The lens index symbolizes the level of compression of the material in the lens and affects the thickness and weight of the lens.
The higher the index, the thinner and lighter the lens.
A high index is important due to the comfort of the glasses and also for the aesthetics since thick lenses in the glasses will stand out and in addition the eyes of the glasses component will look large.
However a high index is only necessary in cases where the number is high, in cases where the standard number does not need to choose a high index because we will get the same result.
Our recommendation for indexing the number of lenses:
|1.56 The thickest lens.||0.25-\+ to 3.00-\+|
|1.6||3.25-\+ to 5.00-\+|
|1.67||5.25-\+ to 6.75-\+|
|1.74 The thinnest lens.||7.00- and up.|