I asked my eye doc for computer bifocal Rx. Got it, had them made, they are perfect. I ordered them online. I didn’t tell the vendor that it was a “computer” bifocal Rx.
Now I want a pair of “regular” bifocals, from the same online vendor. Can I just change some of the values in the other prescription and use those changed values to fill out the form on the vendor’s website?
How?
I suspect that naming the vendor in question might be helpful in answering the question.
What’s the diff between a computer bifocal and a regular bifocal?
a computer bifocal will have the top of the lens focus at about 2 ft. the lower lens will focus at 1 ft. for reading.
i think the prescription from the doctor would have all the numbers for single vision, trifocals, bifocals, computer bifocals.
How are you possibly going to know how the numbers change? How about simply asking the eye doctor for a new prescription?
eyebuydirect.com
Is that helpful in answering this question. Hope so.
See reply from Johnpost.
(correct, Johnpost)
The prescription in hand is specifically for bifocal computer glasses, nothing else. I was hoping not to have to go back to the doc and pay for another Rx (one for “regular” glasses"). The Rx for the reading portion of the bifocals would of course remain the same; I just thought that there might be something like an algorithm or an analogue that is applied by opthamologists or optometrists to a “regular” eyeglass prescription to arrive at a prescription for “computer” glasses. If that is true, then knowing what it is, I could easily arrive at the values in the original prescription for “regular” glasses.
Thanks for your reply and the replies of others.
Thanks for your reply. See my comment to Johnpost, re: knowing “how the numbers change”. Perhaps I’m not. That was the crux of my question.
Thanks again.
How the numbers change is going to depend on several factors.
For example, my bifocal Rx contains two sets of numbers. One set is for my distance vision, the other for my near vision. If I wanted a cheap pair of back-up glasses, for, example, driving, I could get single-vision lenses using just the distance numbers. Likewise, if I wanted glasses dedicated just to reading I could use the near vision numbers.
There are various configurations of bifocals, such as glasses that devote a larger portion of the lens to one or the other Rx, or a variation where the near vision component is at the top of the lenses instead of the bottom.
If you have your various sets of numbers, know what they mean, and can plug them into an order form sure, you can cook up your own Rx… but how thoroughly do you know your own script and what the various parts of it mean?
Now, if you have near and distance numbers and want to somehow extrapolate a middle range… not entirely sure you can do that on your own. You could try it and get a cheap pair on line to test your conclusions. This may require some trial and error, and may or may not cost more than a doctor’s eye exam. Or you could go out and get an Rx from someone who actually has some expertise in these things.
It’s the difference between doing your own plumbing and hiring a plumber. Some things any idiot can manage, other things do require a professional.
There is no way to answer the OP’s question.
The top of ordinary bifocials is the distance vision - which is myopia correction.
This correction has to be accurate.
presbyopia comes in all sorts of strengths too, so there is no easy guessing from the prescription what the long distance vision would be.
if you had a full vision test then your doctor can supply you with all the numbers.
I agree. And if the doctor already did the exam, the OP may be able to get a new prescription without paying a second fee.
If the OP, or anyone else, has paid for an exam from an optometrist, he or she should be able to get a copy of the prescription (and apparently the OP did, since he/she did order glasses online).
One of my pet peeves with optometrists, though, is how ridiculously resistant they are to providing the prescription to the patient. I know this is because they want to sell you the eyeglasses, of course, but it still pisses me off. If they won’t give you the prescription, then the cost of the exam should be included in the glasses they sell you. But they always charge separately for the exam. To my mind, that means I’ve paid for the exam independently of any purchase of glasses, and I am absolutely fucking entitled to a copy of the prescription.