A "red eye" can be caused by many conditions. Some causes are common and readily identified while others may be subtle. It is important to distinguish those conditions that can have serious consequences to the patient from those that are more mundane.
Differential diagnosis of red eye:
(1) bacterial infection
(2) viral infection
(3) other infection (fungal, parasitic)
(4) uveitis
(5) iritis
(6) keratitis
(7) acute glaucoma
(8) allergic conjunctivitis
(9) dry eye
(10) blepharitis
(11) scleritis
(12) episcleritis
(13) topical drug or chemical reaction
(14) foreign body
(15) contact lens use
(16) occult conjunctival injury
(17) factitious injury
(18) entropion
(19) lagophthalmos
(20) trichiasis (ingrowth of the eyelashes)
(21) blepharitis (inflammation of the eyelids)
(22) cellulitis in orbital soft tissues
(23) ocular pseudotumor
(24) ocular neoplasm
The initial assessment should include an evaluation for:
(1) ocular pain
(2) blurred vision
(3) photophobia
(4) itching of the eyes
(5) type of discharge (none, watery or purulent)
(6) examination for foreign bodies or focal lesions
Common Findings |
Consider |
purulent discharge |
bacterial conjunctivitis |
watery discharge AND no itching |
viral conjunctivitis |
watery discharge AND itching |
allergic conjunctivitis |
no pain AND no vision blurring AND no discharge AND itching |
dry eye, allergic conjunctivitis, blepharitis |
A patient should be referred to an ophthalmologist if the patient has:
(1) ocular pain
(2) blurred vision with photophobia
(3) suspicion that the patient has uveitis, iritis, keratitis, acute glaucoma, intra-ocular foreign body, tumor, chemical exposure or any significant ocular pathology
Specialty: Ophthalmology, Infectious Diseases, Immunology/Rheumatology
ICD-10: ,