It’s fun to experiment with the way we look by changing up our hairstyle or hair color, wearing new clothes or trying out dramatic, new looks. And our eyes are no exception.

Many people turn to colored and cosmetic contact lenses to achieve a temporary, striking difference in the way their eyes appear. Whether it’s simply changing your eye color, completely transforming your eye into that of a cat or snake for a costume, or even turning your eyes entirely white or black, the options are endless.

However, some colored contact lenses bring risks with them. In fact, nonprescription colored or cosmetic contact lenses can damage your eyes.

This doesn’t mean you have to scrap your plans for a Halloween or party costume. There are steps you can take to wear colored contacts safely and protect your eye health so you can continue to incorporate different eye colors in your look.

Much like the surface of our skin and our digestive system, our eyes also host a microbiome of beneficial bacteria. Wearing contact lenses can disrupt the balance of this delicate system, leaving us more prone to eye infection and disease.

This is why it’s so important to be extra discerning when it comes to what kind of contact lenses you wear and where you get them. Nonprescription colored contact lenses can be an especially risky choice for many reasons.

Over-the-counter lenses have little quality control

The U.S. Food and Drug Administration (FDA) considers contact lenses to be medical devices, even if they’re only worn for cosmetic purposes. For this reason, it’s illegal for retailers to sell them over the counter and for consumers to buy them without a prescription. These rules don’t apply to overseas retailers, however, and plenty of cosmetic contacts are available for purchase through online stores.

This doesn’t mean all contact lenses sold online are unsafe, and many people turn to the internet to buy their contact lenses because it’s convenient. But it’s important to know that a trustworthy retailer will require a prescription before selling you any contact lenses.

When you buy colored contact lenses from unregulated online stores or from malls, gas stations or salons, there’s little to no control or supervision over how the lenses themselves were made or packaged. For instance, they can be sold in nonsterile cases that leave the lenses covered in bacteria that is too small to see, or the pigment that gives the lenses their color and design may contain chemicals that are unsafe for our eyes. Without regulation, there’s just no way to know what you’re really putting on your eyes.

Ill-fitting contact lenses are hard on the eyes

No two sets of eyes are the same, so there is no such thing as “one size fits all” contact lenses – corrective or not. This is why getting a prescription for contact lenses requires a visit to an eye care professional, most commonly an optometrist and optician. Optometrists are health care professionals who specialize in fitting the eyes for contact lenses. They measure the specific shape of your eyes – including curve, diameter, and iris and pupil size – to write a contact lens prescription for you. Opticians are contact lens technician specialists who use that prescription to fit you for the right contact lenses.

Contact lenses that don’t fit properly can cause serious damage to the delicate surface of your eyes in the form of cuts, scrapes and scratches. These injuries are difficult to heal and may invite infection, which can cause more serious eye health issues. If your contact lenses are too small, they can squeeze your cornea and deprive it of oxygen, allowing for bacteria growth. This is known as tight lens syndrome.

Cosmetic contact lenses can obstruct vision

Our eyes are structured in a way that allows us to see well. Wearing contact lenses that cover part of the pupil or sclera (the white part of the eye) can interfere with your central (front-facing) and peripheral (side) vision. Having part of your vision blocked can increase your level of risk in a multitude of day-to-day activities, like driving and walking.

For this reason, cosmetic contact lenses, especially the kind that change the shape of your pupil, should only be worn for a maximum of 10-12 hours at a time – and only when you know you won’t be doing any driving – to preserve your vision, eye health and overall safety.

Some cosmetic contact lenses cover too much of the eye

Circle, or “big eye,” contact lenses are a specific type of cosmetic contact lens that extends beyond the iris and cornea to cover part of the sclera, or the white part of the eye. This makes the iris look much larger.

Circle contact lenses have not been approved by the FDA and are illegal in the U.S. because they pose a serious risk to eye health. They prevent oxygen from reaching the eye, encourage bacterial growth, and can cause extremely dry eyes, infection, scarring and even blindness.

How to wear cosmetic contact lenses safely

Don’t worry. You can still wear colored contact lenses safely. But we encourage you to follow these tips to keep your eyes safe.

See an eye care specialist for a contact lens prescription

Some people have certain health conditions and circumstances that make contact lenses an unsuitable option for them. The only way to find this out for sure is to have an assessment by an eye care specialist.

Your eye care specialist can make sure your eyes are healthy enough for contact lenses and give you the right amount of vision correction if you need it. They will also take your exact eye measurements so your contact lenses can fit perfectly. Once your assessment is complete, your eye care specialist can give you a prescription to take to the optician, who can then identify whatever cosmetic contacts suit your needs.

Practice proper contact lens care

If you’ve never worn contact lenses before, it’s important to learn how to properly care for them before putting them in your eyes. Your eye care specialist can teach you how during your contact lens appointment, and they may even give you materials to take home for further education. Following proper care instructions can help you avoid dangerous eye infections and injuries.

Here are some quick tips:

  • Don’t nap or go to bed while wearing contacts. Always remove your contacts before sleeping.
  • Before putting contact lenses in, make sure your hands are clean, dry and free of lotion. Wash your hands after as well.
  • Put in soft lenses before applying makeup. Put in “hard” lenses (also known as rigid gas-permeable lenses) after applying makeup.
  • Never let someone else wear your contact lenses. There is no such thing as “borrowing” contacts.
  • Do not shower, bathe or go swimming while wearing contacts.
  • Discard your contact lenses for fresh ones as directed, depending on the type of lenses you have: every day, every week or two, or once a month.
  • Clean your contact case once a day and let it air dry before using again. Replace your case at least once every three months, or sooner if it gets damaged.
  • After wearing your contact lenses and before putting them back in their case, completely change out the old contact solution for new solution every time, instead of just topping it off.

Your eyes are uniquely yours – take care of them

Colored contact lenses can let you try on many different appearances, but remember, you only have one set of eyes. It’s important to appreciate them just the way they are and to take care of their health. If you want to try something new – whether for a costume or a daily look – always start with a visit to an eye care specialist.