January 28, 2010 — Diagnosis and management of red eye in the primary care setting are reviewed in the January 15 issue of the American Family Physician. Eye discharge, redness, pain, photophobia, itching, and visual changes are the characteristic signs and symptoms of red eye.

"Red eye is the cardinal sign of ocular inflammation," write Holly Cronau, MD, Ramana Reddy Kankanala, MD, and Thomas Mauger, MD, from the Ohio State University College of Medicine in Columbus. "The condition is usually benign and can be managed by primary care physicians. Conjunctivitis is the most common cause of red eye."

Both viral and bacterial conjunctivitis are usually self-limiting and rarely lead to serious complications. Most patients with conjunctivitis are typically treated with broad-spectrum antibiotics because, to date, there is no specific diagnostic test to distinguish viral from bacterial conjunctivitis. Allergies or irritants also may cause conjunctivitis.

Other common causes of red eye conjunctivitis include blepharitis, corneal abrasion, foreign body, subconjunctival hemorrhage, keratitis, iritis, glaucoma, chemical burn, and scleritis.

Complete patient history and thorough eye examination are needed to diagnose the cause of red eye. Useful questions to cover in the history include duration of symptoms and whether they are unilateral or bilateral, type and amount of discharge, visual changes, pain severity, photophobia, response to previous treatments, use of contact lenses, and history of allergies or systemic illness.

Ocular examination should include thorough inspection of the eyelids, lacrimal sac, pupil size and reactivity to light, corneal involvement, and the pattern and location of hyperemia, as well as visual acuity and the presence or absence of preauricular lymph node involvement.

In viral conjunctivitis, vision, pupil size, and reaction to light are typically normal. Findings may include diffuse conjunctival injections (redness), preauricular lymphadenopathy, and a lymphoid follicle on the undersurface of the eyelid. Pain is usually mild or absent, but there may be occasional gritty discomfort with mild itching and watery to serous discharge. Photophobia is uncommon but, when present, is often unilateral at onset, becoming bilateral within 1 or 2 days. Severe cases may be complicated by subepithelial corneal opacities and pseudomembranes. Adenovirus is the most common cause of viral conjunctivitis, and other causes include enterovirus, coxsackievirus, varicella zoster virus, Epstein-Barr virus, herpes simplex virus, and influenza.

Herpes zoster ophthalmicus is associated with a vesicular rash, keratitis, and uveitis. Rash and conjunctivitis usually precede the pain and tingling sensation in a dermatomal distribution, followed by periocular vesicles. Someone presenting with these symptoms should be referred to an ophthalmologist.

Bacterial conjunctivitis may be hyperacute, acute, or chronic. The most serious form is hyperacute, caused by Neisseria gonorrhoeae, presenting with rapid onset, purulent discharge, pain, and leading to corneal perforation.

Acute and chronic bacterial conjunctivitis are associated with eyelid edema, conjunctival injection, mild to moderate pain with stinging foreign-body sensation, and mild to moderate purulent discharge. Visual acuity is usually preserved, with normal pupil reaction and no corneal involvement. The most predictive factor is the presence of mucopurulent secretions with bilateral glued eyes on awakening. Staphylococcus aureus is the most common pathogen in adults, and Streptococcus pneumoniae and nontypeable Haemophilus influenzae are most common in children.

The underlying cause of red eye determines the appropriate course of treatment. In the primary care management of red eye, a crucial objective is to recognize when emergent referral to an ophthalmologist is required. Conditions mandating referral include severe pain refractory to topical anesthetics, need for topical steroids, vision loss, copious purulent discharge, corneal involvement, traumatic eye injury, recent ocular surgery, distorted pupil, herpes infection, or recurrent ocular infections.

"Red eye is one of the most common ophthalmologic conditions in the primary care setting," the review authors write. "Inflammation of almost any part of the eye, including the lacrimal glands and eyelids, or faulty tear film can lead to red eye. Primary care physicians often effectively manage red eye, although knowing when to refer patients to an ophthalmologist is crucial."

Specific key clinical recommendations for practice, and their accompanying level of evidence rating, are as follows:

• Meticulous hand washing and other good hygiene practices are keys to reducing transmission of acute viral conjunctivitis (level of evidence, C).
• For the treatment of acute bacterial conjunctivitis, any ophthalmic antibiotics may be considered because of their similar cure rates (level of evidence, A).
• An over-the-counter antihistamine/vasoconstrictor agent, or a more effective second-generation topical histamine H₁ receptor antagonist, may be used to treat mild allergic conjunctivitis (level of evidence, C).
• For moderate dry eye, appropriate therapies include anti-inflammatory agents, such as topical corticosteroids, topical cyclosporine, and systemic omega-3 fatty acids (level of evidence, C).
• An oral tetracycline or doxycycline may be helpful for patients with chronic blepharitis in whom response to eyelid hygiene and topical antibiotics is inadequate.

"To prevent the spread of viral conjunctivitis, patients should be counseled to practice strict hand washing and avoid sharing personal items; food handlers and health care workers should not work until eye discharge ceases; and physicians should clean instruments after every use," the review authors conclude. "Referral to an ophthalmologist is necessary if symptoms do not resolve after seven to 10 days or if there is corneal involvement. Topical corticosteroid therapy for any cause of red eye is used only under direct supervision of an ophthalmologist. Suspected ocular herpetic infection also warrants immediate ophthalmology referral."

The study authors have disclosed no relevant financial relationships.

Am Fam Physician. 2010;81:137-144.

For more information on this topic and materials helpful for patient education, readers are referred to the Mayo Clinic's site entitled Pink eye

Clinical Context

Clinical Implications

• Causes of red eye include conjunctivitis (viral, bacterial, and allergic), corneal abrasion, dry eye, blepharitis, trauma, and subconjunctival hemorrhage.
• Treatments that involve topical corticosteroids or surgery require ophthalmologic referral.

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