Current Diagnosis

• Patients with traumatic injury to the eye, loss of vision, extreme pain not explained by pathology, keratitis, suspected uveitis or glaucoma, chemical injury, or nonhealing corneal abrasion should be referred to an ophthalmologist.

• Bacterial, viral, and allergic conjunctivitis can often be distinguished by the type of ocular discharge present.

• Subconjunctival hemorrhage can occur from trauma, from increased intrathoracic pressure, from anticoagulants, or idiopathically.

Current Therapy

• Do not use eye patches in patients with corneal abrasions.

• Do not use topical anesthetics for the eye outside a clinic or hospital setting, because corneal toxicity can occur.

• Patients with corneal abrasions should be reexamined the following day.

• Patients with corneal abrasions from extended-wear contact lenses often become colonized with Pseudomonas aeruginosa and should be treated with appropriate antibiotics (quinolones).

In the primary care office, the most common causes of red eye are conjunctivitis, subconjunctival hemorrhage, and foreign body causing corneal abrasions. Other common causes of red eye include blepharitis and hordeolum. Less common but serious causes of red eye include viral keratitis, uveitis, scleritis, and angle-closure glaucoma. Other usually less serious causes of red eye include episcleritis, pingueculum, and pterygium. All primary care physicians should have expertise in recognizing and treating the common causes of red eye, and should recognize and refer patients with higher-stakes diagnoses (Boxes 1 and 2).

Box 1
Approach to the Patient with Red Eye
The following questions are often helpful in making the diagnosis in patients with red eyes.

Is one eye or are both eyes involved? Infections, allergy, and systemic illness are more likely to cause bilateral eye involvement.

• Does the patient have intense eye pain? If yes, likely diagnoses include acute angle closure glaucoma, uveitis, scleritis, keratitis, foreign body, or corneal abrasion.

• Does the patient have a foreign body sensation? If so, consider corneal abrasion, trauma, dry eye, keratitis, and other corneal disorders.

• Is there a discharge? If it is very copious and purulent, consider gonococcal conjunctivitis. If it is discolored and purulent, consider bacterial conjunctivitis. Copious watery discharge is typical of viral conjunctivitis. Stringy, mucoid discharge is typical of allergic or chlamydial conjunctivitis.

• Do the eyes itch? If so, consider blepharitis or allergy in the differential.

•   Are the eyelids swollen? Consider allergy or infection.

• Do the eyelids have lumps? Hordeolum and chalazion should be considered.

•   Do the eyes burn? Consider blepharitis or dry eye.

• Is the eye redness recurrent? Consider herpes keratitis, uveitis, and allergic conjunctivitis.

• Does the patient have photophobia? Corneal problems (abrasions, keratitis) and uveitis should be considered.

• Is there loss of vision? Consider corneal ulcer, uveitis, and angle closure glaucoma.

• Is the patient using ocular medications? Prolonged use of neomycin and sulfa ophthalmic medications can cause sensitization and redness of the eyes.

Box 2
 Eye Red
Common Causes

•   Conjunctivitis: bacterial, viral, allergic

•   Subconjunctival hemorrhage

•   Corneal abrasion

•   Blepharitis

Less Common Causes

Less Serious

•   Episcleritis

•   Pingueculum

•   Pterygium

More Serious

•   Viral keratitis

•   Uveitis

•   Scleritis

•   Angle closure glaucoma

Physical Examination

Always check visual acuity in any patient with an eye complaint. Fluorescein strips (Flu-Glo, Fluorets), topical anesthetic drops, and cobalt blue light are used to examine the cornea for abrasions, keratitis, and ulceration. Cotton-tipped applicators are used to evert the upper eyelid and look for a foreign body.

Pupillary reaction is often affected by angle closure glaucoma and uveitis, but it is rarely affected by conjunctivitis, blepharitis, and corneal disorders. The pupil may be irregular in the patient with uveitis.

Patients with uveitis often have pain in the closed affected eye when a bright light is shined in the normal eye or with convergence of the eyes. This is due to consensual reflex of the pupils to light and accommodation.

The diagnosis of conjunctivitis is made by pulling the lower eyelid down with the examiner’s finger. If the bulbar or palpebral conjunctivae are inflamed (i.e., hyperemic, edematous, discharge), conjunctivitis is present. Palpable preauricular nodes may be present with viral conjunctivitis and chlamydial conjunctivitis.


Conjunctivitis is the most common cause of red eye encountered by primary care providers. Among the etiologies of conjunctivitis, viral conjunctivitis is the most common. Although patients with conjunctivitis might have some minor irritation of the eyes, they usually do not complain of pain in the eye or loss of vision. Ocular discharge is generally considered to be an important diagnostic feature of conjunctivitis (Table 1). Although much has been written about characterizing conjunctivitis by the nature of the discharge, one meta-analysis failed to find evidence of the diagnostic usefulness of clinical signs and/or symptoms in distinguishing bacterial conjunctivitis from viral conjunctivitis.

Table 1


Viral Conjunctivitis

Viral conjunctivitis is often seen in epidemics and is most commonly caused by members of the Adenovirus family. Typically, viral conjunctivitis starts in one eye and spreads to the other eye a few days later. The conjunctivae appear red and swollen, with copious watery discharge (Figure 1). The natural course of viral conjunctivitis is self- limiting, lasting 10 to 14 days. Tender preauricular lymph nodes, when present, indicate the presence of viral or chlamydial conjunctivitis. Management should be directed at scrupulous hygiene. Patients must be informed that their infection is highly contagious.

They should avoid close contact with other persons (e.g., towels, direct contact, swimming pools) for 2 weeks and wash hands frequently to prevent the spread of their infection. Topical antibiotics have been prescribed to try to prevent bacterial superinfection, but there is no good evidence that they have any significant impact.

Symptomatic treatment with cold compresses and topical vasoconstrictors may be helpful. Conjunctivitis has very recently (end of 2015) been reported in patients with Zika virus.

FIGURE 1    Viral conjunctivitis. (Reproduced with permission from the University of Michigan Kellogg Eye Center,

Bacterial Conjunctivitis

Bacterial conjunctivitis typically starts abruptly in one eye and spreads to the other eye in 1 to 2 days. Usually a purulent discharge is present that persists throughout the day. A variety of gram-positive and gram-negative organisms cause bacterial conjunctivitis, but the most common etiologies are Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus pneumoniae. Treatment of bacterial conjunctivitis is usually empiric, but conjunctival scraping for smears and cultures should be done in infants, immunocompromised patients, and patients with hyperacute conjunctivitis in which Neisseria gonorrhoeae or Chlamydia trachomatis infection is suspected.

Treatment of bacterial conjunctivitis (excluding gonococcal or chlamydial conjunctivitis) usually consists of a topical antibiotic used four times a day (Table 2). Topical antibiotics are usually prescribed for 5 to 7 days, and resolution of conjunctivitis is expected within that time.

Table 2

Topical Antibiotics Used to Treat Bacterial Conjunctivitis


3  Exceeds dosage recommended by the  manufacturer.

Hyperacute bacterial conjunctivitis has an abrupt onset, copious purulent discharge, and rapid progression, and it is usually associated with gonococcal infection in a sexually active patient. Chemosis (edema of the conjunctivae) may be present.

Chlamydial conjunctivitis is acquired through exposure to infected secretions from the genital tract, either direct or indirect. The infection is usually unilateral (at least initially), and often there is involvement of the preauricular node on the ipsilateral side. Gonococcal and chlamydial infections are treated systemically (Box 3).

Box 3
Treatment of Chlamydial and Gonococcal Conjunctivitis
Chlamydial Conjunctivitis

•   Erythromycin (Ery-Tab)1 250 mg PO qid × 14 d


•   Doxycycline (Vibramycin) 100 mg PO bid × 14 d

•   Treat partners

Gonococcal Conjunctivitis

•   Ceftriaxone (Recephin 1 g IM)

1 Not FDA approved for this  indication.

Conjunctivitis of the Newborn

Chlamydial conjunctivitis is the most common cause of infectious conjunctivitis of the newborn in the United States. Onset of conjunctivitis is 3 to 10 days after birth, but it has been reported as late as 2 months after birth. Chlamydia trachomatis infection can also cause pneumonia, otitis media, proctitis, and vulvovaginitis in infants.

Treatment consists of erythromycin (EryPed Drops) orally 50 mg/kg/day in four divided doses for 14 days. Erythromycin ointment (Ilotycin 0.5%) or tetracycline ointment2 given shortly after delivery is effective in preventing chlamydial conjunctivitis but not systemic chlamydial infections.

Gonococcal conjunctivitis of the newborn is a hyperacute infection that occurs 2 to 4 days after birth. It can cause corneal ulceration and loss of vision. Gonococcal conjunctivitis can be prevented with silver nitrate drops2 or erythromycin (Ilotycin) or tetracycline ointment2 administered shortly after delivery. Silver nitrate commonly causes a self-limited chemical conjunctivitis, which can delay visual bonding of the infant to the parents in the first few hours of life. Therapy of gonococcal conjunctivitis of the newborn consists of IV penicillin G1 given four times a day for 7 days or ceftriaxone (Rocephin) IV or IM once a day for 7 days or gentamicin (Garamycin)1  IM given twice a day for 7 days.

Conjunctivitis–Otitis Media Syndrome

Conjunctivitis–otitis media syndrome is a common condition in which children with otitis media also have purulent bilateral ocular discharge. It responds to treatment of otitis media; no topical treatment of conjunctivitis is required.

Methicillin-Resistant Staphylococcus Aureus


Increasing numbers of cases of bacterial conjunctivitis are caused by methicillin-resistant S. aureus (MRSA). MRSA conjunctivitis manifests as bacterial conjunctivitis resistant to conventional therapy and is treated with the same drugs used to treat MRSA in other parts of the body (Doxycycline [Vibramycin],1 vancomycin [Vancocin], sulfamethoxazole-trimethoprim [Bactrim]1). Cultures should be obtained when MRSA is suspected.

Allergic Conjunctivitis

Allergic conjunctivitis is an immunoglobulin E (IgE)-mediated condition characterized by bilateral eye involvement, itchy eyes, and mucoid discharge. Seasonal conjunctivitis is caused by exposure to common allergens (e.g., pollens, dander) and usually accompanies allergic rhinitis. Perennial allergic conjunctivitis is similar to seasonal allergic conjunctivitis, but the symptoms are usually less severe.

Patients are usually treated with a systemic antihistamine. Ophthalmic (topical) medications include antihistamine or decongestants, mast cell inhibitors, nonsteroidal antiinflammatory drugs (NSAIDs), H1-antagonists, and various combinations of these (Table 3). Milder cases can be treated with a decongestant- antihistamine combination for about 2 weeks. Moderate to more severe cases can require longer use of these medications or the addition of systemic antihistamines or mast cell inhibitors. Some patients require topical corticosteroids or cyclosporine (Restasis)1 for severe allergic conjunctivitis, but these should be evaluated by an ophthalmologist because of potential complications of therapy.

Table 3

Topical Medications for Allergic Conjunctivitis

Abbreviation: NSAID = nonsteroidal antiinflammatory  drug.

1  Not FDA approved for this indication.

Subconjunctival Hemorrhage

In subconjunctival hemorrhage, the redness of the eye is localized and sharply circumscribed, and the underlying sclera is not visible (Figure 2). Conjunctivitis is not present, and there is no discharge. There is typically no pain or visual change. Subconjunctival hemorrhage may be spontaneous, but it can also result from trauma, hypertension, bleeding disorders, or increased intrathoracic pressure (e.g., straining, coughing, retching). No treatment is necessary, but investigation may be warranted if the etiology is in question or the hemorrhage is recurrent. Referral to an ophthalmologist should be considered if the subconjunctival hemorrhage is from trauma or has not resolved within 2 to 3 weeks.

FIGURE 2 Subconjunctival hemorrhage. (Reprinted with permission from American Academy of Ophthalmology: Managing the Red Eye. Eye Care Skills for the Primary Care Physician Series. San Francisco: American Academy of Ophthalmology, 2001.)

Corneal Abrasion

Corneal abrasions typically result from scratching of the corneal epithelium due to trauma, but they can also occur from extended- wear contact lenses. Patients with corneal abrasions present with pain, excessive tearing from the involved eye, photophobia, a foreign-body sensation (like having sand in the eye), and blurry vision.

Corneal abrasions are identified by staining the cornea with fluorescein and examining under cobalt blue light (Figure 3). The eye should also be examined carefully to check for foreign bodies. Topical anesthetic is administered to make the patient comfortable during the examination, but continued use can cause corneal damage.


FIGURE 3    Corneal abrasion with fluorescein stain with cobalt  blue light. (Reprinted with permission from American Academy of Ophthalmology: Managing the Red Eye. Eye Care Skills for the Primary Care Physician Series. San Francisco: American Academy of Ophthalmology, 2001.)

Management of corneal abrasions consists of pain relief and prevention of infection. Pain can be relieved with topical NSAIDs such as ketorolac (Acular)1 and Diclofenac (Voltaren),1 oral over-the- counter analgesics, and occasionally oral narcotics. Topical antibiotics are usually prescribed to prevent infection. Antibiotic ointments are lubricating and soothing to the eye, making them a good option for traumatic corneal abrasions. Topical ophthalmic antibiotic ointments commonly used are bacitracin (Bacticin), erythromycin (Ilotycin), and gentamicin (Gentak).

In patients who have corneal abrasions from contact lens overwear, eyes are commonly colonized with Pseudomonas aeruginosa. These patients should be treated with topical antibiotics such as ciprofloxacin (Ciloxan) or ofloxacin (Ocuflux) solutions.

Patching of the eye, though a common practice of the past, has not shown evidence of benefit in recent studies. It was found that eye patching can actually cause harm, so this practice is no longer recommended.

Infrequently, patients have traumatic uveitis accompanying corneal abrasion. Traumatic uveitis usually causes significantly more pain than a corneal abrasion, and, if uveitis is suspected, the patient should be evaluated by an ophthalmologist.

Patients with corneal abrasions should be reexamined in 24 hours. Corneal abrasions typically should be healed or greatly improved in 24 hours. If the abrasion is not completely healed after 24 hours, the patient should be examined again in 2 or 3 days. Referral should be considered if any worsening occurs or if the abrasion does not heal within 5 days. Corneal abrasions can be prevented by using protective eyewear.

Other Causes of Red Eye

Other causes of red eye are somewhat less common.


Blepharitides are inflammatory conditions of the eyelid caused by infection or obstruction of eyelid glands (Table 4). Blepharitis may be accompanied by conjunctivitis. Staphylococcal blepharitis arises from the accessory glands to the eyelashes and causes discharge from the eyelid, often associated with erythema, induration, loss of eyelashes, and crusting of the eyelid (Figure 4). This is treated with hot, moist packs to the eyes, baby shampoo scrubs (3 oz. water and 3 drops baby shampoo used on a washcloth bid), and erythromycin ointment (Ilotycin) at bedtime. Seborrheic blepharitis, a more chronic form of blepharitis, arises from the meibomian glands and causes scaling of the eyelids (Figure 5). Seborrheic blepharitis is often associated with skin disorders such as rosacea, eczema, and seborrheic dermatitis.

This is treated with hot, moist packs and baby shampoo scrubs. Resistant cases are treated with oral tetracycline (Sumycin) (or one of its derivatives).

FIGURE 4    Staphylococcal blepharitis. (Reprinted with permission from American Academy of Ophthalmology: Managing the Red Eye. Eye Care Skills for the Primary Care Physician Series. San Francisco: American Academy of Ophthalmology, 2001.)

FIGURE 5    Seborrheic blepharitis. (Reprinted with permission from American Academy of Ophthalmology: Managing the Red Eye. Eye Care Skills for the Primary Care Physician Series. San Francisco: American Academy of Ophthalmology, 2001.)

Table 4


Hordeolum (Stye)

A hordeolum is an acute, painful mass of the eyelid that is caused by inflammation of the glands (Figure 6). It does not usually cause the eye to become red as well. Warm compresses to the eyelid four times a day for 3 to 5 minutes typically causes resolution within 1 week.

Because they arise from the same glands, hordeola and blepharitis commonly occur together.

FIGURE 6    Hordeolum. (Reprinted with permission from American Academy of Ophthalmology: Managing the Red Eye. Eye Care Skills for the Primary Care Physician Series. San Francisco: American Academy of Ophthalmology, 2001.)


Episcleritis is a self-limited inflammation of the episcleral vessels and is believed to be autoimmune. It has a rapid onset and usually minimal discomfort. Redness is most often confined to a sector of the eye. Episcleritis usually resolves in 7 to 10 days. Recurrence is not uncommon. Oral NSAID drugs may be prescribed, but treatment is usually not necessary.


Scleritis is, fortunately, much less common than episcleritis. Patients with scleritis experience intense inflammation and deep eye pain.

Scleritis is commonly associated with rheumatoid arthritis and inflammatory bowel disease. The patient should be promptly referred to an ophthalmologist if scleritis is suspected.

Acute Angle Closure Glaucoma

Acute angle closure glaucoma is characterized by acute ocular pain and is often accompanied by vomiting, blurred vision, acute photophobia, pupils unreactive to light, and circumcorneal redness (ciliary flush). Treatment of glaucoma with pilocarpine (Isopto Carpine), topical timolol (Timoptic), and acetazolamide (Diamox) should be started, and the patient should be given an urgent referral to an ophthalmologist.

Anterior Uveitis

Uveitis is the inflammation of the iris and ciliary muscle, often associated with autoimmune disease. Trauma can also cause uveitis. Signs of uveitis include ocular pain, ciliary flush, and occasionally irregularity of the pupil. Prompt referral should be arranged for a patient in whom uveitis is suspected.

In general, referral to an ophthalmologist should strongly be considered for:

•   Traumatic injury to the eye

•   Loss of vision

•   Extreme eye pain not explained by pathology

•   Keratitis

•   Suspected uveitis or glaucoma

•   Chemical injury (especially alkali)

•   Corneal abrasion not healing


1.     American Optometric Association. Optometric clinical practice guideline: Care of the patient with anterior uveitis. June 23, 1994. Revised March 1999. PDF available at June 23, 1994 [accessed July 10, 2015].

2.    Arbour J.D., Brunette I., Boisjoly H.M., et al. Should we patch corneal abrasions? Arch Ophthalmol. 1997;115(3):313–317.

3.     Au Y.K., Henkind P. Pain elicited by consensual pupillary reflex: a diagnostic test for acute iritis. Lancet. 1981;2:1254–1255.

4.    Avdic E., Cosgrove S.E. Management and control strategies for community-associated methicillin-resistant Staphylococcus aureus. Expert Opin Pharmacother. 2008;9(9):1463–1479.

5.     Boder F., Marchant C., et al. Bacterial etiology of conjunctivitis- otitis media syndrome. Pediatrics. 1985;76:26–28.

6.      Bradford C.A. Basic Ophthalmology. ed 8 San Francisco: American Academy of Ophthalmology; 2004.

7.    Centers for Disease Control and Prevention. Zika Virus. Symptoms, diagnosis, and treatment. Available at Accessed Feb. 3, 2016.

8.    De Toledo A.R., Chandler J.W. Conjunctivitis of the newborn. Infect Dis Clin North Am. 1992;6(4):807–813.

9.       Frith P., Gray R., MacLennan S., et al. The Eye in Clinical Practice. Oxford: Blackwell Scientific; 1994.

10.       Jackson W.B. Blepharitis: Current strategies for diagnosis and treatment. Can J Ophthalmol. 2008;43(2):170–179.

11.    Liebowitz H.M. The red eye. N Engl J Med. 2000;343(5):345–351.

12.    Patterson J., Fetzer D., Krall J., et al. Eye patch treatment for the pain of corneal abrasion. South Med J. 1996;89(2):227–229.

13.     Prochazka A.V. Diagnosis and treatment of red eye. Primary Care Case Reviews. 2001;4:23–31.

14.    Rietveld R.P., van Weert H., Riet G., Bindels P. Diagnostic impact of signs and symptoms in acute infectious conjunctivitis: Systematic literature search. BMJ. 2003;327(4):789.

15.    Tarabishy A., Jeng B. Bacterial conjunctivitis: A review for internists. Cleve Clin J Med. 2008;75(7):507–512.

16.    Talbot E.M. A simple test to diagnose iritis. BMJ. 1987;295:812– 813.

17.    Trobe J.D. The Physician’s Guide to Eye Care. ed 2 San Francisco: Foundation of the American Academy of Ophthalmology; 2001.

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2  Not available in the United  States.

1  Not FDA approved for this  indication.

1  Not FDA approved for this  indication

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