Polycarbonate vs High-Index Lenses: Okotoks 2026 Guide

2026-07-22

Polycarbonate vs. High-Index Lenses: Which is Best for Your Prescription in Okotoks?

Choosing new eyeglasses involves a lot of decisions – frames, coatings, and of course, the lenses themselves. If you have a stronger prescription, you’ve likely encountered the terms “polycarbonate” and “high-index” lenses. Both are designed to create thinner, lighter eyeglasses, but they achieve this in different ways and aren’t equally suited to every situation. As an optometrist, I often guide patients through these choices, and here’s a breakdown to help you understand which might be best for your needs here in the Okotoks area.

Understanding Lens Materials: Beyond Just "Glass"

For decades, most eyeglasses were made from CR-39 plastic. It’s perfectly adequate for lower prescriptions, but becomes quite thick and heavy as the prescription increases. Both polycarbonate and high-index lenses are designed to overcome this issue by bending light more efficiently, allowing for thinner lenses. But they’re fundamentally different materials with different properties.

Polycarbonate: The Impact-Resistant Choice

Polycarbonate is a plastic polymer known for its exceptional impact resistance. It’s the material of choice for safety glasses, sports eyewear, and glasses for children because of this feature. While it does create a thinner lens than standard plastic, the reduction isn’t as dramatic as with high-index options.

• Refractive Index: Typically 1.59. This number indicates how much the lens bends light. Higher numbers mean more bending, and thus thinner lenses.
• Thickness: Thinner than CR-39 plastic, but generally thicker than high-index lenses for the same prescription.
• Weight: Lighter than standard plastic, but heavier than high-index lenses.
• Durability: Exceptionally high impact resistance. More resistant to scratches than standard plastic, but still benefits from a scratch-resistant coating.
• Cost: Generally the most affordable of the thinner lens options.
• Best For: Individuals who prioritize impact resistance – those with active lifestyles, children, or people working in environments where eye protection is critical. Also a good choice for moderate prescriptions where extreme thinness isn’t a primary concern.

High-Index Lenses: The Thin & Light Option

High-index lenses are made from materials with a higher refractive index than polycarbonate. This means they bend light even more efficiently, resulting in significantly thinner and lighter lenses, especially for stronger prescriptions. They are available in a range of indices, typically 1.67 and 1.74 being the most common.

• Refractive Index: Ranges from 1.67 to 1.74. The higher the number, the thinner and lighter the lens.
• Thickness: Significantly thinner than polycarbonate, especially for higher prescriptions. A 1.74 index lens will be noticeably thinner than a 1.67.
• Weight: The lightest option available, reducing strain on the nose and ears.

Durability: While still reasonably durable, high-index lenses are generally less* impact-resistant than polycarbonate. They require a scratch-resistant coating.

• Cost: The most expensive lens option, with the price increasing as the refractive index goes up (1.74 being the most costly).
• Best For: Individuals with strong prescriptions (generally anything over -3.00 or +3.00 diopters) who prioritize thinness and comfort. Also a good choice for those who dislike the look of thick lenses.

Which Lens is Right for Your Prescription?

Here's a practical guide to help you decide, keeping in mind that a professional consultation is always best:

• Low Prescription (under -2.00 or +2.00 diopters): Standard plastic or polycarbonate lenses are usually sufficient. The difference in thickness and weight won’t be significant enough to justify the added cost of high-index lenses.
• Moderate Prescription (-2.00 to -3.00 or +2.00 to +3.00 diopters): Polycarbonate offers a good balance of affordability, impact resistance, and thinning. High-index 1.67 is also a viable option if you prefer a lighter weight and thinner profile, but the cost difference might not be substantial.
• High Prescription (over -3.00 or +3.00 diopters): This is where high-index lenses truly shine. A 1.67 index lens will offer noticeable improvement, but for a very strong prescription, a 1.74 index lens will provide the thinnest, lightest, and most aesthetically pleasing result. While polycarbonate is still an option, the lenses will be significantly thicker and heavier.

A Note on Aspheric Design: Regardless of the material you choose, ask about aspheric lens design. Aspheric lenses have a flatter curvature, reducing distortion and allowing for thinner, lighter lenses overall. They’re particularly beneficial when combined with high-index materials.

Cost Considerations

While the 3-for-1 lens options can provide excellent value, remember that upgrading to high-index lenses will add to the overall cost. A typical price range for lenses in the Calgary/Okotoks area (as of 2026) is:

• Polycarbonate: $100 - $200
• High-Index 1.67: $200 - $300
• High-Index 1.74: $300 - $500+

These are estimates, of course, and will vary based on coatings, frame selection, and specific retailer pricing.

The Importance of Professional Advice

Ultimately, the best lens material for you depends on your individual prescription, lifestyle, and budget. A comprehensive eye exam and consultation with an optometrist is the best way to determine the optimal solution. We can assess your needs, discuss your options, and ensure a comfortable and clear vision experience.

Book an Appointment today to discuss your vision needs and find the perfect lenses for you.