Question on eyeglass prescriptions
 

I have glasses for driving (-1.25), not very strong, the prescription has not changed in 25 years. I can drive fine without them if I have to, but street name are a little fuzzy until I get closer.

I also occasionally use over-the-counter reading glasses (+1.25), mostly when working on the car or other small details and close in work.

I have accumulated several pairs of the prescription "driving" glasses over the years, they are all still good, and I use them for various activities. For example, I have an old pair of lighter brown perception sunglasses with a thin metal frame and big geeky lenses that I love for track events, they are a lighter shade of brown and the large round lenses allow for good peripheral vision...my kids will not be seen in public with me if I wear them:)

One thing that bothers me is when I use any of the prescription glasses for driving, my dash instruments are a little fuzzy. Also when riding my bicycle, I mount my phone on the handlebars and use a tracking app, but have difficulty seeing the information. This occurs if I wear any of the driving glass, or just plain sunglasses.

Let me get to the point before I bore you to death...

I have found some stick-on (and removable) bifocal lens that i could put on the various glasses.

https://www.amazon.com/Optx-20-Stick-Bifocals-125/dp/B000W7EDAY/ref=sr_1_1?ie=UTF8&qid=1488820252&sr=8-1&keywords=Optx%2B20%2F20%2BStick-On%2BBifocals%2C%2B%2B125&th=1

So...the question is, are the prescription numbers additive. If I put the stick-on lenses on a set of -1.25 driving glasses, and I want the bifocal "reading" value to be +1.25...do I need +2.5 stick-on lenses?

I know that the ideal solution is a pair of progressive bifocals, but I really like those big geeky glasses, and with the drawer full of glasses, I thought I'd try this $15-$30 option first.

Thanks,
Andrew

I have reader glasses strength 2.50. These are good for around the house, painting, fixing things etc. However for driving I have progressive lens which are excellent for driving. I can see how fast I am driving and read the street signs. I bought the latter at Costco several years ago for $300 can or about $225 US. My prescription has not changed for a long time. Would suggest you look at Costco. They have lots of different frames. Maybe they even have geeky styles. As a caveat I am not an eye professional.

Yes, the RX numbers are additive.

So your RX is
OD: -1.25
OS: -1.25

An "ADD" of +2.50 on both eyes would give an effective RX of +1.25 at near.

I used to get new prescription lenses every year or two, with (over-priced) frames.

Every time I would walk out pissed off at the high-pressure sales tactics to upgrade to this, pay extra for that, you need this coating and this option and you need these really expensive frames. Bah.



But over the past 4 or 5 years I've done just fine with the $19 reading glasses at the local drug store.

I doubt I'll ever go to an ophthalmologist and put up with the time-share tactics again.

If they had just played it straight and honest they wouldn't have chased away another customer.
(lesson for the marketing majors out there).

This is why I bought several pair of glasses from Zenni. I'm all for supporting the local guys, but I feel like I was reamed dry even with insurance.

http://www.zennioptical.com/

Thank you! just the confirmation I was looking for...

Interesting. I didn't know how that worked. It all looks like magic to me anyhow.