keratitis (ker-a-tit'is) [ kerato- + -itis]
Inflammation of the cornea, usually associated with decreased visual acuity and, if untreated, sometimes resulting in blindness. Eye pain, tearing, light sensitivity, and low vision are the most common symptoms.
It is often caused by contact lenses, but it may also result from drugs, microorganisms, immunodeficiency, trauma, or vitamin A deficiency.
Therapy depends upon the underlying cause. Bacterial infections respond to antibacterial medications (typically administered in drops); herpes simplex viral infection requires antiviral agents; fungal keratitis is treated with antifungal agents; exposure keratitis, as in Bell's palsy, is preventable with topical lubricants.
Because of the seriousness of keratitis, patients experiencing eye inflammation or pain should seek immediate medical attention. The patient is assessed for a history of recent upper respiratory infection accompanied by cold sores, pain, central vision loss, the sensation of a foreign body in the eye, contact lens use, photophobia, and blurred vision. The eye is inspected for loss of normal corneal luster and inflammation. A slit lamp examination is often used for optimal viewing of the eye to confirm the condition. Fluorescein staining helps determine the extent and depth of corneal ulcerations. The patient should refrain from rubbing the eye, which can cause complications. Prescribed therapies are administered, and the patient is instructed in their use. Warm compresses are applied as prescribed to relieve pain. If the patient complains of photophobia, the use of dim lighting or sunglasses is recommended. The patient should follow the prescribed treatment regimen carefully for the entire course and return for follow-up examination.
Patient education: the correct instillation of prescribed eye medications and the importance of thorough handwashing before and after touching the eye are emphasized. Contact lenses are removed and are not replaced until infectious forms of keratitis are cured. Any potentially contaminated lenses or lens solutions should be discarded. Stress, traumatic injury, fever, colds, and overexposure to the sun may trigger flare-ups. Both patient and family are taught about safety precautions pertaining to visual sensory or perceptual alterations. They are encouraged to verbalize their fears and concerns. Appropriate information and emotional support and reassurance are provided.
Because many common forms of keratitis are infectious, examiners should use standard precautions during the evaluation of the eye.
Corneal ulcerations that accompany chlamydial infection of the conjuctiva.
Superficial branching corneal ulcers.
A gray, disk-shaped opacity in the middle of the cornea.
Epithelial defects of the cornea that result from inadequate protection of the eye by the eyelids, as in Bell's palsy.
A corneal ulcer resulting from phlyctenules that spread from limbus to the center of cornea accompanied by fascicle of blood vessels.
Dendritic keratitis in herpes zoster or herpes simplex infections.
A serpent-like ulcer with pus in the anterior chamber of the eye.
A deep form of nonsuppurative keratitis with vascularization, occurring usually in syphilis and rarely in tuberculosis. It commonly occurs between ages 5 and 15. Symptoms include pain, photophobia, lacrimation, and loss of vision. Synonym: parenchymatous keratitis
Drying due to air exposure of the cornea resulting from a defective closure of the eyelids.
Keratitis due to bacterial infection, often in patients who wear contaminated contact lenses.
Keratitis produced by fungi.
The dull and slightly cloudy insensitive cornea seen in lesions of the fifth nerve. Synonym: neurotrophic keratitis
neurotrophic keratitisNeuroparalytic keratitis.
parenchymatous keratitisInterstitial keratitis.
Circumscribed inflammation of the conjunctiva and cornea accompanied by the formation of small projections called phlyctenules, which consist of accumulations of lymphoid cells. The phlyctenules soften at the apices, forming ulcers. See: phlyctenular keratoconjunctivitis
Punctate epithelial defects on the cornea epithelium, often seen in dry eye. Synonym: superficial punctate keratitis
Keratitis with the formation of pus.
Corneal inflammation caused by grain dust.
A triangular opacity in the deeper layers of the cornea, associated with scleritis.
superficial punctate keratitisPunctate keratitis See: Thygeson disease
Damage to the cornea resulting from a burn.
A form of chlamydial keratitis. See: pannus
Keratitis caused by a wound of the cornea.
Softening, desiccation, and ulceration of cornea resulting from dryness of the conjunctiva.
inflammation of the cornea. Keratitis may be deep, when the infection causing it is carried in the blood or spreads to the cornea from other parts of the eye, or superficial, caused by bacterial or viral infection, trauma, or by allergic reaction. The clinical signs include pain, blepharospasm, ocular discharge, and when chronic, pigmentation.
chronic superficial keratitis
a progressive cellular infiltration with vascularization and eventually pigmentation of the cornea that usually commences at the temporal (lateral) quadrant and advances towards the center. The whole cornea may become involved. It occurs in dogs, particularly German shepherd dogs. The cause is unknown, but exposure to ultraviolet light may be a factor. Cellular infiltrates suggest immune mechanisms are involved in the pathogenesis. Called also CSK, degenerative pannus, Uberreiter's syndrome.
a superficial neovascularization and cellular infiltration of the cornea, beginning at the temporal limbus, in adult cats. Eosinophils and plasma cells are found in conjunctival or corneal scrapings and biopsies, and a peripheral eosinophilia is sometimes present. The cause is unknown, but it may be immune-mediated.
keratitis resulting from ineffective or incomplete closure of the eyelids with drying of the corneal tear film. Occurs in paralysis of the eyelids, brachycephalic dogs with prominent globes, and cats during ketamine anesthesia. See also lagophthalmos
herpesvirus infections of the cornea occur in feline and bovine rhinotracheitis infections, and are suspected in dogs. In cats there may be ulcerative keratitis with dendritic ulcers; in cattle conjunctivitis is more common than keratitis.
inflammation of the substantia propria, causing dense corneal clouding.
neurotrophic keratitis, neuroparalytic keratitis
a chronic keratopathy resulting from impairment of the sensory (trigeminal) innervation of the cornea.
superficial diffuse keratitis
see chronic superficial keratitis (above).
superficial pigmentary keratitis
a pigmentation of epithelium and superficial stroma of the cornea, resulting from chronic keratitis from a variety of causes. Seen most commonly in brachycephalic dogs in which the contributing factors are exposure keratitis, distichiasis, irritation from the nasal folds and sometimes keratoconjunctivitis sicca.
superficial punctate keratitis
a keratopathy with discrete opacities of the cornea, without ulceration. Can be caused by irritation.