Hi llevesqu and welcome to this forum .....
Sorry you are experiencing new symptoms this many years post-op. I am not a doctor, but double vision is not a typical symptom of tumor regrowth. However, everyone is individual/unique so you definitely need another MRI with contrast to be sure.
I had surgery to remove a 2.6 cm acoustic neuroma (via retrosigmoid/suboccipital approach) in February, 2008, with the surgeon assuring me it was total tumor removal. On the first MRI 5 months post-op, there was an "area of enhancement" that both the reading radiologist and the neurosurgeon felt was surgical changes/scar tissue. Subsequent MRIs continued to show this same area until February, 2011 when it had grown 3 mm from the previous year. It was then read as a 1.3 cm recurring acoustic neuroma. My only new symptoms were a tiny bit of additional hearing loss (I had maintained 20% of my hearing after surgery.)
Yes, current research still says that treated ANs can regrow 5-9% of the time.
Because of massive doses of radiation to my head as a teenager, I am not a good candidate for radiation treatment. Therefore, my AN was surgically removed a second time, via translabyrinthine approach in May, 2011.
I am, of course, deaf in my AN ear now and have some stability issues due to no vestibular system on either side ...... but, otherwise, doing everything I would have been doing if none of this had happened. I feel very fortunate in so many ways.
Private message me if you have any specific questions on my situation.
Clarice