What is the Highest Index in Eyeglass Lenses?

When choosing eyeglass lenses, one important factor to consider is the lens index. The index of refraction, or refractive index, indicates how well a lens bends light. A higher index means the lens can bend light more effectively, which allows for a thinner and lighter lens compared to standard options.

Understanding Lens Index

Standard lenses usually have an index of 1.50.

Mid-index lenses range from 1.56 to 1.60, providing a thinner profile than regular lenses.

High-index lenses go from 1.67 to 1.74; these lenses are much slimmer and perfect for stronger prescriptions.

What is the Highest Index Lens?

Currently, the highest commercially available lens index is 1.74. These lenses are ultra-thin and designed for people with high prescriptions, typically above ±6.00. They cut down on the bulk and weight of glasses, offering a more comfortable and attractive look.

Benefits of 1.74 High-Index Lenses

Slim and lightweight; perfect for strong prescriptions.

Better appearance; reduces the “thick lens” look.

Comfort; less weight on your face.

Durability; often combined with coatings like anti-scratch, anti-reflective, and UV protection.

Should You Choose the Highest Index?

Not everyone needs the highest index. If you have a mild prescription, a mid or standard index lens may be sufficient. However, if you want sleek, thin, and modern lenses with strong vision correction, the 1.74 high-index lens is the best choice.