II. Definitions
- Cornea
- Transparent front refractive window of eye
- Cornea's steep curvature provides most of Refraction needed to direct light onto Retina
- Lens performs fine, variable focus adjustments
III. Anatomy
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Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
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Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
IV. Physiology
- Dimensions
- Vertical: 11.6 mm
- Horizontal: 11.5 mm
- Thickness
- Peripheral: 1 mm
- Central: 0.55 mm
- Five distinct layers
- Epithelium (Exterior layer of Cornea, a few cells thick)
- Prevents infection
- Smooth refractive surface
- Produces the tear film
- Continually regenerates
- Bowman's Membrane
- Stroma (90% of Corneal thickness)
- Composed of Collagen fibrils intertwined
- Supportive structure of Cornea
- Endothelium
- Dehydrates Cornea via Na-K ATP Pump
- Relative Dehydration maintains Corneal clarity
- Descemet's Membrane (Interior Layer of Cornea)
- Endothelium basement membrane
- Epithelium (Exterior layer of Cornea, a few cells thick)
- Function
- Barrier protection
- UV light filtration
- Refraction
- Cornea provides 65-75% of eye's focusing power
- Lens performs remainder of focus, the fine, variable focus adjustments
- Unlike the lens, the Cornea's Refraction power is fixed
- Contact Lenses modify the Corneal surface to optimize non-variable focus
- Blood supply
- No direct blood supply to maintain transparency
- All nutrition supplied indirectly
- Tears
- Ambient oxygen
- Aqueous Humor of anterior chamber
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Related Studies
| 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
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）, ｶｸﾏｸｼｮｳｶﾞｲ, ｶｸﾏｸｼｮｳｶﾞｲ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- |
