Contact lenses provide effective vision correction for approximately 4.5 million people in the UK [1]. However, their improper use and poor hygiene practices contribute to increased risk of contact lens-related complications. Furthermore, a study in the USA showed that 99% of contact lens wearers report at least one hygiene related risk behaviour, and alarmingly, one third of wearers recall never receiving any lens wear or care instructions [2]. Therefore, the importance of proper patient education is invaluable.
This article aims to provide guidance for eyecare professionals, including optometrists, ophthalmologists and other healthcare providers on advising contact lens wearers, with a focus on hygiene, early recognition of complications and preventive strategies.
Figure 1: Acanthamoeba keratitis.
Common complications of contact lens use
Microbial keratitis
Corneal infection is the most serious complication associated with contact lens wear, as it can be sight-threatening [3]. In the UK, microbial keratitis occurs in approximately four cases per 10,000 contact lens wearers each year [3]. Symptoms typically include eye pain, redness, blurred vision and a sensation of a foreign body in the eye [4]. This condition is usually treated with antibiotic drops. An important step for patients is to stop wearing contact lenses while the infection is present and for several weeks after it has resolved, as continued use can lead to worsening of the condition [4].
Acanthamoeba keratitis
Acanthamoeba keratitis is a rare but severe form of microbial keratitis. It is strongly associated with water exposure while wearing contact lenses, including activities such as showering, swimming and hot tub use. In the UK, approximately 85% of cases occur in contact lens wearers [5]. The organism is commonly found in tap water and can readily stick to contact lenses and their storage cases. The risk of acanthamoeba keratitis is around three times higher with reusable contact lenses compared with single-use disposable lenses [6]. This condition is often extremely painful and may result in prolonged treatment, corneal scarring and, in severe cases, the need for corneal transplantation [5].
Others
- Corneal ulcers: painful open sores on the cornea can lead to permanent blindness if not promptly and effectively treated.
- Dry eye syndrome: 40% reported their eyes became too dry with long-term use.
- Other eye infections: various bacterial, fungal and viral infections can occur with improper contact lens hygiene [7].
Essential guidance for eyecare professionals
Eyecare providers, whether an optometrist, ophthalmologist or any healthcare provider in the field, must communicate these recommendations at initial fitting, regular checkups and during complication-related visits.
Hand and lens hygiene:
- Wash and thoroughly dry your hands before handling contact lenses or touching your eyes
- Rub and rinse contact lenses with an appropriate disinfecting solution every time they are removed
- Never use tap water, distilled water, well water or saliva to clean contact lenses
- Replace lenses according to the recommended schedule.
Lens solution and case care:
- Check the instructions on your contact lens solution before use
- Replace the caps on solution bottles immediately after use
- Always use fresh solution when storing your lenses
- After each use, rub and rinse the lens case with contact lens solution (not water)
- Dry the lens case with a clean tissue and store it upside down with the caps off to allow air drying
- Replace the lens case every three months to reduce the risk of biofilm formation
- Lens cases can develop bacterial biofilms, particularly with tap water exposure, so regular replacement is essential.
Critical behaviours to avoid
Extended-wear contact lenses should be avoided as they carry a significantly higher risk of infection compared with daily wear lenses. Where appropriate, daily disposable lenses are preferred, as they eliminate overnight wear, lens cleaning and storage, thereby substantially reducing the risk of infection. Contact lenses should be removed before showering, swimming or using hot tubs, as water exposure introduces microorganisms, including acanthamoeba, which can stick to lenses and lens cases and cause severe, difficult-to-treat keratitis.
Interestingly, a study by Anna, et al. found that showering while wearing contact lenses was the strongest risk factor for microbial keratitis. Daily showering in contact lenses, compared with never showering in lenses, increased the risk of microbial keratitis by more than sevenfold [3]. Furthermore, studies have shown that sleeping in contact lenses is associated with a six-to-eight-fold increased risk of microbial keratitis [8].
Warning signs
Contact lens wearers should remove their lenses immediately and seek urgent medical attention if they notice any of the following:
- Eye pain or discomfort
- Excessive tearing
- Vision changes or blurred vision
- Redness of the eye
- Increased light sensitivity
- Eye discharge or excessive mucus
- Swelling around the eye.
These symptoms could signal serious conditions, such as corneal ulceration, infection or corneal abrasion, and require prompt evaluation by an eyecare professional.
Conclusion
Proper patient education is essential to minimising contact lens-related complications and safeguarding ocular health. Microbial keratitis and other serious complications, while relatively uncommon, can have sight-threatening consequences if hygiene practices and safe lens-wear behaviours are neglected. Evidence shows that high-risk behaviours such as showering or sleeping in lenses dramatically increase the likelihood of infection, highlighting the critical role of patient awareness. Regular follow-up care, adherence to lens-replacement schedules, proper case hygiene and immediate attention to warning symptoms are all essential components of safe contact lens wear.
By providing targeted education and reinforcing adherence to recommended lens-care practices, clinicians can help patients maximise the benefits of contact lens wear while minimising the risk of sight-threatening complications.
References
1. https://premiereyecare.co.uk/are-contact
-lenses-really-safe-for-your-eyes/
2. 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):865–70.
3. Stellwagen A, MacGregor C, Kung R, et al. Personal hygiene risk factors for contact lens-related microbial keratitis. BMJ Open Ophthalmol 2020;5(1):e000476.
4. www.moorfields.nhs.uk/
eye-conditions/microbial-keratitis
5. www.moorfields.nhs.uk/
eye-conditions/acanthamoeba-keratitis
6.www.aao.org/eyenet/article/
risk-of-acanthamoeba-keratitis-in-contact-lens-use
7. https://precisionvisionlondon.com/
complications-of-long-term-contact-lens-wear/
8. Stapleton F, Keay L, Edwards K, et al. The incidence of contact lens–related microbial keratitis in Australia. Ophthalmology 2008;115(10):1655–62.
[All links last accessed April 2026]
Declaration of competing interests: None declared.
