How come you can buy reading glasses for a few bucks at pharmacies or Wal-Mart, but they don’t make them for being able to see farther away?

Question

Is the lens grinding process more complicated or is there just too much variation in eyesight to make them feasible on a mass scale?

In: Other

Answer 1

The difference is your prescription lenses are made so you can see perfectly at “infinity” (very far distance). You don’t want to be near or far sighted with your glasses on, so the lenses need the exact power to correct your eyes. For example if you were near sighted and got too strong glasses prescription you would be far sighted instead.

Reading glasses make you near sighted. You can no-longer see things far away, but you can focus on things closer to you now (this is actually true of people who are near sighted as well). That’s why you don’t wear them all the time you put them on just to read then take them off.

Because they’re already making you near sighted and stuff far away is blurry with them on you don’t need them to match your eyes, they just need to be strong enough that you can hold a book at whatever their focus distance is and read it. So you can sell just a few powers and people can pick the one that gives them their ideal reading distance.