Are Contact Lenses Safe? What You Should Know Before Buying

Why contacts are regulated in Canada

Contact lenses sit directly on your cornea – the clear tissue at the front of your eye that is responsible for most of your focusing power. The cornea has no blood vessels. It gets its oxygen directly from the air through the tear film. A contact lens that fits well allows enough oxygen through and moves appropriately with each blink. A lens that does not fit well can starve the cornea of oxygen, trap debris, and create conditions for infection.

This is why Health Canada classifies all contact lenses as Class II medical devices – the same regulatory category as surgical gloves and blood pressure monitors. This includes coloured lenses, cosmetic lenses, and costume lenses, even if they have no vision correction at all. The classification is not about the prescription power. It is about the fact that the device sits on a living tissue and needs to fit properly to be safe.

A contact lens prescription is not just a power number. It includes a base curve (the curvature of the lens) and a diameter (the size of the lens), both of which are determined during a fitting based on the shape of your cornea. Two people with the same prescription may need different base curves. A lens with the wrong curve can be too tight – restricting oxygen and movement – or too loose – sliding and scratching the cornea with every blink.

Are coloured contacts safe?

Yes – when they are fitted properly.

We fit coloured contact lenses at Spadina Optometry. There is nothing inherently riskier about a coloured lens compared to a clear one, as long as:

• The lens is manufactured to Health Canada standards
• The pigment is embedded within the lens material, not printed on the surface
• The lens has been fitted to your eyes by an optometrist
• You follow the same care and replacement guidelines as any other contact lens

The problems start when coloured lenses are purchased without a prescription from unregulated sources – beauty supply stores, online marketplaces, Halloween pop-up shops, or social media sellers. These lenses may not meet manufacturing standards, may have rough edges or poor oxygen permeability, and are almost certainly not fitted to your eyes.

If you want coloured lenses, come in for a fitting. We can match you with a lens that gives you the look you want and actually fits your eyes safely. Bring a photo of what you are going for.

Can I share contacts?

No – even for a few minutes, even “just to try them.”

Contact lenses are fitted to a specific person’s corneal shape. Your friend’s eyes are a different size and curvature than yours. A lens that fits them comfortably may be too tight or too loose on your eyes.

Beyond fit, sharing transfers bacteria and microorganisms between eyes. The combination of a poorly fitting lens and transferred bacteria is exactly the setup for a corneal infection.

This applies to all lenses: clear, coloured, cosmetic, daily, monthly. There is no “safe” way to share a contact lens.

Buying contacts online

Buying contact lenses online is fine – if you have a current prescription and you are ordering the exact brand, base curve, diameter, and power your optometrist prescribed. Reputable online retailers in Canada are required to verify your prescription before dispensing.

Where it becomes risky:

• Buying from sites that do not ask for a prescription – if they are not checking, they are not regulated, and the lenses may not be either
• Guessing at your parameters – ordering lenses with a different base curve or diameter than what was fitted is not a minor detail; it affects how the lens sits on your cornea
• Buying brands that were not fitted to your eyes – different brands have different materials, water content, and shapes; switching without a fitting is a gamble

If cost is the reason you are considering an unverified source, talk to us. We can often find a lens option that works for your budget without compromising on safety.

Halloween and costume lenses

Every October, optometrists across Canada see patients with corneal damage from costume lenses bought without a prescription. The pattern is predictable: lenses purchased from a costume shop or online seller, worn for a night, symptoms the next morning.

Costume lenses sold without a prescription are not regulated by Health Canada. They may have:

• Pigments printed on the lens surface that can flake off and irritate the eye
• Rough or unfinished edges that scratch the cornea
• Poor oxygen permeability that starves the cornea during wear
• One-size-fits-all dimensions that do not account for individual eye shape

You can get the same look safely. Prescription costume and coloured lenses are available in a wide range of colours and effects. A fitting takes one appointment. If you plan ahead – even a week or two before Halloween – we can have you fitted and ready.

What happens when it goes wrong

We do not say this to scare you. Most contact lens complications are mild and resolve quickly with treatment. But serious complications from unregulated or shared lenses do happen, and they tend to be worse because the patient often does not seek care immediately.

Complications can include:

• Corneal abrasion – a scratch on the cornea from a poorly fitting or damaged lens
• Microbial keratitis – a bacterial or fungal infection of the cornea that can cause pain, light sensitivity, and vision loss
• Acanthamoeba keratitis – a rare but severe infection associated with water contact and unregulated lenses, extremely difficult to treat
• Corneal neovascularisation – blood vessels growing into the cornea in response to chronic oxygen deprivation from a tight-fitting lens
• Corneal scarring – permanent damage that can affect vision even after the infection or inflammation resolves

Early treatment makes a significant difference in outcomes. If you are having any symptoms after wearing contacts – especially contacts that were not prescribed for you – do not wait. Call us at 416-703-2797.

Even film and television sets use eye care professionals

If you have ever watched a movie or TV show where an actor has visibly different eyes – supernatural colours, slit pupils, whited-out sclera – those lenses were fitted and supervised by an eye care professional on set.

Film and television productions hire optometrists or qualified lens technicians to fit custom contact lenses for every actor who wears them. The lenses are prescribed individually, checked for fit before each use, and monitored throughout the shoot. Actors do not just grab a pair from a box and put them in. On major productions, the eye care provider is on set the entire time the lenses are being worn.

The industry does this because the risk is real and well understood. A poorly fitting specialty lens on a 14-hour shoot day under hot lighting is a recipe for a corneal abrasion or worse – and productions cannot afford an actor with an eye injury any more than you can. If a movie studio with an unlimited budget still insists on professional fitting and on-set supervision for cosmetic lenses, that should tell you something about wearing them without a prescription.

Spadina Optometry has worked with film and television productions in Toronto, providing contact lens fittings and eye care for cast and crew. We are located in the heart of Toronto’s production district near King and Spadina.

Getting fitted for coloured or cosmetic lenses

A contact lens fitting for coloured lenses is the same process as any other contact lens fitting:

1. We measure your corneal curvature and eye surface
2. We select a trial lens in the colour and style you want
3. We check the fit, movement, and comfort on your eyes
4. We confirm your prescription (or fit plano lenses if you do not need correction)
5. You leave with a prescription you can fill with us or with any reputable retailer

If you have never worn contacts before, we also teach you how to insert, remove, and care for them.

You do not need vision correction to book a fitting. Plano (zero power) coloured lenses still need to be fitted, and we are happy to do it.

For film, television, and production teams in Toronto

If you are a producer, production assistant, or performer working on a production in Toronto that requires cosmetic or specialty contact lenses, Spadina Optometry can help.

What we offer productions:

• Custom cosmetic and specialty lens fittings for cast members – coloured, scleral, prosthetic, and effect lenses
• Flexible scheduling that works around production timelines – we understand that fittings may need to happen quickly and on short notice
• On-set guidance on safe lens wear during long shoot days, including wear time limits, reinsertion protocols, and what to watch for
• Emergency availability if a lens issue comes up during production

Why productions work with us:

We have direct experience working with film and television productions in Toronto. Our clinic specializes in specialty and complex contact lens fittings, including scleral lenses that vault over the entire cornea – the same lens type used for many theatrical and special-effect applications. We understand that production schedules are tight, that the look needs to be exact, and that the actor’s eye health is non-negotiable.

We are located at 477 Richmond St W, Suite 809, in the heart of Toronto’s production district near King and Spadina.

To discuss your production’s needs, call us directly at 416-703-2797 or contact us. We are happy to work out timing and logistics before the fitting.

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