Lenses Flashcards
What are our standard index lenses made out of? When do we use it?
We use CR-39, a type of plastic, for prescriptions weaker than +/-4.00 sphere.
What are our high index lenses made out of? When do we use it?
Denser polycarbonate lenses are able to accommodate stronger prescriptions without adding thickness or weight. They have a higher index of refraction - meaning they have more optical bang for your (spatial) buck. These lenses are essential for stronger prescriptions and cost a little extra than standard index lenses. We use them for prescriptions stronger than +/-4.00 sphere
How does polarization work?
Lenses that contain layered material that blocks UV rays. Polarization is inside the lenses - the lenses themselves feature layered film that filters out light like a net.
What are the benefits of polarization?
They not only turn down the light, they cut the glare, making the sun’s rays easier on the eyes. **This is especially effective for light eyed people or others with sensitive eyes
Coatings: What are the (4) features of our (2) lens coatings? What is their selling point?
1 Anti-glare 2 Anti-scratch Hydrophobic (water) Oleophobic (oil) These coatings are often “extras” with other companies but come standard - included in the $89 price - with all our glasses.
What are the selling points of CR-39?
It has better visual acuity than polycarbonate (meaning you can see through it with superior clarity)
What are the selling points of high index polycarbonate?
A hybrid of plastic and glass, polycarbonate is inherently scratch-resistant, shatter-proof, and lightweight. They are thinner lenses for strong prescriptions, to avoid needing thick lenses sticking out of the frame.
