Your lenses are truly the most important component of your new eyeglasses and choosing the correct thickness is vital for your vision. For most people, the stronger their prescription, the thicker the lenses will need to be. The most common choices are standard plastic lenses, impact resistant polycarbonate lenses, and high index lenses. Standard plastic lenses are the most common and usually are the least expensive. They are also readily available nearly anywhere, should you need to replace them quickly. Polycarbonate lenses, which make a great choice for those with an active lifestyle or for children, are much more impact resistant that standard lenses. The final of the options, high index lenses, are known for their thin and lightweight design and construction, as well as for their comfort and style. Here is a breakdown of some common lens thickness options:
Standard Index 1.50: These lenses hold a high Abbe value for visual acuity and are made of CR-39. These lenses are often a popular basic choice for full rim frames.
Index Trivex 1.53: Lenses of this thickness are extremely strong, much lighter weight than the standard index lenses, and more resistant to impact as well. These are often selected by people who are involved in active sports or for children.
Mid Index 1.57: This category of lenses is very basic, has a low to medium Abbe value, and is not recommended for rimless frames due to low structural integrity.
Mid Index Xirm 1.58: This mid index lens choice made with Xirm material is a good compromise between strength and affordability. The Abbe value is much higher than on a basic Mid Index 1.57 and these lens are nearly as strong as the Trivex option.
High Index Polycarbonate 1.59: This lens option, made from polycarbonate materials, is very durable and impact resistant, but the Abbe value for optical clarity is extremely low.
High Index 1.61: If you have selected a frame that is semi rimless or rimless, High Index 1.61 lenses may be a good choice. These lenses are lightweight and comfortable to wear, even for those requiring strong prescriptions.
Extra High Index 1.67: For those who need impact resistance, but require prescriptions too high for other lens options, this makes a great choice. Extra High Index 1.67 lenses can be used with all styles of frames and have a moderate Abbe value.
Premium High Index 1.74: This lens option is constructed from plastic that is extremely thin, and is the most lightweight option on the market currently. Due to its composition, it is only recommended for use by those having a very strong prescription.