The American Optician

Summer 2017

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1 7 Available from your favorite laboratory. NuPolar is a registered trademark of Younger Mfg. Co. G R A Y / G R A Y P O L Y B R O W N / G R A Y P O L Y B R O W N / B R O W N P O L Y N O W AVA I L A B L E I N T H R E E C O LO R O P T I O N S Now style-conscious patients can get the gradient they want with the polarization they need! NUPOLAR GRADIENT P O L A R I Z E D L E N S E S ® for the cylinder power and axis too, as well as the add power if it's a multifocal. You'll follow the same hunting expedition for the other lens, and then you'll determine any prescribed prism, PDs, etc. Neutralizing as accurately as possible is essential for opticians, especially in those states where licensing allows opticians to make new eyeglasses for patients based on the neutralization of their current eyeglass lenses. Any inaccuracy of the neutralization procedure can lead to Rx errors, resulting in patients receiving less than perfect replacement power for their new eyeglasses. While you'll use the lensometer to verify the power accuracy of lenses you ordered for a patient's eyeglasses, and while the procedure shares some similarity with neutralization, the two tasks are critically different. Assuming your eyepiece is in focus for your eye, you'll place the eyewear on the lensometer's stage and center the right lens in front of the lens stop. So far, it's the same procedure, but here's where things take a major turn. Why? You don't need to hunt for the lens's power because you already know what it's supposed to be. How? You ordered it using the patient's prescription. You don't need to hunt for the powers because you know what they are. Instead, set the sphere power of the right eye on the lensometer's power drum, and set the axis wheel to the proper axis. Now look into the lensometer's eyepiece. If the sphere power lines are clear, the lens's sphere power is correct; if it's blurred, it's incorrect. If the prescription has cylinder, add the sphere and cylinder powers of the Rx together (you are adding signed algebraic numbers) and set this power on the lensometer's power drum. When you look into the instrument now, you should see the cylinder lines clearly if the cylinder power is correct, and you will see the cylinder lines unbroken if the axis is correct. If the cylinder lines are blurred, the cylinder power is incorrect. If the cylinder lines are broken, the cylinder axis is wrong. It's that simple. Here's a cylinder lens example . Instead of hunting like you did in the neutralization above, you're validating the lens's powers in verification…no hunting required. To say this another way, when performing lens verification, tell the lensometer what powers and axis you want by setting them on the lensometer's power drum and axis wheel, then look into the instrument to determine if you got what you ordered. In neutralization, you're asking the lensometer to tell you what powers are in the lenses. See the difference? Are you hunting and validating properly with your lensometer? Ed De Gennaro is editor emeritus for First Vision Media Group.

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