My prescription says “+1” under “Reading Addition”, and has check marks next to “trifocal” and “progressive.”
Does this mean the middle section of the trifocal would be +1 relative to the distance vision prescription, and lower section would be +2? Or is it +0.5 and +1?
I think the “trifocal” and “progressive” are selected just because I told the optometrist I want those. If I change my mind and get a non-progressive and/or a bifocal, would any of the numbers need to change? Or can I just take this to a store and ask them to make it a +1 lined bifocal?
Former optician. The numbers are the same whether used for bi, tri, or progressive. A competent optician can even use those numbers to make reading only lenses.
I’ve got progressives as my main pair, but I also have a pair of single vision intermediate glasses for computer work. The optician just took the mid point distance script and the ADD.
I’m curious what’s involved in making reading-only glasses from these prescription. Is there more to it than just adding +1 to the distance vision prescription? (Or were you being sarcastic when you said “competent”?)
No, I’m not being sarcastic. There is, unfortunately, not much regulation of opticians in most states, and as a result there are a lot of “opticians” who don’t really know what they’re doing. One of the problems is that too many don’t know enough about it to even know what they don’t know. This leads to people who think “X” type of lens doesn’t work for them, when the real problem is that the person who fitted them didn’t do it properly. This goes double for online sales. There are necessary measurements, like vertex distances and OC heights, that are specific to THAT frame on THAT person that cannot be done without face to face time.
A distance only Rx tells you little about what’s suitable for reading and vice versa.
If you get an Rx for just one, this might mean you don’t need correction for the other. Be sure to verify this.
It is rather simple to get a somewhat ok Rx for computer glasses by taking the average of distance and reading Rxes. But since people sit at different distances from screens (a lot depends on screen size), etc., a more nuanced calculation is best.