keratitis(redirected from parenchymatous keratitis)
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- poor contact lens care; overuse of contact lenses
- illnesses or other factors that reduce the body's ability to overcome infection
- cold sores, genital herpes, and other viral infections
- crowded, dirty living conditions; poor hygiene
- poor nutrition (especially a deficiency of Vitamin A, which is essential for normal vision)
Herpes simplex keratitis
- chronic inflammation of the cornea
- development of tiny blood vessels in the eye
- loss of vision
- usually affects people with weakened immune systems
- often results in infection within the eyeball
- may cause stromal abscesses
Peripheral ulcerative keratitis
- rheumatoid arthritis
- relapsing polychondritis (connective-tissue inflammation)
- Wegener's granulomatosis, a rare condition characterized by kidney disease and development of nodules in the respiratory tract
Superficial punctate keratitis
Causes and symptoms
- bacterial, viral, or fungal infections
- dry eyes resulting from disorders of the eyelid or diminished ability to form tears
- exposure to very bright light
- foreign objects that injure or become lodged in the eye
- sensitivity or allergic reactions to eye makeup, dust, pollen, pollution, or other irritants
- vitamin A deficiency, which people with normal diets rarely develop
- sensitivity to light
- inflammation of the eyelid
- decrease in vision
- permanent scarring
- ulceration of the cornea
See also: keratopathy.
keratitis/ker·a·ti·tis/ (ker″ah-ti´tis) inflammation of the cornea.
keratitisCorneal inflammation, caused by nonspecific irritants or microorganisms.
keratitisOphthalmology Corneal inflammation, caused by nonspecific irritants, or microorganisms. See Interstitial keratitis.
See also: keratopathy
keratitisInflammation of the outer lens of the eye (the CORNEA).
This implies a prior invasion of the cornea with blood vessels (vascularization). Keratitis commonly follows inadequately or incorrectly treated infections with cold sore (Herpes simplex) viruses and is also a feature of TRACHOMA and congenital SYPHILIS. There is pain, watering and acute sensitivity to light. Vision is severely affected if the centre of the cornea is involved. See also KERATOCONJUNCTIVITIS.
keratitisinflammation of the cornea, the transparent part of the outer coat of the eyeball - the 'window' in front of the the iris and the pupil. Organisms do not usually infect an intact healthy cornea so this is more likely to occur when hygiene is poor, especially if contact lenses are worn. photokeratitis (also known as snowblindness) occurs as a result of excessive exposure to UV light, as when sunlight is reflected in snow and water sports. It can be very painful, may occur several hours after exposure and may last up to 2 days.
acanthamoeba keratitis A rare type of keratitis caused by the microorganism acanthamoeba, which invades the cornea. The symptoms begin with a foreign body sensation, which turns into pain, photophobia, tearing, blepharospasm and blurred vision. The signs are infiltrates that develop into a ring, and the cornea may eventually become opaque. Diagnosis of the disease is made by laboratory analysis of a corneal scraping. Contact lens wear has been found to be associated with this disease in about three-quarters of the cases, especially when the patient has used homemade or unpreserved saline. The other cases were due to contact with stagnant water or following an abraded cornea. The therapy is with repetitive doses of antiamoebic agents (e.g. biguanide) and an antibiotic (e.g. propamidine isethionate) or a combination of propamidine and neomycin. However, strict compliance with contact lens regimens and avoidance of exposure to dirty, stagnant water diminishes the risks of contracting the disease. See corneal infiltrates; disinfection; propamidine isethionate.
actinic keratitis See actinic keratoconjunctivitis.
acute epithelial keratitis See herpes zoster ophthalmicus.
acute stromal keratitis A complication of scleritis in which there are superficial and mid-stromal infiltrates in the limbal region. Lesions can also be noted in the central cornea and may develop vascularization and permanent opacification. In cases of scleritis that are limited (i.e. not diffuse), corneal changes are noted only in the bordering corneal region.
dendritic keratitis See herpes simplex keratitis.
disciform keratitis A deep localized keratitis involving the stroma, usually characterized by a disc-shaped grey area (Wessley ring) that may spread to the whole thickness of the cornea. It is due to a viral infection (e.g. herpes simplex virus) or to an immune reaction, or it may also occur as a sequel to trauma. It may heal without residue or may cause scarring and vascularization of the cornea. Treatment is with steroid and antiviral agents. See central corneal clouding; keratic precipitates; Wessley ring.
epithelial keratitis See punctate epithelial keratitis.
exposure keratitis See exposure keratopathy.
filamentary keratitis Keratitis characterized by the presence of fine epithelial filaments. It can occur as a result of herpes, thyroid dysfunction, corneal abrasions, keratoconjunctivitis sicca, etc.
fungal keratitis A keratitis caused by a fungus, such as Fusarium, Aspergillus, or Candida albicans. The condition may develop after eye injury (e.g. fingernail or contact lens scratch, tree branch), especially in agricultural areas. However, it has become more common since the use of corticosteroids. It may also occur in eyes suffering from corneal disease, after keratoplasty, diabetes or extended-wear contact lenses. It is characterized by greyish-white, rough ulcers with indistinct and feathery edges with filaments infiltrating into the stroma (filamentary keratitis). There is ciliary and conjunctival injection and it may be accompanied by ring abscesses and, in severe cases, hypopyon. The ulcers have oval or round outlines with a plaque-like surface and the cornea is fully oedematous. Differential diagnosis is facilitated by corneal scraping or biopsy of the ulcer. Management consists mainly of antifungal agents. Syn. mycotic keratitis. See keratomycosis.
herpetic keratitis Keratitis caused by either herpes simplex or herpes zoster viruses. See herpesvirus; herpes simplex keratitis.
herpes simplex keratitis An inflammation of the cornea, which occurs occasionally as a result of a blepharoconjunctivitis caused by the herpes simplex virus (usually type 1). The disease begins with skin vesicles typically spread over the lids, conjunctiva and periorbital area. Symptoms include irritation, photophobia, tearing, reduced corneal sensation and blurred vision if the central cornea is involved. The characteristic sign is a dendritic ulcer, which enlarges progressively resulting in a configuration referred to as a geographical ulcer. Treatment is with an antiviral agent (e.g. aciclovir) or debridement of the epithelium if unresponsive to antiviral agents. Syn. dendritic ulcer. See herpesvirus; disciform keratitis; interstitial keratitis; punctate epithelial keratitis; ulcerative keratitis.
hypopyon keratitis Purulent keratitis with ulcer resulting in the presence of pus in the anterior chamber, which gravitates to the bottom. The ulcer is a dirty grey colour and the conjunctiva is also inflamed. The usual cause of the infection is the pneumococcus which gives rise to a corneal ulcer (often called serpiginous ulcer because of its tendency to creep forward in the cornea). See hypopyon; ulcerative keratitis; corneal ulcer.
interstitial keratitis Keratitis involving the stroma. It is characterized by deep vascularization of the cornea and is often associated with iridocyclitis. Formerly, the most common cause was congenital syphilis (syphilitic keratitis). However, nowadays it is usually the result of a herpes simplex infection, or it may be part of a syndrome (Cogan's) or other systemic diseases (e.g. leprosy, tuberculosis). Management involves cycloplegics, topical antiviral agents and in severe cases corticosteroids. Syn. stromal interstitial keratitis. See Wessley ring; Hutchinson's sign.
lagophthalmic keratitis See exposure keratopathy.
marginal keratitis A condition characterized by subepithelial peripheral corneal infiltrates which may spread circumferentially and are separated from the limbus by a clear zone, which may eventually become invaded by blood vessels. It is a hypersensitivity response to staphylococcal exotoxins. There is discomfort, pain, redness and photophobia. Treatment is with topical steroids.
microbial keratitis, contact lens induced A keratitis caused by a microorganism such as a bacteria (e.g. Pseudomonas aeruginosa, Serratia marcescens), amoeba (e.g. Acanthamoeba), or less commonly a virus or fungus. The incidence of the condition is relatively low. It has been estimated to be 2 to 5 individuals with daily wear of soft lenses and 10 to 20 with extended wear of soft lenses per 10 000 per year. High oxygen permeability leads to less infection. Signs and symptoms include pain, infiltrates, redness, lacrimation, photophobia, corneal oedema, reduced vision, discharge, swollen lids and aqueous flare. The condition may have been precipitated by non-compliance, poor hygiene, dirty lens case, etc. Management includes cessation of lens wear and drug therapy.
mucous plaque keratitis See herpes zoster ophthalmicus.
mycotic keratitis See fungal keratitis.
non-ulcerative keratitis See contact lens acute red eye.
neuroparalytic keratitis Keratitis caused by a failure of blinking or infrequent or incomplete blinking causing inadequate spread of tears. See exposure keratopathy.
neurotrophic keratitis See neurotrophic keratopathy.
peripheral ulcerative keratitis A severe form of keratitis most often associated with a systemic disease, the most common being rheumatoid arthritis, Wegener's granulomatosis, lupus erythematosus and polyarteritis nodosa. It is characterized by pain, usually redness and peripheral ulceration with corneal thinning. Treatment is urgent and directed towards the primary cause. See Mooren's ulcer.
phlyctenular keratitis See phlyctenular keratoconjunctivitis.
punctate epithelial keratitis (PEK) An inflammation of the cornea characterized by either multiple, small, superficial, punctate lesions or minute, flat, epithelial dots resulting from bacterial infection (e.g. chlamydial, staphylococcal), vitamin B2 deficiency, virus infection (e.g. herpes) and also from exposure to ultraviolet light, injury to the eye with aerosol products or contact lens solutions. The condition is usually associated with conjunctivitis. Treatment depends on the causative agent (e.g. antiviral agents will be used to suppress symptoms in herpes simplex keratitis). Syn. superficial punctate keratitis (SPK), although this term is more often used to describe a PEK of viral origin. See adult inclusion conjunctivitis; Thygeson' superficial punctate keratitis.
rosacea keratitis Keratitis associated with acne rosacea of the face. It is characterized by marginal vascularization at the limbus. The vessels extend into the cornea surrounded by a zone of grey infiltration. The infiltrates and vascularization are in the cornea proper and not raised above the surface (unlike phlyctens). There is little tendency to ulcerate. It is usually associated with an inflammation of the conjunctiva (keratoconjunctivitis). Treatment involves topical steroid drops as well as systemic antibiotic therapy. See acne rosacea; phlyctenular keratoconjunctivitis.
keratitis sicca See keratoconjunctivitis sicca.
superficial punctate keratitis See punctate epithelial keratitis.
stromal keratitis; syphilitic keratitis See interstitial keratitis.
Thygeson's superficial punctate keratitis A rare type of punctate epithelial keratitis. It is characterized by circular or oval, greyish-white epithelial lesions commonly located centrally and slightly elevated with a cluster of granular dots. The lesions show punctate staining with fluorescein. The cause is unknown, although a virus is suspected. It gives rise to mild irritation, photophobia and slight blurring of vision. Treatment includes artificial tears, corticosteroids (but this may induce recurrence) and therapeutic soft contact lenses. Untreated, it may subside within a few years.
ulcerative keratitis Any keratitis in which there is an ulcer of the cornea. The cause may be bacterial or viral infection, trauma or contact lens wear (particularly extended wear). The ulcer is a dirty grey coloured area on the cornea, the eye is red, the pain can be severe, there is photophobia, lacrimation, and vision may be affected. Immediate treatment is necessary: if due to contact lenses, cessation of wear and topical antibiotics will be used. See herpes simplex keratitis; corneal ulcer.
ultraviolet keratitis See actinic keratoconjunctivitis.