- CN III palsy (diabetic neuropathy, PICA aneurysm) - pupil may be normal or dilated
- Myasthenia gravis
- Botulism
- Age-related (sagging eyelid)
- Eyelid inflammation or deformity (aponeurotic ptosis due to levator disinsertion)
- Congenital
- Progressive external ophthalmoplegia (mitochondrial myopathy)
CONSTRICTED PUPIL
- Horner's syndrome