Fitting eyeglass frames begins with "Do you like the way the glasses look on your face?" If you like the way the glasses look on your face, and the frames are comfortable, then you don't need to do anything else. If the eyeglass frames are not comfortable or are slightly crooked, an optical professional can make minor adjustments to the bridge, nosepads, and temples to customize the eyewear to the uniqueness of your face. If you have a stronger prescription, we strongly recommend that you have your eyeglasses fitted by an eyecare professional.
We recommend that you visit a qualified eyecare professional to have your frames fitted properly. A proper fitting by an eyecare professional is important to ensuring the comfort of your eyewear. An optician begins by aligning and "truing" eyeglass frames, so that they are even from every angle, with the frame front slightly curved (face form) and the bottom of the frame closer to the face than the top (pantoscopic tilt). Brand new glasses are almost always aligned and trued at the factory. In the rare case in which new frames are out of alignment, the optician bends the frame into proper alignment using a combination of hands, pliers, and heating equipment (for plastic frames). The next step in the fitting process involves adjusting a "true" pair of frames for the unique characteristics of your face. Eyeglasses fit properly when they feel comfortable to the wearer, and the lenses are equidistant from the face. Once this position has been established, the optician checks to be certain the lenses are positioned in the correct spot in front of your pupil. The characteristics of your prescription determine the special details that need to be adjusted by a qualified eyecare specialist.
Multifocal lenses (progressive, bifocal, or trifocal) all have a line that divides the distance vision lens from the near vision lens. The line may be visible in the case of a bifocal, or invisible in the case of a progressive lens. The optician must determine the correct position for this line, by marking on the demo lenses the "seg" height -- the height from the bottom of the lens up to the correct position for the line. In order to determine the correct "seg" height, the optician must fit and adjust the eyeglass frames on the wearer's face. The "seg" height will be different for every pair of glasses, and can only be determined after the eyeglasses have been fit to your face by an optical professional. As a result, the seg height must be measured again for every pair of glasses. If you send us a frame with multifocal lenses in it already, we can copy the "seg" height from those lenses and make new lenses for that frame with our Replacement Lens service. You could also ask your local optician to mark your "seg" height on the demo lenses of your frame, and then send it to us. With the "seg" height marked, we will be able to make multifocal lenses for you.