I am confused,
I have been told to make an extended reader for computer/Reading you shift half the ADD
example script Sphere +1.50 ADD +2.00 = +2.50 on the sphere +1.00 on the ADD for the computer Reader
Script from Opto has if Access lens then RX is +1.50 ADD is +2.25 ?????????
The Access lens only had a couple of powers of regression. But if I recall correctly only .75 or 1.25. Unless they are now digital like everything else.
I wouldn't assume it is the traditional half the true add. The criteria was similar to contacts. If add below 150, use the lower power. +1.75 or above, use the higher power.
"Some believe in destiny, and some believe in fate. But I believe that happiness is something we create."-Something More by Sugarland
but the script is +1.50 ADD +2.00 and the optometrist has said to use is +2.25 on the bottom and +1.50 on the top that doesnt make sense to me should it not be +1.5 on the bottom and +2.25 on the top ??Originally Posted by Jubilee
He was trying to specify that the patient get a +1.50 add for the top/computer portion.
If you are going to do that in an Access lens, you have two choices for the bottom: +0.75 more, or +1.25 more.
He was opting for +0.75 more.
His communication is awkward. The correct way to specify an Access lens is to describe it in SV form, and specify the DEGRESSION.
To wit: +3.75 DS, Access Low Power (-0.75 degression).
It's a great lens I use all the time, but it's so dang old it apparently wasn't conceptualized as a computer lens* (since it was probably before they took off) but as a "near variable focus", i.e. a SVNO with some play out into the intermediate. Hence the "SVNO with degression" specification protocol.
*Maybe it's even old enough that Machol worked on it. Naw.
not using access lenses so if he has a +1.75 int single vision computer would be +3.25 how do we split for computer/Reading ?
what lens are you using?
ST28/35?
not a trifocal
a lined bifocal? or some other type of occupational lens?
If the optometrist specified the sola access, I would stick with that.
There are a few alternatives that are similar, but most are more expensive, and offer more add/material options.
Other than that, they are basically the same.
so my original question if he has a +1.75 int single vision computer would be +3.25 how do we split for computer/Reading ?
+1.75 is the intermediate Rx?
+3.25 is the full reading/computer Rx?
If the the above is correct, and if you are using some type of bifocal,
the rx entered/ordered/read would be +1.75, add +1.50
edit:
just realized you are asking for splitting/shifting the add
in an ideal situation, you don't want to calculate this.
You will want/need to refract for this, and I don't think anyone online will do that for you.
Talk to the prescribing doctor about the refracted distances,
and communicate with the patient on what the intended uses for these glasses are.
Splitting/Halving the add is a somewhat decent method.
But don't expect it to work all the time, especially if you don't know working distances and patient history.
Last edited by ml43; 06-24-2015 at 02:28 AM.
RX is +1.50 with an ADD of +2.25 he wants computer Reading glasses
need to refract/trial frame for the intermediate/computer portion.
If you want the absolute powers to be the same as an access low add, then use:
+3.00, add +0.75
Hope that helps,
but it's basically a summary of what drk already posted.
Fill it this way, if that's what it says on the Rx. It's would be wise to double check the work distances.
Bumping the add for PALs is not recommended, is unnecessary, and will do more harm than good with today's PALs. Since you're not using the Access, it's moot.Script from Opto has if Access lens then RX is +1.50 ADD is +2.25 ?????????
Drk,
Good description of the Access. It's important to note that the degression is over the entire height of the lens, from 10mm above the primary gaze to 20mm below. The Access with 1.25 degression on a +2.50 add will have slightly more than +1.75 D available on the primary gaze- too much for desktop monitors at typical distances.
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.
We like to fit it low...about 4-5 mm below the pupil in order to avoid the "neck" of the transition and put the intermediate portion higher. It seems to work. I didn't know about the degression rate being so slow, however. As a practical matter, we don't have issues with it.
Except for the "Relax" type lenses (.65 add), the office/computer PALs seem to run the progressive optics from top to bottom. As I've mentioned before, I think they do this for a variety of reasons, including making it nearly impossible to use off label as general purpose lens.
The Sola Access was designed to have the fitting point 5mm below center pupil and aligned with the near PD. When fit this way, the zone width looking straight ahead is 6mm, and 45mm 15mm below. There is no drop, that is, the fitting point is aligned with the PRP. I've never fit it, but I suppose it was a good lens for very close tasks, sewing and other hobbies.
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.
Was? WAS?
Take a look at the iot office reader,
pretty similar in design, comes in three digressions, instead of two.
decently similar in price, but comes in more materials, and is slightly asymmetrical.
From a lab standpoint, it's better as well(less blanks to carry)
The IOT office lenses and their wide range of distance specific designs are a huge hit at our office
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