The disorder is most often idiopathic or associated with older age but can also be caused by connective tissue diseases (eg, Sjögren syndrome Sjögren Syndrome Sjögren syndrome is a relatively common chronic, autoimmune, systemic, inflammatory disorder of unknown cause. It is characterized by dryness of the mouth, eyes, and other mucous membranes due... read more , rheumatoid arthritis, systemic lupus erythematosus). See Keratoconjunctivitis Sicca Keratoconjunctivitis Sicca Keratoconjunctivitis sicca is chronic, bilateral desiccation of the conjunctiva and cornea due to an inadequate tear film. Symptoms include itching, burning, irritation, and photophobia. Diagnosis... read more for a discussion of dry eyes.
Discharge is often accompanied by a red eye Red Eye Red eye refers to a red appearance of the opened eye, reflecting dilation of the superficial ocular vessels. Dilation of superficial ocular vessels can result from Infection Allergy Inflammation... read more and commonly is caused by allergic Allergic Conjunctivitis Allergic conjunctivitis is an acute, intermittent, or chronic conjunctival inflammation usually caused by airborne allergens. Symptoms include itching, lacrimation, discharge, and conjunctival... read more or infectious conjunctivitis Viral Conjunctivitis Viral conjunctivitis is a highly contagious acute conjunctival infection usually caused by an adenovirus. Symptoms include irritation, photophobia, and watery discharge. Diagnosis is clinical... read more , blepharitis Blepharitis Blepharitis is inflammation of the eyelid margins that may be acute or chronic. Symptoms and signs include itching and burning of the eyelid margins with redness and edema. Diagnosis is by history... read more , and, in infants, ophthalmia neonatorum (neonatal conjunctivitis Neonatal Conjunctivitis Neonatal conjunctivitis is watery or purulent ocular drainage due to a chemical irritant or a pathogenic organism. Prevention with antigonococcal topical treatment at birth is routine. Diagnosis... read more ). Infectious discharge may be purulent in bacterial infection, such as staphylococcal conjunctivitis or gonorrhea Gonorrhea Gonorrhea is caused by the bacteria Neisseria gonorrhoeae. It typically infects epithelia of the urethra, cervix, rectum, pharynx, or conjunctivae, causing irritation or pain and purulent discharge... read more . Less common causes include dacryocystitis Dacryocystitis Dacryocystitis is infection of the lacrimal sac that sometimes leads to abscess formation. The usual cause is a staphyloccocal or streptococcal species, typically as a consequence of nasolacrimal... read more and canaliculitis Canaliculitis Canaliculitis is inflammation of the canaliculus. The most common cause of canaliculitis is infection with Actinomyces israelii, a gram-positive bacillus with fine branching filaments, but other... read more .
Diagnosis is usually made clinically. Allergic conjunctivitis can often be distinguished from infectious by predominance of itching, clear discharge, and presence of other allergic symptoms (eg, runny nose, sneezing). Clinical differentiation between viral and bacterial conjunctivitis is difficult. Cultures are not usually done, but are indicated for patients with the following:
Clinically suspected gonococcal or chlamydial conjunctivitis
A vulnerable eye (eg, after a corneal transplant Corneal Transplantation Corneal transplantations are done for several reasons: To reconstruct the cornea (eg, replacing a perforated cornea) To relieve intractable pain (eg, severe foreign body sensation due to recurrent... read more , in exophthalmos due to Graves disease Etiology Hyperthyroidism is characterized by hypermetabolism and elevated serum levels of free thyroid hormones. Symptoms are many and include tachycardia, fatigue, weight loss, nervousness, and tremor... read more )
Ineffective initial therapy
Halos around light may result from cataracts; conditions that result in corneal edema, such as acute angle-closure glaucoma Angle-Closure Glaucoma Angle-closure glaucoma is glaucoma associated with a physically obstructed anterior chamber angle, which may be chronic or, rarely, acute. Symptoms of acute angle closure are severe ocular pain... read more or disorders that cause bullous keratopathy; corneal haziness; mucus on the cornea; or drugs, such as digoxin or chloroquine.
Certain conditions may cause a blue tint to the visual field (cyanopsia), such as cataract removal or use of sildenafil. Cyanopsia may occur for a few days after cataract removal or as an adverse effect of sildenafil and possibly other phosphodiesterase-5 (PDE5) inhibitors.
Scotomata are visual field deficits and are divided into
Negative scotomata (blind spots)
Positive scotomata (light spots or scintillating flashes)
Negative scotomata may not be noticed by patients unless they involve central vision and interfere significantly with visual acuity; the complaint is most often decreased visual acuity Acute Vision Loss Loss of vision is usually considered acute if it develops within a few minutes to a couple of days. It may affect one or both eyes and all or part of a visual field. Patients with small visual... read more . Negative scotomata have multiple causes that can sometimes be distinguished by the specific type of field deficit Types of Field Defects The optic pathway includes the retina, optic nerve, optic chiasm, optic radiations, and occipital cortex (see figure Higher visual pathways). Damage along the optic pathway causes a variety... read more as identified by use of a tangent screen, Goldmann perimeter, or computerized automated perimetry (in which the visual field is mapped out in detail based on patient response to a series of flashing lights in different locations controlled by a standardized computer program).
Positive scotomata represent a response to abnormal stimulation of some portion of the visual system, as occurs in migraines.