2024-05-01
Coloured contacts can look amazing. Whether you want a subtle enhancement of your natural eye colour or a dramatic change for a costume, the technology has gotten really good. But coloured lenses also come with real risks that are not well understood by most people buying them, and the consequences of getting it wrong can be severe.
We are not trying to scare you away from coloured contacts. We are trying to make sure you use them safely.
In Canada, All Contact Lenses Require a Prescription
This is the single most important thing to understand. In Canada, contact lenses are classified as medical devices under Health Canada regulations. Every contact lens, even one with zero corrective power (called plano), requires a valid prescription from an optometrist or ophthalmologist. This is not bureaucracy for its own sake. It is because an improperly fitted contact lens can damage your cornea.
A contact lens prescription is not the same as a glasses prescription. It includes the base curve (the curvature of the lens), the diameter, and the specific brand and material. These measurements come from a contact lens fitting, where your eye care provider examines your cornea's shape and evaluates how the lens sits on your eye.
This applies to coloured lenses, costume lenses, Halloween lenses, and any other contact lens that sits on your eye. No exceptions.
What Actually Goes Wrong with Unfit Lenses
We see the aftermath of cheap, unfitted coloured contacts several times a year, usually in early November. Here is what happens:
Corneal Abrasion
A lens that does not fit your eye properly moves unpredictably. It can scrape the surface of your cornea, creating an abrasion. This is acutely painful, like having sand under your eyelid, and it puts you at risk for infection. A corneal abrasion from a poorly fitting lens can take days to heal, during which you cannot wear any contact lenses.
Corneal Ulcer (Microbial Keratitis)
This is the one that keeps optometrists up at night. Bacteria, fungi, or other microorganisms get into a corneal scratch and establish an infection. A corneal ulcer can scar permanently, and severe cases can threaten your vision. Treatment involves aggressive antibiotic drops, sometimes hourly, and in the worst cases, a corneal transplant.
Unlicensed coloured lenses are particularly risky because they may not be manufactured to the same oxygen permeability standards as legitimate lenses. Your cornea needs oxygen from the air, delivered through the lens. A cheap lens that blocks too much oxygen weakens your cornea's defences against infection.
Allergic Reaction to Dyes
The pigments used in coloured lenses sit within the lens material in regulated products. In unregulated lenses, the colour may be painted or printed on the surface, where it can leach out and irritate the eye. Some patients react to the dyes themselves, developing red, swollen, painful eyes.
A patient came in the day after Halloween with what turned out to be a corneal ulcer from coloured lenses bought at a flea market. She was 19, and the scarring affected her vision permanently. That lens cost her $8. The treatment cost thousands. This is not a scare tactic. This is a real outcome we have seen more than once.
Where to Buy Coloured Contacts Safely
The process should go like this:
- Book a contact lens fitting with your optometrist. If you have never worn contacts, you will need a full fitting. If you already wear contacts, a shorter assessment for the coloured lens is usually enough.
- Try the specific coloured lens during your appointment. Your optometrist will evaluate the fit on your eye and check for adequate movement and centration.
- Get a prescription that specifies the brand, base curve, diameter, and power (even if the power is plano).
- Purchase from a licensed source. Your optometrist's office, a licensed optical retailer, or a legitimate online retailer that requires a valid prescription.
Where NOT to buy them: flea markets, beauty supply stores, costume shops, gas stations, or any website that ships you lenses without asking for a prescription. If a seller does not ask for your prescription, that is your first red flag. If they ship from outside Canada without Health Canada approval, that is your second.
Fitting Matters More for Coloured Lenses
Coloured lenses are slightly thicker than regular clear lenses because the colour layer adds material. This means they behave differently on the eye. The lens needs to move slightly with each blink to allow fresh tears underneath. A coloured lens that is too tight on your eye restricts this movement and can cause problems even if a clear lens in the same parameters would have been fine.
The pupil opening in coloured lenses also matters. In a well-designed lens, the clear optical zone over the pupil is large enough to provide unobstructed vision. In cheaper designs, the opaque colour pattern can encroach on the pupil area, causing a ring of blur around your vision, especially in dim light when your pupil dilates.
Good Coloured Lens Brands That We Trust
Several major manufacturers make coloured lenses that meet Health Canada standards and come in a range of colours and prescriptions. Brands like Air Optix Colors, FreshLook, and Acuvue Define are all properly manufactured with good oxygen permeability and well-designed colour patterns. They cost more than the cheap imports, but your cornea is not something to bargain-shop for.
If you want a subtle enhancement (brightening your natural eye colour or adding a slight tint), enhancement tints on a quality lens look very natural. If you want a dramatic change (brown eyes to blue, for example), opaque tints are available in the same quality brands.
Care Instructions Are Non-Negotiable
Coloured contacts follow the exact same care rules as any other contact lens:
- Wash your hands before handling them
- Never sleep in them unless specifically approved for overnight wear (most coloured lenses are not)
- Never share them with anyone, ever, no matter what
- Replace them on schedule — do not stretch a monthly lens to two months because they are more expensive
- If your eyes are red, painful, or your vision is blurry, take the lenses out immediately
Sharing lenses is probably the single riskiest behaviour we see. It happens constantly at parties and sleepovers. You are sharing bacteria, and bacteria that are harmless in one person's eye flora can cause a raging infection in someone else's.
The Bottom Line
Coloured contacts are perfectly safe when they are properly fitted by an eye care professional, purchased from a licensed source, and cared for correctly. They are genuinely unsafe when bought without a prescription from unregulated sellers. There is no middle ground here.
The fitting appointment takes about 20 minutes and gives you peace of mind that the lenses on your eyes are the right fit, the right material, and approved for use in Canada. That is a small investment for something that sits directly on one of the most sensitive and important organs in your body.