Contact lenses have been in common usage for decades, with many people over 50 having worn them for all of their adult lives.
They are a practical and comfortable way of maintaining good vision, but they do come with risks, and research indicates that the risk is much greater for those who reuse disposable lenses.
A study conducted by UNSW Sydney, University College London (UCL) and Moorfields Eye Hospital has found that those who wear reusable contact lenses are nearly four times as likely as those wearing daily disposables to develop a rare sight-threatening eye infection.
However, daily disposable users who ‘bend the rules’ and reuse their lenses increase their infection risk by more than five times.
Getting an extra day out of those lenses might be a money saver, but it will bump up your risk of an infection that could lead to blindness.
Take the case of Irene Ekkeshis who developed a watery, itchy eye – a common problem among contact lens wearers and non-wearers alike. For most, it’s little more than an annoyance for a few hours, or perhaps a few days.
That was not the case for Ms Ekkeshis. Her eyes rapidly became excruciatingly painful, and within five days she was blind.
Ms Ekkeshis’ case is extremely rare, but in almost all cases this condition, known as Acanthamoeba keratitis (AK), is preventable.
AK is an infection caused by a cyst-forming microorganism that makes the front surface of the eye, the cornea, painful and inflamed. The most severely affected patients – a quarter of the total – end up with less than 25 per cent vision or become blind and face prolonged treatment.
Overall, 25 per cent of people affected require corneal transplants to treat the disease or restore vision. And even then, it is not always successful. More than a decade and two corneal implants later, Ms Ekkeshis’ sight has not been restored.
Professor Nicole Carnt, lead author of the study published in the journal Ophthalmology in August, says “contact lenses act as a vector to transport and retain the microbes close to the eye allowing a greater opportunity for infection to occur, compared to not wearing contact lenses”.
Prof. Carnt found that people who wear reusable contact lenses are nearly four times as likely as those wearing daily disposables to develop the infection.
But reusing daily disposable lenses increased the infection risk by 5.4 times, making it greater than for those who wear reusable lenses.
Follow the directions
The key is to follow the directions, something many simply don’t do.
Failing to follow medical directions opens you up to serious risks and that’s why most of us adhere to the advice on our medications.
But, as Prof. Carnt points out, many people do not think of contact lenses as something medical: “They don’t often see contact lenses as a medical device, and so they don’t understand some of the basic things that optometrists understand,” she said.
Prof. Carnt says her team’s research indicates that almost half of all AK infections occur as a result of the reuse of daily disposable lenses. “If everybody stopped reusing their daily disposables, we would eliminate 49 per cent of cases.”
The risk can also be reduced in other ways, including not wearing lenses overnight and avoiding water contamination, which can be washing your face or swimming while wearing lenses.
It’s important to note that the risks remain very low, even when elevated by the factors mentioned here. But with your sight potentially at stake, there’s no reason to take any risk at all.
Are you a contact lens wearer? Have you ever taken ‘short cuts’ with the directions and suffered consequences? Why not share your experience and thoughts in the comments section below?