II. Definition

  1. Transparent front refractive window of eye

III. Anatomy

  1. eyeGlobeXsGrayBB869.gif Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
  2. eyeCorneaLensGrayBB883.gif Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)

IV. Physiology

  1. Dimensions
    1. Vertical: 11.6 mm
    2. Horizontal: 11.5 mm
    3. Thickness
      1. Peripheral: 1 mm
      2. Central: 0.55 mm
  2. Five distinct layers
    1. Epithelium (Exterior layer of Cornea, a few cells thick)
      1. Prevents infection
      2. Smooth refractive surface
      3. Produces the tear film
      4. Continually regenerates
    2. Bowman's Membrane
    3. Stroma (90% of Corneal thickness)
      1. Composed of collagen fibrils intertwined
      2. Supportive structure of Cornea
    4. Endothelium
      1. Dehydrates Cornea via Na-K ATP Pump
      2. Relative dehydration maintains Corneal clarity
    5. Descemet's Membrane (Interior Layer of Cornea)
      1. Endothelium basement membrane
  3. Function
    1. Barrier protection
    2. UV light filtration
    3. Refraction
      1. Cornea provides 65-75% of eye's focusing power
      2. Unlike lens, Cornea's Refraction power is fixed
  4. Blood supply
    1. No direct blood supply to maintain transparency
    2. All nutrition supplied indirectly
      1. Tears
      2. Ambient oxygen
      3. Aqueous Humor of anterior chamber

Images: Related links to external sites (from Bing)

Related Studies (from Trip Database) Open in New Window

Ontology: Corneal Diseases (C0010034)

Definition (MEDLINEPLUS)

Your cornea is the outermost layer of your eye. It is clear and shaped like a dome. The cornea helps to shield the rest of the eye from germs, dust, and other harmful matter. It also helps your eye to focus. If you wear contact lenses, they float on top of your corneas.

Problems with the cornea include

  • Refractive errors
  • Allergies
  • Infections
  • Injuries
  • Dystrophies - conditions in which parts of the cornea lose clarity due to a buildup of cloudy material

Treatments of corneal disorders include medicines, corneal transplantation, and corneal laser surgery.

NIH National Eye Institute

Definition (MSH) Diseases of the cornea.
Definition (CSP) pathological process affecting the transparent anterior portion of the fibrous coat of the eye.
Concepts Disease or Syndrome (T047)
MSH D003316
ICD9 371.9
ICD10 H18.9
SnomedCT 15250008, 155160005, 193856004, 267733008, 193794007
English Corneal Diseases, Disease, Corneal, Diseases, Corneal, cornea disorder, Corneal disorder NOS, Disorder of cornea, unspecified, CORNEAL DIS, Disease of cornea, Corneal disorder (NOS), Disorder corneal, Unspecified disorder of cornea, Corneal Diseases [Disease/Finding], cornea disease, disease cornea, diseases corneal, cornea diseases, diseases of the cornea, cornea disorders, corneal disease, corneal diseases, corneal disorders, cornea, corneal disorder, corneal disorder (diagnosis), Corneal Disorders, Corneal disorders NOS, Corneal disorder NOS (disorder), Corneal disorders, Cornea--Diseases, Corneal disorder, cornea; disorder, disease (or disorder); cornea, Disease of cornea, NOS, Disorder of cornea, NOS, Disease of cornea (disorder), Disorder of cornea, Disorder of cornea (disorder), Corneal Disease, Corneal Disorder, Unspecified corneal disorder
Italian Patologia della cornea, Patologia corneale, Alterazioni corneali non specificate, Patologia della cornea (NAS), Patologia della cornea non specificata, Malattie della cornea
Dutch aandoening cornea, niet-gespecificeerde cornea-aandoening, cornea-aandoening (NAO), cornea-aandoening NAO, aandoening; cornea, cornea; aandoening, Aandoening van cornea, niet gespecificeerd, cornea-aandoening, Corneaziekte, Corneaziekten, Ziekte, cornea-, Ziekten, cornea-
French Trouble cornéen SAI, Affection de la cornée, Trouble cornéen non précisé, Affection cornéenne SAI, Trouble cornéen, Kératopathies, Maladies cornéennes, Maladies de la cornée
German Erkrankung der Hornhaut, Hornhauterkrankung NNB, unspezifische Hornhauterkrankung, Hornhauterkrankung (NNB), Affektion der Hornhaut, nicht naeher bezeichnet, Erkrankung der Kornea, Korneakrankheiten, Hornhautkrankheiten (Auge)
Portuguese Afecção da córnea, Afecção da córnea NE, Alteração da córnea NE, Afecção NE da córnea, Alteração da córnea, Doenças da Córnea
Spanish Trastorno corneal, Trastorno corneano no especificado, Trastorno de la córnea (NEOM), enfermedad de la córnea (trastorno), trastorno corneal NEOM, trastorno corneal, SAI, trastorno corneal, SAI (trastorno), trastorno corneal, Alteración corneal, trastorno de la córnea, trastorno de la córnea (trastorno), enfermedad de la córnea, Enfermedades de la Córnea
Japanese 角膜障害NOS, 角膜障害, 角膜障害(NOS), カクマクショウガイ, カクマクショウガイNOS
Swedish Hornhinnesjukdomar
Finnish Sarveiskalvon sairaudet
Russian ROGOVITSY BOLEZNI, РОГОВИЦЫ БОЛЕЗНИ
Czech Nespecifikované onemocnění rohovky, Onemocnění rohovky NOS, Onemocnění rohovky (NOS), Onemocnění rohovky, kornea - nemoci, nemoci rohovky, rohovka - nemoci
Korean 상세불명의 각막의 장애
Croatian ROŽNICA, BOLESTI
Polish Choroby rogówki
Hungarian Nem meghatározott cornea betegség, Cornea betegség (K.m.n.), Szaruhártya-betegség, Cornea betegség k.m.n., Szaruhártya betegség
Norwegian Hornhinnesykdommer, Korneasykdommer, Corneasykdommer

Ontology: Corneal Stroma (C0010040)

Definition (NCI) The lamellated connective tissue constituting the thickest layer of the cornea between the Bowman and Descemet membranes. (MeSH)
Definition (MSH) The lamellated connective tissue constituting the thickest layer of the cornea between the Bowman and Descemet membranes.
Definition (CSP) lamellated connective tissue constituting the thickest layer of the cornea between the Bowman and Descemet membranes.
Concepts Body Part, Organ, or Organ Component (T023)
MSH D003319
SnomedCT 50546002
English Corneal Stromas, Stroma, Corneal, Stromas, Corneal, corneal stroma, Substantia propria corneae, Stroma of cornea, Substantia propria of cornea, Structure of substantia propria of cornea (body structure), Structure of substantia propria of cornea, Substantia propria of cornea, NOS, Corneal Stroma
French Stroma de la cornée, Stroma cornéen
Swedish Korneal stroma
Czech rohovka - stroma
Portuguese Substância Própria, Estroma Corneano, Estroma da Córnea
Spanish Sustancia Propia, Estroma de la Córnea, Estroma Corneal, estroma de la córnea, estructura de la sustancia propia de la córnea (estructura corporal), estructura de la sustancia propia de la córnea, sustancia propia de la córnea
Finnish Sarveiskalvon strooma
Russian ROGOVITSY STROMA, РОГОВИЦЫ СТРОМА
Latvian Radzenes stroma
Polish Zrąb rogówki
Norwegian Hornhinnelameller, Korneal stroma, Stroma corneae, Støttevev i hornhinnen
German Stroma corneae
Italian Stroma della cornea
Dutch Substantia propria corneae

Ontology: Corneal Endothelium (C0014259)

Definition (MSH) Single layer of large flattened cells covering the surface of the cornea.
Definition (CSP) single layer of large flattened cells covering the surface of the cornea.
Concepts Tissue (T024)
MSH D004728
SnomedCT 65431007
English Endothelium, Corneal, corneal endothelium, Corneal endothelium, Structure of corneal endothelium (body structure), Structure of corneal endothelium, Corneal Endothelium
French Endothélium de la cornée, Endothélium cornéen
Swedish Hornhinneendotel
Czech endotel rohovkový, rohovka - endotel
Portuguese Epitélio Posterior, Endotélio Corneano, Epitélio Posterior da Córnea, Epitélio Posterior Corneano, Endotélio da Córnea
Spanish Epitelio Posterior, Endotelio Corneal, Epitelio Posterior de la Cornea, Epitelio Corneal Posterior, Endotelio de la Córnea, endotelio de la córnea, estructura del endotelio de la córnea (estructura corporal), estructura del endotelio de la córnea
Finnish Sarveiskalvon endoteeli
Russian ROGOVICHNYI ENDOTELII, ENDOTELII PERVICHNOI KAMERY GLAZA, GLAZA PEREDNEI KAMERY ENDOTELII, ENDOTELII ROGOVICHNYI, PEREDNEI KAMERY GLAZA ENDOTELII, ГЛАЗА ПЕРЕДНЕЙ КАМЕРЫ ЭНДОТЕЛИЙ, ПЕРЕДНЕЙ КАМЕРЫ ГЛАЗА ЭНДОТЕЛИЙ, РОГОВИЧНЫЙ ЭНДОТЕЛИЙ, ЭНДОТЕЛИЙ ПЕРВИЧНОЙ КАМЕРЫ ГЛАЗА, ЭНДОТЕЛИЙ РОГОВИЧНЫЙ
Japanese 角膜内皮, 前房内皮, 内皮-前眼房, 前眼房内皮, 内皮-前房
Latvian Radzenes endotēlijs, Endotēlijs, radzenes
Polish Śródbłonek rogówki
Norwegian Endothelium corneae, Hornhinneendotel, Corneaendotel
German Endothel, Kornea-, Endothelium corneae, Korneaendothel, Hornhautendothel
Italian Endotelio della cornea
Dutch Cornea-endotheel, Endotheel, cornea-

Ontology: Structure of corneal epithelium (C0459875)

Definition (NCI) Stratified squamous epithelium that covers the outer surface of the cornea. (MeSH)
Definition (MSH) Stratified squamous epithelium that covers the outer surface of the CORNEA. It is smooth and contains many free nerve endings.
Definition (CSP) stratified squamous epithelium that covers the outer surface of the cornea; it is smooth and contains many free nerve endings.
Concepts Tissue (T024)
MSH D019573
SnomedCT 15775008
English Anterior Corneal Epithelium, Corneal Epithelium, Corneal Epithelium, Anterior, Epithelium, Anterior Corneal, Epithelium, Corneal, Epithelium anterius corneae, Anterior corneal epithelium, Epithelium anterius (Cornea), Epithelium of cornea, cornea epithelium, corneal epithelium, External epithelium of cornea, Corneal epithelium, Structure of corneal epithelium (body structure), Structure of corneal epithelium
French Épithélium cornéen, Épithélium antérieur de la cornée
Swedish Hornhinneepitel
Czech epitel rohovkový
Portuguese Epitélio Anterior, Epitélio da Córnea, Epitélio Anterior Corneano, Epitélio Anterior da Córnea, Epitélio Corneano
Spanish Epitelio Anterior, Epitelio Anterior de la Córnea, Epitelio de la Córnea, epitelio externo de la córnea, estructura del epitelio externo de la córnea (estructura corporal), estructura del epitelio externo de la córnea, Epitelio Corneal Anterior, Epitelio Corneal
Finnish Sarveiskalvon epiteeli
Italian Epitelio corneale anteriore, Epitelio corneale
Russian PEREDNEROGOVICHNYI EPITELII, ROGOVITSY EPITELII, ПЕРЕДНЕРОГОВИЧНЫЙ ЭПИТЕЛИЙ, РОГОВИЦЫ ЭПИТЕЛИЙ
Japanese 角膜上皮, 前部角膜上皮, 角膜上皮-前部
Croatian EPITEL ROŽNICE
Latvian Radzenes epitēlijs, Epitēlijs, radzenes, Radzenes epitēlijs, priekšējais, Epitēlijs, priekšējais, radzenes
Polish Nabłonek rogówki
Norwegian Hornhinneepitel, Cornea-epitel, Kornealt epitel
German Epithel, Hornhaut, Epithel, vordere Hornhaut, Hornhautepithel, vorderes, Hornhautepithel, Vorderes Hornhautepithel
Dutch Cornea-epitheel, Cornea-epitheel, anterieur, Epitheel, cornea-