type of eye infection caused by a free-living ameba that is commonly found in water ⁶. Infection from Acanthamoeba is relatively rare, with 1-21 infections per million contact lens wearers, depending on the geographical location ^3,7-10. It can be difficult to treat and extremely painful—in the worst cases causing blindness ^11,12. Activities such as showering, using a hot tub, and swimming while wearing contact lenses may increase the risk of this infection ^12-14, as well as other types of infections ¹⁵. Due to regional differences in environmental factors and water quality worldwide ^9,11,16 contact lens wearers should always avoid exposure of contact lenses to water—both at home and when traveling. To learn more, visit CDC’s Acanthamoeba keratitis website.

Why? Improper cleaning of contact lenses raises the risk of complications among contact lens wearers ¹. Rubbing contact lenses with a clean finger and rinsing them with disinfecting solution is the most effective way to remove deposits and microbes from soft contact lenses ^1,2. Rinsing contact lenses with multipurpose solution and soaking them overnight without rubbing them first is not as effective at removing microbes ^1,2. Regardless of the type of contact lens worn, rubbing and rinsing the lenses daily is an important step in maintaining contact lens and eye health ^1-4.

Why? For the same reason that showering, using a hot tub, and swimming should be avoided while wearing contact lenses, contacts should not be stored in water at any time ^1-4. Exposing contact lenses to water may increase the risk of different types of eye infections. One serious type of contact lens-related eye infection, Acanthamoeba keratitis ^1-4, is caused by a microscopic ameba commonly found in water ⁵. Even though infection from Acanthamoeba is rare, it can be difficult to treat and extremely painful—in the worst cases causing blindness ^{1, 6-8}. To learn more, visit CDC’s Acanthamoeba keratitis website.

Why? While the effects of not replacing contact lenses as regularly as recommended by an eye care provider have not been fully examined ^1-4, studies have shown that contact lens wearers who do not follow recommended replacement schedules have more complications and self-reported discomfort than contact lens wearers who follow the replacement recommendations ^2,4. Some contact lens wearers have also reported poorer vision as a result of wearing contact lenses longer than indicated by their eye care providers ².

Why? Contaminated contact lens cases have been linked to rare but serious eye infections in contact lens wearers in recent years ^{1, 2} . An invisible layer in the case called a biofilm ^{3, 4} can become a breeding ground for microscopic germs that can cause infections ^5-7. Biofilms in contact lens cases can be best removed by rubbing and rinsing the case with disinfecting solution, and wiping dry with a tissue ^8-10, and then allowing to air-dry face down with the caps off ¹¹. Fewer than half of contact lens wearers report always cleaning their contact lens cases ^{1, 12} , even though the number of moderate to severe contact lens-related infections could be cut in half through improved lens case cleaning procedures ¹.

Why? Infrequent replacement of contact lens cases, along with poor cleaning of cases, has been linked to serious eye infections in contact lens wearers ¹. A significant number of contact lens wearers report not changing their lens case on a regular basis ^{2, 3}. Even when cleaned properly by rubbing and rinsing the case with disinfecting solution, contact lens cases can still be contaminated with microscopic germs ⁴ that can cause infections when they come into contact with the eye ^{5, 6}. The ideal frequency for lens case replacement has not been scientifically established ⁷, but there is agreement among experts in the vision care field that cases should be replaced every three months, or when a new bottle of solution is purchased that comes with a case—whichever comes sooner ^8-10.

Why? Topping off solution—or mixing fresh solution with used solution in the case for storing contact lenses—has been an important risk factor in serious outbreaks of contact lens-associated infections ^{1, 2}. Used solution in the case can become contaminated by germs that are on contact lenses or in the contact lens case ³. An invisible layer called a biofilm can grow in the case ⁴. The presence of biofilms can make contact lens disinfecting solution less effective at killing germs ³ that can cause serious eye infections, and adding new solution to used solution can lower germ-killing power ⁵. It is important to use only fresh solution—never water—in the contact lens case when storing contact lenses overnight to help prevent infections ^{6, 7}.

Why? It is important to use the type or brand of contact lens solution recommended by your eye care provider. An eye doctor or optician recommends a contact lens solution based on each patient’s eyes and medical history. In addition, certain types of contact lenses and solutions may interact and cause eye irritation when used together ¹. An eye doctor can help determine the best solution for each type of contact lens ². Eye doctors should be consulted before changing the type or brand of contact lens solution, and contact lens wearers should always be sure to read the package insert carefully before using any type of solution.

Why? The eye care community generally agrees that yearly eye exams are recommended for contact lens wearers in order to keep their eyes as healthy as possible while wearing contact lenses ¹—particularly given that wearing contact lenses increases the risk for eye infections and complications ². Additionally, contact lens wearers often need to have a yearly exam to confirm their prescription so that they may order new supplies of contact lenses. In some instances, eye doctors may recommend that patients return more frequently for eye exams.