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@5cdc9c39[Figure caption and citation for the preceding image starts]: TrichiasisPrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Entropion: inward turning of the eyelid margin com.bmj.content.model.assessment.Caption@766f19e[Figure caption and citation for the preceding image starts]: EntropionPrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Ectropion: outward turning of the eyelid margin com.bmj.content.model.assessment.Caption@64fb514[Figure caption and citation for the preceding image starts]: EctropionPrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Blepharitis: inflammation of the eyelid margin com.bmj.content.model.assessment.Caption@52ad7b9f[Figure caption and citation for the preceding image starts]: BlepharitisPrivate 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@6aa808a7[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@5a72fe6d[Figure caption and citation for the preceding image starts]: Bacterial conjunctivitisPrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Viral conjunctivitis: inflammation of the conjunctiva caused by viral infection com.bmj.content.model.assessment.Caption@216e1722[Figure caption and citation for the preceding image starts]: Viral conjunctivitisPrivate 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@18a6e113[Figure caption and citation for the preceding image starts]: Allergic (vernal) keratoconjunctivitisPrivate 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@32e12f90[Figure caption and citation for the preceding image starts]: Subconjunctival haemorrhagePrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Subtarsal foreign body com.bmj.content.model.assessment.Caption@7f2d3e37[Figure caption and citation for the preceding image starts]: Subtarsal foreign body: vertical corneal abrasions seen with fluorescein stainPrivate 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@2eabe1f7[Figure caption and citation for the preceding image starts]: Corneal ulcer seen with fluorescein stainPrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Viral corneal ulcer: corneal epithelial defect caused by viral infection com.bmj.content.model.assessment.Caption@1aa3348[Figure caption and citation for the preceding image starts]: Dendritic ulcer seen with fluorescein stainPrivate 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@3a0c1142[Figure caption and citation for the preceding image starts]: Corneal foreign bodyPrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Corneal abrasion: corneal epithelial defect usually caused by trauma. com.bmj.content.model.assessment.Caption@2cc65cb2[Figure caption and citation for the preceding image starts]: Corneal abrasion seen with fluorescein stainPrivate 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@5d13b484[Figure caption and citation for the preceding image starts]: Anterior uveitis with posterior synechiaePrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Scleritis: inflammation of the sclera com.bmj.content.model.assessment.Caption@df3ec1d[Figure caption and citation for the preceding image starts]: ScleritisPrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Episcleritis: inflammation of the episclera. com.bmj.content.model.assessment.Caption@57af6ae0[Figure caption and citation for the preceding image starts]: EpiscleritisPrivate collection - courtesy of Mr Hugh Harris [Citation ends].

Traumatic causes

  • Physical com.bmj.content.model.assessment.Caption@49129f6b[Figure caption and citation for the preceding image starts]: Penetrating corneal injury with iris prolapsePrivate 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@9e5b559[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@1be4237c[Figure caption and citation for the preceding image starts]: Bacterial conjunctivitisPrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Allergic conjunctivitis com.bmj.content.model.assessment.Caption@37b0a28a[Figure caption and citation for the preceding image starts]: Allergic (vernal) keratoconjunctivitisPrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Dry eye and other adnexal problems.[6]com.bmj.content.model.assessment.Caption@6a848ad0[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@4eefa5a4[Figure caption and citation for the preceding image starts]: EntropionPrivate collection - courtesy of Mr Hugh Harris [Citation ends].com.bmj.content.model.assessment.Caption@74aa80c6[Figure caption and citation for the preceding image starts]: TrichiasisPrivate collection - courtesy of Mr Hugh Harris [Citation ends].com.bmj.content.model.assessment.Caption@46bcd82b[Figure caption and citation for the preceding image starts]: BlepharitisPrivate collection - courtesy of Mr Hugh Harris [Citation ends].com.bmj.content.model.assessment.Caption@8a01826[Figure caption and citation for the preceding image starts]: EctropionPrivate 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@3bd15e13[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@1b5d551f[Figure caption and citation for the preceding image starts]: Anterior uveitis with posterior synechiaePrivate 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@3b00bbdf[Figure caption and citation for the preceding image starts]: Penetrating corneal injury with iris prolapsePrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Scleritis com.bmj.content.model.assessment.Caption@3369e5b1[Figure caption and citation for the preceding image starts]: ScleritisPrivate 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@2791409[Figure caption and citation for the preceding image starts]: Anterior uveitis with posterior synechiaePrivate collection - courtesy of Mr Hugh Harris [Citation ends]. human leukocyte antigen-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@73fd5cf4[Figure caption and citation for the preceding image starts]: ScleritisPrivate collection - courtesy of Mr Hugh Harris [Citation ends]. connective tissue disorders including rheumatoid arthritis, granulomatosis with polyangiitis (formerly known as Wegener's granulomatosis), systemic lupus erythematosus (SLE), and relapsing polychondritis.

  • Episcleritis: com.bmj.content.model.assessment.Caption@4d9ddf17[Figure caption and citation for the preceding image starts]: EpiscleritisPrivate collection - courtesy of Mr Hugh Harris [Citation ends]. connective tissue disorders including rheumatoid arthritis, granulomatosis with polyangiitis (formerly known as Wegener's granulomatosis), and SLE.

  • Angle-closure glaucoma: com.bmj.content.model.assessment.Caption@3125ff78[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@7bb66c09[Figure caption and citation for the preceding image starts]: Subconjunctival haemorrhagePrivate 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@62b59577[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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