Monocular diplopia

My 7 year old daughter began to see double (verticle) out of her right eye only about a month ago.  Left eye is fine and both eyes together see fine. I did a pinhole test and the double vision went away in that eye.  Then, just this week, her double vision went away.  Any ideas what is going on?  She sees an ophthalmologist in 4 weeks.

Note that she has a very tiny chalazion high up on the upper eyelid of that eye.

[Doreen Fazio, M.D.]

It is possible that the chalazion may be distorting the lid and inducing some astigmatism.  This will go away when the chalazion resolves.  Until you see the ophthalmologist, do some warm compresses on the lid, which may help resolve the chalazion.  Monocular diplopia is usually due to uncorrected refractive error, such as astigmatism, near- or far-sightedness.