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Related to Corneal diseases: keratoconus


see eyeeye,
organ of vision and light perception. In humans the eye is of the camera type, with an iris diaphragm and variable focusing, or accommodation. Other types of eye are the simple eye, found in many invertebrates, and the compound eye, found in insects and many other
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the anterior transparent part of the outer tunic of the eye that is part of the eye’s light-refracting apparatus and protects the eye from injury and dust.

There are five layers in the cornea: the anterior epithelium, the anterior limiting membrane (Bowman’s membrane), the substantia propria (connective-tissue stroma), the posterior, or Descemet’s, membrane, and the endothelium of the anterior chamber. Corneal epithelium is multilayered—in man it is composed of eight to ten layers with a total thickness reaching 50 micrometers. It is lined with Bowman’s membrane, which is an acellular part of the postepithelial stroma consisting of a network of collagenous fibers that run in various directions parallel to the surface of the cornea.

A membrane without a distinct boundary becomes the substantia propria of the cornea. In man the substantia propria occupies as much as 90 percent of the entire thickness of the cornea. It is solidly packed with collagenous fibers that are produced by fibroblasts; the intercellular matter of this layer contains mucopolysaccharides, chondroitin sulfate, chondroitin, and keratosulfate. The transparency of the cornea depends on the degree of dehydration and orderliness of the molecules of the acellular portion of the cornea’s basic matter.

Descemet’s membrane lines the basic matter of the cornea and is tough and elastic; its posterior surface is covered by the single-layered endothelium of the anterior chamber of the eye.

There are no blood vessels in corneal tissues. In man the cornea is innervated by 70–80 radial nerve trunks that originate in the optical branch of the fifth pair of cranial nerves; the branching of the trunks penetrates the entire thickness of the cornea, except Descemet’s membrane and the endothelium.

The most common diseases of the cornea include traumas, blennorrhea, keratitis, and staphyloma.



The transparent anterior portion of the outer coat of the vertebrate eye covering the iris and the pupil.
(invertebrate zoology)
The outer transparent portion of each ommatidium of a compound eye.


the convex transparent membrane that forms the anterior covering of the eyeball and is continuous with the sclera
References in periodicals archive ?
The prevalence of corneal disease in the coloured community of a Karoo town.
9% were blind because of traumatic and infectious corneal diseases, followed by optic atrophy and congenital glaucoma.
Corneal diseases and conditions can cause redness, watery eyes, pain, lower vision, or a halo effect.
Mr Muhtaseb, who has trained in both the UK and abroad, is developing a new service for the treatment of corneal diseases in Mid and West Wales.
They consider such topics as the optics of the cornea, the topographical presentation of common corneal diseases, refractive surgery treatments that combine wavefront and topography approaches, and a number of commercial topographic systems now available.
Fisher, Corneal Diseases Program, NEI, Bldg EPS, Ste 350, 3120 Executive Blvd, Rockville, MD 20892 USA, 301-451-2020, fax: 301-402-0528, e-mail: rf75s@nih.
The team will focus on all types of Opthalmic Pathology cases, including temporal arteritis, melanoma, epithelial, hematologic and soft tissue tumors of the eye, lacrimal gland pathology, eyelid skin and mucosal lesions, retinal and macular pathology, corneal diseases, infections of the eye and orbital bony lesions.
Corneal diseases constitute a significant cause of visual impairment and blindness in the developing world.
In these countries corneal diseases constitute 8% to 25% cases of blindness which are responsible for 20% of childhood blindness.
Subjects having bilateral uveitic involvement, corneal diseases, and history of contact lens wear or ocular surgery were excluded.

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