What is Thickness Index?
Lens Thickness index is a number that describes how thick or thin your lenses are. The higher a lens' index is, the thinner it becomes. Higher prescriptions require higher index lenses, while lower prescriptions require lower index lenses.
Recommended lens index
| Lens index | Features | SPH | CYL | |
|---|---|---|---|---|
 |
1.5 INDEX LENS | Conventional single-vision lenses.Available starting from $0. | + 2.25 to -2.25 | +/- 2.00 or below |
 |
1.57 INDEX LENS | For people with moderately-strong prescriptions.Thinner and lighter than standard lenses. | -2.50 to -5.00 or +2.50 to +5.00 |
+/- 3.00 or below |
 |
1.59 INDEX LENS | Made with premium polycarbonate.Features 100% UV protection.Durable and impact-resistant. | -4.25 to -6.75 or +4.25 to +6.75 |
-2.25 to -3.00 or +2.25 to +3.00 |
 |
1.6 INDEX LENS | Stylish and extra-thin.Great choice for stronger prescriptions. | -4.25 to -6.75 or +4.25 to +6.75 |
-2.25 to -3.00 or +2.25 to +3.00 |
 |
1.67 INDEX LENS | Extremely thin.Good choice for extra-strong prescriptions. | -7.00 to -9.00 or +7.00 to +9.00 |
-3.25 to -4.00 or +3.25 to +4.00 |
 |
1.74 INDEX LENS | As thin as possibleBest for the highest prescriptions. | +/-9.25 and above | -4.25 to -6.00 or +4.25 to +6.00 |