Post Strabismus surgery problem

Hello. I am 59 and had retinal reattachment, vitrectomy on my right eye about 3 years ago.
I ended up with muscle damage and have diplopia (image elevated and lateral). I had an inferior rectus recession of 3.5mm about a year ago. The lateral deviation is very little (according to my  Ped. Ophth) .
I still have  vertical deviation (and the lateral)-on exam, my eyes are aligned by the cover/uncover exam, and they are not misaligned by visual exam (they never were).  My Ped Ophth says that the vertical is corrected and that the lateral is so little that an op on that doesn't make sense.
My question is-if the inferior rectus recession of 3.5mm brought the eye into alignment, why does it "drift" vertically after the recession-I sho;uld explain, upon first looking at something (distance or close up), initially the eyes align the image, but after 5 or 10 seconds I start to get a second image above and lateral to the original-it slowly drifts so that I end up with a second image.
Thanks for any help.

[John C Hagan III, MD, FACS, FAAO]

The eye muscle postions are not static like pointing a search light. They are dynamic and affected by multiple factors that determine fusion.  Ask your pediatric ophthalmologist to review this in more detail and give you specific details next visit.

JCH MD