Question
After surgery for strabismus, everything seemed much 'smaller' or 'farther away' suddenly, dependig on how I interpreted the size difference. Especially inside buildings, walls and ceilings appeared too far away. My own hands seemed tiny. This eventually went away on its own, but what could have caused it? I'm just curious.
(Jake)
Answer:
The phenomenon that you describe seems very interesting. I am not definitely sure about its cause, but it may well have to do with a very complex matter, i.e. the mental size of an image is corrected for distance in the brain.
To illustrate this to normal, binocularly viewing people, they could do the following experiment:
a. Put two identical coins 5 cm apart on a whit piece of paper, both with identical images, both upright. Squint to the effect (not everybody can do this !) that you first see 4 coins, then let the middle 2 fuse until you see 3, only the center coin with both eyes. Wait until the image focuses. Remember its size.
b. Now quasi look in the distance. Again you will first see 4, later if you try hard enough 3. Wait until the center coin focuses. It will look much bigger than in case (a).
Why ? In case (a) the left eye viewed the right coin and vice versa, whereas in case (b) the left eye viewed the left coin and vice versa. The only difference between the two conditions was the presence of convergence in case (a).
This may well have changed after the strabismus surgery: I assume you were operated for a phoria, i.e. you could bring the two images together by convergence. After surgery, you needed less convergence, and the mental size of the image was smaller.
Please let me know what you think of this interpretation and give details of your case when the interpretation is wrong.
(Herb Simonsz, MD, PhD)
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