Question about prescriptions and vision?

Question

Someone told me that their eyesight was something like -7.50, -7.75. How bad would that be considered? Is that roughly 20/50, 20/70...better or worse...?

Lori L: Admittedly, I don't know much about optical health, which is why I asked a question to learn. I don't know why you've gotten so worked up about it, but thanks anyways for your answer. I do realize that the numbers are a better measure of an individual's eyesight. I simply wanted to compare how someone with -7.50 would hypothetically do on an eye chart, since the eye chart is something standard I can identify with. I was thinking "with that kind of a prescription, he probably has trouble seeing this line on the chart without his glasses". Just trying to work backwards, that's all.

Answer 1

But, do you REALLY know what the 20/20 scale means? I do not think you even know what that means . The -7.50 to correct tells us so much more about this person's eye than the 20/20 scale. You are so silly. This is like asking...."OK, someone just told me they have cancer...so is this sick, sicker or sickest?" Really.

Answer 2

I assume you mean vision without glasses. Likely the person gets 20/20 with glasses on.

You can't really calculate unaided acuity from prescription. An estimate for -7.50 would be between 20/600 and 20/1200.

Most eye charts do not have letters that big.

Answer 3

U are actually not hyperoic or myopic in authentic eye. on each occasion there is cylinder there must be an axis seeing it quite is the area of the lense. ur left eye has an astigmatism . Ur eye is formed like a soccer while u have an astigmatism. while ur eye is formed around that imeans this is like a basketball! Plano potential NO prescription necessary UR not nearsided or fare sided in basic terms have an astigmatism I even have one too they might reason headache's if u do not waer ur glasses while u have an astigmatism innovations u I artwork for an Optometrist ( a watch surgeon )

Answer 4

You can improve your vision just by practicing the correct approach for ten minutes a day.
You can check this technique: http://improvevision.toptips.org

Basically what glasses do is bolt the eyes into their refractive state and in order to transparent your lenses you need to keep up the poor vision that the lenses are intended to correct.
This program demonstrates to you a proved method to improve your vision naturally, permanently and with complete results.

Answer 5

Considerably worse. More like 20/400 (the big E).