A friend of mine is doing an article on how to fit Occupational lenses (Double D, Ribbon Segs, etc.).
I'd appreciate any responses with tips on frame selection, fitting recommendations and such.
Thanks,
Pete
A friend of mine is doing an article on how to fit Occupational lenses (Double D, Ribbon Segs, etc.).
I'd appreciate any responses with tips on frame selection, fitting recommendations and such.
Thanks,
Pete
Pete Hanlin, ABOM
Vice President Professional Services
Essilor of America
http://linkedin.com/in/pete-hanlin-72a3a74
You are joking, right?
I would suggest he check out a modern occupational lens...variable in design like the Shamir Office Occupational lens.
: )
Laurie
My advice for fitting double-D's or quads:
Get specific information on the visual task, even to the point of creating a "mock-up" situation in the office.
Demonstrate the distance window and the seg heights with tape, and the depth of focus with each add power, etc.
Know availablities of add combinations, especially in materials other than CR-39.
Try to use adjustable pads for a better margin of error.
Make sure the materials charge includes the extra time it takes to design specialty lenses!
Avoid double execs!
Pete,
I don't have any recommendations on a DD but a Shamir Office lens would work as well. At least for the near visual tasks to 10 feet. If I remember, you need about 13mm sepearation for a DD. Generally, a good hefty B measurement frame.
Lee Prewitt, ABOM
Independent Sales Representative
AIT Industries
224 W. James St.
Bensenville, IL 60106
Cell : (425) 241-1689
Phone: (800) 729-1959, Ext 137
Direct: (630) 274-6136
Fax: (630) 595-1006
www.aitindustries.com
leep@aitindustries.com
More Than A Patternless Edger Company
as lee said a deep "b" measurement, but most critical is to make sure of the seg height, as once you determine what the bottom seg is you get whats ever left over on the top, typically what will happen is the optician will set the bottom seg high not leaving much on the top, causing diifficulty to the person trying to see thru the upper seg.
.....As an example, lets say your "b" measurement is 41 mm, and you set the bottom seg height at 20 mm, assuming a 13 mm seperation, you now have the top seg of only 8 mm. To have both segs equal the height would have to be 14 mm.
Double D's are still needed. Especially for the electrician and plumbers we see. We fit to the bottom of the lid and use larger B measurement frames. Ribbon segs' depending what the useage' is for are fit by us sometimes at bottom pupil. Again in larger B measurement frames to accommodate the segs.
it's early and i've only had 1/2 a cup of coffee, but how would a office lens take the place of a double D? I've always fit a DD on painters, electricians,etc anyone doing overhead stuff at an intermediate distance.
Paul:cheers:
On DD's, I have found it better to get the top seg fit 11mm down from the top of the frame; and let the bottom seg fall where it may; in Harry's example of a 41 B, 11 for the top seg, 13 for the distance rx, and 17mm for the bottom seg..and, if it's with adjustable pad arms, you can fine tune the positions from there..
Pete,
Remember the Varilux double PAL? I think it was called Overview. Here's an idea...Varilux double Liberty.
One might not want to use a metal frame for electricians.
Robert
Robert, you're right about the electricians, I used to do safety glasses for TXU Energy, they were not allowed any metal frames. Now, plumbers, that's different. We used to do some quad segs for senior pilots, but mos5t have converted to Multigressive II or Vx Panamics...the flight engineers still prefer the double segs or quads. we're having a lot of disgruntled pilots that had been fit in F-D trifocal for years, and they dc'd that lens and there just isn't a good substitute..is there?
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