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Lens distance compensation

Lens distance compensation

 

An eye prescription is usually based on the corrective powers that are needed when wearing glasses. The distance between the eyes and the corrective lenses has to be taken into account since it does make a difference if the lenses are close to the eye or further away. Therefor when contact lenses are used the standard prescription has to be adjusted to the different eye-lens distance (now being nil). The same is true when using prescription diving masks lenses. In this case the eye-lens distance is longer than the average eye-lens distance with glasses (+/- 17mm). The amount of compensation depends on the additional eye-lens length and on the refractive correction needed. The higher the refractive power the more compensation is needed..

The exact amount of compensation is shown in two tables: a minus lens table and a plus lens table. The additional length X is shown in horizontal direction, the refractive powers are vertically ascending. The found compensation values should be rounded to 0.25dpt or 0.50dpt depending on the use of standard or prescription diving mask lenses.

HOWEVER: since most people (specially with higher powers) also need to see with the diving mask on above water, e.g. to orientate. Therefor we do not initially adjust our lenses to compensate for this. We make the lenses to the exact prescription you provide!

For reading lenses the compensation can be disregarded.