[ELI5] Perfect Eyesight/Prescription Glasses



Hi all,


I’ve been curious about this for a while. Lets say there are two people, one with perfect eyesight, and another who does not have perfect eyesight and wears prescription glasses. If the person with perfect eyesight wears the prescription glasses, does that person see the exact way the person who does not have good eyesight does?


Thanks in advance and I hope I was clear!

In: Biology

No, the prescription glasses will interfere with the perfect vision and render it imperfect.

Imagine it like this:
If 0 is perfect, and the glasses wearer has -2 vision without glasses, then the glass corrects by adding 2. Therefore, perfect eye person would now have a +2 sight. Their vision would distort as if they were too close to an object. It doesn’t magnify, just bends the light differently.

Prescription glasses are corrective lenses that allow the person with less than perfect vision to achieve 20/20 vision, or as close to that as is possible depending on the severity of their eyesight dysfunction.

If the person with perfect vision puts on the prescription glasses (corrective lenses), their vision through those glasses is all messed up but it doesn’t equate to them seeing the way the other person does without their glasses, although this might give them an idea of how that person feels without their glasses because it does impair their vision while they are wearing them.

For example, I have 20/70 vision which means that I have to be no more than 20 ft away from an object to see it while a person with 20/20 vision (like my husband) can see that same object at 70 ft away. When my husband put on my glasses he felt like he would fall over and it made him dizzy and nauseous. I don’t feel that way without my glasses, I just can’t see clearly anything further than 20 ft.

A better example is contact lenses. The lens is very close to the lens in the actual eye.

Basically, you can see exactly as well as someone who doesn’t need correction. Perhaps even better, because your eyesight has been corrected perfectly.

For comparison, someone who wore braces to straighten their teeth vs someone who didn’t.

Of course, your eyes can change prescription, you can get dust and scratches on a contact lens, infection, you have to take them out every day to give your eyes 8 hours rest from them, you can get additional reflections or whatever from lights at night. And so soon.

But yes, your vision is otherwise perfect.

So just a fun anecdote. At my last eye exam my vision was found to be 20/20 where I had previously needed a prescription. (It does sometimes get better, it is a thing) I still have an astigmatism so I actually do wear lenses but could go without if I choose.

In addition to what others have said, when you try on a new pair of glasses it’s a bit foggy and hazy in the beginning. This fogginess is more pronounced if you’re trying on glasses which have a power that is too much for you.

Source: I used to try on my sister’s spectacles when I had perfect vision and it was quite weird. Things seemed going in and out of focus. It was uncomfortable overall.