Recently I have taken viagra sildenafil 100 mg two times in the same week. After taking Viagra it seems that my eyes got weakened while I have a good eyesight before. Now sometimes only sometimes like 10 out of 1 time I found difficulty in watching far sight small things. Also I feel some light pain in the black portion of the eye (iris or retina don't know what it is called as) Is there any major issue? Or it will go by itself? It's been 1 week I am experiencing all this. Please help doctor!