follow up query on what 20/20 means

Subject: follow up query on what 20/20 means

Date: Wed Feb 11 08:26:28 2004
Posted by David Hurlburt
Grade level: grad (science) School: n/A
City: Ypsilanti State/Province: MI Country: USA
Area of science: General Biology
ID: 1076509588.Gb

Message:


In a response, Dr. Kenton L. McWilliams, O.D wrote, "Someone with 20/20 vision 
can resolve an object at 20 feet that subtends (occupies) an area of 1 minute 
of arc."  That cannot be correct, because that would make the letter at 20 ft 
away 0.069 inches.  Are you sure it isn't 1 degree - which would make the 
letter 4.2 inches tall.  Or 1/2 degree => 2 inch tall letters.

Re: follow up query on what 20/20 means

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