How can I make contact lens wear and ortho-k as safe as possible?

• All contact lenses can increase risk of eye infection, but the risk is low with proper lens hygiene processes
• Ortho-k has a similar safety profile to wearing daytime reusable soft contact lenses, although ortho-k is safer to wear overnight (while sleeping) than soft contact lenses. Daily disposable contact lenses appear to be the safest.
• Steps to make contact lens wear as safe as possible include proper hand washing, following cleaning processes as described by your optometrist or eye doctor, and attending regular follow-up examinations.
• Tap water should never come into contact with contact lenses, contact lens cases and other accessories as it dramatically increases the risk of serious eye infection.

There are many reasons why children and teenagers may wear contact lenses. Contact lenses can improve satisfaction and self-confidence in children and teens, enabling them to participate more in school and sport compared to spectacles. Both soft contact lenses and ortho-k have been shown to improve satisfaction and quality-of-life for kids and teens compared to wearing glasses.^1,2

Special types of contact lenses can offer the dual benefit of correcting blurred vision due to myopia as well as slowing down the worsening, or progression of myopia in children and teenagers.

The short answer is yes, as long as they are properly fitted by a qualified eye care practitioner and proper care and hygiene processes are followed. Let's go into a little more detail.

When describing how 'safe' a type of contact lens is to wear, researchers describe cases of eye infections which occur per year, across a certain number of wearers.³

An eye infection can occur even in someone who doesn't wear contact lenses.⁴ Firstly here's a little more detail on what causes an eye infection.

An infection occurs when germs cause a reaction in the body. Germs can come from other parts of the body or from the environment. The front surface of the eye has many protective structures to prevent infection, but just like any other part of the body, the eyes' protective structures can be breached to allow an infection to occur.

The most concerning place for infections to occur at the front of the eye is in the cornea (the clear dome over the front of they eye). This is because the cornea is the clear window that allows light into the eye. A reaction generated by the body's immune system to attack a germ in the cornea can result in the cornea losing some of its clearness, which in some unfortunate cases can lead to permanent loss of vision.³

The medical name for infection of the cornea is 'keratitis', and when a germ is considered to be interacting with the cornea to cause infection the medical name becomes 'microbial keratitis'. Microbial is a term covering bacteria, viruses, fungal and other (protozoa) infections.

Any type of contact lens, including soft contact lenses and ortho-k, is considered a risk factor for infection because the lens is brought into contact with the eye, and thereby offers an extra way for germs to come into contact with the eye.³ Germs can be transferred from the skin to the contact lens during lens handling, or from the environment.

Fortunately microbial keratitis is uncommon and likelihood of suffering microbial keratitis can be reduced by adopting good contact lens hygiene practices. Microbial keratitis progressing to the point of becoming sight threatening is extremely rare, even when wearing soft contact lenses or ortho-k.

Here's a comparison of the frequency of eye infections in people who don't wear contact lenses, and in various types of contact lenses.

The risk of an eye infection is:

• 1 case per 7,000 people per year who don't wear contact lenses⁴
• 1 case per 1,000 to 2,000 wearers per year with ortho-k^5,6
• 1 case per 1,000 wearers per year with reusable soft contact lenses³
• 1 case per 5,000 wearers per year with daily disposable soft contact lenses.³

These figures indicate that daily disposable contact lenses are the safest way to wear contact lenses, with a lower risk of eye infection (1 per 5,000 per year) than reusable soft contact lenses or ortho-k. These latter two types of contact lenses have similar safety profiles.

Ortho-k contact lenses are worn overnight and removed upon waking, such that no glasses or contact lenses are required during waking hours to see clearly. They are a type of rigid contact lens, which are very breathable to oxygen and have been shown to be the safest type of reusable contact lens to wear.³

Rigid lenses can be worn during waking hours, and are typically worn by people with very high or complex prescriptions. Ortho-k, by comparison, is increasingly popular in children and teenagers as a way to correct vision and also for myopia control.⁷

Soft contact lenses are flexible and very comfortable to wear. They are either daily disposable, which are thrown away after a day of wear, or reusable for two to four weeks. They can also be worn overnight, or continuously day-and-night, but this is the most risky way to wear contact lenses with the highest risk of infection.³

While ortho-k lenses are worn overnight, they are removed during the day so the eyelids and eye surface get a break from contact lens wear. When soft contact lenses are worn overnight, though, they are often left on the eye day-and-night without a break. Eye care practitioners would rarely recommend this pattern of wear to children and young people, except in special circumstances. This dramatically increases the risk of eye infection to around 1 case per 400 wearers per year,³ which appears to be higher than the 1 case per 1,000 to 2,000 wearers per year with ortho-k.^5,6

Following proper ortho-k lens cleaning and care routines will reduce risk of eye infection, particularly the following steps.

• Always wash your hands and dry them thoroughly before handling contact lenses
• Don’t let the lens care solution nozzle come into contact with hands, the contact lens or any other surface, to reduce risk of bottle contamination 
• Always use fresh contact lens solution that is in date: never reuse or top-up the solution left in the lens case from the previous clean
• Empty the lens case every time the lenses are worn
• After emptying, rinse the lens case with the contact lens cleaning solution, wipe it out with a tissue, and store it face down when not in use away in a protected area
• Routinely replace lens cases: an easy-to-remember rule is to replace the case every time a new bottle of lens care solution is opened
• Ensure that tap water does not come in contact with contact lenses or any devices used with contact lenses, such as lens cases or lens application holders

When ortho-k wear is managed by an experienced optometrist or eye doctor, it appears to be very safe. One study which observed all young patients (up to 16 years of age) who wore ortho-k or soft contact lenses in a single expert clinic showed that there were no cases of corneal infection (microbial keratitis) over 10 years of follow up in either type of contact lens.⁹

A recent research study in 8-12 year olds wearing soft daily disposable soft contact lenses for six years revealed no cases of serious eye infections, and no changes to their eye health appearance when viewed with clinical microscopes.¹⁰

While risk of infection is low, and can be minimized by ensuring that care and hygiene steps are followed, it can still occur. If your child or teen experiences a red eye, sore eye or blurry eye when wearing contact lenses, contact your eye care practitioner immediately.

A further safeguard is to ensure that optometrist or eye doctor follow-up visits are kept up to date.³ Each eye care visit helps to track healthy contact lens wear - providing the chance to identify problems before they become more bothersome or serious, and also reinforcing safety steps and good habits.

1. Walline JJ, Gaume A, Jones LA, Rah MJ, Manny RE, Berntsen DA, Chitkara M, Kim A, Quinn N. Benefits of contact lens wear for children and teens. Eye Contact Lens. 2007;33(6 Pt 1):317-321. 
2. Santodomingo-Rubido J, Villa-Collar C, Gilmartin B, Gutiérrez-Ortega R. Myopia control with orthokeratology contact lenses in Spain: a comparison of vision-related quality-of-life measures between orthokeratology contact lenses and single-vision spectacles. Eye Contact Lens. 2013 Mar;39(2):153-7. 
3. Stapleton F, Keay L, Edwards K, Naduvilath T, Dart JK, Brian G, Holden BA. The incidence of contact lens-related microbial keratitis in Australia. Ophthalmology. 2008 Oct;115(10):1655-62.
4. Jeng BH, Gritz DC, Kumar AB, Holsclaw DS, Porco TC, Smith SD, Whitcher JP, Margolis TP, Wong IG. Epidemiology of ulcerative keratitis in Northern California. Arch Ophthalmol. 2010 Aug;128(8):1022-8.
5. Bullimore MA, Sinnott LT, Jones-Jordan LA. The risk of microbial keratitis with overnight corneal reshaping lenses. Optom Vis Sci 2013;90:937-944.
6. Bullimore MA, Mirsayafov DS, Khurai AR, Kononov LB, Asatrian SP, Shmakov AN, Richdale K, Gorev VV. Pediatric Microbial Keratitis With Overnight Orthokeratology in Russia. Eye Contact Lens. 2021 Jul 1;47(7):420-425.
7. Efron N, Morgan PB, Woods CA, Santodomingo-Rubido J, Nichols JJ; International Contact Lens Prescribing Survey Consortium. International survey of contact lens fitting for myopia control in children. Cont Lens Anterior Eye. 2020 Feb;43(1):4-8. (link)
8. Ibrahim YW, Boase DL, Cree IA. How Could Contact Lens Wearers Be at Risk of Acanthamoeba Infection? A Review. J Optom. 2009;2(2):60–6. (link)
9. Woods J, Jones D, Jones L, Jones S, Hunt C, Chamberlain P, McNally J. Ocular health of children wearing daily disposable contact lenses over a 6-year period. Cont Lens Anterior Eye. 2021 Aug;44(4):101391. 
10. Hiraoka T, Sekine Y, Okamoto F, Mihashi T, Oshika T. Safety and efficacy following 10-years of overnight orthokeratology for myopia control. Ophthalmic Physiol Opt. 2018 May;38(3):281-289.