Coloured and cosmetic contact lenses: the risks

Emerald-green eyes for a fancy-dress party, a white iris for Halloween, cat’s pupils for a photo shoot. Coloured contact lenses are easy to find, sometimes next to the costumes, and anyone who uses them for an evening tends to think of them as an accessory. For the eye, however, they are contact lenses in every respect: they sit on the cornea, the transparent membrane in front of the iris, and can bring the same problems.

The most feared is microbial keratitis, an infection of the cornea. It is rare, but in studies it hits harder those who wear cosmetic lenses without being followed by a professional. In a survey in 12 French university hospitals, six in ten people with an infection linked to cosmetic lenses, at the end of treatment, saw less than 1/10 in the affected eye¹.

In this article

1. What coloured contact lenses are
2. Coloured contact lenses: what the studies on infections say
3. How rare the risk is, in absolute numbers
4. Why coloured lenses cause more concern
5. The rules in Europe and the shared recommendations
6. Frequently asked questions
7. Sources

What coloured contact lenses are

There are two types. There are lenses that correct a refractive error and at the same time change or intensify the colour of the iris, and purely decorative lenses, with no corrective power, designed for people who see well: cosmetic lenses, also called ‘costume’ lenses. It is the latter that worry ophthalmologists most, because they often end up on the eyes without anyone having checked that they are suitable for that eye and without the wearer having learned how to put them in, take them out and store them¹.

The colour does not change the relationship between lens and eye: if handled with dirty hands or kept in a contaminated lens case, the lens can carry microbes onto the cornea⁴. A 2020 Australian review lists the risk of infection linked to decorative lenses, especially in Asia, among the open questions in contact lens practice⁴. We described the various types of lenses in the article on contact lenses.

Coloured contact lenses: what the studies on infections say

The study closest to European readers comes from France. Between 2007 and 2009 doctors in 12 university hospitals collected all the cases of microbial keratitis in contact lens wearers: 256 people, 32 of whom had used cosmetic lenses¹. Compared with the others, those who wore cosmetic lenses were younger, 21 years of age on average against 27, and had worn them for less time, 3 years against 9¹.

‘Twelve times’ is a relative figure, not a share of people who fall ill: it concerns a rare disease.

The same French group then compared 499 lens wearers with keratitis and 508 healthy wearers. Cosmetic lenses again emerged among the factors associated with higher odds of infection, together with disinfecting solutions used for more than three months and overnight wear; fitting of the lenses by an ophthalmologist, on the other hand, was associated with lower odds². In this larger study the increase linked to cosmetic lenses was moderate, about a third more²: the differences between the two studies are a reminder that these are estimates, with the limits of observational studies.

How rare the risk is, in absolute numbers

To understand the proportions we need data on frequency. An Australian study from 2008, which for one year counted all the new cases in the country, estimated about 2 cases of microbial keratitis per 10,000 soft lens wearers a year, with daytime wear only, and a loss of vision in 0.6 wearers per 10,000³. Among the risk factors were buying the lenses on the internet, experience of less than six months and sleeping in the lenses³.

For a single person, therefore, the risk remains low. But when the infection arrives, for those who wear cosmetic lenses without a check-up the toll seems heavier¹. In a Saudi case series, 46 young people with no refractive error had presented with inflammation of the cornea after wearing lenses purely for cosmetic reasons: in 9 the laboratory confirmed an infection, mainly due to the bacterium Pseudomonas, and with targeted treatment the ulcers closed in all of them⁶. An infection of the cornea, a Finnish review reminds us, still leaves a scar and sometimes requires further procedures⁹.

Why coloured lenses cause more concern

The studies focus on the way these lenses end up on the eyes, more than on the lens itself. The TFOS report on the lifestyle of contact lens wearers, an international review from 2023, lists among the harmful choices unsuitable purchasing channels, the lack of check-ups by a professional, sleeping in the lenses and poor care⁵. These are the same habits that the French studies find most often among those who use cosmetic lenses^1,2.

Everyday gestures matter too. The Australian review lists among the heaviest risk factors overnight wear, not washing and drying the hands before touching the lenses and poor hygiene of the lens case⁴. Two of these concern water and sleep, and we look at them in more depth in the articles on lenses and water and on sleeping in contact lenses.

According to the international CLEAR report, about one lens wearer in three experiences some complication, almost always mild and easy to manage⁷: infections are the rare part, but the most serious.

The rules in Europe and the shared recommendations

In the European Union the regulation on medical devices also applies to purely decorative contact lenses, which have to meet safety requirements like corrective ones¹⁰. The rules concern the product, however, not the way it is fitted and used, which in the studies is the weak point^1,2.

The international reviews point in the same direction: be followed by an eye care professional, even for lenses that are only coloured, follow the care rules and do not sleep in the lenses^4,5. In the French studies, fitting by an ophthalmologist was associated with fewer infections².

Frequently asked questions

Are coloured lenses without corrective power bad for your eyes?

The problem is not the colour: they are contact lenses in every respect and carry the same risk of infection as corrective lenses^3,4. In the French studies those who used them less often received instructions from a professional and, if infected, more often had serious damage to vision¹.

Are coloured lenses for a single evening a risk?

Occasional use is no protection: in the Australian study experience of less than six months with lenses was among the risk factors, and those who slept in daily lenses even only occasionally had an infection rate of 4.2 cases per 10,000 wearers a year, against 2.0 for those who always took them out³.

Are coloured lenses bought online safe?

Buying on the internet was associated with a higher risk of keratitis in the Australian study³, and the TFOS report lists unsuitable purchasing channels among the choices that can harm the eye⁵. According to the French studies the main problem is the lack of a check-up and of instructions, more than the shop itself¹.

Coloured lenses are not make-up, but a device resting on the cornea. The studies do not ask people to give them up: they show that the most serious problems are concentrated where professional check-ups and instructions for use are missing^1,2.