|Reichert’s AL200 autolensometer can measure 0.01D, 0.12D, and 0.25D steps in sphere and cylinder.|
Autolensometers and lens inspection systems incorporate the highest degree of automated functions.
It’s interesting to note that the lensometer (more accurately defined as a focimeter) is about 90 years old. Introduced by American Optical in 1921, the manual lensometer has changed little since its beginning. The problem with this is that lenses have changed a great deal over the last 100 years.
In addition, the industry has power and fabrication tolerances as recognized quality parameters that were initiated in the 1950s, some of which are specified in 0.01D. No manual lensometer can read more accurately than 0.12(5)D, and that accuracy depends on the ability of the operator to focus it properly and interpret its target accurately, which can be very subjective. Clearly something new needs to be added to the modern optical office in order to get it in synch with today’s lens and eyewear products. That something new is a lens inspection system.
What makes an instrument a lens inspection system? While there is no recognized definition for this, the distinctions for the purposes of this article are: the unit uses computerized measuring so the operator does not have to interpret when the focusing target is clear; and it provides features other than just power and prism reading.
LENSOMETERS ON STEROIDS
Think of a lens inspection system as your manual lensometer on steroids and you’ll have a comical but clever way of envisioning these devices. For starters, lens inspection systems have no eyepiece because they use an LCD screen to display their data.
Some of the more advanced units can determine the type of lens being read such as progressive, single vision, bifocal, and trifocal. Others determine the manufacturer on a progressive based on the engravings in the lens. Some automatically lay out and block lenses too.
Modern autolensometers don’t just measure the power of the lenses, most analyze a complete pair of glasses. This includes the dioptric power, cylinder power, axis, add power, pupillary distance, and prism (if any), while others have additional features.
|Marco’s LM-600 has card readers for wireless data transmission.|
Marco’s LM-600 and LM-600PD devices have easy-to-read color screens that display the measurements. Using Hartmann-Shack Wavefront Technology, these units are capable of handling powers up to +/-20.00D and prism of 0.0D to 17.0D horizontally and 0.0D to 20.0D vertically, in 0.01D, 0.06D, 0.12D, and 0.25D increments (as selected by the user). Try doing this accurately on your manual lensometer. Both instruments have card readers for wireless data transmission. The LM-600PD also has a PD ruler and a printer.
The EZ-200 Advance Automatic Lens Analyzer from Topcon Medical Systems uses Hartmann-Shack Wavefront Technology to read 108 data points on each lens. According to Topcon, the instrument is not a lensometer for a final prescription but rather a lensometer for a quick and easy screening, perfect for the front desk. After placing eyeglasses into the EZ-200 Advance, press a button and it automatically positions, aligns, and measures the eyeglasses while displaying the required data. If you’re measuring a progressive addition lens, it will show the progressive map too. The EZ-200 Advance also connects to your EMR (electronic medical records) software and the Topcon CV-5000 Automated Refraction System.
CBD/TOMEY’s TL-5000 and Reichert Technologies, Inc.’s AL200 and AL500 autolensometers are capable of measuring 0.01D, 0.12D, and 0.25D steps in sphere and cylinder. The TL-5000 features an automatically locking table when the optical center is found. This can increase the accuracy of cylinder readings and determining prism. The unit can measure the amount of ultra-violet transmitted through a lens while reading its power. Large optical frames, such as high-curved sunglasses, are also supported.
The HLM 7000 from USOphthalmic has an adjustable tilting LCD screen that can be angled for easy viewing. The diopter power range is from +20.00D to -25.00D and can read up to 10 prism diopters.
LENS INSPECTION SYSTEMS
|PRINT IT OUT A feature such as a built-in printer saves the time needed to write down an Rx that has been neutralized. Having a built-in printer avoids potential errors in writing or reading a technician’s handwriting. It also provides paper documentation of the Rx for the job tray and/or for the patient’s record, or for a doctor who wants to see evidence of a lens’ accuracy if a patient complains of not seeing well with her new glasses.|
If you have a busy practice, an auto-blocking system can save a lot of time by automatically aligning the axis of a lens and orienting it for blocking for single vision, segmented multifocals, and progressive lenses. By automatically determining the manufacturer’s markings on progressive lenses, you don’t have to either add marks or reapply those marks. And with today’s ultra-slippery coatings, reapplying these marks can sometimes be tricky. Because there is less chance of human error by handling, there is also less chance of spoilage—either by scratching or blocking them off-axis.
Gerber Coburn’s new Verifier Pro Turbo is built for high-speed lab production. It is fast and accurate while reducing operator skill and labor costs. According to the company, this machine will virtually eliminate blocking errors and breakages. The Verifier Pro Turbo automatically centers and blocks most single vision, bifocal lenses, and progressive lenses in an average of 40 seconds without a lensometer and without any parallax error. The investment will pay for itself in as little as one year, says the company.
WHICH ONE SHOULD I GET?
So which kind do you really need, an autolensometer or a lens inspection system? It depends on the level of automation you want. Some questions to ask are: How much convenience do you need? Do you require a printout? How proficient is your staff with your current lensometer? Do you want to transmit results directly to the phoropter? Should results be transmitted to your EMR? Do you have a lot of turnover? Do you want the unit to lay out and block lenses for your lab? Does your practice do a lot of prism work? The answers to these questions will guide your decision.
You trade in your car every five years and get a new cell phone every two years. Shouldn’t that same kind of “upgrading” logic apply to your lensometer? After over 90 years of the same lensometer technology, it’s time for a change.
Kenneth N. Johnson is the Optical Manager at Professional Eyecare in Waterford CT.
WHERE TO FIND IT
888-449-4045 • tomeyusa.com
800-843-1479 • gerbercoburn.com
800-874-5274 • marco.com
Reichert Technologies, Inc.
888-849-8955 • reichert.com
Topcon Medical Systems
800-223-1130 • topconmedical.com
888-334-4640 • usophthalmic.com