Clinical Tip When fitting multifocals, especially in higher powered Rxs, although you normally place the MRPs or optical centers at unequal decentrations to agree with unequal monocular pd's, you may wish to equalize the decentration of the segs for a better cosmetic result. This will require the patient to turn his head slightly for reading if he is to have the benefit of the full width of the seg.
Clinical Tip Patients who have lost an eye tend to carry their heads turned somewhat to the side of the lost eye. This should be taken into account when measuring the monocular pd by taking the pd with a pd rule with the patient's head in its slightly turned position.
Clinical Tip When the decentration needed to meet the monocular pd requirements looks like it might be a problem, try decreasing the eyesize, using turnback temples to get the needed eyewear width. This can significantly decrease thickness and magnification problems.
Clinical Tip You can increase the effective width of both the corridor and the reading area of a progressive lens by using more illumination. This decreases the pupil sizes and increases the depth of focus of the eyes. It is a temporary measure that helps in adaptation, especially if the patient has not previously worn PAL lenses.
Clinical Tip If the frame of choice has a temple attachment at the top of the eyewire, the available range for changing the near vertex distance is twice as great as it would be if the temple attachment were halfway from the top of the lens to the bottom. This is especially important to keep in mind when fitting first-time progressive lens wearers or difficult to fit patients.
Clinical Tip It's good technique to take a careful full (i.e., binocular) distance pd, and then add the monocular pd's to be sure the total is the same as the distance pd. Remeasure as needed if the total doesn't match. In every case the separation of the distance MRPs and the patient's full pd (i.e., the sum of the distance monocular pd's) must be equal.