Etiology

Etiology

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@6213bc07[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@17a34127[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@5d435d55[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@d771061[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@727b764c[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@7fdcab5d[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@3832f806[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@df31379[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 hemorrhage com.bmj.content.model.assessment.Caption@2493cd9d[Figure caption and citation for the preceding image starts]: Subconjunctival hemorrhagePrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Subtarsal foreign body com.bmj.content.model.assessment.Caption@3e8f1c11[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@11d2210e[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@42f8096[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@3eea5aab[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@78c3a6f3[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@781922b4[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@4a3611[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@6c190bb1[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@988ccff[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 intraocular pressure. com.bmj.content.model.assessment.Caption@383543f8[Figure caption and citation for the preceding image starts]: Angle-closure glaucoma: central corneal edema with an oval-shaped mid-dilated pupilPrivate 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@699e1051[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@4d7eca50[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@2de1834[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@10e6b114[Figure caption and citation for the preceding image starts]: EntropionPrivate collection - courtesy of Mr Hugh Harris [Citation ends].com.bmj.content.model.assessment.Caption@9e337c1[Figure caption and citation for the preceding image starts]: TrichiasisPrivate collection - courtesy of Mr Hugh Harris [Citation ends].com.bmj.content.model.assessment.Caption@327450e7[Figure caption and citation for the preceding image starts]: BlepharitisPrivate collection - courtesy of Mr Hugh Harris [Citation ends].com.bmj.content.model.assessment.Caption@4099e125[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@65d29633[Figure caption and citation for the preceding image starts]: Angle-closure glaucoma: central corneal edema with an oval-shaped mid-dilated pupilPrivate collection - courtesy of Mr Hugh Harris [Citation ends].

  • Chemical injuries

  • Conditions affecting the cornea

  • Trauma

  • Anterior uveitis. com.bmj.content.model.assessment.Caption@759ff877[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@657c6d4b[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@6a633808[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@1bf14879[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 disease, and pauciarticular juvenile chronic arthritis.

  • Scleritis: com.bmj.content.model.assessment.Caption@11275730[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 granulomatosis), systemic lupus erythematosus (SLE), and relapsing polychondritis.

  • Episcleritis: com.bmj.content.model.assessment.Caption@17b7666a[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 granulomatosis), and SLE.

  • Angle-closure glaucoma: com.bmj.content.model.assessment.Caption@64e7bfec[Figure caption and citation for the preceding image starts]: Angle-closure glaucoma: central corneal edema with an oval-shaped mid-dilated pupilPrivate collection - courtesy of Mr Hugh Harris [Citation ends]. hypermetropia, mydriatics, and systemic anticholinergic medications.

  • Subconjunctival hemorrhage: com.bmj.content.model.assessment.Caption@75c49189[Figure caption and citation for the preceding image starts]: Subconjunctival hemorrhagePrivate collection - courtesy of Mr Hugh Harris [Citation ends]. hypertension, systemic anticoagulation, bleeding abnormalities (leukemia, clotting disorders), conjunctival vascular lesion, trauma (including contact lens-related injury), and diabetes.

  • Dry eye: com.bmj.content.model.assessment.Caption@5ef1d6d6[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 syndrome, rheumatoid arthritis, and SLE.

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