Sport goggles

Strongly tilted lenses

Athletic performances in all liberty

What do you have to consider by ordering strongly tilted lenses? Which side effects can be caused by using a wrong lens calculation? You find out this and even more in our new brochure "Sportsline".

The brochure contains also an example of optimised lens calculation and an overview of the range we can supply.

Normal lenses: the glasses are parallel to the frontal plan

The frames with a strong bow shape associated with strongly tilted lenses, impose to recalculate the prescription . In this type of glazing the glasses do an angle of 15 ° to 25 °. This position of the glasses in the frame  induce aberrations.

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1.Astigmatism of the oblique beams,  When the gaze is oblique to the lens, it creates an astigmatism.

2.  Rotation of the axis of the cylinder: In the oblique astigmatic corrections, the projection of the axis of the cylinder on the frontal plan induces a modification of his value.  This modification of the axis does not appear for the astigmatism to 0 and 90 °. 

3. Prismatic effect: The line of vision is not passing through the optical center of the lens,  the gap, between the line of gaze and and the line of the optical centre, create a prismatic effect.

4. Centration:  In respect to the pupillary distance measured, the centration point is shifting to the temporal side, depending of the tilted angle from the lens. This must be taken in account in the final centration of the lens.

Specific of calculation: The aberration induce by the tilted lens are compensated by a specific calculation giving the same visual comfort as with the traditional frames. The software take a great number of parameters not used in ordinary optical correction.

The following parameters have to be used: The distance between the eyes, the facet position, the frame size, the angle of the tilted lens and the optical power of the lens.