OPTX 20/20 Stick On Magnification Reusable Bifocal Lenses - +2.50 Diopter (Pack of 2)

After cataract surgery I needed sunglasses with readers. Already had three pair of plain Maui Jim sunglasses and wasn’t looking forward to buying all new Maui Jim’s w’readers. Found these lenses by accident and thought for this price I’d try them. They install easily and the vision is better than expected. Main concern was they were a bit large, but the directions said they could be trimmed. Positioned the lenses where I wanted them, used an ultra fine point sharpie to mark the area sticking out below the lens and then slowly trimmed them with sharp small scissors. Worked like a charm and didn’t hamper the vision a bit. Like the idea of being able to switch lens power for reading, driving, etc. In a perfect world they could be a bit thinner, but that’s not as much of an issue after they’re cut down. Hope they sell a lot of these for a long time so they’ll be available down the road if needed.

I wasn't super optimistic given the many mixed reviews I've seen about whether these actually stick to your mask and make it through multiple mask defogging rinses.I followed the best directions I found on the web (not the packaging) to a tee - wash out the mask carefully with toothpaste/brush, rinse mask well & dry completely, soak the stick-on lenses in warm water, apply them to the inside bottom corners with the convex side pointing up/away from the mask lens (concave side down), press firmly in place and blot off any residual moisture, press firmly again, let dry overnight.I followed this procedure the day before I went diving in Thailand last December, and they stayed on just fine through defogging and mask clearing. Two dives that day, then three dives a few days later and they were still going strong. Worked perfectly! Could see my computer/guages and camera settings clearly, and marine life in the distance perfectly. Can see how it would be great for snorkeling masks as well. Made my diving experience perfect!

At first no issue...maybe its the heat..they keep coming off later on..

I purchased a pair of Ray Ban Meta, but I need +2.50 to read. These did the trick! I just put a drop of water on them and applied them to the glasses. I adjusted the position to fit my vision and made sure to remove any air bubbles with a Q-tip. I let them dry for a day, and they stuck. I can see my phone, read my Apple watch, etc. The bad reviews gave me pause, but I ordered them anyway, and I'm glad I did. I wonder if those who said they didn't adhere to the glasses forgot to use water.

This was a waste of money. I bought the two pack and the lenses showed varying degrees of damage from very light to heavy scuff marks. Kept it for emergency use. As a reviewer mentioned, the bifocal doesn't stay on low prescription glasses even after diligently following instructions. Already lost 2 of 4 bifocal lenses as of writing this review. However, it adheres well to the 2.0+ prescription side. I can't recommend until quality is improved.

Mentally taxing to apply. They also don't always stay attached. Even when you follow directions explicitly!

I have tried several makers of these things. These are NOT Fresnel lenses - as were the very first set I tried years ago. They are optically and cosmetically much better. So far, for my purposes, these seem the best in terms of quality and adhesion.How you you install matters. 1) Clean everything w/soap+water. 2) Get a puddle of water on the lens inside surface. 3) Drop this thing into that puddle - water should cover it. 4) Slide it around in the puddle until the right spot for you - may take a couple attempts. 5) Invert glasses and let extra water run off - do NOT wipe. 6) Let glasses dry untouched for 24 hours on an absorbent cloth to catch drips. 7) Once 24 hours have passed hold them up to the light - there should be few, if any, visible bubbles or else adhesion will suffer.I have found that once I followed all the above steps, the adhesion is quite good. I am able to rinse my glasses - as I normally do - with soap and water, then dry carefully with an absorbent cloth. The stick-ons stay in place. Pretty cool.Note: these have a distinct curvature molded into them. I doubt they would ever stick to the outside surface of glasses (I tried without success) or onto a flat surface - like a scuba mask (there are other brands that might). And it is possible that the curve/shape/RX of your eyeglass lenses will not be a good match for this curve.Also note: while there are others, bifocal lenses come in 2 very standardized sizes - D28 and D35 - with the D28 most standard, I think. The "D" refers to the shape - which is obvious with these. The number that follows refers to the width of the lens (in mm) at its widest point - which MAY not be at the very top. In this case, it seems to be. And I measure mine at about 28mm. I am not sure if there are any stick-ons that are wider. But if you need or care about that, ask first.All-in-all, I am not sure that these are as "good" as custom-made bifocals as there are many factors which must be taken into consideration. But it is a good, cheap way to test things out and see how/if they work for you before taking the plunge. And for some they may be all you need.

Why did you pick this product vs others?:Repeat customer!!! Have given my stupid expensive sunglasses a new life!!!