Red Eye 

Updated: Jun 11, 2019
Author: Robert H Graham, MD; Chief Editor: Andrew A Dahl, MD, FACS 

Overview

Background

A red eye is one of the cardinal signs of ocular inflammation, which can result from many conditions. Subconjunctival hemorrhage (see the image below), defined as blood between the conjunctiva and the sclera, is usually not secondary to inflammation.[1, 2] Most cases of subconjunctival hemorrhage are benign and can be effectively managed by the primary care provider.[3] The key to management is recognizing cases with underlying disease that require ophthalmologic consultation.

Follicular conjunctivitis and subconjunctival hemo Follicular conjunctivitis and subconjunctival hemorrhage.

For patient education resources, see the Eye and Vision Center and the Glaucoma Center, as well as Anatomy of the Eye, Pinkeye, Iritis, Subconjunctival Hemorrhage (Bleeding in Eye), Black Eye, and Glaucoma Overview.

Pathophysiology and Etiology

A red eye most often results from dilation of blood vessels in the anterior portion of 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 the application of topical vasoconstrictors.[4]

Numerous conditions may be associated with red eye, including conjunctivitis, blepharitis, canaliculitis, corneal injury, dacryocystitis, episcleritis, scleritis, iritis, keratitis, dry eye syndrome (DES; also referred to as keratoconjunctivitis sicca [KCS]), glaucoma, subconjunctival hemorrhage, bacterial or viral infection, or trauma.

Conjunctivitis, the most common cause of red eye, is characterized by vascular dilation of the superficial conjunctival blood vessels, cellular infiltration, and exudation; it must be differentiated on the basis of etiology (viral, bacterial, or allergic).

Blepharitis is an inflammation of the eyelids, usually involving the lid margins. It 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.

Numerous causes or corneal injury exist, which can be grouped into infective, toxic, degenerative, traumatic and allergic conditions.

Dacryocystitis is inflammation of the lacrimal sac caused by obstruction of the nasolacrimal duct. In infants, this results from failure of the canalization that normally occurs by the end of the first month. In adults, acute forms are due to Staphylococcus aureus or beta-hemolytic Streptococcus. Acute cases in children are due to Haemophilus influenzae.

The episclera is the layer between the conjunctiva and the sclera. Episcleritis is an inflammation of the episcleral vessels, usually of autoimmune origin; it can be caused by virtually any inflammatory systemic condition affecting the body, such as rheumatoid arthritis, Sjögren syndrome, coccidioidomycosis, syphilis, zoster, or tuberculosis. Most often, no specific cause can be determined even after these inflammatory conditions have been tested for.

Iritis is an inflammation of the anterior uveal tract. In most cases, the cause cannot be determined. Like episcleritis, however, iritis can be caused by any systemic inflammatory disease. More than 50% of patients have human leukocyte antigen (HLA) B27 (HLA-B27) or HLA-B8 and the many diseases associated with them. Trauma is a common cause.

Keratitis is an inflammation of the cornea and can be of bacterial, viral, fungal, or parasitic origin.

DES may result from any disease that is associated with deficiency of tear film components and lid surface or epithelial abnormalities. In particular, KCS 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 increased risk when there has been enlargement of the lens.

Associated systemic disease (eg, rheumatoid arthritis, herpes zoster ophthalmicus, or gout) is found in 40% of all patients with scleritis (anterior).

Subconjunctival hemorrhage results from bleeding of the conjunctival or episcleral blood vessels into the subconjunctival space. It may be spontaneous, traumatic, or related to systemic illness.[5, 6, 7, 8] The classic presentation involves a patient without eye pain or visual disturbance who discovers the red eye in the mirror or from a concerned friend or family member. Occasionally, the subconjunctival hematoma may be more extensive, thereby elevating the overlying conjunctival tissue and leading to excessive discomfort and surface irritation due to exposure or blinking. In rare cases, the elevated redundant conjunctiva becomes trapped and compressed between the lids, creating even more discomfort and superficial punctate conjunctival staining or frank conjunctival abrasions. Persistent elevated limbal conjunctiva may cause a dellen, which may cause other clinical complications. Causes of a subconjunctival hematoma include the following:[9, 10]

  • Idiopathic
  • Valsalva (eg, coughing, straining, weightlifting, working under a sink)
  • Traumatic (mild isolated lesion due to eye rubbing or sports injuries or a more serious lesion associated with retrobulbar hemorrhage or ruptured globe)
  • Hypertension or arteriosclerosis
  • Bleeding disorders (if recurrent or in young patients without a history of trauma or infection), including hematologic or hepatic disease, diabetes, systemic lupus erythematosus, parasites, and vitamin C deficiency [11]
  • Certain viral infections of the conjunctiva, especially in children
  • Various antibiotics, anticoagulants (eg, warfarin), analgesics (eg, nonsteroidal anti-inflammatory drugs [NSAIDs]), steroids, contraceptives, and vitamins A and D [12, 13]
  • Normal sequelae of ocular surgery, even if there was no conjunctival incision
  • Suction ring due to femtosecond laser-assisted cataract surgery (FLACS) or Lasik surgery
  • Febrile systemic infections, such as meningococcal septicemia, scarlet fever, typhoid fever, cholera, rickettsia, malaria, and viral infections (eg, influenza, smallpox, measles, yellow fever, and sandfly fever).
  • Emboli from long bone fractures, chest compression, cardiac angiography, open-heart surgery, and other remote operations [14]

Bacterial pathogens in keratitis and corneal ulcers include Pseudomonas aeruginosa, S aureus, Streptococcus pneumoniae, and coagulase-negative Staphylococcus. Viral pathogens include herpes simplex and adenovirus.

Epidemiology and Prognosis

Red eye is very common, and conjunctivitis is the most frequent cause. Subconjunctival hemorrhage also occurs frequently, but, because it is a self-limited disorder, exact figures are not available since many asymptomatic individuals do not seek medical care. Subconjunctival hemorrhage can occur at all ages, but it is more common with increasing age; no sex-based or racial predilection has been noted.

The prognosis depends on the cause of the red eye. For example, subconjunctival hemorrhage is a self-limited condition when not associated with systemic illness or significant trauma; thus, the prognosis is excellent. Complications also depend on the cause of the red eye.

 

Presentation

History and Physical Examination

Obtain the following information:

  • Onset

  • Visual changes

  • Foreign body sensation

  • 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

Perform a complete ophthalmologic examination on all patients, to include the following:

  • Visual acuity (each eye should be tested separately)

  • Extraocular movements

  • Pen light examination (should test for pupil reactivity, pupil shape, discharge, pattern of injection, and corneal opacity)

  • Tests for direct and consensual photophobia

  • Slit-lamp examination (examine the cornea for edema, defects, or opacification with and without fluorescein) – Mastery of slit-lamp technique is a prerequisite for making the correct diagnosis

  • Anterior chamber evaluation should be performed for depth, cells, and flare

  • Intraocular pressure (IOP) measurements

  • Eyelid inspection with eversion

Certain signs help distinguish among the various causes of a red eye.

Conjunctivitis

Conjunctivitis (see the image below), the most common cause of red eye, is characterized by vascular dilation of the superficial conjunctival blood vessels, cellular infiltration, and exudation. Patients with conjunctivitis usually do not experience visual changes or ocular pain. Conjunctivitis may be allergic, toxic, viral, or bacterial. Because it is often difficult to distinguish precisely among the different types, the clinician often assumes a bacterial cause if the etiology is unclear.

Conjunctivitis. Courtesy of Wikipedia Commons. Conjunctivitis. Courtesy of Wikipedia Commons.

Allergic conjunctivitis often presents with pruritus in individuals with a history of allergic disease. Viral conjunctivitis tends to be associated with enlarged, tender preauricular nodes, watery discharge, and upper respiratory tract infection. Viral conjunctivitis, particularly due to adenovirus infection, is highly contagious; proper hygiene and hand washing habits should be emphasized to all patients, roommates, colleagues, and coworkers. Bacterial conjunctivitis tends to be associated with a more mucopurulent or purulent discharge. Toxic conjunctivitis may result from episodic or chronic exposure to chemical irritants, some capable of causing significant ocular surface damage. It is essential to identify the toxin or chemical in cases of acute exposure in order to render appropriately aggressive treatment.

Blepharitis

Blepharitis (see the image below) is often associated with conjunctivitis and may be caused by allergic, infectious or dermatologic processes. Staphylococci are the most common etiologic organisms.

Blepharitis. Courtesy of Wikipedia Commons. Blepharitis. Courtesy of Wikipedia Commons.

Canaliculitis

Canaliculitis (see the image below) is characterized by a mildly red eye (usually unilateral) with slight discharge. Discharge can be expressed from the canaliculus. Actinomyces, herpes simplex virus, staphylococci, and pneumococci are the most common causative organisms.[15] Retained foreign bodies such as dacryoliths and silicone plastic punctal plugs must also be considered.

Canaliculitis of the left lower lid. Courtesy of P Canaliculitis of the left lower lid. Courtesy of Peter Rubin, MD, Director, Eye Plastics Service, Massachusetts Eye and Ear Infirmary, Harvard Medical School.

Keratitis

Keratitis can be of bacterial, viral, fungal, or parasitic origin. Patients may have decreased visual acuity and photophobia and often complain of severe eye pain. An epithelial defect may be evident on slit-lamp examination or may require fluorescein staining for visualization. Corneal inflammation or infection may be accompanied by anterior chamber reaction.

Bacterial keratitis (see the image below) is often associated with contact lens wear, particularly overnight wear. A mucopurulent discharge is often observed, as well as corneal opacity with conjunctival hyperemia and photophobia. Viral keratitis usually presents with watery discharge and a grayish corneal opacity with photophobia and foreign body sensation. Any opacification of the cornea in a red eye is considered to represent a corneal infection until proven otherwise so is an emergent condition. The opacification may or may not take up fluorescein. This condition warrants prompt ophthalmic evaluation.

This photograph depicts a child with a bilateral e This photograph depicts a child with a bilateral eye condition known as interstitial keratitis (IK), a stigma related to congenital syphilis.

Dacryocystitis

Dacryocystitis (see the image below) is characterized by localized pain, edema, and erythema over the lacrimal sac at the medial canthus of the eye. It is usually unilateral. Often, purulent discharge from the puncta is noted. Staphylococci are the most common causative organisms.[16]

Acute dacryocystitis. Acute dacryocystitis.

Scleritis

Scleritis (see the image below) is universally accompanied by pain, especially with tenderness exacerbated by digital pressure. Gradual onset of red eye and insidious decrease in vision are typically noted. Recurrent episodes are common. Anterior chamber inflammation or posterior involvement may affect visual acuity. The globe is usually tender and the sclera swollen. Deep scleral injection is accompanied by inflammation of the overlying episclera and conjunctiva. Scleritis is bilateral in 50% of patients.

Scleritis. Courtesy of Wikipedia Commons. Scleritis. Courtesy of Wikipedia Commons.

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 because this may be due to ischemia. It is an ophthalmic condition that warrants prompt ophthalmologic referral. Most patients have some form of autoimmune condition.

Episcleritis

In episcleritis, unlike conjunctivitis, the inflammation tends to be limited to isolated patches, not involving the eye diffusely. Dilated episcleral vessels are observed between the white sclera. Injection of the more superficial conjunctival vessels should be differentiated from that of the deeper violaceous episcleral vessels. Some more persistent cases may encompass the entire visible ocular surface, as well as more posterior episclera.

A history of recurrent episodes is common. Mild-to-moderate tenderness over the area of injection may be observed. Vision is usually unaffected. A watery discharge may be present. Patients should be examined for corneal complications (15%) and uveitis (7%). Episcleritis is usually a self-limited process, but ophthalmologic consultation is required if the condition is persistent or recurrent. A much smaller percentage of patients with episcleritis test positive for systemic autoimmune disease than do patients with scleritis.

Corneal injury

First and foremost, the patient’s eye should be stained with fluorescein to detect evidence of corneal abrasion (see the image below). Penetration of the globe should be excluded via thorough slit-lamp examination, IOP testing, and Seidel testing with a fluorescein strip, when indicated. The lid should always be everted to exclude retained foreign material.

Corneal abrasion. Corneal abrasion.

Iritis

In iritis, the eye develops a perilimbal redness known as ciliary flush due to dilation of the radial vessels. In conjunctivitis, by way of comparison, the intensity of vascular engorgement decreases toward the limbus. Cells and flare are present in the anterior chamber and may be seen with the slit lamp under high magnification in specific light conditions. Visual acuity, direct and consensual photophobia, pain in the involved eye, posterior synechiae between the iris and lens, and keratitic precipitates on the endothelium may be observed.

The pupil of the affected eye is usually constricted and irregular if synechiae have formed. A mild watery discharge may be present. Iritis is often unilateral or asymmetric. Complications include glaucoma, cataract formation, and macular dysfunction; ophthalmologic consultation is required. Unfortunately, iritis is often overlooked in the context of the overwhelmingly higher incidence of bacterial conjunctivitis, as well as a strong reluctance for primary care providers to prescribe topical steroids or even seek ophthalmologic evaluation for what might erroneously be perceived as a self-limited bacterial surface infection. Thus, significant damage can occur when iritis goes unnoticed by the first provider to encounter these patients.

Dry eye syndrome

In most cases of dry eye syndrome (DES), or keratoconjunctivitis sicca (KCS), the eye appears normal. On slit-lamp examination, decreased tear meniscus at the lower lid margin may be noted.[17] The corneal epithelium shows areas with varying degrees of fine punctate stippling in the interpalpebral fissure, which stain with rose bengal or fluorescein if more severely damaged.

Glaucoma

Narrow-angle glaucoma is an ophthalmologic emergency. Patients complain of severely painful red eye. Visual acuity is reduced and worsens over time. Haloes around light are common owing to corneal edema. Patients are usually older than 50 years and frequently hyperopic with a short axial length and small anterior chamber depth. The pupil may be mid-dilated and may be nonreactive to light. Slit-lamp examination reveals corneal edema and a shallow anterior chamber with mild cells and flare.

IOP is elevated, usually to a level higher than 45 mm Hg (reference range, < 21 mm Hg). The anterior chamber angle may be very narrow. Nausea and vomiting are common. Gonioscopy should be performed to confirm the diagnosis and immediate referral made for appropriate medical and laser surgical therapy to create the essential peripheral iridotomy.

Pterygium

Pterygium is a benign conjunctival growth made of triangular band of fibrovascular tissue caused by long-term exposure to ultraviolet light, dust, and low humidity. It usually arises from the nasal side of the sclera. It may encroach onto the cornea (pterygium) or extend on either side of the cornea (pinguecula).

Subconjunctival hemorrhage

Subconjunctival hemorrhage may appear as a flat, thin hemorrhage or as a thick collection of blood. The most common visual manifestation is a bright red patch with relatively normal surroundings. There may be a history of red eye and, possibly, mild irritation; however, patients are usually asymptomatic. Slit-lamp examination reveals the precise location of the hemorrhage under the conjunctiva. The view of the sclera may be obscured by blood, which may be dark red if the collection is thick.[18]

 

DDx

Diagnostic Considerations

The differential diagnosis is so large that the caregiver must be comfortable with all diagnoses and must be able to distinguish between them. Misdiagnosis is a major medicolegal pitfall, in that the truly emergent conditions that may cause red eye have major vision-threatening sequelae.

The occurrence of subconjunctival hemorrhage in an eye after scleral buckle indicates buckle infection until proved otherwise, even if the surgery was performed years before. Usually, there is focal tenderness somewhere over the buckle.

Conjunctival neoplasms that give rise to secondary hemorrhage must also be considered in the differential diagnosis.

Differential Diagnoses

 

Workup

Approach Considerations

Laboratory studies are not required for most patients. Check visual acuity, IOP, and blood pressure in every patient.

The diagnosis of scleritis and iritis generally requires further workup for associated systemic disease, including complete blood count (CBC), erythrocyte sedimentation rate (ESR), and levels of antinuclear antibody (ANA), rheumatoid factor (RF), uric acid, and rapid plasma reagin (RPR). Uncomplicated episcleritis and iritis warrant further evaluation if more than 1 episode occurs. Send exudate from patients with conjunctivitis for bacterial culture, especially in cases of corneal ulceration or significant conjunctival disease.

In the setting of potential subconjunctival hemorrhage, if there is a history of trauma, rule out a ruptured globe or retrobulbar hemorrhage.[19] If the condition is recurrent or there is a history of bleeding problems (eg, epistaxis or easy bruising), then bleeding time, prothrombin time (PT), activated partial thromboplastin time (aPTT), CBC with platelets, and protein C and S levels should be obtained, and consultation with an internist should be considered.[11]

 

Treatment

Approach Considerations

The key to management is making the correct diagnosis in a timely fashion. Uncomplicated cases of blepharitis, conjunctivitis, foreign bodies, corneal abrasion, and subconjunctival hemorrhage may be managed by the primary care physician.[3, 20, 21, 22, 23] However, other possible causes of red eye require ophthalmologic consultation within an appropriate time period. Corneal ulcers, iritis, endophthalmitis, penetrating foreign bodies, and other conditions must be seen by a specialist promptly.[24]

All patients with acute changes in vision require immediate consultation. Primary care physicians should refrain from treating any patients with corticosteroids without first obtaining an appropriate consultation. Referral to an internist or a family physician should be made as indicated for hypertension or bleeding diathesis.[1, 2]

Cause-Specific Management

All cases of conjunctivitis are treated with antibiotic drops to address the bacterial cause or prevent secondary bacterial infection. The common practice of prescribing a topical antibiotic ointment creates poor compliance owing to patient frustration with ointment application, as well as poor clinical response due to the limited sensitivity spectrum of the most commonly available ophthalmic ointments. Allergic conjunctivitis is treated with topical antihistamines and pulse vasoconstrictors, when indicated, occasionally in conjunction with antibiotic drops. Vasoconstrictors should never be prescribed on a long-term basis owing to the high risk of dependency. Herpes conjunctivitis and keratitis require systemic treatment with acyclovir (800 mg orally 5 times daily) and with 3% acyclovir ophthalmic ointment, topical trifluridine, or topical ganciclovir.

Red eye caused by conjunctivitis may be contagious. Washing hands and avoiding use of contaminated tissues or washcloths helps prevent spread to the other eye or to other individuals.

In blepharitis, cleaning the eyelids with soap eyelid-specific soapy applicators (Avenova, Ocusoft, Oasis brands) several times a day usually leads to symptomatic improvement. Antibiotic drops or pills may also be necessary.

Treatment of episcleritis and scleritis involves administration of nonsteroidal anti-inflammatory drugs (NSAIDS) such as diclofenac 50 mg orally 3 times daily and referral to an ophthalmologist.

Patients with iritis should be promptly (ie, within 1-2 days) referred to an ophthalmologist. Topical steroids are usually initiated by the ophthalmologist, along with cycloplegic agents to prevent synechiae.

For keratitis, the use of antibiotic eye drops or the appropriate topical antiviral agent is indicated, depending on the etiology, along with referral to an ophthalmologist.

Angle-closure glaucoma is a medical emergency that may lead to blindness; therefore, prompt treatment and evaluation by an ophthalmologist are warranted. Temporizing treatment consists of miotic drops (eg, pilocarpine 1% or 2% every 5 minutes up to 1 hour), acetazolamide (500-1000 mg orally or intravenously [IV]), antiemetics, analgesia, and, in some cases, IV mannitol. Peripheral iridotomy, usually performed with a YAG laser, is essentially curative.

In cases of subconjunctival hemorrhage with no history of trauma, no treatment is required. Artificial tears can be used 4 times per day for mild irritation. Elective use of aspirin products or NSAIDs should be discouraged. With time and blood breakdown, the hemorrhage may become green or yellow, like a bruise, spreading around the circumference of the globe. Usually, this disappears within 2 weeks. Patients are told to return if the bruiselike appearance does not fully resolve, if pain ensues, or if the hemorrhage recurs.

Treatment of red eye from a corneal or conjunctival foreign body consists of removal of the foreign body, administration of antibiotic drops, and follow-up with an ophthalmologist to monitor for the development of an infection. An Alger brush or metal rotating burr is often required to remove the painful and cicatrizing residual rust ring seen commonly after iron-containing metallic foreign body removal.

Treatment of red eye caused by dry eye syndrome (DES), or keratoconjunctivitis sicca (KCS), consists of administration of artificial tear drops and referral to an ophthalmologist if symptoms persist.

 

Medication

Medication Summary

Medications used to treat red eye depend on the underlying cause of the condition and may include antivirals, nonsteroidal anti-inflammatory drugs (NSAIDs), cholinergic agents, carbonic anhydrase (CA) inhibitors, and osmotic diuretics.

Topical Antiviral Agents

Class Summary

Antiviral agents inhibit viral replication when their phosphorylated form becomes incorporated into viral DNA.

Trifluridine ophthalmic (Viroptic)

Trifluridine is a fluorinated pyrimidine nucleoside. Trifluridine demonstrates in vitro and in vivo activity against herpes simplex virus types 1 and 2, vaccinia virus, and some strains of adenovirus.

Trifluridine Ophthalmic Solution 1% is also effective in the treatment of dendritic epithelial keratitis. Trifluridine interferes with DNA synthesis in cultured mammalian cells. However, its antiviral mechanism of action is not completely known. The solution contains thimerosal 0.001% as a preservative.

Ganciclovir ophthalmic (Zirgan)

Ganciclovir ophthalmic gel (Zirgan) 0.15% contains the active ingredient ganciclovir, which is a guanosine derivative. When phosphorylated, it inhibits DNA replication of HSV. Ganciclovir is transformed by viral and cellular thymidine kinases (TK) to ganciclovir triphosphate, which works as an antiviral agent by inhibiting the synthesis of viral DNA in 2 ways: competitive inhibition of viral DNA-polymerase and direct incorporation into viral primer strand DNA, resulting in DNA chain termination and prevention of replication. Since it does not affect uninfected cells, the toxicity is minimal.

Acyclovir (Zovirax)

Acyclovir is a prodrug activated by phosphorylation by virus-specific thymidine kinase (TK). Herpes virus TK, but not host cell TK, uses acyclovir as a purine nucleoside, converting it into acyclovir monophosphate, a nucleotide analogue. Guanylate kinase then converts the monophosphate form into diphosphate and triphosphate analogues that inhibit viral DNA replication.

Acyclovir has affinity for viral TK and, once phosphorylated, causes DNA chain termination when acted on by DNA polymerase. The result is potent inhibition of viral growth with minimal toxic effects on to uninfected epithelial cells. Acyclovir inhibits the activity of both herpes simplex virus (HSV)-1 and HSV-2.

The topical acyclovir formulation (3% ointment), equal in efficacy but less toxic, is not commercially available in the United States.

Topical Nonsteroidal Anti-inflammatory Drugs (NSAIDs)

Class Summary

NSAIDs inhibit prostaglandin synthesis, and this inhibition results in vasoconstriction, decreased vascular permeability, leukocytosis, and no steroid-induced effect on intraocular pressure (IOP). However, these agents have no significantly favorable effect on IOP. They are potent analgesics and potentiate pupillary mydriasis. They also significantly reduce photophobia in patients with corneal surgery or corneal abrasions.

Diclofenac (Voltaren Ophthalmic)

Diclofenac is one of a series of phenylacetic acids that have demonstrated anti-inflammatory and analgesic properties in pharmacologic studies. It is believed to inhibit the enzyme cyclooxygenase, which is essential in the biosynthesis of prostaglandins. It may facilitate outflow of aqueous humor and decrease vascular permeability. Any equivalent topical NSAID can be used in place of diclofenac.

Ketorolac tromethamine 0.5% (Acular, Acuvail)

This nonsteroidal anti-inflammatory drug inhibits prostaglandin synthesis by decreasing cyclooxygenase activity, decreasing the formation of prostaglandin precursors. It may facilitate outflow of aqueous humor and decrease vascular permeability. This drug has been available for decades and therefore has a substantial track and safety record. The topical preparations tend to sting.

Flurbiprofen (Ocufen)

Flurbiprofen facilitates outflow of aqueous humor by inhibiting prostaglandin synthesis, causing a subsequent decrease in vascular permeability. This is the least potent of the available topical ophthalmic NSAIDs.

Miotics, Direct-Acting

Class Summary

Cholinergic agonists add to the antiglaucoma effects of beta blockers, CA inhibitors, and sympathomimetics as an adjunctive therapy. They produce pupillary constriction and therefore tighten the iris plane, which is extremely useful in patients with angle closure glaucoma. Some patients experience a brow ache, particularly within the initial few days of dosing.

Pilocarpine (Isopto Carpine, Pilopine HS)

Patients may be maintained on pilocarpine as long as the IOP is controlled and no deterioration in the visual fields is present. Pilocarpine may be used either alone or in combination with other miotics, beta blockers, epinephrine, CA inhibitors, or hyperosmotic agents to decrease IOP. The frequency of instillation and concentration are determined by the patient's response. Individuals with heavily pigmented irises may require higher strengths.

Antiglaucoma, Carbonic Anhydrase Inhibitors

Class Summary

CA is an enzyme found in many tissues of the body, including the eye. It catalyzes a reversible reaction whereby carbon dioxide becomes hydrated and carbonic acid dehydrated. By slowing the formation of bicarbonate ions and thus subsequently reducing sodium and fluid transport, CA inhibitors may reduce the action of CA in the ciliary processes of the eye. This effect decreases aqueous humor secretion, reducing IOP.

Acetazolamide (Diamox Sequels)

Acetazolamide, an agent chemically derived from sulfa drugs, reduces the rate of aqueous humor formation by directly inhibiting the action of CA on secretory ciliary epithelium, thereby causing a reduction in IOP by as much as 40-60%. More than 90% of CA must be inhibited before IOP reduction can occur. Effects become apparent in about 1 hour, peak in 4 hours, and reach trough values in about 12 hours.

Acetazolamide is used adjunctively for treatment of chronic simple (open-angle) glaucoma and secondary glaucoma and preoperatively for acute angle-closure glaucoma when delay of surgery is required. It is available as a 500-mg sustained-release capsule, as well as a 250-mg generic tablet. If one form of the drug is not well tolerated, another form or a lower dose of the same form may be better tolerated.

Diuretics, Osmotic Agents

Class Summary

Osmotic diuretics increase the osmolarity of the glomerular filtrate and induce diuresis. This in turn hinders the tubular reabsorption of water, causing sodium and chloride excretion to increase as well. The diuretic effect of these agents can subsequently reduce IOP.

Mannitol (Osmitrol)

Mannitol reduces elevated IOP when the pressure cannot be lowered by other means. Caution should be exercised in patients with renal failure. Initially assess for adequate renal function by administering a test dose of 200 mg/kg IV over 3-5 minutes. In adults, this should produce urine flow of at least 30-50 ml/hr over 2-3 hours; in children, it should produce urine flow of at least 1 mL/kg over 1-3 hours.

Ophthalmic Lubricants

Class Summary

Lubricants act as humectants in the eye. The ideal artificial lubricant should be preservative-free; contain potassium, bicarbonate, and other electrolytes; and have a polymeric system to increase its retention time. Lubricating drops are used to reduce ocular surface disease morbidity and to prevent complications. Lubricating ointments prevent complications from dry eyes. Ocular inserts such as carboxymethylcellulose (Lacrisert) reduce symptoms resulting from moderate-to-severe dry eye syndromes.

Artificial tears (Advanced Eye Relief, Bion Tears, Hypo Tears, Murine Tears, Tears Naturale II)

Artificial tears are used to increase lubrication of the eye.

Hydroxypropyl methylcellulose (GenTeal, Isopto Tears, Natural Balance Tears, Nature's Tears, Systane Overnight Therapy, Gonak, ImproVue)

These substances serve as lubricants and emollients.

Antihistamines, Ophthalmic

Class Summary

These agents are used to treat symptoms of itching and to prevent future symptoms by controlling the degranulation of mast cells. Mast cell–stabilizing medications/antihistamine combination drops are most likely to achieve the therapeutic effect with minimal complications.

Olopatadine (Patanol, Pataday, Pazeo)

This is a relatively selective H1 receptor antagonist and inhibitor of histamine release from mast cells.

Ketotifen (Zaditor, Alaway, Claritin Eye, Zyrtec Itchy Eye)

Ketotifen is a relatively selective H1 receptor antagonist and inhibitor of histamine release from mast cells. It is available over the counter.

Topical Antibiotics, Ophthalmic

Class Summary

Therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.

Ofloxacin ophthalmic (Ocuflox)

Ofloxacin is a pyridine carboxylic acid derivative fluoroquinolone with broad-spectrum bactericidal effect. It inhibits bacterial growth by inhibiting DNA gyrase. It is indicated for superficial ocular infections of the conjunctiva or cornea due to susceptible microorganisms.

Trimethoprim/polymyxin B ophthalmic (Polytrim Ophthalmic Solution)

This combination is used for ocular infection of the cornea or conjunctiva caused by susceptible microorganisms. It is available as a solution (polymyxin/trimethoprim) and as an ointment (polymyxin/bacitracin). Polymyxin shows potency against gram-negative organisms. Both trimethoprim and bacitracin show potency against a wide variety of gram-positive and gram-negative organisms.

Ciprofloxacin (Ciloxan)

Ciprofloxacin has activity against Pseudomonas and Streptococcus species, methicillin-resistant Staphylococcus aureus (MRSA), S epidermidis, and most gram-negative organisms; it has no activity against anaerobes.

Moxifloxacin (Vigamox, Moxeza)

Moxifloxacin has activity against susceptible gram-negative and gram-positive bacteria. Antibiotics in this class inhibit bacterial DNA synthesis and thus growth by inhibiting DNA gyrase. Vigamox is self-preserved and used topically for ocular surface infections, perioperative prophylaxis, and intracamerally to reduce the risk of postoperative endophthalmitis.

Erythromycin ophthalmic (Ilotycin)

Erythromycin is indicated for infections caused by susceptible strains of microorganisms and for prevention of corneal and conjunctival infections.

Sulfacetamide ophthalmic (Bleph 10)

This agent interferes with bacterial growth by inhibiting bacterial folic acid synthesis by competitively antagonizing para-aminobenzoic acid. It is available in solution, ointment, and lotion form. Use of this class of antimicrobial has decreased owing to the presumed risk of Stevens-Johnson syndrome and similar severe allergic reactions.

Tobramycin ophthalmic (Tobrex)

Tobramycin is an aminoglycoside that interferes with bacterial protein synthesis by binding to 30S and 50S ribosomal subunits, causing a defective bacterial cell membrane. It is available in solution, ointment, and lotion form. The aminoglycosides show excellent activity against methicillin-resistant Staphylococcus epidermidis and Staphylococcus aureus.

Gentamicin (Gentak, Garamycin)

Gentamicin is an aminoglycoside antibiotic that covers gram-positive and gram-negative bacteria.

Polymyxin B/bacitracin ophthalmic (Ak-Poly-Bac, Polycin Ophthalmic)

Bacitracin prevents transfer of mucopeptides into the growing cell wall, which causes inhibition of bacterial cell wall synthesis. Polymyxin B damages bacterial cytoplasmic membrane and alters permeability, causing intracellular constituents to leak. Used to treat open excoriations and erosions.

 

Questions & Answers

Overview

What is red eye?

What is the pathophysiology of red eye?

What causes red eye?

What is the role of subconjunctival hematoma in the etiology of red eye?

What are infectious causes of red eye?

What is the prevalence of red eye?

What is the prognosis of red eye?

Presentation

Which clinical findings suggest a conjunctivitis etiology for red eye?

Which clinical findings suggest a blepharitis etiology for red eye?

Which clinical findings suggest a canaliculitis etiology for red eye?

Which clinical findings suggest a keratitis etiology for red eye?

Which clinical findings suggest a dacryocystitis etiology for red eye?

Which clinical findings suggest a scleritis etiology for red eye?

Which clinical findings suggest a pterygium etiology for red eye?

Which clinical findings suggest a subconjunctival hemorrhage etiology for red eye?

What is the focus of clinical history for the evaluation of red eye?

What is included in the physical exam for red eye?

Which clinical findings suggest an episcleritis etiology for red eye?

Which clinical findings suggest a corneal injury etiology for red eye?

Which clinical findings suggest an iritis etiology for red eye?

Which clinical findings suggest a dry eye syndrome (DES) etiology for red eye?

Which clinical findings suggest a glaucoma etiology for red eye?

DDX

Which conditions should be included in the differential diagnoses of red eye?

What are the differential diagnoses for Red Eye?

Workup

How is the etiology of red eye determined?

Treatment

When is a specialist consultation indicated for the treatment of red eye?

How is red eye treated?

Medications

Which medications are used in the treatment of red eye?

Which medications in the drug class Topical Antibiotics, Ophthalmic are used in the treatment of Red Eye?

Which medications in the drug class Antihistamines, Ophthalmic are used in the treatment of Red Eye?

Which medications in the drug class Ophthalmic Lubricants are used in the treatment of Red Eye?

Which medications in the drug class Diuretics, Osmotic Agents are used in the treatment of Red Eye?

Which medications in the drug class Antiglaucoma, Carbonic Anhydrase Inhibitors are used in the treatment of Red Eye?

Which medications in the drug class Miotics, Direct-Acting are used in the treatment of Red Eye?

Which medications in the drug class Topical Nonsteroidal Anti-inflammatory Drugs (NSAIDs) are used in the treatment of Red Eye?

Which medications in the drug class Topical Antiviral Agents are used in the treatment of Red Eye?