Painful
Caustic keratoconjunctivitis
Ocular foreign body
Orbital trauma
Contact lens problems
Conjunctivitis
Blepharitis
Allergic reaction
Thyroid disease
Carotid-cavernous fistula
Painless
Conjunctivitis
Blepharitis
Allergic reaction
Thyroid disease
Caustic keratoconjunctivitis
Ocular foreign body
Orbital trauma
Contact lens problems
Conjunctivitis
Blepharitis
Allergic reaction
Thyroid disease
Carotid-cavernous fistula
Conjunctivitis
Blepharitis
Allergic reaction
Thyroid disease
Bilateral red eyes
Painful
Unilateral red eye
Caustic keratoconjunctivitis
Red eye 
Ocular foreign body
Ocular palsy
Orbital trauma