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Editors

MattiSeppänen

Red Eye

Essentials

  • Conditions such as acute angle closure glaucoma, suspected endophthalmitis, scleritis, iritis, keratitis or prolonged corneal ulcer require treatment by an ophthalmologist.
  • Red eye may also be a symptom of a disease leading to permanent loss of vision if diagnosed too late.
  • The most common cause of red eye is allergic or bacterial conjunctivitis.
  • Other causes that can be treated by a GP include conditions such as mild dry eye symptoms, corneal foreign body and corneal erosion.

Symptoms and findings

  • See also table T1 and picture .

Symptoms and findings related to red eye in cases that can be treated by a GP (if symptoms persist, refer the patient to an ophthalmologist)

DiagnosisSymptoms and findings
RednessDischargePain, other sensationsCorneal appearanceVisual acuity, other things to consider
Dry eye Dry Eye SyndromeConjunctival rednessWatery dischargeForeign body or gritty sensation; if prolonged, painThe lower cornea may be opaqueIn advanced cases, reduced visual acuity
Conjunctivitis ConjunctivitisConjunctival rednessBacterial: purulent discharge. Viral: clear, watery discharge.Itching, foreign body or gritty sensationClearBlurring due to discharge. In allergy, often also swelling of the eyelids.
Conjunctival or corneal foreign body A Foreign Body on the Cornea* Conjunctival or pericorneal rednessOften watery dischargeForeign body sensation or painA piece of metal often appears as a round, rusty spot.Reduced visual acuity if a corneal foreign body is in a central area.
Corneal ulcer Corneal Ulcers* Redness not necessarily presentOften watery dischargeForeign body sensation or painAn ulcer can be detected in blue light after fluorescein staining.Reduced visual acuity if a corneal ulcer is in a central area.
Superficial scleritis (episcleritis) EpiscleritisSectoral episcleral rednessNo dischargeEye tender on palpation, sensitivity to draughtClearVisual acuity often normal
Sugillation in the absence of trauma Subconjunctival Haemorrhage (Suggillation)Circumscribed, extensive, dark red patch underneath the conjunctivaNo dischargeForeign body sensationClearNormal visual acuity. Measure blood pressure, note the possibility of injury.
Intraocular pressure is usually normal in these disorders. N.B. sections marked with an asterisk (*): If the intraocular pressure is lower than in the healthy eye, note the possibility of a penetrating injury!
Conjunctival redness
  • Most pronounced at the conjunctival fornix
  • The pericorneal area typically remains light-coloured.
  • When the conjunctiva is moved, the vessels move together with it.
  • Often bilateral
  • Causes: dry eye, conjunctivitis (bacterial, viral, fungal, allergic)

Pericorneal redness, or redness surrounding the cornea

  • Circular zone of redness at the edge of the cornea
  • The anterior ciliary arteries of the eye are dilated as a sign of inflammation of the cornea, iris or the ciliary body.
  • Often unilateral
  • Causes: iritis (anterior uveitis) Iritis (Inflammation of the Iris), acute angle-closure glaucoma Glaucoma

Local redness

  • In episcleritis Episcleritis (picture ), local, often sectoral redness of the blood vessels in the connective tissue surrounding the sclera (episclera)
    • When the conjunctiva is moved with a cotton-tipped swab, the accentuated deeper blood vessels do not move.
  • In sugillation, there is a solid, dark red subconjunctival accumulation of blood.

Workup

  • If a patient with conjunctivitis has severe or prolonged symptoms, samples for microbial analysis should be taken right away. If the patient has simultaneous urinary tract symptoms, a conjunctival sample or urine sample from men and swab sample from women should be obtained to test for chlamydia.
  • Fluorescein staining (an eye drop or a fluorescein strip applied to the conjunctiva) and examination in blue light will help to differentiate between keratitis and corneal erosion Corneal Ulcers.
  • Asymmetry of the pupils, photophobia and pericorneal redness suggest iritis Iritis (Inflammation of the Iris). Vision may also be reduced in iritis.
  • Tenderness of the eye on palpation and local redness suggest episcleritis Episcleritis.
  • Clearly elevated intraocular pressure (30-50 mmHg), eyeball hard on palpation, severe pain, impaired vision, opaque cornea and a mid-dilated pupil are signs of acute angle closure glaucoma Glaucoma.

Referral to an ophthalmologist

  • If symptoms of a disease treated by a GP (table T1) are prolonged, the patient should be referred to an ophthalmologist.
    • Dry eye: if not alleviated by treatment in 1-3 months with moisturising eye drops to be used 4-6 times a day
    • Conjunctivitis: if not alleviated by treatment in 1-2 weeks or if a chlamydia infection is suspected
    • Corneal or conjunctival foreign body: if attempted removal is still unsuccessful at the second visit
    • Corneal ulcer: if it does not start healing in 4-5 days or if it is a complicated ulcer in a rheumatoid patient
    • Episcleritis: if it does not start healing in 2-3 weeks, or sooner, if scleritis is suspected
    • Sugillation in the absence of trauma: further investigations if the patient's blood pressure is elevated
  • Diseases to be treated by an ophthalmologist
    • Keratitis Corneal Ulcers
      • Pericorneal redness
      • In viral infections, clear, watery discharge, in bacterial infections possibly purulent discharge
      • Ophthalmodynia, pain, photophobia; adenovirus infections cause severe symptoms
      • Opaque cornea, inflammatory changes on fluorescein staining
      • Reduced visual acuity
    • Iritis Iritis (Inflammation of the Iris)
      • Pericorneal redness
      • Eye pain, photophobia
      • Inflammatory cells may accumulate on the inner surface of the cornea.
      • Intraocular pressure normal but may be elevated in patients with the Posner-Schlossmann syndrome
      • Visual acuity often normal at first but, as the disease progresses, often severely reduced
      • Pupil on the affected side often smaller
    • Acute angle-closure glaucoma Glaucoma
      • Pericorneal or overall redness
      • Severe eye pain, headache and nausea
      • Whole cornea opaque
      • High intraocular pressure, usually above 50 mmHg, sometimes even 80 mmHg
      • Visual acuity often severely reduced; halo phenomenon
      • Eyeball hard on palpation
    • Endophthalmitis
      • Keep this in mind particularly if symptoms occur within 2-5 days after an injection into the vitreous body or after cataract surgery.
      • Severely bloodshot eye
      • Chemosis (fluid beneath the conjunctiva)
      • Collection of inflammatory cells in the anterior chamber (hypopyon) may be seen with the naked eye as a white sediment in the anterior chamber
      • Pain, photophobia, headache
      • Opaque cornea
      • Possibly elevated intraocular pressure
      • Significantly reduced vision
    • Scleritis
      • Rare but vision-threatening if the diagnosis is delayed
      • Local redness of scleral blood vessels
      • Deeper blood vessels do not move when the conjunctiva is moved.
      • Slight watery discharge
      • Mild to severe pain; local tenderness
      • Possibly photophobia
      • Visual acuity may be reduced

    References

    • Seppänen M, Kaarniranta K, Setälä N, Uusitalo H (eds.). [Handbook of Ophthalmology]. 3rd revised edition. Duodecim Publishing Company 2022. Available in Finnish.