Where contact lens wearers cut corners and what it can cost them

Contact lenses have come a long way since the earliest glass and plexiglass designs, and today’s silicone hydrogel and rigid gas-permeable materials give wearers more comfort and oxygen permeability than ever. Even so, a lens is only as safe as the habits of the person wearing it. Skipped hand washing, tap water exposure, overwear, and sleeping in lenses remain common, and these lapses can open the door to microbial and Acanthamoeba keratitis, which can become sight-threatening quickly and is difficult to treat. In this Q&A, Zachary Keaney, CPOA, lead ophthalmic technician at BostonSight, discusses the unsafe habits seen most often in practice, the lens care steps patients most commonly skip, how quickly lens-related infections can progress, and how evolving lens materials and modalities have changed the safety picture.

Note: transcript edited lightly for clarity and length.

What are the most common unsafe habits you see, and why do you think they persist?

Zachary Keaney, CPOA: Contact lens care non-compliance is unfortunately all too common. In my experience, contact lens wearers often practice unsafe habits in terms of lens hygiene. Namely hand hygiene, water exposure, and overwear. The surface of the eye should maintain low levels of microbes, such as harmless bacteria.¹ However, when unclean surfaces like unwashed hands or non-sterile water come into contact with the eyes, one risks infection. Contact lenses serve as a physical barrier for microbes to grow in, so wearers need to take special precautions to maintain good hand hygiene and avoid water exposure.

Avoid storing or rinsing contacts with tap or bottled water (even distilled!) and avoid showering or swimming with contacts in your eyes. Tap, shower water, as well as natural water from lakes and the ocean, contain a plethora of microbes such as Acanthamoeba — which can cause severe infections that lead to blindness; these infections are discussed in details below. Follow the directions of your optometrist or ophthalmologist to store, rinse, and disinfect your contact lenses.^2-4

Another unsafe habit that many contact lens wearers practice is overwear and sleeping in contacts. The cornea, which contacts sit on, requires strict access to oxygen in the air. In fact, it is the only part of the body without oxygen supply from the blood.

Although modern contacts have sophisticated technology which allows for oxygen permeability, habits like wearing contacts for too long or sleeping in contacts reduce the oxygen available to the cornea. This can increase the risk of irritation, corneal damage and disease, and infection.⁵ Be sure to always follow the directions of your optometrist or ophthalmologist. Dispose of contacts when directed, and, in general, avoid sleeping with contacts in your eyes.

Which steps of lens care do patients skip most often?

Keaney: In our fast-paced world, it seems like everyone is in a rush. Between emails, meetings, and deadlines, many people look to cut corners to save time. However, it is not a good idea to skip steps in contact lens hygiene or the instructions of an eye care professional. In my experience, the most often skipped step of lens care is handwashing. Even in front of an eye doctor, many patients will boldly remove contacts without using the sink. Objects that we touch constantly, like our phones, door handles, keyboards, and money are covered in germs. Touching contact lenses or your eyes with unclean hands increases the risk of severe eye infections, many of which are difficult to treat and can lead to pain and vision loss.

The general consensus is before inserting or removing contacts, always wash hands thoroughly with non-moisturizing soap and water, and dry with a lint-free cloth.⁶ Be sure to follow the directions of your eye care provider and be seen if you begin to have symptoms like redness, itchiness, pain, discharge, or changes to vision.

How quickly can a contact lens–related infection, such as microbialor Acanthamoeba keratitis, become sight-threatening?

Keaney: Contact lens-related infections can vary in course, depending on factors like which microbe is involved, and the individual’s eye health and immune system. In many cases, such as with Acanthamoeba infection, symptoms do not begin until hours, days, or even weeks after exposure.⁷ This can make it difficult to catch and diagnose early, which then complicates treatment. For Acanthamoeba keratitis, early diagnosis is critical, as corneal damage and vision loss can occur rapidly after symptom onset, and it can be resistant to many treatments. This reaffirms that proper care like handwashing, avoidance of non-sterile water and lens overwear can reduce the risk of these infections.⁸

How has contact lens safety changed as lens materials and modalities have evolved?

Keaney: Contact lens safety and comfort have changed dramatically over the years, as materials and technologies have become much more sophisticated. One consideration that highlights how far contacts have come is to look back at the very first contact lenses produced in the 1800s. They were made of polymethyl methacrylate—also known as plexiglass, which had exceptionally low oxygen permeability and a high incidence of complications. Years later, rigid gas-permeable contact lenses (RGPs), made of other types of hard plastics, were manufactured.⁹ These became safer with each advancement.

In 1971, soft contact lenses were developed, and made of thinner, more flexible plastics like hydroxyethyl methacrylate and later silicone hydrogel, which is what most contact lenses today are made of. These weren’t without issues, as low oxygen permeability and poor comfort were still problematic. However, as technology advanced, so did these modalities —which led to our modern world where soft and hard contacts are much safer and comfortable.⁹

References

1. DeLuca L, Menna F, Lupo S, et al. The ocular surface bacterial microbiome and the impact of contact lens use: A literature review. Microorganisms. 2026;14(3):518. https://doi.org/10.3390/microorganisms14030518
2. Radford CF, Bacon AS, Dart JK, Minassian DC. Risk factors for Acanthamoeba keratitis in contact lens users: A case-control study. BMJ. 1995;310(6994):1567-1570. doi:10.1136/bmj.310.6994.1567
3. Legarreta J, Nau A, Dhaliwal D. Acanthamoeba keratitis associated with tap water use during contact lens cleaning: Manufacturer guidelines need to change. Eye Contact Lens. 2013;39(2):158-161. doi:10.1097/ICL.0b013e31827a79ee
4. CDC. Preventing Eye Infections When Wearing Contacts. Healthy Contact Lens Wear and Care. Updated May 27, 2025. Accessed October 16, 2026. https://www.cdc.gov/contact-lenses/prevention/index.html
5. Michaud L, Giasson C. Overwear of contact lenses: Increased severity of clinical signs as a function of protein adsorption. Optom Vis Sci. 2002;79(3):184-92. doi:10.1097/00006324-200203000-00013
6. McMonnies CW. Hand hygiene prior to contact lens handling is problematical. Cont Lens Anterior Eye. 2012;35(2):65-70. doi:10.1016/j.clae.2011.11.003
7. CDC. Clinical Overview of Acanthamoeba Keratitis. Acanthamoeba Infections. September 11, 2025. Accessed October 16, 2026. https://www.cdc.gov/acanthamoeba/hcp/clinical-overview-acanthamoeba-keratitis/index.html
8. Carnt N, Stapleton F. Strategies for the prevention of contact lens-related Acanthamoeba keratitis: A review. Ophthalmic Physiol Opt. 2016;36:77–92. doi:10.1111/opo.12271
9. Caroline PJ, Norman CW. History of contact lenses. PentaVision. August 1, 2023. Accessed October 15, 2026. https://www.clspectrum.com/issues/2023/august/history-of-contact-lenses/