What is 20/40 vision like?I'm wondering exactly why you're asking this. I expect you've heard of 20/20 vision and you may be thinking that 20/40 vision means vision that's twice as good as 20/20 vision, but it doesn't.
20/20 vision is not "perfect" vision, it's just a good level to achieve. It means being able to see at 20 feet what most people can see at 20 feet, specifically the ability to read clearly printed letters that are 8.7 mm tall. (Sorry about the mix of measuring units, that's the definition.)
20/40 vision means being able to see at 20 feet what most people can see at 40 feet so that's only half as good. If you're wondering what you'd call vision that's twice as good as 20/20 that would be 20/10.
I would have absolutely no idea what it would be like to have 20/40 vision. When I first had to start wearing glasses, when I was 12, my doctor told me I had to wear them any time I was awake. I could only take them off for bathing, swimming, and sleeping. Without them, I am legally blind. My vision, until I was 58 years old was 20/400, with glasses. Today it is >20/400, meaning even with glasses I am legally blind. Actually, my right eye vision is >20/800, I have the sight for shapes and color, but not vision. My left eye is >20/400, with only central vision. No peripheral or depth perception. I cannot drive. I use a 32″ TV as my monitor, zoomed to 150% to see it. I cannot see curbs or stairs. If I am looking at someone and they side to the side by 2 steps, I can no longer see them. I would love 20/40 vision, but I will never have it.
I do not have an eye disease. I have birth-defects in my eyes that cannot be corrected. Eventually, I will be totally blind, so I enjoy what I can see now.
20/40 vision is not bad. Most people do not have 20/20 vision. As people have noted earlier you can see things clearly at 20 feet while people with 20/20 vision can see it clearly at 40 feet. I used to have 20/40 vision from about college into my 50s, then the left eye went to 20/70 (each eye can be different). At 20/40 I was not required to wear corrective lenses to drive, now I do. Most of the time I don't wear my glasses, since I don't need to, but besides driving, wear them for watching TV or movies (better clarity) and when I'm in the great outdoors to better enjoy the scenery.
The answer to this question would be relative to the person asking it because eyesight is a fraction. 20/40 being 1/2. So for somebody who has 20/20 vision, 20/40 would mean their vision would be half as sharp (many variables are included such as distance of blurriness etc). Each fraction pertains to one eye. For example you can have 20/20 vision in your right eye and 20/40 in your left eye.
Its equal to 6/12 vision
One sees the world like one huge Impressionist painting.