Arimidex and double vision

I had a mastectomy over 3 years ago and took Tamoxifen for 3 months and it was then changed to Arimidex as the hot flushes were unbearable. On Arimidex I still have hot flushes and joint pains but now 3 and a half years on I have started to have intermittent (not every day) episodes of double vision lasting about a minute each time. I see that one of the side effects of Arimidex is vision problems but I can’t find out anywhere what they are. Has anyone experienced double vision on Arimidex? The optician says I do not have a tumour at the back of my eyes and eyesight is fine. I’d love to hear from anyone who can shed some light for me.
Thanks