Well, I believe that nobody has got the evidence that mood condition directly affect our vision. Anyway, any theory must be based on evidence, right? But, from what I know, bad mood,even depression, will definitely affect our health.Consequently, it might be possible that our vision would be affected. Common sense tells that mental condition and physical condition are not separated, they are linked with each other. So, I suggest you keep a good mood and have a optimistic attitude to everything you encounter, there's nothing to be worried about right?Just live your life.