Originally Posted by
Laurie
...I was busy in the shoe section, ; )
Two thoughts:
Catagory I: Multi-use PAL
Catagory II: Wide Intermediate Range, suitable for long hours w/computer.
Catagory I:
Autograph II can be ordered in Fixed, where the 'corridor', or 'transitional zone' in the vertical is fixed. You can fit a fixed 11 at 11mm, for example, and the corridor/transitional area will be fixed. If you choose to fit the fixed higher (11mm fixed at 15, for example), you will not change the Intermediate, but will add to the amount of reading area in the vertical.
Autograph Variable: The corridor/transitional area/intermediate will vary, depending on seg height. A rule of thumb, is you will have approx. 5mm of reading area in the vertical meridian (i.e. no cutting off adds), and the length of the intermediate will vary in length.
A quick tip:
Fixed: when you want to have clear control over the amt. of vertical mm of each zone: A bifocal convert, for example, will enjoy getting to the add right away, and can have more depth in their reading area.
Variable: new presbyopes, and dispensers who don't feel comfortable, or a need to maniupulate the parameters. The computer default will ensure that approx. 5mm full reading in the vertical meridian will exist, and contour the design based on additional information. Running parameters through additional software will keep within design criteria, as I mentioned in a previous post.
Finally,
Catagory II:
It is my opinion that, if a client is spending ample time at the computer, they need occupational lenses. The Shamir Office Lens comes in two catagories as well:
Catagory I:
Molded front surface (digital mold, not ceramic-to-glass mold), traditionally surfaced back curves. The lens begins at total near power, and 'digresses' out to around 10-13 feet, depending on Add power. There are four 'dynamic powers' to choose from (how much regression, or deduction of plus towards the top)....I would let the lab choose, unless you have very specific working distance requests outside the norms...the 'top part' of the lens ends up being over-plussed by around +0.50 - +0.75 D, they are not meant to yield 20 ft. vision. By dumping the idea of 20 ft. focus, they gain the widest intermediate, edge-to-edge.
Order like a regular PAL...distance Rx and Add power, mono PD's, and mono fitting cross heights, center pupil.
Catagory II:
Office/Autograph II: this is a design that is custom manipulated per Rx. It is generated via freeform, entirely on the back surface. There are unlimited amounts of 'dynamic powers'/'digression of plus power' towards the top, with the Rx parameters run through 'eyepoint technology' (ray-tracing system), and 'freeframe technology' considers additional information, like the exact positioning of the lower eyewire under the pupil, not just the boxed 'B' dimension. It is best to send the frame to the freeform lab to digitally trace it beforehand.
In addition, you can give additional 'as-worn' measurements: distance to computer, angle of monitor above or below line of sight, designate sitting or standing, ect. Again, the computer software will default to norms if this info is not given.
These new technologies are evolving at a fast rate...alot to keep up with!
Hope this helps,
: )
Laurie
(incase I haven't 'disclosed' in a while, in addition to teaching optics full time 'GO HCC!'), I give CE's for Shamir.
Bookmarks