It's an eye chart, but all backwards and with big letters at the bottom! Why? Any ancient optometrists in the audience? A nice conversation piece for the front room, non?
Tuesday, January 01, 2008
One more Christmassy post
I meant to blog this before now. I saw it out in the Beaches at a little antiques store, and hemmed and hawed about it, and then went back a couple of weeks later, being careful to take my friend who always buys more than me, just to make me feel better. (She did indeed buy more than me, yet again!) I gave it to Stephen for Christmas, but maybe it was really for me...
It's an eye chart, but all backwards and with big letters at the bottom! Why? Any ancient optometrists in the audience? A nice conversation piece for the front room, non?
It's an eye chart, but all backwards and with big letters at the bottom! Why? Any ancient optometrists in the audience? A nice conversation piece for the front room, non?
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I know why! At least, I know why the letters are all backwards. It's so you can do optometry tests in a small room, using a mirror to double the effective length of the room. The chart is mounted on the wall behind and above the patient's head, and they view it in a mirror on the opposite wall. The optometrist I went to in my home town had one just like it. Except with the big letters at the top. Happy New Year!
ReplyDeleteBah! Alison beat me to it - I was going to say exactly the same thing - the chart should be 6m from the patient, which is quite a long way, so placing it on the wall of a 3m room with a mirror makes much more sense. (Incidentally, 20-20 vision refers to being able to see objects clearly 20m away that should be seen at 20m. Most people have 6-3 vision (with specs if they need them) - i.e. they can see at 6m objects that are expected to be seen at 3m.
ReplyDeleteCan't tell you why the letters get bigger at the bottom rather than at the top though.