it sounds like you may have 2 issues going on. Can you tell me a bit more about the dark area tha moves when you look side to side. When did it come on ? any flashing lights ? do they seem like floaters if you are familiar with that term ?
Second, what type of implant was used, multifocal (bifocal) or distance correction lens ? What did the ophthalmologist say about these ?
if you dont know what type of implant was placed, it must have been the standard distance correction only lens, which is a wonderful lens and has less risk for glare and haloes. If you are seeing the dark spot off to the side, this is called lens edge dysmorphopsia, basically blurred and dark vision due to light crossing the edge of the lens. If there is central glare and starburst effects in low light conditions, you may have a posterior capsule opacity, a scar forming on the membrane that is holding the implant in place. What you need to do is get in with the surgeon and let him look at the implant and check for posterior capsule opacity (secondary cataract) and check to make sure lens is centered. The posterior capsule opacity can be lasered clean quickly. If the lens is centered, the dark vision off to the side may simply be something you may have to live with, obviously we need to make sure there is no other retinal problem that can be accounting for that as well, Best wishes, Dr. Stevens