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

Your eyeball muscles should only focus to infinity, not past it. It’s relaxing for both eyes to rest at that focus. Fixing nearsightedness should get you just exactly there, and one eye will likely take more than the other.

The diopter of your prescription lenses are a reciprocal of how far you can see. If I can focus to 50 cm but no further I need a negative 1/0.50 or a minus-two prescription.

But with farsightedness I could just get bifocals that let the top of my vision be in focus and my near vision “better”. Since my eyeball still has some focus abilities and I can move closer to or farther from my object of interest it all works.