After applying some comfortable eye drops, the tears on my face dried up and there was a white scab. Why?

Eye protection and warm tips

If you spend too much time using the computer or playing with your mobile phone, if you feel dry eyes, or if your eyes are hot, tearful and itchy when you close your eyes, you must stop immediately and look far away so that your eyes can rest, so as not to cause serious eye inflammation. Take a break and put on a golden blindfold! Can protect your eyes from harm!

Gold eye patch-medical grade does not explain.