I have been on Neurontin since about last June starting at about 800mg and worked up to 1600mg. I have had problems with my eyesight as well including vertical double vision and vision deterioration with some blurring and double vision. I am currently undergoing a weaning from Neurontin and Tegretol and I am still having trouble with my eyesight.
I guess I am of no real help as they have not come up with any other reason for the vertical double vision although it occured while I was having other symptoms at the same time and they don't feel that it is a relapse of MS.
I, myself would talk to my pharmacist at the very least and see what he thinks and if he thinks it best to speak to your doctor about it. One would hope that your physician is aware that Neurontin can cause double vision but like I say, be proactive to cover your own backside...it's the only way you can be sure!
I have been on neurontin for a year now, and don't have double vision as a side effect. I have however suffered from the side effect of weight gain.
Neurontin can cause a wide variety of side effects, many of which are exactly the same as some of the symptoms that we might have had to begin with. For example, I suffer from dizziness and vertigo, and a decrease in my fine motor skills and sensation in my hands.
My neuro and I talked about these symptoms and she pointed out that we won't know if my symptoms cleared up and if I'm now suffering side effects of the Rx, or if the symptoms are still the symptoms of my neuro issues. Unfortunately we won't know for sure until I'm off the neurontin, and because of the chronic pain I suffer from, that is unlikely to happen soon.
You didn't mention why you've been prescribed neurontin. However, most likely your neuro thought that managing your condition (pain? spasticity?) outweights any potential risks of side effects of the drug.
Talk to your neuro about it if you have doubts. That is always the safest way to go.