In ophthalmology,<unk> is an abnormally low position (drooping) of the upper eyelid. The drooping may be worse at night, when the individual's muscles are tired. This condition is sometimes incorrectly referred to as a "lazy eye," a separate condition known as Amblyopia. If severe enough and left untreated, the drooping eyelid can cause other conditions, like Amblyopia or Astigmatism. This is why it is especially important for this disorder to be treated in children at a young age, before it can interfere with vision development.
Ptosis 
Photophobia
Mydriasis
Excessive tearing
Athetosis
Oscillopsia
Nystagmus
Quassia