The guide to eyeglass lens types, materials, and coatings.

Choosing new glasses involves more than just the frames. The lenses you select are critical for clear vision, comfort, and durability. When it comes to prescription lenses, it's important to understand different types of eyeglass lenses, materials, and coatings—which form the core of all corrective eyewear. This guide breaks down your options so you can make an informed decision.

What are corrective lenses?

Corrective lenses are optical devices designed to bend light before it enters your eye, helping it focus correctly on the retina. For most people, this means using lenses with a spherical correction for nearsightedness or farsightedness. For those with astigmatism, a cylindrical correction is added to account for an irregular curvature of the eye.

Lens types based on vision correction.

Lenses are first categorized by the type of vision correction they provide.

Single vision.

These are the most common lenses. They have a single prescription power to correct for one field of vision—either distance (nearsightedness), near (farsightedness/reading), or intermediate (computer use). Smart glasses like Even G1 support a wide range of single-vision prescriptions, making advanced technology accessible to most users.

Multifocal lenses.

These lenses contain more than one prescription power.

• Bifocals: Contain two distinct powers separated by a visible line. The top portion is for distance vision, and the bottom segment is for near vision.
• Trifocals: Similar to bifocals but with a third segment for intermediate vision, separated by two visible lines.
• Progressives: Offer a gradual transition between distance, intermediate, and near vision without any lines. They provide a more modern look compared to bifocals and trifocals.

Plano lenses.

Plano prescription glasses have zero corrective power. These non-prescription lenses are used for several reasons:

• Fashion: To wear stylish frames without vision correction.
• Blue Light Filtering: To reduce eye strain from digital screens.
• Technology Integration: For smart glasses where users need the digital display but not vision correction.
• Safety: As protective eyewear in environments with a risk of eye injury. Nearly 20,000 Americans suffer workplace eye injuries each year, many of which could be prevented with proper safety glasses.

Lens materials: the foundation of your lenses.

The material of your lenses affects their thickness, weight, and clarity. Two key properties differentiate them:

• Refractive Index: This measures how efficiently the material bends light. A higher index allows for thinner and lighter lenses.
• Abbe Value: This measures the amount of chromatic aberration (color fringing) a lens produces. A higher Abbe value means better optical clarity.

Comparison of lens materials.

Advanced eyewear takes this further. Even G1 uses digitally surfaced lenses, which are individually carved for precision, and bonds them to a waveguide lens. This composite lens, made from a tough Japanese organic resin, remains as thin as a standard lens while integrating a digital display.

Lens coatings and treatments.

Coatings add functionality to your lenses.

Anti-reflective (AR) coating.

AR coating reduces glare from headlights and screens, minimizes reflections on the lens surface, and improves visual clarity. It's a standard recommendation for most glasses.

Scratch-resistant coating.

This is a hard, protective layer that increases durability against everyday wear. Most modern lenses, including those in Even G1, have a basic scratch-resistant coating.

UV-blocking treatment.

This acts like sunscreen for your eyes, protecting them from harmful ultraviolet (UV) radiation. Polycarbonate, Trivex, high-index, and specialized resin lenses often include built-in UV protection.

Blue light filtering.

This coating filters a portion of the blue-violet light emitted by digital screens and the sun, which can help reduce digital eye strain.

Photochromic lenses.

Also known as transition lenses, these automatically darken when exposed to UV light outdoors and lighten when indoors.

Polarized lenses.

Primarily for sunglasses, these lenses have a filter that blocks intense horizontal glare from surfaces like water, snow, and roads.

How to choose the right lenses.

Your choice should be based on your specific needs.

For strong prescriptions.

High-index lenses are the best option to keep the lenses thin, light, and comfortable.

For children and active lifestyles.

Polycarbonate or Trivex lenses are recommended for their high impact resistance and durability.

For office work and screen use.

Lenses with a blue light filter and an anti-reflective coating can reduce eye fatigue and improve comfort during long hours at a computer.

For outdoor use.

UV protection is essential. Photochromic lenses offer convenience by adapting to light conditions, while polarized sunglasses are ideal for high-glare environments.

On a budget.

Standard CR-39 plastic lenses provide excellent optical quality at a lower cost and are suitable for weaker prescriptions.

Conclusion.

Matching the right lens technology to your prescription and lifestyle is key to getting the most out of your eyewear. Whether you need simple single-vision lenses or advanced high-index progressives, understanding your options is the first step. If you're still unsure what the numbers on your prescription mean, our guide on how to read your eyeglass prescription can help.

FAQs.