Aetiology

Aetiology

The causes of acute red eye can be considered within the following categories: [4]

Adnexal causes

  • Trichiasis: posterior misdirection of the eyelashes from the normal site of origin com.bmj.content.model.assessment.Caption@557ca915 [Figure caption and citation for the preceding image starts]: Trichiasis Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Entropion: inward turning of the eyelid margin com.bmj.content.model.assessment.Caption@b45887d [Figure caption and citation for the preceding image starts]: Entropion Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Ectropion: outward turning of the eyelid margin com.bmj.content.model.assessment.Caption@634546ba [Figure caption and citation for the preceding image starts]: Ectropion Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Blepharitis: inflammation of the eyelid margin com.bmj.content.model.assessment.Caption@47fd3af6 [Figure caption and citation for the preceding image starts]: Blepharitis Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Dry eye: symptoms or signs consistent with a deficiency of the precorneal tear film. com.bmj.content.model.assessment.Caption@7779071d [Figure caption and citation for the preceding image starts]: Dry eye (stained with rose bengal) Private collection - courtesy of Mr Hugh Harris [Citation ends].

Conjunctival causes

  • Bacterial conjunctivitis: inflammation of the conjunctiva caused by bacterial infection com.bmj.content.model.assessment.Caption@50d87fef [Figure caption and citation for the preceding image starts]: Bacterial conjunctivitis Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Viral conjunctivitis: inflammation of the conjunctiva caused by viral infection com.bmj.content.model.assessment.Caption@196193d8 [Figure caption and citation for the preceding image starts]: Viral conjunctivitis Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Allergic (vernal) conjunctivitis: inflammation of the conjunctiva occurring during an allergic response com.bmj.content.model.assessment.Caption@37e52088 [Figure caption and citation for the preceding image starts]: Allergic (vernal) keratoconjunctivitis Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Neonatal conjunctivitis: inflammation of the conjunctiva within the first month of life

  • Subconjunctival haemorrhage com.bmj.content.model.assessment.Caption@89b8886 [Figure caption and citation for the preceding image starts]: Subconjunctival haemorrhage Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Subtarsal foreign body com.bmj.content.model.assessment.Caption@1b2fa97d [Figure caption and citation for the preceding image starts]: Subtarsal foreign body: vertical corneal abrasions seen with fluorescein stain Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Conjunctival foreign body.

Corneal causes

  • Bacterial corneal ulcer: corneal epithelial defect caused by bacterial infection com.bmj.content.model.assessment.Caption@e451693 [Figure caption and citation for the preceding image starts]: Corneal ulcer seen with fluorescein stain Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Viral corneal ulcer: corneal epithelial defect caused by viral infection com.bmj.content.model.assessment.Caption@10ba96b3 [Figure caption and citation for the preceding image starts]: Dendritic ulcer seen with fluorescein stain Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Fungal corneal ulcer: corneal epithelial defect caused by fungal infection

  • Contact lens-related

  • Corneal foreign body com.bmj.content.model.assessment.Caption@44b1f39a [Figure caption and citation for the preceding image starts]: Corneal foreign body Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Corneal abrasion: corneal epithelial defect usually caused by trauma. com.bmj.content.model.assessment.Caption@2233ce30 [Figure caption and citation for the preceding image starts]: Corneal abrasion seen with fluorescein stain Private collection - courtesy of Mr Hugh Harris [Citation ends].

Inflammatory causes

  • Anterior uveitis: inflammation of the anterior portion of the uveal tract com.bmj.content.model.assessment.Caption@4e4b56b [Figure caption and citation for the preceding image starts]: Anterior uveitis with posterior synechiae Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Scleritis: inflammation of the sclera com.bmj.content.model.assessment.Caption@402fb44a [Figure caption and citation for the preceding image starts]: Scleritis Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Episcleritis: inflammation of the episclera. com.bmj.content.model.assessment.Caption@b49a2f6 [Figure caption and citation for the preceding image starts]: Episcleritis Private collection - courtesy of Mr Hugh Harris [Citation ends].

Traumatic causes

  • Physical com.bmj.content.model.assessment.Caption@37b7bfe1 [Figure caption and citation for the preceding image starts]: Penetrating corneal injury with iris prolapse Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Chemical.

Other

  • Angle-closure glaucoma: closure of the iridocorneal angle leading to an acute rise in intra-ocular pressure. com.bmj.content.model.assessment.Caption@16d91b91 [Figure caption and citation for the preceding image starts]: Angle-closure glaucoma: central corneal oedema with an oval-shaped mid-dilated pupil. Private collection - courtesy of Mr Hugh Harris [Citation ends].

Most common conditions

Those commonly presenting to a primary care physician are:

  • Infective conjunctivitis [5] com.bmj.content.model.assessment.Caption@2be970e4 [Figure caption and citation for the preceding image starts]: Bacterial conjunctivitis Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Allergic conjunctivitis com.bmj.content.model.assessment.Caption@6d71297d [Figure caption and citation for the preceding image starts]: Allergic (vernal) keratoconjunctivitis Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Dry eye and other adnexal problems. [6] com.bmj.content.model.assessment.Caption@67b3db85 [Figure caption and citation for the preceding image starts]: Dry eye (stained with rose bengal) Private collection - courtesy of Mr Hugh Harris [Citation ends]. com.bmj.content.model.assessment.Caption@39685171 [Figure caption and citation for the preceding image starts]: Entropion Private collection - courtesy of Mr Hugh Harris [Citation ends]. com.bmj.content.model.assessment.Caption@59e668e8 [Figure caption and citation for the preceding image starts]: Trichiasis Private collection - courtesy of Mr Hugh Harris [Citation ends]. com.bmj.content.model.assessment.Caption@3d388868 [Figure caption and citation for the preceding image starts]: Blepharitis Private collection - courtesy of Mr Hugh Harris [Citation ends]. com.bmj.content.model.assessment.Caption@442e13b9 [Figure caption and citation for the preceding image starts]: Ectropion Private collection - courtesy of Mr Hugh Harris [Citation ends].

Sight-threatening causes

Causes of red eye that can threaten vision by leading to reduced visual acuity include:

  • Angle-closure glaucoma com.bmj.content.model.assessment.Caption@3fb62194 [Figure caption and citation for the preceding image starts]: Angle-closure glaucoma: central corneal oedema with an oval-shaped mid-dilated pupil. Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Chemical injuries

  • Conditions affecting the cornea

  • Trauma

  • Anterior uveitis. com.bmj.content.model.assessment.Caption@55fdafa2 [Figure caption and citation for the preceding image starts]: Anterior uveitis with posterior synechiae Private collection - courtesy of Mr Hugh Harris [Citation ends].

Causes of red eye that can threaten vision by leading to globe rupture or perforation include: com.bmj.content.model.assessment.Caption@2c7f06bd [Figure caption and citation for the preceding image starts]: Penetrating corneal injury with iris prolapse Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Scleritis com.bmj.content.model.assessment.Caption@18f86b50 [Figure caption and citation for the preceding image starts]: Scleritis Private collection - courtesy of Mr Hugh Harris [Citation ends].

  • Physical trauma

  • Corneal ulceration

  • High-velocity foreign bodies.

These are discussed further with initial management in Emergencies: Urgent Considerations.

Risk factors

Risk factors associated with specific causes of red eye include:

  • Anterior uveitis: com.bmj.content.model.assessment.Caption@16cc535a [Figure caption and citation for the preceding image starts]: Anterior uveitis with posterior synechiae Private collection - courtesy of Mr Hugh Harris [Citation ends]. HLA-B27 histocompatibility complex-positive patients, tuberculosis, syphilis, Lyme disease, sarcoidosis, Behcet's disease, and pauciarticular juvenile chronic arthritis.

  • Scleritis: com.bmj.content.model.assessment.Caption@2e747e9e [Figure caption and citation for the preceding image starts]: Scleritis Private collection - courtesy of Mr Hugh Harris [Citation ends]. connective tissue disorders including rheumatoid arthritis, granulomatosis with polyangiitis (Wegener’s), systemic lupus erythematosus (SLE), and relapsing polychondritis.

  • Episcleritis: com.bmj.content.model.assessment.Caption@7aeacf03 [Figure caption and citation for the preceding image starts]: Episcleritis Private collection - courtesy of Mr Hugh Harris [Citation ends]. connective tissue disorders including rheumatoid arthritis, granulomatosis with polyangiitis (Wegener’s), and SLE.

  • Angle-closure glaucoma: com.bmj.content.model.assessment.Caption@219389e5 [Figure caption and citation for the preceding image starts]: Angle-closure glaucoma: central corneal oedema with an oval-shaped mid-dilated pupil. Private collection - courtesy of Mr Hugh Harris [Citation ends]. hypermetropia, mydriatics, and systemic anticholinergic medications.

  • Subconjunctival haemorrhage: com.bmj.content.model.assessment.Caption@5531480e [Figure caption and citation for the preceding image starts]: Subconjunctival haemorrhage Private collection - courtesy of Mr Hugh Harris [Citation ends]. hypertension, systemic anticoagulation, bleeding abnormalities (leukaemia, clotting disorders), conjunctival vascular lesion, trauma (including contact lens-related injury), and diabetes.

  • Dry eye: com.bmj.content.model.assessment.Caption@58bc4cb8 [Figure caption and citation for the preceding image starts]: Dry eye (stained with rose bengal) Private collection - courtesy of Mr Hugh Harris [Citation ends]. connective tissue disorders including Sjogren's syndrome, rheumatoid arthritis, and SLE.

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