I went to a doctor for my eye checkup. And I couldn’t read the last line at all. Doctor said this is the limit to your eye and no matter how strong a lens, you would never be able to read the last line

Question

But I don’t get it. Why would if I put a stronger lens, I wouldn’t be able to read the last line? She said you must have never been able to read the last line in your life, and she was correct, but I don’t understand the science at play here

In: 58

Answer 1

From the test distance a single lens over your eye is only going to adjust your ability to focus not substantially the size of the image on your retina.

So for a given base acuity (resolution) the average human would not be able to discern the last line. Which with normal or corrected vision is called 20:20.

That said there are humans who due to genetic differences have 20:10 vision or a little better. Which means they can see at 20 feet what the rest of us (even with glasses) can only see from 10 feet.

Having been an astronomer for quite a while I’ve found by observing & sketching the planets that for my right eye only & for a small sections lightly off-center I have an acuity of approx 30:10.