Getting Adjusted—Part 2

By Andrew Bruce, ABOM

In Part 1 of “Getting Adjusted” we reviewed pre-fitting the frame prior to taking segment and O.C. height measurements, the effects of pantoscopic, “standard alignment” and the “table-top test.” We described the delivery of finished eyewear, vertex distance and its effect on effective lens power, nose pads adjustment, and how to adjust for tilted frame fronts. See the January issue of 20/20 Magazine. In Part 2 we will discuss tilt and its importance on quality vision; address hori zontal misalignment; review the “fitting triangle” and three point touch. Frame fitting pearls; temple shortening and the results of a survey of what patients expect from their opti cian round out this course.

Here’s the scene: The lab has returned the patient’s new eyewear and you sit before the patient ready to dispense the glasses. The nose pads are sitting well on the bridge and the frame front has been made level.

Pantoscopic Tilt — Check the amount of pantoscopic tilt applied—as mentioned earlier, it should be between 5 and 15 degrees. Have the patient turn their head so the angle of tilt can be evaluated from the side. For most lenses, the need to precisely measure the pantoscopic angle rarely presents itself. However, for new personalized lenses, there are PD rulers and gauges that display protrac tor markings or have a needle device that points to a particular angle. The new personalized freeform lenses do require vertex, tilt and faceform mea surements so get ready.

Become familiar with the visual appearance of angles between 5 and 15 degrees (Figure 1). This allows the optician to estimate the angle required when the patient is wearing the frame.

This is especially important with a bifocal or progressive, making sure the segment is in the correct position when looking down to read. If there is an insufficient amount of pantoscopic tilt, the patient can be look ing under the frame or, at least, the field-of-view for near work will be narrowed due to the increased vertex distance between the eye and the segment. This is also referred to as the “keyhole effect.”

As the eye rotates along the vertical axis, to look up or down to read, the tilt of the frame maintains equal distances between the lens and eye maximizing fields-of-view, ensur ing the optical axis of the lens passes through the center of rotation of the eye to maximize visual comfort.

When changing pantoscopic tilt, use the wide-jaw angling pliers to change the angle of the temples while bracing the frame front with a sepa rate pair of pliers. Carefully apply force in the direction needed. This is especially important when handling three-piece rim less mountings. Protect the lens from the force necessary to change the tilt (Figure 2) with bracing pliers such as the “three-piece adjusting pliers.”

Vertex Distance— Lenses should appear equidistant to each eye. With the patient seated and tilting their chin down, observe the frame front from above by standing and looking down. If one lens appears closer to the eye than the other, the fitting error may be due to the temples being at unequal angles to the frame front from the endpiece, when extending backwards. On the other hand, the patient’s eyes may simply be more inset on one side than the other (Figure 3).

Whichever lens is closer to the eye, the same side temple needs to be brought clos er to the head. Reduce the horizontal angle between the frame front and the temple using a pair of flat/round metal pliers at the end piece (Figure 4).

Conversely, increasing the horizontal angle between the frame front and the tem ple of the opposite side is also an option, effectively moving the temple away from the head. The same way pantoscopic tilt affects the vertical placement of the lens optical center, face form— positive or negative—will also affect the horizontal placement of the lens optical center.

However, it is NOT recommended to compensate for face form by ordering an incorrect PD. It will create lateral prism. On occasion, patients’ glasses will get out of adjustment due to wear and tear, and the patient resorts to bending them—adding face form. The patient then adapts to look ing through their lenses this way and when receiving new glasses, may complain about the difference in the PD and its effects on vision. Some adjustment and period of adaptation may be necessary to make the patient comfortable while the optician works with the patient to get back to the way their eyewear should fit. Applying positive face form so the frame follows the natural curve of the face is a good rule of thumb, thus minimizing visual problems for the patient as their eyes move laterally (Figure 5).

THE FITTING TRIANGLE

The frame should touch at only three points, which form “the fitting triangle”— the nose, and the top of each ear. If the frame is touching the head at other plac es, the frame selected may be too small for the patient.

Temples leave “rail-road tracks” (impres sions of the temples) along the sides of the head toward the ears; this will actually force the frame to slide forward. Try spreading the temples out horizontally away from the frame front at the end piece; again for metal frames use a flat/round metal plier. With zyl frames, heat up the frame at the end piece and apply pressure using the hands to increase the horizontal angle between the temple and frame front equally on both sides. Then using eye-wire shaping pliers (or well-trained fingers) with the concave side facing toward the inside (Figure 6), apply a gentle curve to the tem ples so they are not in contact with the head. With zyl temples, heating may be necessary to permit this manipulation. Try for touch only at the top of the ear.

BEHIND THE EARS

When adjusting behind the ears, the temple should curve just above the ears and follow the line of the back of the ear. Temple bending pliers can be used or welltrained fingers (Figure 7). It should be at an angle of approximately 45 degrees from the temple bend at the crest of the ear and it should not put excessive pressure on the back or top of the ear (Figure 8).

If the bend begins too soon before the crest of the ear, it will rub and irritate the top of the ear. It will also cause the temples to rise up from the ears adding tilt to the frame front. If the bend begins after the top of the ear, the temple will either not conform to the curve of the ear or it will need to be bent at a greater angle than 45 degrees and the tip will rub and irritate the back of the ear. The glasses will also slide down the nose.

When adjusting temples, be careful to be aware of the mastoid process. This is a bone that protrudes from the skull, behind the ear; in some patients it is more prominent than others. If the temple tip rubs against the mastoid process, it can cause serious discomfort so should be avoided. Regardless of the optician’s skill level, a visual inspection of the temples behind the ears should always be done to ensure optimum comfort for the patient.

Prior to checking behind the ears for fit, always ask the patient for permission. Some patients are uncomfortable with an invasion of their personal space. If the patient is a minor, always check with the parent. When checking behind the ears, look for white pressure points where the temple tip is touching the head and ear. If present, adjust the temple tip away from the pressure points until resolved. The temple bend should also follow the line of the side of the head. In order to do this the tip will need some angling in toward the head.

Be sure the bend point of the temple is NOT the only part of the temple touching the head behind the ear leaving a space at the bottom between the head and temple tip. Conversely, the temple should not just be touching the head with the lower tip of the temple creating a space between the head and the temple at the top of the ear. In the first instance, if the temple is in contact with the head only at the bend at the top of the ear, adjust the temple tip so that it angles in toward the head just enough to gently touch. In the second, if there is a space between the temple and head at the bend, the tip is angled in toward the head an excessive amount; adjust the temple tip away from the head so it is bending in less.

Occasionally, in this case, the temple itself may need angling “in” a little at the end piece. A flat/round metal plier can be used with a metal frame to reduce the horizontal angle between the temple and frame front, in order to provide a snug fit. Heat and pressure using the thumbs, or a tabletop, at the end piece may need to be used with a zyl frame to obtain the same result. The more touch, the more friction and the better the temples will do the job i.e., hold the glasses in place.

TEMPLE LENGTH

Although temple length should be evaluated as a part of the initial frame selection, sometimes a frame may be selected that does not offer the option of an alternate temple length. Although patients may not express a concern if a temple is a little short, extending the temple bend backwards toward the end may provide an acceptable fit. Be sure that there is enough touch to provide good frame stability. If the temple is too long, however, most patients will be unhappy with an inch or more of the temple sticking out below their ear. Once again, don’t settle for second best—take care of every detail.

If the standard temple is metal with slipon covers as temple tips, it can often be easily modified to accommodate the need for longer or shorter, temples. In the case where the standard temple is too short, straighten the temple out and simply slide the tip cover off about 5mm and then readjust the bend. If the standard temple is too long, straighten the temple out and completely remove the tip cover. Using a pair of cutting pliers (Figure 9), shorten the metal temple core by 5mm to 10mm, slip the tip cover back on and reapply the bend. Some metal temples have a different shape or form beyond the tip cover so it may also be necessary to modify the tip cover by shortening it by the same amount as the temple. Using a file or fine emery paper, smooth the rough tip of the core and the left over rough edges of the tip cover before sliding on the temple cover.

Often polishing the cover opening helps reduce any roughness that might irritate the ear and get caught in the patient’s hair. Re-adjust the bend and repeat as needed until the required length is determined. Initially, this may take some time to perfect, but with practice you will become skilled in determining the shortening required.

Unfortunately, this is more complex with zyl temples and often not possible since zyl has a metal core that may protrude from the end once cut. While modifications can occasionally be done, it is often best to discourage zyl frames with inappropriate temple lengths. Most metal temples can also be modified to accommodate cable temple tips, if beneficial for the patient, by using a similar procedure as described above. Specific directions on temple modifications can be found in “System for Ophthalmic Dispensing” 3rd edition by C.W. Brooks, an excellent reference for opticians of all levels.

HOW IMPORTANT ARE ADJUSTMENTS

In order to determine what patients expect the most from opticians, 100 patients were randomly surveyed over a two-month period in a private, three-doctor optometric office.

On a scale of 1 to 5, (1 = “Not at all,” 5 =“The most important”) patients were asked How important is it to you that your optician is:

• Knowledgeable
• Friendly
• Able to fit your glasses well
• Able to select a good choice of frame

The results of the survey were:

• 93 percent of the patients consider being able to fit glasses well as their most important need from their optician.
• 73 percent of the patients indicated their greatest frustration with previous eyewear was that the eyewear was poorly fit and uncomfortable.

This strongly suggests that opticians need to be skilled in the art of eyewear adjusting and fitting, and patient comfort is the key to happier patients.

CONCLUSION

The optician’s major role, although highly technical, is to use their skills and expertise to ensure patient comfort and satisfaction with their eyewear. Taking the extra steps at the time of dispensing will result in less time spent re-adjusting glasses because the patient has to return due to a poor initial fitting. It also ensures less inconvenience for a patient having to return to have done what should have been done in the first place.

Most importantly, having the patient leave the office totally satisfied with ALL of the services they received—having the utmost confidence in the entire staff and their abilities, and excited to tell others about their wonderful experience and show off their new eyewear that they will enjoy wearing for many years to come.