Conjunctivitis, also known aspink eye,[4][5] isinflammation of theconjunctiva, the thin and clear layer that covers the white surface of the eye and the innereyelid.[6] It makes the eye appear pink or reddish.[1] Pain, burning, scratchiness, or itchiness may occur.[1] The affected eye may have increased tears or be stuck shut in the morning.[1] Swelling of thesclera may also occur.[1] Itching is more common in cases that are due to allergies.[3] Conjunctivitis can affect one or both eyes.[1]
The most common infectious causes in adults are viral, whereas in children bacterial causes predominate.[7][3] The viral infection may occur along with other symptoms of acommon cold.[1] Both viral and bacterial cases are easily spread among people.[1] Allergies to pollen or animal hair are also a common cause.[3] Diagnosis is often based on signs and symptoms.[1] Occasionally a sample of the discharge is sent forculture.[1]
Prevention is partly byhandwashing.[1] Treatment depends on the underlying cause.[1] In the majority of viral cases there is no specific treatment.[3] Most cases that are due to a bacterial infection also resolve without treatment; howeverantibiotics can shorten the illness.[1][3] People who wearcontact lenses and those whose infection is caused bygonorrhea orchlamydia should be treated.[3] Allergic cases can be treated withantihistamines ormast cell inhibitor drops.[3]
Between three and six million people get acute conjunctivitis each year in the United States.[1][3] Typically they get better in one or two weeks.[1][3] If visual loss, significant pain, sensitivity to light or signs ofherpes occur, or if symptoms do not improve after a week, further diagnosis and treatment may be required.[3] Conjunctivitis in a newborn, known asneonatal conjunctivitis, may also require specific treatment.[1]
Red eye,swelling of the conjunctiva, andwatering of the eyes are symptoms common to all forms of conjunctivitis. However, the pupils should be normally reactive, and the visual acuity should be normal.[8]
Conjunctivitis is identified by inflammation of the conjunctiva, manifested by irritation and redness. Examination using aslit lamp (biomicroscope) may improve diagnostic accuracy. Examination of the palpebral conjunctiva, which overlies the inner aspects of the eyelids, is usually more diagnostic than examination of the bulbal conjunctiva, which overlies the sclera.[9]
Approximately 80% of cases of conjunctivitis in adults and less than 20% in children are due to viruses, with 65% to 90% of these cases being attributed to adenoviruses.[3][7]Viral conjunctivitis is often associated with an infection of the upper respiratory tract, a common cold, or a sore throat. Other associated signs may includepre-auricular lymph node swelling and contact with another person with a red eye.[7] Eye pain may be present if the cornea is also involved.[7] Its symptoms include excessive watering and itching. The discharge in viral conjunctivitis is usually (but not always) watery.[7] The infection usually begins in one eye but may spread easily to the other eye.[citation needed]
Viral conjunctivitis manifests as a fine, diffuse pinkness of the conjunctiva which may be mistaken foriritis, but corroborative signs onmicroscopy, particularly numerouslymphoid follicles on thetarsal conjunctiva, and sometimes apunctate keratitis are seen.[10]
Allergic conjunctivitis isinflammation of the conjunctiva due to allergy.[11] The specificallergens may differ among patients. Symptoms result from the release ofhistamine and other active substances bymast cells, and consist of redness (mainly due tovasodilation of the peripheral small blood vessels), swelling of the conjunctiva, itching, and increased production of tears.[citation needed]
Bacteria are responsible for approximately 70% of conjunctivitis in children and less than 20% of cases in adults.[7] Common bacteria responsible for bacterial conjunctivitis areStaphylococcus includingStaph aureus,Streptococcus such asstrep pneumoniae,[12]Haemophilus species andMoraxella catarrhalis.[7] Less commonly,Chlamydia spp. and Niesseria species (Neisseria gonorrhoeae andNeisseria meningitidis) may be the cause.[7][13] Infection withEscherichia coli may also cause conjunctivitis, particularly in theneonatal subtypeophthalmia neonatorum.[14] Bacterial conjunctivitis usually causes a rapid onset of conjunctival redness, swelling of the eyelid, and a sticky discharge. Typically, symptoms develop first in one eye, but may spread to the other eye within 2–5 days. Conjunctivitis due to commonpus-producing bacteria causes marked grittiness or irritation and a stringy, opaque, greyish or yellowishdischarge that may cause the lids to stick together, especially after sleep. Severe crusting of the infected eye and the surrounding skin may also occur. The gritty or scratchy feeling is sometimes localized enough that patients may insist that they have a foreign body in the eye.[citation needed]
Typical membranous conjunctivitis
Bacteria such asChlamydia trachomatis orMoraxella spp. can cause a nonexudative but persistent conjunctivitis without much redness. Bacterial conjunctivitis may cause the production of membranes or pseudomembranes that cover the conjunctiva. Pseudomembranes consist of a combination ofinflammatory cells and exudates and adhere loosely to the conjunctiva, while true membranes are more tightly adherent and cannot be easily peeled away. Cases of bacterial conjunctivitis that involve the production of membranes or pseudomembranes are associated withNeisseria gonorrhoeae, β-hemolytic streptococci, andCorynebacterium diphtheriae.C. diphtheriae causes membrane formation in the conjunctiva of unimmunized children.[15]
Chemical eye injury may result when anacidic oralkaline substance gets in the eye.[16] Alkali burns are typically worse than acidic burns.[17] Mild burns produce conjunctivitis, while more severe burns may cause thecornea to turn white.[17]Litmus paper may be used to test for chemical causes.[16] When a chemical cause has been confirmed, the eye or eyes should be flushed until thepH is in the range 6–8.[17] Anaesthetic eye drops can be used to decrease the pain.[17]
Irritant or toxic conjunctivitis is primarily marked by redness. If due to a chemical splash, it is often present in only the lower conjunctival sac. With some chemicals, above all with caustic alkalis such assodium hydroxide,necrosis of the conjunctiva marked by a deceptively white eye due to vascular closure may occur, followed by sloughing off of the deadepithelium. A slit lamp examination is likely to show evidence ofanterior uveitis.[18]
Omics technologies have been used to identify biomarkers that inform on the emergence and progression of conjunctivitis. For example, in chronic inflammatory cicatrizing conjunctivitis, activeoxylipins,lysophospholipids,fatty acids, andendocannabinoids alterations, from which potential biomarkers linked to inflammatory processes were identified.[19]
Inclusion conjunctivitis of the newborn is a conjunctivitis that may be caused by the bacteriumChlamydia trachomatis, and may lead to acute,purulent conjunctivitis.[20] However, it is usually self-healing.[20]
Viruses are the most common cause of infectious conjunctivitis.[3] Bacterial infections, allergies, other irritants, and dryness are also common causes. Both bacterial and viral infections are contagious, passing from person to person or spread through contaminated objects or water. Contact with contaminated fingers is a common cause of conjunctivitis. Bacteria may also reach the conjunctiva from the edges of the eyelids and surrounding skin, from the nasopharynx, from infected eye drops or contact lenses, from the genitals, or from the bloodstream.[21] Infection by human adenovirus accounts for 65% to 90% of cases of viral conjunctivitis.[22]
Conjunctivitis may also be caused by allergens such as pollen, perfumes, cosmetics, smoke,[26][unreliable medical source?] dust mites,Balsam of Peru,[27] or eye drops.[28] The most frequent cause of conjunctivitis is allergic conjunctivitis, and it affects 15% to 40% of the population.[29] Allergic conjunctivitis accounts for 15% of eye related primary care consultations; most including seasonal exposures in the spring and summer or perpetual conditions.[30]
Cultures are not often taken or needed, as most cases resolve either with time or typical antibiotics. If bacterial conjunctivitis is suspected, but no response to topical antibiotics is seen, swabs for bacterial culture should be taken and tested. Viral culture may be appropriate in epidemic case clusters.[33]
Apatch test is used to identify the causative allergen in allergic conjunctivitis.[34]
Although conjunctival scrapes forcytology can be useful in detecting chlamydial andfungal infections, allergies, anddysplasia, they are rarely done because of the cost and the general dearth of laboratory staff experienced in handling ocular specimens. Conjunctival incisional biopsy is occasionally done whengranulomatous diseases (e.g.,sarcoidosis)[35] or dysplasia are suspected.[36]
Neonatal conjunctivitis is often grouped separately from bacterial conjunctivitis because it is caused by different bacteria than the more common cases of bacterial conjunctivitis.[37]
Blepharokeratoconjunctivitis is the combination of conjunctivitis with blepharitis and keratitis. It is clinically defined by changes of the lid margin, meibomian gland dysfunction, redness of the eye, conjunctival chemosis, and corneal inflammation.[40]
Some more serious conditions can present with a red eye, such as infectious keratitis, angle-closure glaucoma, or iritis. These conditions require the urgent attention of an ophthalmologist. Signs of such conditions include decreased vision, significantly increased sensitivity to light, inability to keep the eye open, a pupil that does not respond to light, or a severe headache with nausea.[41] Fluctuating blurring is common, due to tearing and mucoid discharge. Mild photophobia is common. However, if any of these symptoms is prominent, considering other diseases such asglaucoma,uveitis,keratitis, and evenmeningitis orcarotico-cavernous fistula is important.[citation needed]
A more comprehensive differential diagnosis for the red or painful eye includes:[41]
The most effective prevention is good hygiene, especially avoiding rubbing the eyes with infected hands. Vaccination against some of the causative pathogens, such asHaemophilus influenzae, pneumococcus, andNeisseria meningitidis is also effective.[42]
Povidone-iodine eye solution has been found to prevent neonatal conjunctivitis.[43] It is becoming more commonly used globally because of its low cost.[43]
Viral conjunctivitis usually resolves on its own and does not require any specific treatment.[3] Antihistamines (e.g.,diphenhydramine) or mast cell stabilizers (e.g.,cromolyn) may be used to help with the symptoms.[3] Povidone-iodine has been suggested as a treatment, but as of 2008, evidence to support it was poor.[45]
For allergic conjunctivitis, cool water poured over the face with the head inclined downward constricts capillaries, andartificial tears sometimes relieve discomfort in mild cases. In more severe cases,nonsteroidal anti-inflammatory medications andantihistamines may be prescribed. Persistent allergic conjunctivitis may also require topical steroid drops.[46]
Bacterial conjunctivitis usually resolves without treatment.[3] Topical antibiotics may be needed only if no improvement is observed after 3 days.[47] No serious effects were noted either with or without treatment.[48] Because antibiotics speed healing in bacterial conjunctivitis, their use may be considered.[48] Antibiotics are also recommended for those who wear contact lenses, areimmunocompromised, have disease which is thought to be due to chlamydia or gonorrhea, have a fair bit of pain, or have copious discharge.[3] Gonorrheal or chlamydial infections require both oral and topical antibiotics.[3]
The choice of antibiotic varies based on the strain or suspected strain of bacteria causing the infection.Fluoroquinolones,sodium sulfacetamide, ortrimethoprim/polymyxin may be used, typically for 7–10 days.[23] Cases of meningococcal conjunctivitis can also be treated with systemic penicillin, as long as the strain is sensitive to penicillin.[citation needed]
When investigated as a treatment, povidone-iodine ophthalmic solution has also been observed to have some effectiveness against bacterial and chlamydial conjunctivitis, with a possible role suggested in locations where topical antibiotics are unavailable or costly.[49]
Conjunctivitis due to chemicals is treated viairrigation withRinger's lactate orsaline solution. Chemical injuries, particularly alkali burns, are medical emergencies, as they can lead to severe scarring and intraocular damage. People with chemically induced conjunctivitis should not touch their eyes to avoid spreading the chemical.[50]
Conjunctivitis is the most common eye disease.[51] Rates of disease are related to the underlying cause, which varies by age as well as the time of year. Acute conjunctivitis is most frequently found in infants, school-age children, and the elderly.[21] The most common cause of infectious conjunctivitis is viral conjunctivitis.[29]
It is estimated that acute conjunctivitis affects 6 million people annually in the United States.[3]
Some seasonal trends have been observed for the occurrence of different forms of conjunctivitis. In the Northern Hemisphere, the occurrence of bacterial conjunctivitis peaks from December to April, viral conjunctivitis peaks in the summer months, and allergic conjunctivitis is more prevalent throughout the spring and summer.[21]
An adenovirus was first isolated by Rowe et al. in 1953. Two years later, Jawetz et al. published on epidemic keratoconjunctivitis.[52]: 437 "Madras eye" is a colloquial term that has been used inIndia for the disease.
In September 2023, a significant outbreak of conjunctivitis occurred inPakistan. The outbreak began inKarachi and quickly spread toLahore,Rawalpindi, andIslamabad. By the end of the month, over 86,133 cases had been reported inPunjab alone. The rapid spread of the disease led to the temporary closure of schools in the region. This event marked one of the largest outbreaks of Pink Eye in the country's recent history.[53][54][55][56]
Conjunctivitis imposes economic and social burdens. The cost of treating bacterial conjunctivitis in the United States was estimated to be $377 million to $857 million per year.[3] Approximately 1% of all primary care office visits in the United States are related to conjunctivitis. Approximately 70% of all people with acute conjunctivitis present to primary care and urgent care.[3]
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^Sheikh A, Hurwitz B (2008). "BACTERIAL CONJUNCTIVITIS 372.05 (Infective Conjunctivitis, Mucopurulent Conjunctivitis, Purulent Conjunctivitis)".Roy and Fraunfelder's Current Ocular Therapy. Elsevier. pp. 332–334.doi:10.1016/b978-1-4160-2447-7.50182-1.ISBN978-1-4160-2447-7.
^Korkmaz Ekren P, Mogulkoc N, Toreyin ZN, Egrilmez S, Veral A, Akalın T, et al. (October 2016). "Conjunctival Biopsy as a First Choice to Confirm a Diagnosis of Sarcoidosis".Sarcoidosis, Vasculitis, and Diffuse Lung Diseases.33 (3):196–200.PMID27758983.
^Roberts F, Thum CK (2021). "The Conjunctival Biopsy". In Roberts F (ed.).Lee's Ophthalmic Histopathology. Cham: Springer International Publishing. pp. 343–388.doi:10.1007/978-3-030-76525-5_11.ISBN978-3-030-76525-5.
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^Isenberg SJ, Apt L, Valenton M, Del Signore M, Cubillan L, Labrador MA, et al. (November 2002). "A controlled trial of povidone-iodine to treat infectious conjunctivitis in children".American Journal of Ophthalmology.134 (5):681–688.doi:10.1016/S0002-9394(02)01701-4.PMID12429243.
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