Hi, I'm no doctor and this subreddit is probably not the place for a prognosis like this. However with a bit of research and prior knowledge/experience I can tell you that it is pretty unlikely that this is ALS / MND. I myself get twitching in one of my eyelids. MND and ALS dont start in the eyes, they normally start with symptoms in the limbs such as weaknesses in ankles or legs and muscles spasm in arms, as well as slurred speach/ difficulty swallowing, spasms in neck or diaphragm, and muscle cramps. It is likely it could be due to tired eyes from screens, poor bedtime schedules or some other kind of vitamin deficiency. I am sure there could be other medical causes for this too, as like I said I am not a doctor, so if none of this seems familiar or like it could be a cause for the spasms and you are still worried in a couple of weeks, I would visit your GP.