eyeglass prescription process
July 7, 2020 11:50 AM   Subscribe

How does the prescription process work for eyeglasses?

I am new to prescription eyeglasses. The ophthalmologist wrote me a prescription today. I want a pair just for reading, a pair just for the computer, and a pair just for driving. Do I just bring the prescription to an optometrist and the optometrist gives me what I want, or was the ophthalmologist supposed to write a prescription that was specific to each pair of glasses that I want? I tried to ask those questions when I was at the ophthalmologist's today, but I think that it is such common knowledge to them that they couldn't really understand what I was asking.
posted by SageTrail to Health & Fitness (15 answers total) 2 users marked this as a favorite
 
So in general, you only have one prescription; all your glasses would be the same. Since you need them for the computer and reading, I'm guessing you're farsighted--you can see clearly if things are far away, but need help if they're close up? Or do you have problems with both (for driving, do you need help seeing the instruments or the road/signs?)

So the reading glasses and computer glasses will definitely be identical. If you need glasses for driving to see the instruments, then that will be the same set as reading. If you need them to see the road, your prescription is maybe more complex.

But basically, you need just one prescription and all your glasses will be the same.
posted by gideonfrog at 12:00 PM on July 7, 2020 [2 favorites]


That sounds like three different levels of correction and thus you probably should've gotten three prescriptions.
posted by praemunire at 12:01 PM on July 7, 2020


I think the answer to your question is why you want three pairs. Is it because you want different lens characteristics with the same prescription? For instance, some people like to have yellow lenses for gaming to improve contrast, and special visible light sensitive photochromic lenses for driving. These changes to the glasses don't change the prescription, so they aren't the concern of the ophthalmologist/optometrist (sometimes they will recommend certain lens coatings, but those are not part of the prescription). Alternatively, do you want different lens powers for each case? Occasionally people will modify their prescription for particular activities - for instance, they may add a bit of lens power for magnification for close-up activity.

If you just want different frames and different lens coatings, the prescription can stay the same because those aren't part of the prescription.

If you want different lens power for each glass, you should talk to your ophthalmologist/optometrist about that because it's a pretty narrow use case that they won't normally address. Notably, if you use the modified prescription outside of that use case, you'll have a less-than-ideal (and potentially harmful) pair of glasses that they wouldn't normally prescribe.
posted by saeculorum at 12:01 PM on July 7, 2020


I tried to ask those questions when I was at the ophthalmologist's today, but I think that it is such common knowledge to them that they couldn't really understand what I was asking.

Can you explain why you want different glasses for reading and using the computer?
posted by showbiz_liz at 12:02 PM on July 7, 2020 [1 favorite]


It is a bit confusing and I don't pretend to understand the science but I have currently got two pairs of glasses from one prescription. Basically I discussed with the optician what I needed the separate pairs for - one for reading and computer work and one for driving and distance. The reading / computer pair are referred to as enhanced readers, so are made somewhat weaker than the driving pair. I think the optician said something about using a couple of points along the range of my eyesight - told you I didn't get the science.
You might try asking for enhanced readers as a starting point.
posted by Martha My Dear Prudence at 12:16 PM on July 7, 2020 [1 favorite]


Reading glasses & driving glasses will definitely be different prescriptions but you can combine them into one pair of glasses with bifocals. I think you should go back to the eye doctor and get them to clarify.
posted by bleep at 12:17 PM on July 7, 2020


You might not even need different glasses. When I first got mine in my 20s, one prescription did fine for everything (I have a slight astigmatism), but my primary correction was for distance vision. As my prescription changed over the years it just got more comfortable for me to wear my glasses while reading and using the computer as well.

Now that I'm in my 40s and getting standard aging vision issues, when I went in for an exam last they assumed I'd want bifocals and the prescriptions for my distance correction and close-up correction were both written on the same prescription, but I could have instructed the guys making the glasses to just give me straight-up distance glasses without the bifocal part. Functionally, they're blended bifocals, so the top part is distance, middle is more computer range (for me with a desktop and monitor), and bottom is reading.
posted by LionIndex at 12:22 PM on July 7, 2020


fwiw I need to use different strength glasses for reading and computers (except for maybe laptops depending on my setup). My computer glasses are weaker because computer screens are larger and farther from my face than book distance.
posted by ToddBurson at 12:23 PM on July 7, 2020 [2 favorites]


My older brother has what are essentially trifocals now:
  • normal Rx for seeing stuff when he's up and walking around
  • below that a region for focusing on things about two feet away (i.e., a laptop screen) for work
  • and finally a lower band of high magnification for close-in (to take the place of "cheaters")
Honestly I really want a pair: with just contacts I can't see close-up; with contacts+cheaters I can't see screens; with glasses I can't see close-up or screens. St00pid aging human body!
posted by wenestvedt at 12:35 PM on July 7, 2020 [1 favorite]


Best answer: Depending on how you use your computer you may or may not need a separate pair for each. Generally "computer glasses" are for distances beyond reading length (16"). Desktop computers are usually about 20-24" from the user, and so sometimes people want a second set. If you use a laptop or have more flexibility on how you position the screen, then you can usually get away with a reading pair. DO NOT interpret "reading glasses" with the things you see for a few bucks at the pharmacy.

As for progressive lenses, they aren't for everyone. I did not get my first pair of corrective lenses until I was in my early 50s. When I was training to be an optician, I got free glasses essentially. I could NOT adjust to progressive lenses, and when I tried to wear them at the office, I would get frequent headaches. All the things I was used to being in focus 20' and beyond were now slightly not. I had the benefit of having my lenses redone and I played with my own prescription for months and never found anything that I liked. I ended up not wearing frames unless I had to do close up work.

Now that I am no longer working as an optician -- I was laid off in March and am unlikely to go back -- I don't wear my progressives at all and use my reading glasses to read and use my computer. And I adjust my screens to fit my comfort.

This means your mileage may vary, and to communicate the best you can with the optician. I found it frustrating trying to explain the RX and the process to new patients, but that's what opticians do.

One last tip: If you do not have insurance spend the money on the lenses, and skimp on the frames. If you had had glasses before I would say bring them in and have the opticians put the new lenses in the old frames.

As for the Rx, 1 will do fine. The opticians can read and fill that for 1, 2 or 3 pairs of glasses. They do the maths for any conversions that need to be done.
posted by terrapin at 12:43 PM on July 7, 2020 [4 favorites]


Best answer: Short answer: the prescription your ophthalmologist gave you has all the information you need if you want three different glasses. You just have to be clear to the optician exactly what problem you want solved. They have all the necessary data in their hands.

The first number on the prescription is for distance vision. There will be a second number called "Add" which is the amount that needs to be added for close up vision for reading a book, 12 to 18 inches.

If you need a middle distance for using a computer, they just divide the "Add" by two. For example if you are farsighted you might have a distance prescription of -3.0. For reading they need to "Add" +2.0. For computer distance they would add half or +1.0.

You could have two pairs of bifocals. For reading you would have the distance lens on top and the reading lens on the bottom. For computer, you would have the same distance lens on top and the half strength computer lens on the bottom.

Or you could have tri-focal lenses that have all three on one set of glasses.

Or you could get progressive lenses that blend all three together. Some people have trouble adjusting to progressive lenses. They are a compromise that is not always optimal.

If you decide to go with bi-focal or tri-focal you should insist on glass, not plastic lenses. Plastic bi-focals have very disturbing ridges between the two lenses while glass bi-focal or tri-focal lenses are fused together smoothly. Some shops will try to steer you away from glass because their in house shop my not handle them. But if you insist, they can order them for you. It just takes a week or so. Don't let them discourage you.
posted by JackFlash at 5:09 PM on July 7, 2020 [3 favorites]


Best answer: If you have a middle aged pair of eyes like mine, the lens in the eye gets stiff and you need compensation for reading.

If you are short sighted (which is more a matter of eyeball shape), then you may need an overall compensation for distance (which you will typically be able to read through as well; I always have until I needed reading correction a couple of years ago).

If you have a funny shaped eyeball and a stiff lens at the same time, you may need correction for both. If this is your very first prescription ever then that's not terribly likely. The comments above tell you what to look for.

That being the case you probably need one pair of glasses - either for occasional use while reading things, or for general wear if your short sighted. You almost certainly don't need different pairs of glasses for different things, at least not as far as the strength of the lenses goes.

Your average glasses salesperson should be able to give you advice the moment you hand them your prescription. With your prescription in hand, you should probably try a couple of shops and compare the advice you're given, since you're trying to figure out how this works.

(Note: glasses salespeople are often a bit pushy, so I would take a pic of any glasses you like and tell them you'll come back after you've shown your partner/friend/dog.)
posted by How much is that froggie in the window at 6:21 PM on July 7, 2020


My normal glasses are essentially trifocals, or "progressives"... distance on top, computer-range in the middle, reading on the bottom. I went through some difficulty getting them because I learned there are two different ways of grinding progressives, and the place I went with my most recent prescription ground them in a "narrow" way (the only way I can find to describe it), so the middle range was not only fairly narrow top-to-bottom, but side to side as well. (These weren't done in error -- they are definitely different fashions of grinding progressives).

Before I found a place that had the "right" find of progressives, I got two pair from Zenni Optical, one of the online providers...one pair computer glasses, and a traditional pair of bifocals. Now that I have a comfortable set of progressives, I rarely use the other two pair, but they'll make adequate backups in case something happens to my main pair.
posted by lhauser at 7:28 PM on July 7, 2020


So the reading glasses and computer glasses will definitely be identical.

That's not right at all. Reading glasses are for closework, Like a foot away where you hold a book or read a menu.

Computer distance is farther, like 18 inches or so.

The most useful work glasses will cover your computer monitor(s) plus your entire desktop plus the area around the desk in the room where you work. Google "occupational lenses" or "occupational bifocals." A major brand is "Access by Zeiss."
posted by JimN2TAW at 7:17 AM on July 8, 2020


Best answer: A lot of the answers here are assuming you need bifocals (or different prescriptions for reading vs. distance), which will be confusing if you don't. If you do, your ophthalmologist should have discussed your options with you at your appointment.

If you don't have that medical need and simply want different glasses for convenience in the three locations, you can use the same prescription for all three sets of glasses. Different prescriptions are only needed if your eye loses the ability to adapt to different distances, which is generally an age-related thing and again, your ophthalmologist would have gone over this with you if that's the case.

Since you say they were confused when you asked about it, I'm guessing you do not actually need different prescriptions for your different glasses, but you could call them and ask more directly if you didn't already.
posted by randomnity at 7:43 AM on July 8, 2020 [1 favorite]


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