Step 1. Types of Lenses
The types of lenses you choose depend on whether you want the spectacles to suit all activities or single activity.
Single Vision Lens
If you are under age 40 and need a prescription glasses, then single vision lenses may be sufficient enough for your visual correction. Single vision lenses have the same focal power throughout the lens to provide a single focus.
Progressive Lenses (Multifocal Lenses)
Progressive lenses provide a gradual transition in power within the lens to view all distance from near at hand to far across the room. If you are in your 40s or older and have presbyopia, wearing progressive lenses have an advantage to see all distances clearly without taking the eyeglasses off and on.
Step 2. Lens Materials
Resistant to scratches. However glass lenses are heavy compared to plastic lenses and prone to breakage. It’s not recommended for children or those who are active in sports.
Standard plastic lenses, also known as 1.50 index is the most commonly used material for low pwer prescriptions.
Mid-Index lenses range in material index from 1.53 to 1.56. This material is thinner and lighter than standard plastic lenses. Ask your eye care professional which material will be est for you based on your individual Rx and your selection of frame style.
High-Index lenses are typically have a material index of 1.60. High index lenses are thinner than mid-index and an excellent option for drill mount frames.
Ultra High-Index Plastic
This category of lenses ranges in material index from 1.67 to 1.74, the highest index currently available. Ultra High-Index lenses are the thinnest and lightest materials currently available for higher power prescriptions. Ask your eye care professional what material will be best for you, based on your individual prescription and the frame style you select. Remember, the higher the material index the thinner the lens.
Step 3. About Coatings
Application of coatings provides various benefits for the wearer.
- Anti-reflective coatings help transparency in the lens and glare from various lightings.
- UV coatings protect eyes from absorbing harmful UV rays. Long term exposure can damage DNA and it’s cumulative and irreversible. The UV coating blocks the transmission of light in the ultraviolet spectrum.
- Other optional coatings such as scratch resistance, smudge and water resistant surface applications extend the lifespan of the lenswear.