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@3a534f87 [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@861ee15 [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@34f35da8 [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@4df793d0 [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@6d78d29e [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@6a6e8862 [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@44de869a [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@35c6e4c2 [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@1e813cc6 [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@b28aec [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@30683636 [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@320a240d [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@257a5986 [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@310b422f [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@40a31bbe [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@236a75eb [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@54abbe69 [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@3fda84e9 [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@67fc0647 [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@17c9f27e [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@1e185e18 [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@758e7cfe [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@72479236 [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@2a45d402 [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@76f1b7cc [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@701e4c60 [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@3e06b677 [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@3a678071 [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@41531f26 [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@43ac2620 [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@4892852c [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@4ef0e047 [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@17836c90 [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@35bcc566 [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@69db9d18 [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@20e0aabc [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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