SSRIs decrease the concentration of acetylcholine in the brain as a side effect of its mechanism to increase serotonin. Acetylcholine is important in constricting the pupil allowing the correct amount of light into the eye dependent on the environment. I think it also affects the lens muscles too. Basically it means you can't focus properly which gives you blurred vision.

I've been on several SSRIs but not all gave me blurred vision. I'm afraid I can't remember which ones did/not cause that, but I do remember that the side effect eventually went away, or I just got used to it. You say that Prozac/fluoxetine didn't cause it, so maybe there is another SSRI that wouldn't cause blurred vision without the side effects of Prozac? You could always try another class like SNRI such as venlafaxine or even a tricyclic as some are less likely to cause blurred vision than others. Unfortunately it requires you to try it and see as there's no guarantee what works for one works for another with these things.

All the best,

*Willow*