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Anatomy of the Cornea

  • Soosan Jacob
  • Preethi Naveen
Chapter

Abstract

The cornea is a transparent dome-shaped structure covering the iris, lens, and anterior chamber (AC) of the eye. It accounts for nearly two-thirds of the total refractive power of the eye (Fig. 1.1a, b). The adult cornea measures 11–12 mm horizontally and 9–11 mm vertically. The thickness varies from 0.5 mm in the central cornea and gradually increases to around 1 mm near the limbus [1]. The periphery is more aspheric as the curvature decreases from the center toward the periphery. Refractive index of the cornea is 1.376. The radius of curvature anteriorly is 7.8 mm and posteriorly 6.5 mm. The refractive power of the cornea is +48D on the anterior surface and −5D on the posterior surface accounting for a net power of +43 D. The normal keratometric value for the cornea is within the range of 42–45 D. Transparency, avascularity, and immunological privilege are unique properties of the cornea. It derives its nutrition from tears, aqueous, and the perilimbal vasculature. Oxygen supply is from the atmosphere through the tear film and also from the perilimbal capillaries. Aqueous humor is the main source of glucose for all layers of the cornea, while amino acids required for protein synthesis are acquired by passive diffusion from the aqueous.

Keywords

Corneal Epithelium Keratan Sulfate Superficial Cell Corneal Nerve Corneal Transparency 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer India 2016

Authors and Affiliations

  1. 1.Dr. Agarwal’s Refractive and Cornea FoundationDr. Agarwal’s Group of Eye HospitalsChennaiIndia

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