High Time for High Index
Timely tips on what makes high index tick
By Karlen McLean, ABOC, NCLC

The keys to this market include knowing who will be happy in indices higher than 1.58 and spreading the word on the product's benefits. Consider the following ways to get the clock ticking on HI in your dispensary.

WHO SHOULD WEAR HI

Two factors are considered when Edward Hanford, LDO, manager of Cohen's Fashion Optical in Boca Raton, Fla., selects a candidate for high index lenses: Rx and frame size.

"I'll go into high index for Rxs over 4.00D," he says. "But, I also recommend high index in Rxs 3.00D and under in larger frames—say anything in a 62 eye size and over."

High index also can serve as a high end lens option. "We position high index as our best lens. We recommend it for high minus Rxs, and stay with high index if patients are already wearing it," says Ginny Dzengeleski, an optician at Gary Deo's optometry practice in Saline, Mich.

For first-time high index wearers, discuss features and benefits in detail and always show patients comparative demos of all types of lenses, including standard plastic, polycarbonate, and high index.

WHO SHOULDN'T WEAR HI

While high index lenses are rapidly becoming a lens of choice, they're not for everyone. With an Rx of less than 2.50D, it's hard to see the benefits of a thinner, lighter lens, especially in small frames.

Historically, styles such as rimless and wraps were not well suited to high index, although some manufacturers are currently formulating materials for rimless.

"We use high index with both semi-rimless and drilled rimless. I explain that high index isn't as strong as polycarbonate, but that it's still stronger and more stable than regular plastic, with a slimmer, more attractive appearance," Hanford says.

Those who tend to turn their eyes instead of turning their heads when viewing objects will be more aware of chromatic aberration in the HI lens periphery.

Also, hypersensitive patients who notice every nanometer of their eyewear and have difficulty adjusting to every change may not be ideal candidates for high index lenses.

	Show patients the thinner, lighter design of high index compared to standard lenses. Image courtesy of Seiko Optical Products

FIT WITH CARE

Frame selection, proper measuring, and clear communication are key in successfully introducing patients to high index. Small frames that align the center of the lens with the optical center of the eye help maximize the optics and appearance of HI lenses.

When fitting HI lenses, Hanford measures the patient's monocular PD, takes the frame PD, and checks decentration. "I also measure optical centers, especially in a 4.00D and over Rx. And, I'll try to match the base curve the patient is wearing, if at all possible," he adds.

For the best fit, set up the frame with a pantoscopic tilt of 10 to 15 degrees before presenting it to the patient. "In particular with high index, we pre-adjust the frame and are very precise when taking monocular PD measurements and the OC measurements," Dzengeleski says.

When verifying a HI Rx, remember that some automatic lensometers are set with particular reference wavelengths. This can cause varied readings from a standard plastic lens to other lenses, including HI. Check the lensometer wavelength setting to be sure it's calibrated to the U.S. standard Helium D-Line setting.

During the fitting process, discuss magnification and minification in lens appearance and, sometimes, in viewing objects. Assure patients that this slight change is actually more like true natural vision, and they'll appreciate it quickly.

Aspheric and atoric designs correct the spherical and cylindrical optical errors found in ophthalmic lenses. Shown here are non aspheric on the left and aspheric/atoric on the right. Image courtesy of Optima

OPT FOR AR

While glass or plastic lenses block around eight percent of light entering the eye, HI lenses can block 10 to 12 percent of that light. AR dramatically increases visual performance on high index lenses, allowing light transmittance of 99.5 percent.

AR helps stop backside and front surface reflections, and virtually eliminates visual distortions caused by flatter HI curves and chromatic aberration. Many manufacturers produce HI only with AR; it comes that way from the factory.

Most ECPs only dispense HI with AR—making it a practice policy—taking optics and appearance into consideration.

"We always sell high index with AR," Dzengeleski says.

Most HI lenses also feature scratch resistance and ultraviolet protection and are available in photochromic, sunlens, and multiple lens designs like PALs, resulting in a premium lens that has it all.

TRAIN YOUR STAFF

Gary Deo, OD, says a smart staff with staying power is the key to dispensing success, especially when working with premium products such as high index.

"My staff stays up-to-date with the latest lens technology, and they know when and when not to fit certain products. We also control the pace in the office so that my staff and I have time to interact with patients and effectively explain all their options to them, including high index lenses."

Always try to consider all of the angles when it comes to staying informed about high index. Dzengeleski notes that the practice's lab is a partner in the high index selection process: "Our lab is also an integral part of our lens dispensing; we can rely on them to suggest whether a mid index or high index lens would be best for particular patient needs."

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