14 Nov 2024        11:28:16 am

Science

Cornea

Tags : Cornea

Topic: Human Body

Why in the news?

• With corneal blindness becoming one of the leading causes of blindness in the country, and one which can be rectified by transplanting the dome-shaped layer of the eye with another healthy one, the Health Ministry has decided to give a big push to cornea donation. It is considering an “opt-out” method, whereby anyone who dies at a hospital will be presumed to be a cornea donor unless they (while alive) or their families register their dissent.

Source: The Indian Express

About Cornea:

• It is the clear outer layer at the front of the eye. 
• It covers the pupil (the opening at the center of the eye), iris (the colored part of the eye), and anterior chamber (the fluid-filled inside of the eye). 
• Its main function is to refract, or bend light. It is responsible for focusing most of the light that enters the eye.
• Its specific shape plays a key role in how your eyesight works and filters some ultraviolet (UV) rays.
• Except at its margins, the cornea contains no blood vessels, but it does contain many nerves and is very sensitive to pain or touch. 
• Since there are no nutrient-supplying blood vessels in the cornea, tears and the aqueous humor (a watery fluid) in the anterior chamber provide the cornea with nutrients.
• As light passes through the cornea, it is partially refracted before reaching the lens.
  • The curvature of the cornea, which is spherical in infancy but changes with age, gives it its focusing power.
  • When the curve becomes irregular, it causes a focusing defect called astigmatism, in which images appear elongated or distorted.
• As it is the first line of defense for the surface of the eye, it is also prone to injuries and damage. 
  • It tends to repair itself quickly from minor abrasions.
  • However, deeper abrasions may cause scars to form on the cornea, which causes the cornea to lose its transparency, leading to visual impairment.

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