corneal ectasia

(redirected from corneal degeneration)


A bulging forward of the cornea.
Farlex Partner Medical Dictionary © Farlex 2012

ectasia, corneal

A forward bulging and thinning of the cornea. It may result from a disease of the cornea (e.g. keratoconus), trauma, atrophy, raised intraocular pressure or as a complication of photorefractive surgery in which the corneal stroma has been left thinner than about 250 μm. If uveal tissue is included in the protrusion, the condition is called a staphyloma. If the ectasia is limited to a peripheral part of the cornea, it is called Terrien's disease or Terrien's marginal degeneration. It is due to degeneration of marginal corneal tissue with superficial vascularization and lipid deposition. It affects adult males more commonly than females and the eye has progressive astigmatism, typically against the rule. Therapy includes rigid contact lenses and occasionally keratoplasty. Syn. keratectasia; keratoectasia; kerectasis. See pellucid marginal degeneration; keratoglobus; staphyloma.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
References in periodicals archive ?
The results of penetrating keratoplasty for pellucid marginal corneal degeneration. Am J Ophthalmol.
Pre-operative clinical examination showed that 12(2.6%) patients had corneal degeneration and 5(0.01%) had corneal opacities.
Patients having diabetes mellitus, hypertension, history of previous intraocular surgery or ocular trauma, corneal or conjunctival irritation, h/o chemical trauma, uveitis, known corneal degeneration, dystrophies, opacity, high myopia > 5 D pregnant or lactating women, contact lens wearer, dry eye, and family h/o corneal decompensation were excluded.
Those with history of corneal degeneration or ulceration, anterior segment surgical procedures, glaucoma, diabetes mellitus, active conjunctivitis and subjects wearing contact lenses were excluded from the study.
It has also been described that loss of corneal epithelial sulfate leads to corneal degeneration [25], and the health of the ocular surface involves soluble factors whose action may be strongly influenced by HPSE, as in the case of lacritin [26].
BK is a chronic corneal degeneration due to deposition of calcium salts from the tear film at the epithelium, casement membrane, Bowman's layer and anterior itroma.
Material is in sections on corneal degeneration and dystrophy, external eye disease and tumors, infection, contact lenses, trauma, and postoperative issues.
John's corneal degeneration, who reads Henry James through a glass
Such stem cells also are being studied for treatments for corneal degeneration, heart disease, stroke, Parkinson's disease and Alzheimer's.
The most common indication in this category is Pseudophakic Bullous Keratopathy, followed by keratoconus, corneal degeneration and dystrophy, as well as scarring due to keratitis and trauma.
Early clinical studies also suggest that they can helped avert corneal degeneration and restore vision in cases of blindness, can help to restore proper cardiac function to heart attack sufferers and can improve movement in spinal cord injury patients.

Full browser ?