Helmut had suffered a bizarre accident that affected his eyesight.
The doctor said it would be temporary, but for the next 4 weeks, he will have to adjust how he did some things. The accident had affected his focal length. He was only able to focus on objects that were a distance of 6 feet or more away from him.
Helmut was used to shaving close in front of his bathroom mirror. Now, after the accident, how close could Helmut get to the mirror to to see his face clearly enough to shave?
I'm sure the author's intention to to bring out the fact that the virtual image is, in all ways, twice as far from the subject (the person viewing) as the mirror itself. In that point of view, Helmut should be 3 feet away from the mirror so his image is optically 6 feet away, both stereoscopically and for purposes of focussing.
If the problem is focussing, a better solution would be a pair of reading glasses. The three-foot distance of the intended solution, entailing a 6-foot distance to the image, leaves a lot to be desired regarding seeing detail on his face, as well as difficulty finding a place to stand that dives him a view of the image, as the fram of the mirror must include a line of sight between himself and the image.
If, however, the problem lies with the convergence of the eyes (stereoscopic vision), the doctor could have prescribed prismatic component to his lenses so the eyes need not toe-in so much, for the purpose of shaving. Of course he should not wear such glasses regularly, lest his eye-brain system become used to that arrangement.
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Posted by Charlie
on 2022-10-23 09:10:44 |
discussion
