For all the eye docs?

Question

when you give someone an eye test how far do you test their vision for distance

Answer 1

The standard eye exam is set for a distance of 20 feet.  This is because, optically speaking, light entering the eye from a source 20 feet away from the viewer is basically a flat wavefront just like light coming from an object say a mile away.   So rather than have the patient look at an object a mile away through a window for instance, it is simpler (and you get the same results) to set the object (projector screen) 20 feet away in an enclosed room.  Some doctors use shorter rooms than 20 feet and use mirrors to manipulate the optics so that the image APPEARS to be coming from 20 feet or more away.

Answer 2

They will test your vision to make sure your 20/20 by doing a couple of tests. One will have you keep your eyes open and will do a reading from there. Another will make you cover one eye and then another and your eye doctor will put lenses over your eyes to see if you need glasses.

Your doctor may also put eye drops in a dialte your eyes to make sure you don't have any problems.

Best Wishes!