Tuesday, August 26, 2014 11:00 AM
The Opticians Handbook received this question about a prism Rx for a patient experiencing vertigo:
"I recently got a prescription where the doctor asked for 1.5 degrees of prism base down at axis 255 right and 1.5 degree base down in the left at axis 255. What should I order? The doctor told me to order 1.1 base down with 0.50 Base Out right and 1.1 Base Down with 0.50 Base In."
Wednesday, August 20, 2014 1:30 PM
Lou Holtz is a famous football coach and a master motivational speaker. I wonder how he would coach American opticians to prepare for the future.
Monday, August 04, 2014 11:00 AM
In 1972, President Nixon signed into law what is referred to today as the "FDA Impact regulation." This regulation, otherwise known as Title 21 CFR 801.410, has continues to influence our industry to this day.
Tuesday, June 10, 2014 3:00 PM
In a previous Opticians Handbook article, I gave a
of the evolution of the ANSI Z80.1 standard and how it has changed over time.
Wednesday, May 21, 2014 11:00 AM
Glass, Polycarbonate, CR-39, Trivex, 1.60... So many lenses, so little time! Do you ever find yourself overwhelmed by the amount of lens material options available on today's market?
Tuesday, May 13, 2014 3:30 PM
I received this question from a colleague, "Why is sunscreen recommended for when riding in the car? I've always been taught that the windshield absorbs UV. That's why photochromics didn't work in the car. Who's telling the truth?
Wednesday, April 16, 2014 2:00 PM
A few weeks back a pleasant gentleman in his 60s was in our office and delivered to my dispensing table. We chatted about his prescription and when he wears his glasses most. He then pulled out his current glasses and they were a circa 1970 gold metal, modified aviator with a unifit bridge in a 59 eye size. As soon as his glasses were in my hand I realized—these lenses are glass, and very heavy indeed. Immediately I began thinking how happy he would be in his new polycarbonate lenses in a new smaller frame. Quickly I discovered my plan was not his plan. He explained he liked his frame and might even like a larger size. I decided to work on the frame first and then discuss the lenses. I showed him some metal frames in a 54 and 56 eye size as I explained patients often believe they have more viewing area when they have a large lens—but actually it was like walking up to a window or looking through a keyhole.
Tuesday, February 18, 2014 1:00 PM
The most common way of correcting vertical imbalance is to induce a
vertical prismatic effect in the lower half of one lens. This type of
correction is referred to as bi-centric grinding, or slab-off.
Tuesday, February 11, 2014 3:10 PM
"I follow ANSI Standards when inspecting mounted lenses prior to dispensing."
Monday, February 03, 2014 10:30 AM
There are two ways basic ways to verify slab-off: Comparing the vertical prismatic effects of the two lenses
through a lensometer and checking for actual image displacement at the reading level.
Tuesday, December 03, 2013 3:51 PM
First, it is an effect of the prescription as determined by the doctor,
so we cannot fix it, but we can correct for it. Some methods are capable
of correcting for more imbalance than others.
Sunday, November 24, 2013 10:00 AM
According to “The Dictionary of Ophthalmic Optics” (Keeney, Hagman,
& Fratello), Anisometropia is defined as, “Unequal refractive errors
in the two eyes.”
Tuesday, November 19, 2013 1:00 PM
Powered lenses are, in effect, prisms either mounted base to base (plus lenses), or apex to apex (minus lenses).
Wednesday, October 16, 2013 11:00 AM
Children waiting in line get on an amusement park ride dread the sign
that says "You Must Be This Tall to Ride." Particles of light (photons)
on their way to break a molecular bond run into a similar problem.
Wednesday, September 18, 2013 6:29 PM
Digital can be a wonderful tool and in his interactive book on Lensometry, Mark Bullimore, MCOptom, PhD, FAAO brings learning the Lensometer to life through interactive video and an embedded glossary.