|Marco’s two top sellers, the LM-600 (left) and LM-1800 (right) can determine lens type, centration, and prism.|
|Visionix offers the VX35 lensometer which is based on wavefront technology, along with a 130-point simultaneous measurement.|
|Coburn’s Huvitz CLM4000 lensometer has auto-detect for variable focus lenses.|
|ACCOMPLISHED SYSTEMS Although some ECPs call these new lens inspection systems “computerized lensometers,” that’s not a good name for them. They do far more than just read power and prism. Lens inspection systems are designed to analyze a pair of eyeglasses, not just read their power or the power of loose lenses. These instruments take measurements for each lens but they also can tell you the prism imbalance of the mounted lenses, both horizontally and vertically. If you want that information in millimeters of error instead of prism value, no problem, simply press the appropriate button.
Some units can measure the index of refraction of the lenses and UV and HEV absorption. Some display a contour plot of the lens being read, which can be very helpful when a patient complains of not seeing well with their new lenses even though the prescription reads correctly. The print may show a corridor that’s not well aligned or too narrow, which is something you’ll never discover any other way.
The newest lensometers can accomplish many tasks; some ECPs tell us what systems they use.
Eyecare offices are reaching the point where many surfaced lenses fall into the 21st-century free-form category, but most of our verification instruments are stuck in the 20th century. How do we measure protection from UV and HEV radiation, digitally surfaced free-form lenses (both single vision and multifocal), high prism, etc.?
Categories that require verification have increased due to free-form PALs, and options like polarization, selective filtration, photochromics, and more. How do you know the lenses you ordered are right? Of course you can use your conventional lensometer but it will only be accurate to +/-0.25D. When dealing with most free-form lenses, the powers are supplied in 0.01D. The answer to this dilemma is to verify the lenses using a 21st-century lens inspection system.
YOUR LAB’S INPUT
The easy way out is to trust your lab. When you order a free-form lens, the lab will send you a printout that gives you the compensated powers. That printout is almost certainly measured with one of these devices. Those numbers may not look like the original Rx, but they will take into account the information you provided, including position-of-wear (POW) measurements. Accepting this printout is tough for some ECPs because they’ve relied on their own instrumentation and skills for so many years. But can you verify those parameters yourself with manual equipment? No.
The newest incarnation of the lensometer, known as a lens inspection system, does all of the standard power reading tasks and more. It also provides a digital power printout of the lens, along with centration, prism, and whether or not it’s a PAL, lined bifocal, or single vision lens. Due to their expense, these instruments have been primarily used by commercial labs. Now, some ECPs are taking advantage of falling prices and putting them into their practices.
To see how ECPs use this technology, I spoke to several who have this equipment. Frank Pirozzolo, OD, of South Shore Eyecare Associates, Staten Island, NY, mentions: “We have a Huvitz CLM4000 lensometer (distributed by Coburn Technologies, Inc.) and have used it for several years. We utilize it in our pre-testing area, not lab. Technicians learn it easily and I trust the instrument, but the operators have to be well trained to get prism and PDs correct. It has auto-detect for variable focus lenses, but operator technique is important too. If we were to use the Huvitz to duplicate an unknown pair of eyeglasses, we would not trust a reading done by a technician. It would go to a licensed optician and they would invariably go to our manual lensometer. The Huvitz does measure UV light transmission, but I would not say we use it for verification or marketing purposes very often.”
Dr. Pirozzolo points out another use for these instruments. Pre-test technicians may not have the lensometry skills that an optician has, and they are trying to work quickly in order to keep patient flow running on time. These instruments are perfect for that purpose, as they provide instant readouts, and little more than very basic lensometry skills are required.
Huvitz now makes an advanced version of Dr. Pirozzolo’s lensometer. The HLM-7000, also distributed by Coburn, detects progressive lenses with ease, and far or near sight addition is automatically calculated with precision and speed. It can faithfully simultaneously capture the PD of eyeglasses and the power of lenses. Prism can be displayed in rectangular coordinates, polar coordinates, or displacement from the optical center. Other standard features include exact numerical assessments, dark sunglass mode, and a built-in fast, quiet, and reliable printer.
The VX40 by Visionix, Inc. uses innovative wavefront technology to detect all of the parameters you might want to know about a lens including power (in many coordinates) and lens design. With a complete analysis using this lens inspection instrument, each point of a lens can be studied. Progressive and free-form lenses will no longer be a mystery. Since the entire lens area is studied, even free-form progressives can be compared and analyzed. It also features a unique frame/lens holder with one-hand and one-button operation.
Stanton Sessions, OD, from Monroe, WA, is very happy with his instrument. “We purchased the VX40 lens analyzer just over six months ago to use in our pre-test area. Our technicians love it better than any lensometer we have ever owned. It is amazingly easy to use and we love how it integrates with our automated refractors and EMRs. I would recommend the VX40 to anyone looking to upgrade to the latest in lens analysis technology,” he says.
Visionix also offers the VX35 lensometer, and it too is based on wavefront technology, along with a 130-point simultaneous measurement. It has the ability to measure UV transmission and automatically detects the lens type, whether PAL, single vision, or standard bifocal. The VX35 also has an integrated thermal printer and a special mode for contact lens neutralization. PDs and centration are automatically entered.
Marco offers lens inspection systems with a lot of high-tech bonuses. Its LM-600 and LM-1800 series can determine lens type, centration, and prism. Hartmann-Shack sensors detect up to 180 measuring points. They use a green light close to the ISO standard that delivers accurate measurements without having to compensate for Abbe value. They (and most others) have a tilting screen. If you’re a tech or optician using one of these instruments frequently, you’ll find that the ergonomic adjustments available with the tilt screen can make your back and neck a lot more comfortable.
Many of these lens analysis devices will connect directly to office management tools, the refraction systems you might have in place, other diagnostic equipment, and even to the finishing lab. They can also integrate with lab management software that controls everything from job entry, to frame and measurement information, and can “speak” to the edging and surfacing machines, and in some cases can even do invoices and pricing.
Lens inspection systems are like manual lensometers on steroids. Are you optically ready for the 21st century?
Sharon Leonard is a licensed optician and contact lens practitioner in the Syracuse, NY, area.
WHERE TO FIND IT:
Coburn Technologies, Inc.
800-262-8761 • coburntechnologies.com
Marco Ophthalmic, Inc.
800-874-5274 • marco.com
800-292-7468 • visionix.com