Buying Contacts Online? How to Make Sure the Store Measures Up

As a contacts wearer, you typically know how many lenses you have on hand to keep up with your usual routines. 

But sometimes we lose track. There might be a sudden need to get more lenses — whether for a trip, an unexpected emergency, or simply because we forgot to order more. 

In these situations, you might be tempted to purchase your lenses from any online shop — especially ones that have fewer requirements or make promises that might seem too good to be true. 

Often that is the case — especially if the retailer doesn’t require a prescription. Because that matters more than you might realize. 

Consider this: contact lenses are medical devices that sit directly on your cornea. They are designed to fit your unique eye shape and your vision correction needs in order to provide you with clear and comfortable vision for as long as you’re wearing them. 

Those individual measurements are only available by prescription, which is provided by an optometrist or ophthalmologist. 

When you are considering your contact lens purchase, always look for a retailer that requires a valid prescription. This provision is a clear message that the shop is trustworthy and offers products that are both authentic and safe for your eyes. 

[Read our blog: A step-by-step guide for buying contact lenses online]

A prescription might look like just a collection of numbers and symbols, but there’s a lot going on: Those numerals are a map for creating the best possible contact lenses for you. 

Here’s a quick guide to decoding your contact lens prescription:

• OD: Oculus dexter — your right eye
• OS: Oculus sinister — your left eye
• Brand: The brand of lens that your optometrist recommends. Different brands have different features and measurements
• BC: base curve. This is the curvature of the lens, in millimeters, selected to work with the curvature of your eye
• DIA: diameter. This is the full width of your contact lens, in millimeters. This measurement ensures the lens fits comfortably over your cornea
• PWR/SPH: power or sphere. This is the strength of your prescription. The number represents the power of correction you need (diopters). The “+” indicates farsightedness and the “-” indicates nearsightedness.
• CYL, AXIS, ADD, D/N: These terms are used to indicate additional measurements if you have astigmatism or presbyopia 

If you require vision correction, you might assume that eyeglasses and contact lenses have identical prescriptions. This is not the case! Contact lenses are worn directly on the eye, while eyeglasses sit about 12 millimeters from the eye. Not only can the powers differ between your eyeglass and contact prescriptions, a glasses script does not include your individual eye measurements — necessary for perfect-fitting contacts.

This is why your eyeglasses prescription cannot also be used for your contact lenses. 

[Read our blog: 4 new high-tech options for popular contact lens brands]

When you are shopping for new contacts online, always ensure that the retailer requires a valid prescription from an eye doctor. This demonstrates three important things to you as a consumer: 

Trust. When a retailer requires a valid prescription, you can feel confident that the store cares about providing the very best product for your needs. They know that the correct fit is paramount to the comfort and clarity of your lenses and your eye health — and that fit is determined precisely by your prescription.    

Authenticity. Requiring a valid prescription also signals that a retailer itself is valid — in other words, authentic and legitimate. This means that the lenses they sell are provided by tested and trusted brands. 

A sign you're dealing with an untrustworthy retailer? The price seems too good to be true. This can be a flag that the shop is selling products from questionable or unauthorized sources, such as:

• “Grey market” refers to products that are legitimate or genuine, but are not authorized for sale in a given country. For example, not all authentic lenses from Canadian manufacturers can be imported into the US for sale (and vice versa). This comes down to government approvals.  
• “Black market” refers to products that are not authentic or legal. For example, black market lenses could be replicas or knock-offs.

[Read our blog: 5 reasons you should never buy contacts from unauthorized dealers]

Safety. As mentioned above, contact lenses are medical devices that sit directly on your eyes — something we might not always think about. 

Legitimate retailers sell only authorized brands, which are designed for specific needs and with precision focus on eye health. Counterfeit or ill-fitting lenses pose risks to your eye health, such as corneal scratches and ulcers, vision loss, infections, and other issues. 

So when you go to purchase your next set of contacts lenses, confirm that the online shop requires a valid prescription.  In Canada, it is highly recommended for retailers to request a valid prescription.  Some grey market online shops still request prescriptions, that’s when you need to check the price - if it’s too good to be true, then you’re likely dealing with grey market.   If you don’t have a copy of your prescription, many retailers will allow you to place your order and then contact your eye doctor to validate your script (and remember: most prescriptions are valid for 1-2 years, so it’s a good idea to stay on top of your exams.) 

It’s all about ensuring that your vision correction needs and eye measurements are up-to-date, so you can have peace of mind knowing that you’re getting the best possible lenses.  

With this knowledge, and as the year draws to a close, it’s a great time to think about taking advantage of any remaining health benefits you have this year. Find a trusted retailer and maximize any available funds to get some fresh new lenses you can feel good about.