L&T: RxPertise


Eye’d Like to Solve the Puzzle

Lenses just keep getting better and better. Although this is good news, the problem surrounding this advance in technology is the tendency to allow critical fitting to become lax due to the perception that as lens designs get better and more forgiving, errors in measurement are not as important. This perception is, of course, wrong and it must be addressed to assure the integrity of digital performance.

The best lens technology relies upon the eyecare professional’s ability to fit it on the patient. Fitting includes everything from positioning the patient’s perception of the new product by how it is demonstrated at the time of sale through all the standard pupillary and height measurements and ultimately to the adjustment of the finished product. The fact remains that a bifocal is more difficult to fit than single vision, a trifocal more difficult than bifocal and progressive more difficult than a trifocal. This same hierarchy of need applies to each new advanced digital design.

The fitting challenge is the ability to view and execute the entire process of presenting, measuring and delivering a digital lens with the greatest accuracy at every step. Digital technology can be compromised if the patient’s perception of the end product is unrealistic, if precision surfaces are not properly ground or if frames and lenses are not accurately aligned.

When dealing with the very newest technology it is important to get inside of the patient’s perception in order to energize and excite them as to the importance of their choice. Proper positioning and presenting will establish the backdrop of how the “new and different” will become  the “better.”

Measurements for this new product must be conducted with as much precision in, as we have promised that the new lenses will deliver performance out.

Final fitting must exceed the nose pad, temple bend procedures of the past. After positioning and adjusting, the fitting challenge requires a verification that the performance promised will be the performance delivered.

Focusing on Benefits
Sharp natural vision is the ultimate goal of professionals and patients alike. Clearly, a digitally surfaced lens represents the highest evolution of our ability to correct the eye and provide the best vision. As professionals, we know the facts, but the issue as always, is the difficulty of presenting extreme technology to the understanding of the eyewear consumer. Begin at the beginning, you are the lightning rod of any presentation. Show your enthusiasm, you are the expert—tell the patient that you, your doctor and staff have chosen this lens for their personal use.

Let the patient know you are excited about the great feedback you are getting from other patients who wear the lens. How the lenses work is interesting to some, but the fact that the lenses do work is interesting and most pleasing to all.
Don’t draw the famous progressive circle and squiggly lines to represent the advanced surface. You don’t sell a Ferrari by drawing a picture of a roller skate. You sell a Ferrari—or anything for that matter—by letting the consumer know what that something will do for them. In the case of a digitally surfaced lens versus a traditional lens let the customer know what they will experience: 

  • An increase in contrast sensitivity resulting in a more accurate duplication of the visual performance achieved during the eye exam. 
  • The benefit of the first time ever control of the coma aberration, allowing for sharper distance and improved night vision that is superior to all other lenses.
  • An optimized edge to edge performance that goes beyond the peripheral limits of traditional lenses.

A great first step in selling digital lenses is to use the analogy of the performance difference between regular and high-definition television. Most patients will relate since they have already “experienced” the difference. The television gives you great clarity within the confines of a rectangular box, but digitally surfaced lenses will give you great clarity in all that you see… priceless.

Measuring Up
To assure the greatest degree of ease and accuracy, monocular measurements should be taken with a device such as the Corneal Reflex Pupillometer. This instrument enables the dispenser, with a single procedure, to measure both the binocular and monocular pupillary distances. Attaining both measurements is important to assure accuracy since one can be used to verify the other. The monocular distance when added together must equal the binocular distance. If for some reason there is a discrepancy between the two readings, new measurements should be taken.

A simple and accurate technique for obtaining fitting heights involves the use of the demo lens or if the frame is lacking one, transparent tape, a felt tipped marker and a pen light. The transparent tape should be affixed in a vertical direction to the properly sized and fitted frame.

Before making a final measurement it is important to verify that the frame, as fitted, will be the way the person normally wears it. It does no good to fit in a clinically perfect manner if the patient has habits or idiosyncrasies that will result in the frame being worn differently than how it was measured.

Progressive measurements work best when they capture natural head posture. Unfortunately the process of getting the marking in the proper wearing position is complicated by the fact that sticking a marking pen into someone’s lens while they are wearing it is often awkward and unnatural to the wearer. Telling someone to “just be natural” while you get the measurement is too artificial to be effective.
The best approach uses a bit of the magician’s misdirection in order to get the job done quickly before the patient has too much time to think about what “natural” really is. The technique is known as the “Look Up, Look Down, Look at Me” approach. With the frame fitted to replicate real wear, the dispenser avoids telegraphing the final mark-up by telling the patient to “look at the ceiling for a three count, the floor for a three count, then look at me.” Usually the point at which the patient returns his view to the dispenser is a natural position. We should then, as in taking a PD, position ourselves on an equal level and directly across from the patient.

Directing our pen light from our left eye to their right eye and vice versa will create a reflex of light on the patient’s mid-pupil. We should then mark with our pen the point where the reflex shines through the tape. A measurement from our marked reflex dot to the lowest portion of the frame will give us the correct fitting height. A quick dot at this point will locate the most natural position for normal viewing.

Delivering the Fit
If care has been taken in properly presenting the lenses and measuring them for accuracy the patient will have expectations of performance upon delivery. Keep in mind that an improper adjustment could easily undo all the good that has preceded it. Presentation and measurement point to potential, but only proper alignment will insure the performance that we promised and the patient expects.
As lens fitters it is important to note a frame and lens that fits closely will keep the patient’s view in the central area of the lens. This centering of vision will improve visual performance by keeping the wearer’s view away from the peripheral areas that are more likely to present visual issues due to the higher concentrations of lens aberrations. By keeping the lenses close to the face, distance swim is minimized and the width of both near and intermediate areas will be maximized.

Perhaps the easiest way to explain the advantages of a close fit to the patient is to refer to the analogy of the boy, the ballgame and the fence:

A young man wanted to see a game but didn’t have enough money for a ticket. Someone told him there was a knothole in the left field fence, so if he wanted to he could watch the game for free back there. Upon finding the hole the boy stood back about a foot away and was disappointed that he really saw more of the fence than the game. He was then told to step forward and put his eye right up against the knothole where to his great joy the fence disappeared and he was able to see the whole field.

In the case of lenses the central viewing zone (the clearest area of sight) is like the hole and the peripheral area of the lens, which lacks great clarity, is like the fence. In the case of lenses we don’t ask the patient to step up to the central viewing zone, we merely position the lens to naturally perform by resting close to the eye. The way we achieve this by adjustments is through a snug fit with a viewing distance properly adjusted through the use of face form and pantoscopic tilt.

Face Form
Since the eyes are generally recessed from the tip of the bridge, a front that is gently curved around the face will maximize the close fit needed for optimum vision. A flatly fitted front creates a variation of vertex as the eye scans from optical center to the outside perimeter of the lens. This variation in vertex could at times create visual discomfort. In addition to vertex problems, a flatly fitted front could allow more light to reflect off the back surface creating annoying spectral images. On the other hand if there is too much curve built into the front this excessive tilt could cause power errors in the prescription, as well as the creation of unwanted cylinder in the intermediate and near areas of the lens.

Pantoscopic Angle
After the horizontal face form is set we should turn our attention to the vertical consideration of pantoscopic/retroscopic angle. Achieving the correct vertical angle will again maximize and assure the best possible vision. Pantoscopic tilt is achieved by angling the bottom rim of the frame front in towards the face while retroscopic tilt is achieved by angling the bottom rim of the frame front away from the face. Pantoscopic tilt is most always recommended since it helps achieve a close fit by balancing the vertex in the 90 degree meridian. In addition, proper pantoscopic tilt will help maximize the amount of bridge surface resting on the nose. Retroscopic may at times be needed to maximize the amount of bridge surface touching the nose, but generally the purpose of retroscopic is to remove the lower rim of the frame from a protruding cheek.

Upon concluding all the steps of the fitting challenge a positive affirmation of the patient’s choice will go far toward providing long term success. Assure the patient they made a wise decision in selecting the new product and will no doubt get many compliments on their new glasses. Follow up phone calls to check a patient’s progress will serve to show our sincerity as we diffuse their anxiety. Definitely lose the famous negative line, “If you have any problems please come back.’’ Try instead, “You made a great choice, I’m sure that you are going to love them.’’

The fitting challenge goes beyond a PD ruler, pen and pliers, as it begins with your desire to provide the very best product in the most precise manner that will assure the delivery of performance. It only ends with the patient’s enthusiastic affirmation that their new lenses work great.

Michael DiSanto is an independant industry trainer.