Ophthalmology Book

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Cornea

Aka: Cornea, Corneal Epithelium, Bowman's Membrane, Corneal Stroma, Corneal Endothelium, Descemet's Membrane
  1. See Also
    1. Refractive Error
    2. Corneal Abrasion
    3. Fluorescein
  2. Definition
    1. Transparent front refractive window of eye
  3. 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)
        1. Prevents infection
        2. Smooth refractive surface
      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

Corneal Diseases (C0010034)

Definition (MSH) Diseases of the cornea.
Definition (CSP) pathological process affecting the transparent anterior portion of the fibrous coat of the eye.
Definition (NCI) The transparent part of the eye that covers the iris and the pupil and allows light to enter the inside.
Definition (NCI) The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous epithelium, Bowman's membrane, stroma, Descemet's membrane, and mesenchymal endothelium. It serves as the first refracting medium of the eye. It is structurally continuous with the sclera, is avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the trigeminal nerve via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses.
Concepts Disease or Syndrome (T047)
ICD9 371.9
MSH D003316
English Cornea, cornea disorder, CORNEAL DIS, Corneal Disease, Corneal Diseases, corneal disorder, CORNEAL DISORDERS, DISEASE OF CORNEA, DISORDER CORNEAL, Disorder of cornea, Unspecified corneal disorder
Spanish enfermedad de la cornea, trastorno corneal, trastorno de la cornea
Parent Concepts Eye diseases (C0015397), Corneal opacity and other disorders of cornea (C0155097), Eye part (C1268161), Eye (MMHCC) (C1517081), Corneal finding (C0423225), Disorder of anterior segment of eye (C0730121)
Sources AOD , COSTAR, CSP, CST, ICD9CM, MSH, MTH, NCI, NDFRT, SCTSPA, SNOMEDCT
Derived from the NIH UMLS (Unified Medical Language System)


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
English Corneal Endothelium, Structure of corneal endothelium
Spanish endotelio de la cornea, estructura del endotelio de la cornea
Parent Concepts Cornea (C0010031), Anterior chamber of eye structure (C0003151), Endothelium (C0014257), Body tissue (C0040300), Structure of posterior surface of cornea (C0229122), Structure of corneal layer (C0459674)
Sources CSP , MSH, MTH, NCI, SCTSPA, SNOMEDCT, UWDA
Derived from the NIH UMLS (Unified Medical Language System)


Structure of corneal epithelium (C0459875)

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.
Definition (NCI) Stratified squamous epithelium that covers the outer surface of the cornea. (MeSH)
Concepts Tissue (T024)
MSH D019573
English Anterior corneal epithelium, Corneal epithelium, Epithelium of cornea, External epithelium of cornea, Structure of corneal epithelium
Spanish epitelio externo de la cornea, estructura del epitelio externo de la cornea
Parent Concepts Cornea (C0010031), Epithelium (C0014609), Multilaminar epithelium (C0682575), Structure of corneal layer (C0459674), Anterior surface of cornea (C0580756), Conjunctival and corneal surface structure (C1285515), Structure of skin and/or surface epithelium (C1302881), Conjunctival sac (C0229271), Atypical epithelium (C0932011)
Sources CSP , MSH, MTH, NCI, SCTSPA, SNOMEDCT, UWDA
Derived from the NIH UMLS (Unified Medical Language System)


Corneal Stroma (C0010040)

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.
Definition (NCI) The lamellated connective tissue constituting the thickest layer of the cornea between the Bowman and Descemet membranes. (MeSH)
Concepts Body Part, Organ, or Organ Component (T023)
MSH D003319
English Corneal Stroma, Corneal Stromas, Stroma of cornea, Structure of substantia propria of cornea, Substantia propria of cornea
Spanish estroma de la cornea, estructura de la sustancia propia de la cornea, sustancia propia de la cornea
Parent Concepts Cornea (C0010031), Eye part (C1268161), Dense fibrous connective tissue (C0225333), Structure of corneal layer (C0459674), Structure of soft tissues of head (C1276273)
Sources CSP , MSH, MTH, NCI, SCTSPA, SNOMEDCT, UWDA
Derived from the NIH UMLS (Unified Medical Language System)


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