Would You Like Thinner, Lighter Lenses?
Ask Us about “Hi-Index”
“Helping You Look and See Your Best”
What determines the thickness of my lenses?
There are four factors that determine how thick your lenses are:
The front curve
The back curve
The prescription lens power
The index of refraction (see below for an explanation).
The only one that you can significantly change is the index of refraction (called the “index”).
How Do I Minimize My Lens Thickness?
Since you cannot significantly change the front or back curves, plus your eye doctor determines your lens power, there are two ways to reduce lens thickness:
Choose smaller and rounder frames: the larger and more pointed your frame, the thicker the lens.
Choose a “High Index” lens: the higher the index the more the lens material naturally bends light.
Consider “High Index” lenses if your lens prescription is greater than -5.00 or +3.00, or if your astigmatism is greater that -2.50.
“High-Index” lenses do cost more, but the comfort of wearing a lighter pair of glasses is worth it.
How does a “High-Index” Lens Work
A lens bends light based on it’s “Index of Refraction”. The higher the index, the more the light is bent. This means you need less lens thickness to bend the light the same amount. Typical indexes:
Regular plastic lens – 1.50
Mid-Index lens – 1.56
Polycarbonate – 1.59
High-Index – 1.60 or 1.67
Ultra High Index – 1.74