Clinical Notes : Ophthalmology

48. Red Eye

Patients with eye problems account for up to 5% of all general practice consultations (1,2) 

Red eye is a particularly common condition that is caused by inflammation or infection of the eye (2)


  • Common causes of a red eye include conjunctivitis (viral, bacterial, allergic or chemical), foreign body, corneal ulceration and subconjunctival haemorrhage.

  • Uncommon causes include iritis, scleritis, episcleritis and glaucoma.

  • A discharging non-red eye in infants is most likely due to nasolachrymal duct obstruction.


Eye examination in primary care

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Always document :

  • onset and duration of the symptoms

  • whether symptoms are unilateral or bilateral

  • changes in visual acuity

  • pain

  • foreign body sensation

  • discharge

  • photophobia

  • medication

  • history of

    • contact lens use

    • trauma

    • chemical exposure

  • Any relevant past medical history

    • hypertension

    • inflammatory bowel disease

    • connective tissue disorders ​


Red flags

NICE recommends urgent same-day assessment by an ophthalmologist or emergency referral for the following features, which may indicate serious underlying pathology for red eye presentation: (3)

  • reduced vision

  • deep pain in the eye or tenderness of the globe on palpation

  • contact lens use

  • high-velocity injury

  • chemical eye injury

  • fluorescein staining of the eye

  • photophobia

  • corneal foreign body

  • distorted pupil

  • neonatal conjunctivitis



Inflammation of the cornea — the clear, dome-shaped tissue on the front of your eye that covers the pupil and iris. Keratitis is sometimes caused by an infection involving bacteria, viruses, fungi or parasite


Acute Angle-Closure Glaucoma

Unlike POAG (Primary Open-Angle Glaucoma), where the IOP (Intra-Ocular Pressure) increases slowly, in AACG (Acute Angle-Closure Glaucoma), it increases suddenly.

This sudden rise in pressure can occur within a matter of hours and become very painful. If the pressure rises high enough, the pain may become so intense that it can cause nausea and vomiting.
The eye becomes red, the cornea swells and clouds, and the patient may see haloes around lights and experience blurred vision.



Uveitis is the inflammation of the uvea.

The uvea consists of the middle layer of pigmented vascular structures of the eye and includes the iris, ciliary body, and choroid.

Possible causes of uveitis are infection, injury, or an autoimmune or inflammatory disease. Many times a cause can't be identified.



Scleritis is a chronic, painful, and potentially blinding inflammatory disease that is characterized by edema and cellular infiltration of the scleral and episcleral tissues (outermost coat of the eye). Scleritis may be isolated to the eye, but is commonly associated with systemic autoimmune disorders, including rheumatoid arthritis, systemic lupus erythematosus, relapsing polychondritis, spondyloarthropathies, Wegener granulomatosis, polyarteritis nodosa, and giant cell arteritis.

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1.  Kilduff C, Lois C.

Red eyes and red-flags: improving ophthalmic assessment and referral in primary care.

BMJ Quality Improvement Reports 2016; 5: u211608.w4680.


2.  Cronau H, Kankanala R, Mauger T.

Diagnosis and management of red eye in primary care.

Am Fam Physician 2010: 81 (2): 137–144.


3.  NICE. Red eye.

NICE Clinical Knowledge Summary.

NICE, 2016. 


4.  Smith J, Severn P, Clarke L.

BMJ best practice—assessment of red eye.

BMJ, 2018. 


5.  Chong N, Murray P.

en torch test in patients with unilateral red eye.

Br J Gen Pract 1993; 43 (371): 259.


6.  Acute Red Eye

The Royal Children's Hospital Melbourne

Online : accessed May 2017


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