 |
Red eye refers to a red appearance of the opened eye, reflecting dilation of the superficial ocular vessels.
Pathophysiology
Dilation of superficial ocular vessels can result from
Several ocular components may be involved, most commonly the conjunctiva, but also the uveal tract, episclera, and sclera.
Etiology
The most common causes of red eye include
Corneal abrasions and foreign bodies are common causes (See Table 12: Approach to the Ophthalmologic Patient: Some Causes of Red Eye ), but although the eye is red, patients usually present with a complaint of injury, eye pain, or both. However, in young children and infants, this information may be unavailable.
|
Table 12
|
| | |
|
Some Causes of Red Eye
|
|
Cause
|
Suggestive Findings
|
Diagnostic Approach
|
|
Conjunctival disorders and episcleritis*
|
|
Allergic or seasonal conjunctivitis
|
Bilateral, prominent itching, possibly conjunctival bulging (chemosis)
Known allergies or other features of allergies (eg, seasonal recurrences, rhinorrhea)
Sometimes use of topical ophthalmic drugs (particularly neomycin )
|
Clinical evaluation
|
|
Chemical (irritant) conjunctivitis
|
Exposure to potential irritants (eg, dust, smoke, ammonia, chlorine, phosgene)
|
Clinical evaluation
|
|
Episcleritis
|
Unilateral focal redness, mild irritation, minimal lacrimation
|
Clinical evaluation
|
|
Infectious conjunctivitis
|
Scratchy sensation, photosensitivity
Sometimes mucopurulent discharge, eyelid edema, or follicles on tarsal conjunctiva
|
Clinical evaluation
|
|
Subconjunctival hemorrhage
|
Unilateral, asymptomatic focal red patch or confluent redness
Possibly prior trauma or Valsalva maneuver
|
Clinical evaluation
|
|
Vernal conjunctivitis
|
Intense itching, stringy discharge
Preadolescent or adolescent males
Other atopic disorders
Waxing in spring and waning in winter
|
Clinical evaluation
|
|
Corneal disorders†
|
|
Contact lens keratitis
|
Prolonged wearing of contact lenses, lacrimation, corneal edema
|
Clinical evaluation
|
|
Corneal abrasion or foreign body
|
Onset after injury (but this history may be inapparent in infants and young children)
Foreign body sensation
Lesion on fluorescein staining
|
Clinical evaluation
|
|
Corneal ulcer
|
Often grayish opacity on cornea; later a visible crater
Possibly a history of sleeping with contact lenses
|
Culture of ulcer (scrapings done by ophthalmologist)
|
|
Epidemic keratoconjunctivitis (adenoviral keratitis)—moderate or severe
|
Copious watery discharge
Often eyelid edema, preauricular lymphadenopathy, chemosis (bulging of the conjunctiva)
Occasionally, severe temporary loss of vision
Punctate pattern on fluorescein staining
|
Clinical evaluation
|
|
Herpes simplex keratitis
|
Onset after conjunctivitis, blisters on eyelid
Classic dendritic corneal lesion on fluorescein staining
Unilateral
|
Clinical evaluation
Viral culture if diagnosis is unclear
|
|
Herpes zoster ophthalmicus
|
Unilateral vesicles and crusts on an erythematous base in a V1 distribution, sometimes affecting the tip of the nose
Eyelid edema
Red eye
May be associated with uveitis
Possibly severe pain
|
Clinical evaluation
Viral culture if diagnosis is unclear
|
|
Other disorders
|
|
Acute angle-closure glaucoma
|
Severe ocular ache
Headache, nausea, vomiting, halos around lights
Hazy cornea (caused by edema), marked conjunctival erythema
Decreased visual acuity
Intraocular pressure usually > 40
|
Tonometry and gonioscopy
|
|
Anterior uveitis
|
Ocular ache, photophobia
Ciliary flush (redness most concentrated and often confluent around the cornea)
Often a risk factor (eg, autoimmune disorder, blunt trauma within previous few days)
Possibly decreased visual acuity or pus in anterior chamber (hypopyon)
Cells and flare on slit-lamp examination
|
Clinical evaluation
|
|
Scleritis
|
Severe pain, often described as boring
Photophobia; lacrimation
Red or violaceous patches under bulbar conjunctiva
Scleral edema
Tenderness of globe on palpation
Often history of autoimmune disorder
|
Clinical evaluation
Further testing by or in conjunction with ophthalmologist
|
|
*Unless otherwise described, usually characterized by itching or scratchy sensation, lacrimation, diffuse redness, and often photosensitivity, but no change in vision and absence of pain and true photophobia.
|
|
†Unless otherwise described, usually characterized by lacrimation, pain, and true photophobia. Vision affected if the lesion involves the visual axis.
|
|
Evaluation
Most disorders can be diagnosed by a general health care practitioner.
History:
History of present illness should address the onset and duration of redness and whether there is change in vision, itching, a scratchy sensation, pain, or discharge. Nature and severity of pain are addressed, including whether pain is worsened by light (photophobia). The clinician should determine whether discharge is watery or purulent. Other questions assess history of injury, including exposure to irritants and use of contact lenses (including possible overuse, such as wearing them while sleeping). Prior episodes of eye pain or redness and their time patterns are elicited.
Review of systems should seek symptoms suggesting possible causes, including headache, nausea, vomiting, and halos around lights (acute angle-closure glaucoma); runny nose and sneezing (allergies, URI); and cough, sore throat, and malaise (URI).
Past medical history includes questions about known allergies and autoimmune disorders. Drug history should specifically ask about recent use of topical ophthalmic drugs (including OTC drugs), which might be sensitizing.
Physical examination:
General examination should include head and neck examination for signs of associated disorders (eg, URI, allergic rhinitis, zoster rash).
Eye examination involves a formal measure of visual acuity and usually requires a penlight, fluorescein stain, and slit lamp.
Best corrected visual acuity is measured. Pupillary size and reactivity to light are assessed. True photophobia (sometimes called consensual photophobia) is present if shining light into an unaffected eye causes pain in the affected eye when the affected eye is shut. Extraocular movements are assessed, and the eye and periorbital tissues are inspected for lesions and swelling. The tarsal surface is inspected for follicles. The corneas are stained with fluorescein and examined with magnification. If a corneal abrasion is found, the eyelid is everted and examined for hidden foreign bodies. Inspection of the ocular structures and cornea is best done using a slit lamp. A slit lamp also is used to examine the anterior chamber for cells, flare, and pus (hypopyon). Ocular pressure is measured using tonometry, although it may be permissible to omit this if there are no symptoms or signs suggesting a disorder other than conjunctivitis.
Red flags:
The following findings are of particular concern:
Interpretation
of findings:
Conjunctival disorders and episcleritis are differentiated from other causes of red eye by the absence of pain, photophobia, and corneal staining. Within these disorders, episcleritis is differentiated by its focality, and subconjunctival hemorrhage usually is differentiated by the absence of lacrimation, itching, and photosensitivity. Clinical criteria do not accurately differentiate viral from bacterial conjunctivitis.
Corneal disorders are differentiated from other causes of red eye (and usually from each other) by fluorescein staining. These disorders also tend to be characterized by pain and photophobia. If instillation of an ocular anesthetic drop (eg, proparacaine 0.5%), which is done before tonometry and ideally before fluorescein instillation, completely relieves pain, the cause is probably purely a corneal lesion. If pain is present and is not relieved by an ocular anesthetic, the cause may be anterior uveitis, glaucoma, or scleritis. Because patients may have anterior uveitis secondary to corneal lesions, persistence of pain after instillation of the anesthetic does not exclude a corneal lesion.
Anterior uveitis, glaucoma,
acute angle-closure glaucoma, and scleritis usually can be differentiated from other causes of red eye by the presence of pain and the absence of corneal staining. Anterior uveitis is likely in patients with pain, true photophobia, absence of corneal fluorescein staining, and normal intraocular pressure; it is definitively diagnosed by the presence of cells and flare in the anterior chamber. However, these findings may be difficult for general health care practitioners to discern. Acute angle-closure glaucoma usually can be recognized by the sudden onset of its severe and characteristic symptoms, but tonometry is definitive.
Instillation of phenylephrine 2.5% causes blanching in a red eye unless the cause is scleritis. Phenylephrine is instilled to dilate the pupil in patients needing a thorough retinal examination. However, it should not be used in patients who have the following:
Testing:
Testing is usually unnecessary. Viral cultures may help if herpes simplex or herpes zoster is suspected and the diagnosis is not clear clinically. Corneal ulcers are cultured by an ophthalmologist. Gonioscopy is done in patients with glaucoma. Testing for autoimmune disorders may be worthwhile in patients with uveitis and no obvious cause (eg, trauma). Patients with scleritis undergo further testing as directed by an ophthalmologist.
Treatment
The cause is treated. Red eye itself does not require treatment. Topical vasoconstrictors are not recommended.
Key
Points
Dacryocystitis
Dacryocystitis
is infection of the lacrimal sac, usually with staphyloccocal or
streptococcal species and usually as a consequence of nasolacrimal
duct obstruction.
In acute dacryocystitis, the patient presents with pain, redness, and edema around the lacrimal sac. Diagnosis is suspected on the basis of symptoms and signs and when pressure over the lacrimal sac causes reflux of mucoid material through the puncta. Initial treatment is with warm compresses and either oral antibiotics for mild cases ( cephalexin 500 mg q 6 h) or IV antibiotics ( cefazolin 1 g q 6 h) for more severe cases. The abscess can be drained and the antibiotics can be changed based on culture results if the initial antibiotic proves ineffective.
Patients with chronic dacryocystitis usually present with a mass under the medial canthal tendon and chronic conjunctivitis. Definitive treatment for a resolved acute dacryocystitis or a chronic conjunctivitis is usually with surgery (dacryocystorhinostomy).
Canaliculitis
Canaliculitis
is infection of the canaliculus (see Fig. 3: Approach to the Ophthalmologic Patient: Anatomy of the lacrimal system. ).
The most common cause is infection with Actinomyces israelii, a gram-positive bacillus with fine branching filaments, but other bacteria, fungi (eg, Candida albicans), and viruses (eg, herpes simplex) may be causative. Symptoms and signs are tearing, discharge, red eye (especially nasally), and mild tenderness over the involved side. Diagnosis is suspected on the basis of symptoms and signs, expression of turbid secretions with pressure over the lacrimal sac, and a gritty sensation that can be felt during probing of the lacrimal system. Treatment is warm compresses, irrigation of the canaliculus with antibiotic solution, and removal of any concretions, which usually requires surgery. Antibiotic selection is usually empiric but may be guided by irrigation samples.
Last full review/revision April 2009 by Kathryn Colby, MD, PhD
Content last modified April 2009
| |
