Sperry SPBIRCH Eyeglasses

Glass

Glass is the LEAST shatter resistant and heaviest material in today’s market. Glass WILL shatter when struck by certain objects. Know that there is a risk factor when wearing glass lenses. Nonetheless, it still has its place. Glass has the best scratch resistant properties along with excellent optical quality.

High Index 1.67

High Index 1.67 lenses are for those with moderate to high prescriptions. The higher the Index of refraction, the thinner the lens. 1.67 is yet another lens that does well with rimless eyewear. Anti-reflective coating is highly recommended for 1.67 lenses. 1.67 will accommodate prescriptions in the +/- 6.00 range and sometimes higher. UVA and UVB protection is inherent within the lens.

High Index 1.74

High Index 1.74 index lenses are the ultimate in thickness reducing resin lenses. In some cases up to a 40% thickness reduction over standard lenses. Anti-reflective coating is included. 1.74 is the best choice for a cosmetically appealing thin lens. UVA and UVB protection is inherent within the lens.

Trivex®

Trivex® like polycarbonate has high impact resistance properties and inherent UV protection. Also excellent for rimless eyewear, in particular drill mounts, . Trivex® has less chromatic aberration than poly providing slightly better optical clarity. Its lower index of 1.523 will make it slightly thicker than poly with the same RX. Trivex® is recommended for prescriptions up to +/-3.00.

Polycarbonate

Polycarbonate (poly) is known for its high impact resistance properties. Slightly lighter in weight than CR-39, poly is also a thinner material than plastic, glass or Trivex®. Poly is a great candidate for rimless frames. When lens thickness is a concern, poly is recommended for prescriptions up to +/-4.00

Plastic

Plastic lenses, sometimes referred to as CR-39 is a lighter in weight alternative to glass. Also more impact resistant than glass, however with much lower scratch resistance properties.

Standard Multi-Layer

• Reduces eyestrain.
• Helps enhance optics.
• Reduces “star effect” of nighttime lights.
• Reduces annoying reflections that others see when looking at your eyes. Makes it appear if you have no lenses in your frames.
• Repels dust.
• Repels water.

Blue light

• Reduces eyestrain associated with viewing electronic devices and helps block blue light emissions from those devices.
• Helps enhance optics.
• Reduces lens surface reflections.
• Repels dust.
• Repels water.

Superior

• Ultra-resilient anti-scratch layer for optimal durability and increased lens life.
• Oleophobic layer aids in smudge-repellence keeping lenses cleaner longer.
• Hydrophobic water repellant technology helps retain ease of cleaning properties even after long-term use.
• Low reflection properties for enhanced vision during night driving, optimal visual clarity along with improved cosmetic appearance.
• Comparable in performance and formula to high-end name brand more expensive coatings.

Mirror coatings

• Highly reflective mirror-like front surface lens coating for sunglass lenses only.
• Helps “hide” your eyes from others.
• Available in multiple colors.
• Includes back-side multi-layer anti-reflective coating.