What does glass index mean?



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By default, the lenses of our prescription screen glasses and sunglasses have a glass index of 1.5. Index stands for the thickness of the lenses. The thickness of the lenses depends on several factors, such as the strength of your eyes and the size and material of the frame.

The thinner the glass, the higher the index

Glasses that are a bit thinner have a higher lens index. Hans Anders opticians will gladly advise you which lens thickness is best for you. For example, thinner lenses are always recommended for (partially) frameless frames as they are more robust. We offer thinner lenses with a lens index of 1.6 and 1.67.

The refractive index is an important fact

For glass dilution, the refractive index of the material is the most important parameter. This index indicates how light deflects into the lens. The higher the refractive index of the material, the thinner the lenses can be made. The disadvantage of a higher refractive index is that the lens reflects more. This is why the lenses of our prescription spectacles and sunglasses are fitted with a custom anti-reflective coating as standard.

Also read: What is the difference between single and progressive lenses?

What four factors determine the thickness of your lenses?

  1. Frame size
  2. The strength of the lenses
  3. The position of the eyes (pupil distance)
  4. The type of frame

Thin lenses are more aesthetic, lighter, safer and offer better optical quality. The lenses of our vision glasses and prescription sunglasses can all be equipped with these thin lenses (with a lens index of 1.6 and 1.67).

Extra thin lenses are often chosen to keep the prescription screen glasses or sunglasses as light as possible and to avoid edges of the glass sticking out of the frame. Thus, it looks more attractive. In addition, the glasses feel more comfortable because they are lighter. And thinner lenses enlarge the eyes less with positive lenses and reduce the eyes less with negative lenses.

Your employees are welcome at all Hans Anders stores throughout the Netherlands for fitting the right pair of Seeh custom-fit monitor glasses and sunglasses. Currently, only qualified opticians and audiologists work at Hans Anders. Thus, you will always get the best assistance in fitting your prescription monitor glasses or sunglasses.

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