As every eyecare professional (ECP) knows, lensometry is the backbone of lens inspection.

With the advancements in lens technology and designs, instrument manufacturers have upgraded the basic lensometer with computer software, graphics and the ability to read lens powers within 0.01D, a critical capability when modern digital/free-form lenses are involved. In addition, modern lensometers can be linked to printers to document test results and be interfaced with other instrumentation, building a cohesive layer of technology in the modern dispensary.

The lensometer is used by opticians/technicians to perform a number of critical tasks in the dispensary, including:

• neutralization to determine unknown lens powers

• verification of known lens powers

• orientation of uncut lenses prior to the edging process

• detection of unwanted prism and/or verification of prescribed prism in an Rx

A prime example of modern lensometer technology is the VISULENS 500 from Carl Zeiss Meditec. The unit has the capability to inspect single vision, multifocals and progressive lenses. Additional capabilities include reading tinted lenses and UV transmission levels using four different wavelengths (365, 375, 395 and 405 nanometers). For the ECP who fits contact lenses, the ZEISS VISULENS 500 has a mode for soft and hard lens power verification.

Furthermore, the unit can effectivily “read” a wide variety of lens materials and indices without the ECP having to take into account the Abbe value in the dioptric measurements. Operator comfort and efficiency are taken into account with a large 5.7-in. display screen (adjustable), featuring a large target and reticle with numeric readouts reporting sphere, cylinder, axis, add powers and prism values.

Operator controls are easy to see and allow for switching modes, right to left lens, and PD measurements. Results can be documented via an internal printer within the instrument, sent to a remote device utilizing a RS 232 cable link or with a PDF report in the ZEISS FORUM data management system using the ZEISS connectivity accessory VISUCONNECT 500.

The Marco LM 1800PD is a valuable tool in the ECP’s arsenal of instrumentation. Faster acquisition of measurements and functionality make this unit a pleasure to use. Accuracy is achieved by the use of Hartmann-Shack wavefront technology with 108 sensors recording information. Sensors detect high-index lenses and progressives. UV light transmission values can be detected and recorded in addition to the amount of green light transmittance. The LM 1800PD can read lens powers of sphere from -25.00D to +25.00D and cylinder from plano to 10.00D in = or – form.

Furthermore, prism can be noted up to 20^, and the instrument has a prism layout mode for dispensaries with finishing labs. The LM 1800PD has a lens marking system that can mark lenses with water repellant lens finishes. Operator friendly, the unit utilizes a 5.7-in. LCD monitor and touch screen display that can be accessed by the technician either sitting or standing. Job/Rx data can be verified using the printer option or transferred via “Smart” IC card and Ethernet interface.

The new HLM-1 from Coburn uses Wavefront Analysis Technology with more measurement points than previous generations. The HLM-1 has a processing speed per frame of 65 ms with an expanded prism range, and it easily measures dark tinted or mirrored sunglasses by automatically amplifying the amount of light and calculating its refractive power.

The Tomey-7000/ TL-6000 instruments use Hartmann sensor wavefront technology in the determining dioptric lens powers. These 117 points also increase measurement accuracy with narrow corridor progressive lenses. To further assist the technician in lens inspection, the Tomey -7000/TL6000 encompasses grid patterns on the LCD screen to help locate critical lens markings for proper orientation.

In addition, the grid patterns are selectable to further assist in lens orientation. Peak wavelengths of UV light of 375nm and blue light of 465nm are easily detected and documented. Exclusive to the TL-7000 is a power mapping procedure utilizing the PD and L value in lens computations.

Inspection results are reported by the instrument in several ways: Visually, with a 7-in.-wide color touch panel and a built-in thermal printer generating a 58mm wide print out, or electronically, via external ports RS-232C,USB3.0, Ethernet.

The Topcon CL-300 auto lensometer is packed with features in a slim-body ergonomically designed package. Diopter measurements are obtained using a Green Light/E line process at 546nm to reduce the chances for error in lens measurements. UV measurements are also accurately reported for either dress or dark sunglass eyewear. The lens stop/support extends 6mm in height over comparable models, allowing the technician to check high minus lens powers much easier without scratching lens surfaces.

The 5.7-in. color LCD screen allows a 160˚ viewing angle to accommodate the height of different technicians. Furthermore, the rich color graphics allow the technician to readily distinguish between various single vision, multifocal and progressive lens designs. The Topcon CL-300 uses a unique white ink cartridge that enables the technician to mark/spot lenses that have various anti-stain/fog surfaces.

The Topcon CL-300 is an excellent addition to the dispensary lab with its simplicity for lens layout. The process involves four steps consisting of frame placement and three color-coded steps involving optical center placement, alignment verification and marking. Reporting of findings is accomplished by a thermal paper printer with an easy load feature or electronic transfer utilizing external interfaces RS-232C, or LAN.

Today’s modern auto lensometers are much more simple to operate due to computer controls and functionality. This translates to more productive technicians with less training time and more accurate, reproducible findings. Finally, these instruments can function as a standalone instrument or be linked to a system of technology that not only serves the dispensary but the doctors’ office as well.

Richard W. McCoy, BA, LDO, ABOC, NCLEC, is the head of the opticianry program at Reynolds Community College in Richmond, VA.

WHERE TO FIND IT: Carl Zeiss Meditec, Inc. 800.342.9821 • Meditec.Zeiss.com/USA // Marco 800.874.5274 • Marco.com // Tomey 888.449.4045 • 
TomeyUSA.com // Topcon Medical Systems, Inc. 800.223.1130 • TopconMedical.com // Coburn Technologies, Inc. 800.262.8761 • CoburnTechnologies.com •


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