Depending on the type of your prescription, the frame you choose and the needs of your everyday life, it is determined which type of lens and which sharpness is ideal for you.
What is the Refractive Index or Lens Thinning?
Refractive index is a number that refers to how thick or thin a lens will be. The higher the index of refraction, the finer the construction of a lens.
In powerful recipes* lenses with higher refractive indices are recommended, while lenses with lower refractive indices are recommended for lower prescriptions.
*Strong recipe = When the SPH and CYL numbers are very far from zero (eg SPH +- 4.00 )
What are the differences between a high and a low Refractive Index?
Higher indices of refraction in lenses are recommended for stronger prescriptions, as they can cover more vision needs. Higher refractive index lenses are thinner, lighter and aesthetically elegant.
Accordingly, lower indices of refraction in lenses are more economical, as they can cover less vision needs, i.e. they cannot satisfy stronger prescriptions.
In any case, you have the ability to choose more than one option in refractive indices, depending on the type of your prescription and your optical needs.
An ideal choice that covers the widest range of prescriptions are lenses with a refractive index of 1.6, which are extremely durable, slim and stylish.
| High D.D | Low D.D | ||
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| Powerful Recipes | Compatible Recipes | ||
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| D.D | Specifications | SPH | CYL | |
| 1,5 |
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+ 2.00 to -2.00 |
+ / - 2.00 And below |
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| 1,6 |
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-2.00 to -4.00 or +2.00 to +4.00 |
-2.25 to -3.00 or +2.25 to +3.00 |
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| 1,67 |
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-4.00 to -6.00 or +4.00 to +6.00 |
-3.25 to -4.00 or +3.25 to +4.00 |
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| 1,74 | As thin as possible The best choice for super strong recipes |
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-4.25 to -6.00 or +4.25 to +6.00 |
Read more:
How to read / fill your prescription
Types of Lenses
Size
Koriki
