Reusable contact lenses ‘raise risk of eye infection’

Posted: 28/09/2022

Recent research conducted by teams at the University College London and Moorfields Eye Hospital have found that wearers of reusable contact lenses are almost four times as likely to develop a sight-threatening eye infection, when compared with those who use daily disposable contact lenses. Those who wear lenses in the shower and overnight are also at increased risk.

Acanthamoeba keratitis (AK) is a serious infection of the eye that can cause permanent vision loss or blindness. It is caused by microscopic amoebae (single-celled organisms) called Acanthamoeba, which are commonly found in bodies of water, including domestic tap water and contact lens solution. When acanthamoeba attach to the cells of the outer surface of the cornea, the eye’s clear protective outer layer, it begins a process of destroying the corneal cells and can invade further into the eye, resulting in irrevocable damage. Symptoms of AK include a sensation of something in the eye, eye pain, eye redness, blurred vision, light sensitivity and excessive tearing.

When contact lenses are used more than once, they are more likely to come into contact with water or fluid contaminated with acanthamoeba. Re-placing of a contact lens, which has potentially been contaminated with acanthamoeba, onto the eye increases the risk of infection of the cornea.  

Diagnosis of AK requires the eye doctor to elicit the patient’s history and symptoms, as well as conduct an examination under a microscope to check for any signs of inflammation of the cornea. The doctor may take a small sample from the surface of the eye to check for presence of the infection. If AK is diagnosed, the patient is usually treated with antiseptic drops.

AK affects fewer than one in 20,000 contact lens wearers each year in the UK, but there is a high morbidity in those who do develop the infection: 25% of patients with the AK infection end up with severely impaired vision or suffer total blindness. The recent research study indicates that the number of patients suffering visual impairment per annum from AK could be significantly reduced by people switching to daily disposable lenses, which are more hygienic and less likely to be contaminated with acanthamoeba.

Arran Macleod, a solicitor in the clinical negligence team who specialises in ophthalmic claims, says: “As with other infections, the later the diagnosis of AK infection, the worse the outcome is likely to be. Any delay in diagnosis and treatment allows the infection to develop within the eye, ultimately increasing the risk that the infection will permanently affect the patient’s sight. AK has the potential to have devastating consequences if it occurs, and it is important that contact lens wearers know of the risk of AK, how to minimise their risks for developing AK – by wearing daily disposables, rather than re-usable contact lenses – and its symptoms, in order to obtain treatment quickly if the infection occurs.

“I have acted for patients who have tragically lost their sight because of a delay in diagnosing and treating an eye infection. An example can be found in this case study. Issues can arise when a patient attends their GP or an emergency eye unit and infection is inappropriately dismissed as a possible cause for the symptoms, or the investigations are negligently performed. The impact of a sight limiting eye infection can be significant, resulting in the need for increased levels of care and assistance, additional equipment and, in some circumstances, a change in career.”

If you or a family member have any concerns that an eye infection was missed, or was not treated quickly enough, then please get in touch with our specialist clinical negligence team for preliminary advice.

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