Redness may be due to hyperemia of the conjunctival, ciliary, or episcleral vessels; erythema of the eyelids; or subconjunctival hemorrhage (eFigure 7–1). The major differential diagnoses are conjunctivitis, corneal disorders, acute glaucoma, and acute uveitis (see Table 7–1).
Spontaneous subconjunctival hemorrhage while receiving warfarin. (From the University of California, Davis, Cornea and External Diseases. Reproduced, with permission, from Riordan-Eva P, Augsburger JJ. Vaughan & Asbury’s General Ophthalmology, 19th ed. McGraw-Hill, 2018.)
Table 7–1.The inflamed eye: differential diagnosis of common causes. |Favorite Table|Download (.pdf) Table 7–1. The inflamed eye: differential diagnosis of common causes.
| ||Acute Conjunctivitis ||Acute Anterior Uveitis (Iritis) ||Acute Angle-Closure Glaucoma ||Corneal Trauma or Infection |
|Incidence ||Extremely common ||Common ||Uncommon ||Common |
|Discharge ||Moderate to copious ||None ||None ||Watery or purulent |
|Vision ||No effect on vision ||Often blurred ||Markedly blurred ||Usually blurred |
|Pain ||Mild ||Moderate ||Severe ||Moderate to severe |
|Conjunctival injection ||Diffuse; more toward fornices ||Mainly circumcorneal ||Mainly circumcorneal ||Mainly circumcorneal |
|Cornea ||Clear ||Usually clear ||Cloudy ||Clarity change related to cause |
|Pupil size ||Normal ||Small ||Moderately dilated ||Normal or small |
|Pupillary light response ||Normal ||Poor ||None ||Normal |
|Intraocular pressure ||Normal ||Usually normal but may be elevated ||Markedly elevated ||Normal |
|Smear ||Causative organisms ||No organisms ||No organisms ||Organisms found only in corneal infection |
et al. Clinical evaluation of red eyes in pediatric patients. J Pediatr Health Care. 2016 Sep–Oct;30(5):506–14.
et al. Approach to red eye for primary care practitioners. Prim Care. 2015 Sep;42(3):267–84.
et al. Red eye: a guide for non-specialists. Dtsch Arztebl Int. 2017 Apr 28;114(17):302–12.
et al. More than meets the (painful red) eye. Aust Fam Physician. 2016 Jun;45(6):383–4.
et al. Ocular emergencies: red eye. Med Clin North Am. 2017 May;101(3):615–39.
Ocular pain may be caused by trauma, infection, inflammation, or rapid or marked increase in intraocular pressure.
Foreign body sensation may be due to corneal or conjunctival foreign bodies, disturbance of the corneal epithelium, or rubbing of eyelashes against the cornea (trichiasis).
Photophobia is usually due to corneal inflammation (keratitis) or anterior uveitis (iritis). Other causes are albinism, aniridia, cone dystrophy, or fever associated with various systemic infections.
Itching is characteristically associated with allergic eye disease.
Scratching and burning from dryness of the eyes may be due to lacrimal gland hypofunction, secondary to systemic disorders (eg, Sjögren disease) or drugs (eg, atropine-like agents); ocular surface disease; or dry environment.