Contact lens hygiene: the most common mistakes

Nearly 99% of contact lens wearers adopt at least one risky hygiene habit, the leading preventable cause of corneal infections. Letting lenses come into contact with water, handling them with poorly washed hands, neglecting the case or exceeding the recommended wearing time are everyday habits that, when repeated, weaken the surface of the eye and open the door to micro-organisms. The good news is that these mistakes are simple to correct. Knowing them, understanding why they are dangerous and adopting a few good reflexes is enough to wear lenses safely over the long term while protecting your eyes.

KEY POINTS

Sources: Cope 2015; Stapleton 2012 (see references at the bottom of the page).

Why contact lens hygiene matters so much

A contact lens is a medical device placed each day directly on the cornea: its cleanliness determines the health of the eye. The cornea, the transparent window at the front of the eye, is protected by a thin layer of cells and by the tear film that constantly cleans it. A poorly maintained lens introduces micro-organisms onto this surface and can weaken it, which makes it easier for an infection to take hold Stapleton 2012.

The problem is that hygiene mistakes are extremely widespread and often played down. A large survey of adult wearers showed that nearly 99% of them adopted at least one risky hygiene habit, and that nearly one wearer in three had already experienced a red or painful eye requiring a consultation Cope 2015. These risky habits are therefore not the exception: they are the rule.

These habits are not limited to adults. A complementary survey found at least one risky behavior in 85% of adolescents, 81% of young adults and 88% of older adults who wear contact lenses Cope 2017. In other words, at any age, the vast majority of wearers would benefit from reviewing one or more of their daily habits. That is precisely the aim of this article.

MISTAKE NO. 1

Contact with water: the most dangerous mistake

Letting your lenses come into contact with water — from the tap, the shower, the swimming pool or the sea — is the mistake with the most serious consequences. Contrary to a common belief, tap water is not sterile. It can contain a microscopic parasite responsible for a rare but particularly serious and hard-to-treat corneal infection, amoebic keratitis. By trapping this parasite against the eye, lenses significantly increase the risk Cope 2016.

In practice, several situations should be avoided while wearing lenses or during their care:

• showering or washing your face without having removed your lenses;
• swimming in a pool, the sea or a lake with your lenses, without watertight swimming goggles;
• rinsing your lenses or case with tap water instead of the care solution;
• moistening a lens with saliva or water when it feels dry.

The rule is simple and admits no exception: no contact between lenses and water. For swimming, the ideal is to remove your lenses or to wear watertight swimming goggles, or even daily disposable lenses to throw away right afterwards. This essential topic is covered in our dedicated article on water-related amoebic keratitis.

MISTAKE NO. 2

Poorly washed hands before handling

Handling your lenses without having washed and dried your hands transfers micro-organisms directly onto the surface of the eye. Hands are in constant contact with contaminated surfaces, and the fingers are used to place and then remove the lens right up against the cornea. Careful washing before each handling is therefore one of the most effective basic habits, and yet one of the most often neglected Cope 2015.

The right routine takes a few seconds, in the following order:

1. wash your hands with soap, paying special attention to the fingertips;
2. dry them with a clean, lint-free towel, not by letting them air-dry;
3. put the lens in before applying make-up, and remove it before taking make-up off;
4. avoid rinsing your hands or the lens with water right after washing.

Drying matters as much as washing: wet hands carry water, and therefore the micro-organisms it may contain, back into contact with the lens. A clean towel, changed regularly, usefully rounds out this simple but decisive habit.

MISTAKE NO. 3

A neglected case, rarely cleaned, never replaced

The lens case is the main reservoir of micro-organisms, and its upkeep is one of the best-documented risk factors. A landmark case-control study showed that daily lens wear with a poorly maintained case multiplies the risk of moderate to severe microbial keratitis by 6.4, and that a case replaced too rarely multiplies it by 5.4 Stapleton 2012. The case, often forgotten, therefore deserves just as much attention as the lenses themselves.

A case left damp, never dried and kept for months encourages the formation of a biofilm, a film in which micro-organisms settle and resist care solutions. The good habits for avoiding it are simple:

• empty the case after each use and rinse it with the care solution, never with water;
• let it air-dry, turned upside down, on a clean surface;
• never top up the old solution, but replace it entirely;
• replace the case every three months, or as soon as it is damaged or dirty.

Replacing the case regularly is in fact one of the official prevention messages addressed to wearers, alongside keeping water at a distance and renewing the solution every day Cope 2015. A new, clean and dry case is a simple, inexpensive barrier against infection.

MISTAKE NO. 4

Topped-up solution, exceeded wearing time

Reusing or topping up the care solution, and exceeding the wearing time of your lenses, are two common mistakes that add to the previous ones. The care solution loses its disinfecting power once used: topping it up rather than renewing it amounts to soaking lenses in an already contaminated liquid. The type and use of the solution are, moreover, among the identified risk factors, with a keratitis risk multiplied by 7.2 depending on the practices Stapleton 2012.

Wearing time is the other classic pitfall. A monthly lens kept for two months, a daily lens worn for several days or a pair kept well beyond its date: all are situations where the material degrades, retains deposits and becomes less permeable to oxygen. The principles to remember are clear:

• fully renew the case solution at each use, without ever topping it up;
• use only the prescribed solution, suited to the type of lenses, never water or an improvised saline;
• respect the wearing time (daily, two-weekly, monthly) without extending it;
• never reuse a daily lens: it is thrown away the same evening.

Added to these mistakes, finally, is sleeping in your lenses, which further increases the risk of infection. Occasional overnight wear multiplies the risk of moderate to severe keratitis by 6.5 Stapleton 2012. This major point is covered in detail in our article on the dangers of sleeping in your lenses.

WARNING SIGNS

The signs that should raise the alarm

Certain signs make it essential to remove your lenses immediately and seek care, because they may herald a corneal infection. A hygiene mistake does not always lead to a problem, but when the eye reacts, you need to know how to listen to it. Redness that sets in, pain that increases, marked discomfort in bright light or vision that becomes blurred should never be neglected.

Faced with these signs, do not put another lens in and do not wait for it to pass. A corneal infection treated early generally has a better outcome than a neglected one. Contact your ophthalmologist or go to an ophthalmic emergency department, always mentioning that you wear contact lenses: this information immediately guides the examination Cope 2016.

PREVENTION

The right habits every day

Good contact lens hygiene comes down to a few simple habits, applied consistently. None of them is complicated, and their combined effect clearly reduces the risk of infection. Here is the routine to adopt every day:

• wash and dry your hands before any handling;
• keep lenses away from water: shower, pool, sea, tap;
• fully renew the case solution at each use;
• rinse the case with solution, air-dry it and replace it every three months;
• respect the prescribed wearing and replacement schedule;
• remove your lenses before sleeping, naps included.

Regular ophthalmic follow-up rounds out these habits: it makes it possible to check that the lenses are well tolerated and to spot any early signs before they become a problem. Contact lenses remain a comfortable solution suited to many lifestyles, provided these basic rules are respected. If you are in any doubt about a habit or a symptom, a professional’s opinion always takes precedence over routines built up over time Cope 2015.

FREQUENTLY ASKED QUESTIONS

Frequently asked questions

Scientific sources

1. Cope JR, Collier SA, Rao MM, et al. Contact Lens Wearer Demographics and Risk Behaviors for Contact Lens-Related Eye Infections – United States, 2014. MMWR Morb Mortal Wkly Rep. 2015;64(32):865-870. PMID 26292204
2. Stapleton F, Edwards K, Keay L, et al. Risk factors for moderate and severe microbial keratitis in daily wear contact lens users. Ophthalmology. 2012;119(8):1516-1521. PMID 22521083
3. Cope JR, Collier SA, Nethercut H, et al. Risk Behaviors for Contact Lens-Related Eye Infections Among Adults and Adolescents – United States, 2016. MMWR Morb Mortal Wkly Rep. 2017;66(32):841-845. PMID 28817556
4. Cope JR, Collier SA, Srinivasan K, et al. Contact Lens-Related Corneal Infections – United States, 2005-2015. MMWR Morb Mortal Wkly Rep. 2016;65(32):817-820. PMID 27538244

Further reading

• Sleeping in your lenses: what are the dangers for your eyes?
• Amoebic keratitis: the danger of water with contact lenses
• When should you seek emergency eye care?

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Medical disclaimer

This article is intended as general information and does not replace a medical consultation. Wearing contact lenses should be the subject of a prescription and follow-up by a healthcare professional. In the event of a red, painful eye, reduced vision or persistent discomfort while wearing lenses, remove your lenses and promptly consult an ophthalmologist or an ophthalmic emergency department.