About three days ago I suddenly noticed astigmatism/double vision in my right eye, I started to see the light sources stretched to one side or if say, double. I searched the internet and I've found monocular diplopia, with further search I realized monocular diplopia can't happen all of sudden (I'm not sure yet)
I saw an ophthalmologist yesterday, she said I have irregular astigmatism, and it is probably due to keratoconus, she sent me to see a corneal specialist. I insisted that I didn't have this problem before, but she said it is not possible and you probably had it for a long time.
But I'm very sure that I didn't have any of my current symptoms before, but now I see the light bulbs or any bright objects stretched to one side with my right eye and I can't work with my PC as long as before.
Other than keratoconus, what else can cause a sudden onset astigmatism/double vision in one eye only?