Contact Lens Prescriptions
Posted at November 10, 2017 | by Lucas Fratzke | in Guides

You thought only eyeglasses prescriptions had weird and scary numbers? Think again!

Though one would not be faulted for thinking so, prescriptions for eyeglasses and contact lenses, though they contain a few of the same components, are actually quite different. Here’s how.

To start off, the same Latin categories are used for contact lenses as in eyeglasses: ‘OD’or oculus dexter translates to ‘right eye’ and ‘OS’ or oculus sinister translates to left eye. On your prescription sheet, however, do not be confused by the fact that the column for your right eye in on the left and the column for your left eye is on your right. The prescriptions are written from the perspective of the doctor looking at you, thus the two categories are flipped.

The first row, power (PWR), corresponds to the amount in diopters of correction the lens must provide each eye to correct your vision back to 20/20. As it was with the eyeglasses prescription, a positive number (+) corrects for farsightedness and a negative number (-) corrects for nearsightedness. If you need clarification on what nearsightedness and farsightedness is, click here (insert link to other article).

Base curve (BC) simply refers to the amount of back curvature in the contact lens in millimeters; the lower the number, the steeper the curve.

Diameter (DIA) corresponds to the measure from one end of the contact to the other, its diameter, in millimeters.

Cylinder (CYL) and Axis (AXIS) will only have values if you have astigmatism in either eye (read more about those here- and put a link to the eyeglasses prescription article) and the ADD category refers to added magnifying power for bifocal contact lenses, though at the moment Dualens does not offer contact lenses with either of those options.

Lastly, the color and brand refer to which color and brand, if any, you decided on buying with your eye doctor.

No matter your prescription, at Dualens we have a wide-ranging variety of affordable colors, sizes, and brands to fit all of your contact lens requirements.