Eye chart test 20/40?!
Question: Eye chart test 20/40?
I recently decided to join the Navy to become a SEAL, it is required that you have vision no worse than 20/40 in one eye and 20/70 in the other, correctable to 20/20, no color blindness.
Now instead of paying like $50 for an eye exam, if I was to print out a eye chart and use it, would it be accurate?
And if a 20/20 person can see at 40ft what a 20/40 person can at 20ft, would it be equivalent if I stood 10ft away from the eye chart to test if I was 20/40 or not? Sort of like reducing the ratios if you know what i mean.
Now instead of paying like $50 for an eye exam, if I was to print out a eye chart and use it, would it be accurate?
And if a 20/20 person can see at 40ft what a 20/40 person can at 20ft, would it be equivalent if I stood 10ft away from the eye chart to test if I was 20/40 or not? Sort of like reducing the ratios if you know what i mean.
Answers:
Yes, however 10 feet is a rather short distance. You could be 20/40 at 10 feet even if you were not properly corrected for distance.
Try using a longer test distance.
You can make an eye chart. The letters are 5 minutes of angle high for 20/20. I believe that's 8.9 mm high for 20/20 letters at 20 feet.
20/40 letters are twice that tall. 20/70 letters are 3 1/2 times as tall.