Compensated lens designs have improved the ability of the laboratory and optician to tailor lenses for each patient and frame. Due to many of our accounts using compensated designs for the first time we want to talk about what is going on and what to expect.
Compensated designs take into account how the frame and lenses sit on a patients face, and this nearly always differs from the angle of a phoropter the doctor uses. Due to this, we need to consider the differences and make changes to the refracted prescription so that the patient receives non-distorted vision.
The measurements used to calculate the differences are called position of wear measurements (POW). They typically include pantoscoptic tilt, frame wrap angle, back vertex distance, and sometimes near working distance.
To improve a patient’s vision with compensated lens designs the optician does not need to take the additional position of wear measurements, but if done, will produce an even more most accurate pair of lenses.
Some designs, like as our IOT Universal progressive use default values for pantoscopic tilt, vertex, and frame wrap that is closer to the actual measurements vs the refracted prescription. So even though the POW measurements weren’t done the result is a more accurate lens.
When ordering a compensated (most digital lens designs) lens, make sure that you check the prescription measured in a lensometer against the bold values next to the ordered prescription. This is the compensated prescription cut into the lens for best visual acuity.
