Dear Pharmacist, Sometimes after I take Viagra, my vision turns blueish-grey and it gets blurry. Is this this an expected side effect? I can’t ask my doctor because he may stop prescribing it for me. --C.G., Long Island, New York Answer: Viagra, and the two other FDA approved medications for erectile dysfunction, Cialis and Levitra are blockbuster drugs that are known to affect vision and many men fear they will go blind by using these drugs. But this doesn’t stop men from using th