HI Index lenses

1.6

25% thinner and 25% lighter in weight compared to a 1.5 standard lens. Suitable for thinning mild to moderate powers up to +/-4.00D

 1.67

up to 40% thinner than 1.5 standard lenses and 35% lighter in weight

1.74

Up to 50% thinner lens available, 37% lighter in weight than 1.5 standard lens. This is for those that want the thinnest option. Worthwhile for high prescription values >+/-6.00D