eMedicine Specialties > Ophthalmology > Ophthalmology for the General Practitioner

Red Eye Evaluation

Author: Gino A Farina, MD, Program Director, Associate Professor of Clinical Emergency Medicine, Department of Emergency Medicine, Long Island Jewish Medical Center, Albert Einstein College of Medicine
Coauthor(s): Gregory I Mazarin, MD, Assistant Professor, Department of Emergency Medicine, Department of Emergency Medicine, Montefiore Medical Center, Albert Einstein College of Medicine; Consulting Staff, St Vincent's Midtown, North Shore University Hospital
Contributor Information and Disclosures

Updated: Jul 30, 2009

Introduction

Background

A red eye is a cardinal sign of ocular inflammation, which can be caused by several conditions. Most cases are benign and can be managed effectively by the primary care provider. The key to management is recognizing cases with underlying disease that require ophthalmologic consultation.

Pathophysiology

A red eye is caused by dilation of blood vessels in the eye. Diagnosis may be aided by the differentiation between ciliary and conjunctival injection. Ciliary injection involves branches of the anterior ciliary arteries and indicates inflammation of the cornea, iris, or ciliary body. Conjunctival injection mainly affects the posterior conjunctival blood vessels. Because these vessels are more superficial than the ciliary arteries, they produce more redness, move with the conjunctiva, and constrict with topical vasoconstrictors.¹

Clinical

History

Obtain the following information:

• Onset
• Visual changes
• Trauma
• Photophobia
• Pain
• Discharge, clear or colored
• Prior episodes
• Ophthalmologic history including eye surgery
• Bilateral or unilateral
• Contact lens use
• Comorbid conditions such as collagen vascular disease

Physical

• Visual acuity
• Extraocular movements
• Pupil reactivity
• Pupil shape
• Tests for direct and consensual photophobia
• Slit lamp examination of the cornea for edema, defects, or opacification with and without fluorescein
• Anterior chamber evaluation for depth, cells and flare
• Intraocular pressure (IOP) measurements
• Eyelid inspection with eversion
• Certain signs help to distinguish among the various causes of a red eye.
  • Blepharitis is inflammation of the eyelids usually involving the lid margins. It often is associated with conjunctivitis.
  • Canaliculitis is characterized by a mildly red eye (usually unilateral) with slight discharge. Discharge can be expressed from the canaliculus.
  • Conjunctivitis is characterized by vascular dilation, cellular infiltration, and exudation.
    • Allergic disease often has papillary projections and pruritus in individuals with a history of allergic disease.
    • Viral infections tend to have lymphoid follicles on the undersurface of the lid and enlarged tender preauricular nodes.
    • Bacterial disease tends to have more purulent discharge.
    • Differentiating these different types is imprecise, requiring the physician to assume that a bacterial etiology is involved when unclear.
  • Corneal inflammation or infection
    • Patients may have decreased visual acuity and photophobia.
    • They often complain of severe eye pain.
    • An epithelial defect may be evident on slit lamp examination or may require staining with fluorescein.
    • Corneal inflammation or infection may be accompanied by anterior chamber reaction.
    • Any opacification of the cornea in a red eye is an infection of the cornea until proven otherwise. The opacification may or may not take up fluorescein. This is an ophthalmic emergency.
  • Dacryocystitis is characterized by localized pain, edema, and erythema over the lacrimal sac at the medial canthus of the eye. Dacryocystitis is usually unilateral. There is often purulent discharge from the puncta.
  • Episcleritis
    • Episcleritis must be differentiated from injection of the more superficial conjunctival vessels and from the deeper scleral vessels.
    • Unlike conjunctivitis, the inflammation tends to be limited to an isolated patch, not involving the eye diffusely.
    • A history of recurrent episodes is common.
    • There may be mild-to-moderate tenderness over the area of injection.
    • Patients should be examined for corneal complications (15%) and uveitis (7%).
  • Foreign body
    • The patient's eye should be stained with fluorescein to detect evidence of corneal abrasion. Penetration of the globe should be excluded by thorough slit lamp examination.
    • The lid should always be everted to exclude retained material.
  • Iritis
    • The eye develops a perilimbal flush due to dilation of the radial vessels. Compare to conjunctivitis, in which the intensity of vascular engorgement decreases toward the limbus.
    • Cells and flare are present in the anterior chamber as seen under high magnification under specific light conditions with the slit lamp.
    • There may be decreased visual acuity, direct and consensual photophobia, posterior synechia between the iris and lens, and keratitic precipitates on the endothelium.
    • Iritis is usually unilateral.
  • Keratoconjunctivitis sicca (dry eye)
    • In most cases, the eye appears normal.
    • On slit lamp examination, there may be decreased tear meniscus at the lower lid margin.²
    • The corneal epithelium shows varying degrees of fine punctate stippling in the interpalpebral fissure, which stain with rose bengal or fluorescein if more severely damaged.
• Narrow-angle glaucoma
  • Patients complain of severely painful red eye.
  • Haloes around light are common.
  • Patients are usually older than 50 years.
  • The pupil may be mid dilated and may be nonreactive to light.
  • Slit lamp examination reveals corneal edema with a shallow anterior chamber with mild cells and flare.
  • IOP is elevated (reference range is <21 mm Hg).
  • The anterior chamber may be narrow.
  • Nausea and vomiting are common.
  • Gonioscopy should be performed.
• Pinguecula or pterygium
  • A triangular band of fibrovascular tissue on either side of the cornea (pinguecula) may encroach onto the cornea (pterygium).
  • Both may become inflamed.
• Scleritis (anterior)
  • Scleritis is usually accompanied by pain, especially with pressure.
  • Usually gradual onset of red eye and insidious decrease in vision are noted.
  • Recurrent episodes are common.
  • Anterior chamber inflammation or posterior involvement may affect visual acuity.
  • The globe is often tender and the sclera swollen.
  • Deep scleral injection is accompanied by inflammation of the episclera and conjunctiva.
  • A deep violet discoloration of the globe may be observed because of dilation of the deep venous plexus.
  • The clinician must beware of the white eye, since this may be due to ischemia.
  • Scleritis is bilateral in 50% of patients.
• Subconjunctival hemorrhage may appear as a flat thin hemorrhage or a thicker collection of blood.

Causes

• Blepharitis may be seborrheic or may be caused by staphylococcal infection.
• Canaliculitis often is caused by Actinomyces israelii, but Candida or Aspergillus species also may be involved.
• Conjunctivitis must be differentiated, based on viral, bacterial, or allergic etiology.
• Corneal injury: Numerous causes exist, which can be grouped into infective, toxic, degenerative, traumatic and allergic conditions.
• Dacryocystitis
  • Dacryocystitis is inflammation of the lacrimal sac is due to obstruction of the nasolacrimal duct.
  • In infants, this results from failure of canalization that normally occurs by the end of the first month.
  • In adults, acute forms are due to S aureus or beta-hemolytic Streptococcus. Acute cases in children are due to Haemophilus influenzae.
• Episcleritis
  • The cause can be any inflammatory systemic condition of the body such as rheumatoid arthritis, Sjögren syndrome, coccidioidomycosis, syphilis, zoster, and tuberculosis.
  • Most often, no etiology can be determined even after testing for the above inflammatory conditions.
• Iritis
  • In most cases, the cause cannot be determined. However, any systemic inflammatory disease can cause iritis.
  • More than 50% of patients have human leukocyte antigen B27 (HLA-B27) or human leukocyte antigen B8 (HLA-B8) and the many diseases associated with them.
  • Trauma is one common etiology.
• Keratoconjunctivitis sicca
  • Dry eye may result from any disease that is associated with deficiency of tear film components and lid surface or epithelial abnormalities.
  • Keratoconjunctivitis sicca may be associated with rheumatoid arthritis and other autoimmune diseases (Sjögren syndrome).
• Narrow-angle glaucoma occurs in patients with preexisting narrowing of the anterior chamber angle. Far-sighted patients and older patients are at an additional risk when there has been enlargement of the lens.
• Scleritis (anterior): Associated systemic disease (eg, rheumatoid arthritis, herpes zoster ophthalmicus, gout) is found in 40% of all patients.
• Subconjunctival hemorrhage may occur spontaneously or with trauma.

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