What does sudden onset double vision in the left eye mean? i am a 76 year old man.

Double : Double vision is almost always binocular (with both eyes open). Lots of things can cause this - most are benign and will self correct (high blood pressure, diabetes, - any microvascular disease). I recommend seeing your local ophthalmologist (www.Aao.Org) to have it looked at. It may be something more serious and they can help you decide if it is truly monocular or binocular and act appropriately.

You : You need to be sure that the double vision is only in one eye. Cover your left eye and see if it is single, then cover the left one and do the same. If you only have double vision with both eyes open, it is most likely a problem with a nerve controlling one eye movement muscle. This is seen most often in diabetic patients, and those with high blood pressure. So if your double vision is only with both eyes open, you need to see your primary care doctor. If the double vision is truly only in the left eye, then you may have a problem in the retina in the back of your eye. For this problem, you need to see your ophthalmologist, and have the dilate that eye.

I : I agree with dr. Goldstein. First identify the double vision as being monocular or binocular in nature as dr. Goldstein explained. Either way, a visit to a physician seems to be order.