amblyopia and crossed eyes continued...

Okay...thank you that was helpful and reassuring. As it turns out she didn't have her glasses on today at school....I can not remember if she had her glasses on or off the other time that I noticed her eyes crossed. So can you explain why her eyes cross when she takes off the patch and doesn't have the glasses on? Thank you! I am so happy to get an understandable reponse.

[Forum-OD-MP]

well, its complicated but i'll give it a shot.

most non-surgical cases of "crossed" eyes are from "accommodative esotropia", or significant FARSIGHTEDNESS in one or both eyes that causes a crossed eye.

this gets a little hard to explain, but a human cannot "focus" their eyes without also "crossing" them at the same time.  you cant do one w/o the other.  its impossible.  if you focus your eyes, you must also converge them simultaneously.  well a farsighted person must "focus" their eyes in order to see clearly.  consequently, as soon as they focus enough to clear the image up, their eyes cross significantly.  so w/o glasses on, all significantly farsighted kids end up crossing one or both eyes.  we see this all the time.  i see it almost daily at my office.  my son had this problem at age 3 (i was not an eye doc at that time...i was in college).

the glasses is what "uncrosses" your daughter's eyes.  they take away the need to focus in order to see clearly.  now your daughter sees clearly w/o focusing, so she doesnt cross either.  the patch does nothing for the uncrossing.  the patch just forces her to use or look through the eye that was formerly crossed.  a crossed eye doesnt develop very well (thats the "amblyopia"), and the patch kind of rehabilitates the VISION in the formerly crossed & ignored eye.

hard to wrap your brain around.  hard to explain as well.  but really common.  i think something like 8% of all school aged children have amblyopia.