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Working the Angles

Karlen McLean, ABOC, NCLC

There's more to pantoscopic angle (panto) and retroscopic tilt (retro) than just the angle and tilt of the frame front as determined by temple adjustment. Understanding this can help you both troubleshoot and lower remakes.

It took me awhile to be an angle expert. One early experience taught me how to handle retro. The frame was bench aligned—set to standards—but my patient's ears were very low set. The top of the frame rested against the brow and the bottom fit far away from his cheeks. My manager intervened and taught me to angle both temples incrementally downward to reach the correct pantoscopic angle of eight to 12 degrees. My patient appreciated the time and care my manager and I put in to ensure a proper fit.

PANTO POINTERS

The first rule of thumb: slow down! Next, consider the following pointers that I learned the hard way.

■ ALL EARS. A bench alignment typically places a frame's pantoscopic angle between eight and 12 degrees. But some patients have low- or high-set ears, or, more often, one ear higher than the other.

Low-set ears require a retroscopic tilt, with both temples angled downward. High-set ears require more of a pantoscopic angle with both temples angled upward. For patients with uneven ears, the tilt must be aligned with the ears, not a table. Explain to these patients that their eyewear is adjusted to fit them and not to worry if it sits unevenly on a flat surface.

■ VERTICAL PLANE. When panto is induced, sphere power is increased and cylinder power is introduced. Increasing panto lowers the top of a multifocal or PAL segment, and adding retro works the opposite way. Always follow manufacturers' directions for PAL panto/retro degree. A standard (eight to 12 degree) panto can equal three to eight degrees with a lower-set endpiece and five to seven degrees (12 total) with a higher-set endpiece.

■ ALWAYS CHECK. Every frame, whether pre-dispensing or in for adjustment, should have panto and retro checked. It's most important to double-check them when patients complain of blurred viewing. A simple adjustment may fix it. Use two pliers, an angling plier, and a cushioned parallel-jaw one to bend the hinges (NOT the temples). EB

Senior editor Karlen McLean has been in the optical industry for 35 years. She has spent half of that time in the dispensary. In this monthly column, Karlen shares her own experiences, and hopes you'll share yours. Contact her via email at Karlen.McLean@wolterskluwer.com or online at facebook.com/eyecarebusiness.