Just in case you have some time off over the long weekend and find yourself bored you might want to read this. Being an old fart myself I found it quite interesting.
Prismatic displacement effect of progressive multifocal glasses on reaction time and accuracy in elderly people
https://ia902604.us.archive.org/3/it...PTH.S58193.pdf
I have always wondered when I would be sued for a first time PAL wearer tripping over the curb on their way out to the car. Been in the business since 1998, and have never had to deal with a PAL-caused fall. I think it has quite a bit to do with patient education.
Absolutely, the wondrous design aspect of the PAL is the intermediate and it's ability to bring into focus objects 100' to arms length. Critical is the education of the customer. I treat PAL dispenses like a C/L I and R class; you have to be able to demonstrate to me that you can safely use it and that requires navigating steps. Good point on your part Dick regarding the elderly and the PAL. Waiting too hear about the joys of adult diapers. HAPPY NEW YEAR!
I didn't attend the funeral, but I sent a nice letter saying I approved of it. Mark Twain
I could not even blame any progressives this time....................................
Originally Posted by rbaker
That is why I am wearing my progressives only at a New Years party only forever. Because then I can blame it, or any fall, on my progressives and not on the liquids consumed.
However we are spending the first Winter in 25 years up North, because my Canadian Travel Insurance insisted on charging me $ 7,000 Can for the time spent in Florida with no coverage for my heart which is the only culprit in my old body that is acting up from time to time. So my bad record is that I was 3 days in the Hospital for observation 6 month ago.
No I have to stay 6 feet away from any hospital for another 6 month, for a total of 12 month to get coverage again next year.
However last Tuesday, 3 days ago we had a nasty freezing rain fall. The front stairs on my house had a polished sheet of ice on them. My dog slid 4 of the six stone steps down onto the driveway. I followed to help her, slow and careful made it, and then slid on the highly polished driveway and landed on my back on the driveway.
Right hip and shoulder have been hurting less and less every day and the only thing that stayed normal was my ST35 glasses in the plastic frame. I could not even blame any progressives this time.
.....and by the way, I do not wear adult diapers.
That's not how I read it. The conclusion was...
andOlder people appear to adapt to the false projection of progressives in the central visual axis. This adaptation means that swapping to new glasses or a large change in prescription may lead to a fall. Frequently updating glasses may be more beneficial.They recommend that partial changes in correction should be prescribed and that updating glasses should therefore occur more frequently.In conclusion, this study suggests that updating glasses should possibly occur more often in the elderly population to avoid abrupt changes in prismatic displacement.
It's not to unusual to discover, when I call my client's ophthalmologist for the latest Rx, that there was no refraction performed, and that in some cases a refraction hadn't been performed in over five years, even when they were receiving annual care. What were they thinking?
Last edited by Robert Martellaro; 12-29-2016 at 06:11 PM.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
I experience this as well. Many techs (who really do the bulk of the refraction work) bustle them through and think they are doing them a "favor" by not saying they've had an RX change. They also are the worst culprits of increasing cyl by a whole diopter or an add increase of +.75, yet the patients often are told "your old glasses are fine unless you want new ones" and then are flabbergasted after I make them the new RX that there is such a different visual experience.
This is in contrast to some of the turn and burn shops around here that will RX -.25 or +.25 contact lenses to people to grab that fitting fee. (true stories)
-Ian
...Yet...
Sorry to learn that news Chris. Ice is a female dog... Hope you're on the mend and feeling better. Happy new year.
Dick, interesting post...I have always wondered how PALS were so easily adaptable by most and accepted by the folks that develop the optical lens standards. I've had both OD's and opticians reject a pair of SV lenses with only 0.25D to 0.50D of vertical imbalance, yet most PALS have 1D-3D of prismatic displacement from the fitting cross (actual viewing area) to the MRP.
I used to say it is only a quarter, try it on the patient and see, yet they accept the PALS with no issues. Even worse is that the manufacturers add on even more base down prism for prism thinning. The funny thing is people aren't crashing into buildings or falling off sidewalks.
the market research for today's largest corporation ..........................
That made me remember the time in 1963 when I had to make the market research for today's largest corporation to find out if their products would fit into the Canadian market.
I had to interview a 150 opticians and optometrists from Quebec City to Winnipeg and show them the Varilux lenses and Nylor frames, and get their opinions on it.
I could not find one that would say that it was a cute idea ..................
One hundred percent found that this was a bad lens full of distortion.
Those were the good old days..............
I'm lost, The study compared PAL to SV lenses not other multifocals.
Will there be a followup study comparing the incidence of vertigo throught the day by switching from SVD to SVN dozens times daily?
Lab Insight,
Vertical prism imbalance should be less acceptable to the wearer than vertically yoked prism. Vertically yoked prism is usually tolerated up to 3D or so, especially for myopes (maybe due to their habitual nature, having worn eyeglasses since their preteen years).
The Effects of Vertical Yoked Prisms on Gait.
http://iovs.arvojournals.org/article...icleid=2189154
Vertical yoked prism--patient acceptance and postural adjustment.
https://www.ncbi.nlm.nih.gov/pubmed/3684280
Best regards,
Robert Martellaro
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
In 2010 the British Journal of Medicine published a study about this topic. Discussion on optiboard is available in "similar threads".
I believe the link to the BBC article is still valid.
Eyes wide open
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
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