keratoconus


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keratoconus

 [ker″ah-to-ko´nus]
conical protrusion of the central part of the cornea, resulting in an irregular astigmatism.
Keratoconus. From Dorland's, 2000.

ker·a·to·co·nus

(ker'ă-tō-kō'nŭs), [MIM*148300]
A conic protrusion of the cornea caused by thinning of the stroma; usually bilateral.
See also: Fleischer ring, Munson sign.
Synonym(s): conic cornea
[kerato- + G. kōnos, cone]

keratoconus

/ker·a·to·co·nus/ (-ko´nus) conical protrusion of the central part of the cornea.

keratoconus

[ker′ətōkō′nəs]
Etymology: Gk, keras + konos, cone
a noninflammatory protrusion of the central or paracentral region of the cornea. It is worse in allergy sufferers and may result in marked irregular astigmatism. It is also associated with Down syndrome. Gas permeable contact lenses often significantly improve visual acuity as compared with spectacles, although a corneal transplant is indicated in about 15% of patients with this condition. The cause of the condition is unknown, but it likely has a genetic basis.

ker·a·to·co·nus

(ker'ă-tō-kō'nŭs)
A conic protrusion of the cornea caused by thinning of the stroma; usually bilateral.
See also: Fleischer ring, Munson sign
Synonym(s): conic cornea.
[kerato- + G. kōnos, cone]

keratoconus

A growth disorder (dystrophy) of the CORNEA causing central peaking or conicity and affecting vision. The main disability is from image distortion. Keratoconus is a familial condition that usually starts in adolescence, affecting girls more than boys. Spectacles may help at first, the progressive distortion usually calls for correction with hard contact lenses. Corneal grafting is often eventually required but the results are usually good.

Keratoconus

An eye condition in which the cornea bulges outward, interfering with normal vision. Usually both eyes are affected.

keratoconus (KC)

A developmental anomaly in which the central portion of the cornea becomes thinner and bulges forward in a cone-shaped fashion. Two types of cones are commonly described: a round cone and an oval (or sagging) cone. It usually appears around puberty, is bilateral, although one eye may be involved long before the other. Other corneal signs may be Vogt's striae, Fleischer's ring, scarring and corneal hydrops, as well as myopia and irregular astigmatism. The condition may be associated with osteogenesis imperfecta, ectopia lentis, aniridia, retinitis pigmentosa, Down's syndrome, Ehlers-Danlos syndrome, Marfan's syndrome. The main symptom is a loss of visual acuity due to irregular astigmatism and myopia. Correction is usually best achieved with contact lenses, especially rigid gas permeable, but if these cannot be worn or the condition is very severe, a corneal transplant is carried out (Fig. K1). Syn. conical cornea. See central corneal clouding; pellucid marginal degeneration; corneal ectasia; acute hydrops; keratoscope; combination lens; piggyback lens; lenticonus; blue sclera; Munson's sign; Rizzuti's sign; stria; corneal topography.
Fig. K1 Schematic diagram of a keratoconus corneaenlarge picture
Fig. K1 Schematic diagram of a keratoconus cornea

Table K1 Differential diagnosis between keratoconus and related thinning disorders. (Adapted from Krachmer JH, Feder RS, Belin MW. Surv Ophthalmol 1984; 28:293-322)
keratoconuspellucid marginal degenerationkeratoglobusposterior keratoconus
frequencymost commonless commonrareleast common
lateralityusually bilateralbilateralbilateralusually unilateral
age of onsetpuberty/early adulthoodAge 20 to 40susually at birthbirth
corneal thinningcentral or paracentralinferior crescent-shaped band 1-2 mm widegeneralized and slightly more in peripheryparacentral posterior excavation
protrusionapicalabove band of thinninggeneralizednone
iron line
(Fleischer's ring)
commonrarenoneoccasional
scarringcommononly after hydropsrarecommon
progressionyesyesusually nono
induced astigmatismirregularhigh, irregular and varies with locationnonevery slight effect

keratoconus

conical protrusion of the central part of the cornea.

Patient discussion about keratoconus

Q. Has anyone had experience with a corneal transplant because of keratoconus?

A. my uncle had to do a transplant- it took 5 weeks until he could see anything , another year to get his vision straightened up. but now he is fine! i know that he looked for information in the "National Keratoconus Foundation". they were very helpful (and nice!), they have a website with information on all forms of treatment:
http://www.nkcf.org/

good luck :)

More discussions about keratoconus
References in periodicals archive ?
Corneal topography is an essential tool for the assessment of corneal curvature in complex contact lens fitting and for the detection and monitoring of keratoconus and other ectatic disorders.
The report provides a snapshot of the global Keratoconus market clinical trials landscape along with top level data related to the clinical trials by Region, Country (G7 & E7), Trial Status, Trial Phase, Sponsor Type and End point status.
Dipika Patel, Associate Professor of Ophthalmology from the University of Auckland in New Zealand said Keratocyte density (the cells that help keep the cornea transparent and maintain its healing ability) was up to 25 per cent lower in cases of Keratoconus patients who wore contact lenses than 'control' corneas.
Quawasmi added this new method of treatment is based on doing some changes to the corneal topography, thickness and the short-sightedness effect that occurs in keratoconus, adding any patient diagnosed with keratoconus or a high astigmatism can now do this new operation with a low cost instead of replacing the cornea.
The Keratoconus was getting worse and Kristian's eyes were getting sore, red and itchy, until he could only bear to wear the lenses for an hour a day.
The purpose of this book is to spread a message of hope and inspiration to those who whose lives have been uprooted by Keratoconus.
Ian Jennings, founders and owners of Rose K International Limited, who have grown the Rose K business from little New Zealand to a global business that has established the Rose K lens as the market leader for keratoconus, will join the global Menicon group and continue to act as the main figures of the global Rose K operations.
They address the physics and fundamentals, keratoconus screening, evaluation of LASIK flaps, evaluation and management of anterior lamellar surgery, penetrating and posterior lamellar keratoplasty, corneal opacities, refractive corneal implants, intracorneal ring segments, glaucoma evaluations, quantitative measurement of the anterior chamber angle, intraocular lens implantation, anterior segment tumors, measurement of accommodation, intraocular lenses and cataracts, clear corneal cataract incisions, and future applications.
In 1983, Bryn had first been diagnosed with keratoconus, an affliction which had caused the corneas in both eyes to become cone shaped, progressively restricting the entry of light.
The team's starting shooting guard will be fitted Monday with one of four sets of specialized contact lenses designed to put pressure on the cornea and stem the disease called keratoconus.
The Company's advanced cross-linking technology makes the treatment of keratoconus and post-LASIK ectasia faster, while also making possible an entirely new cross-linking procedure, Lasik Xtra[R], intra-operative cross-linking following the creation of the LASIK flap and/or excimer laser ablation during LASIK or PRK.
This article considers the options for the long-term management of keratoconus by discussing when it may be appropriate for patients currently wearing contact lenses to consider alternative treatment interventions.