Cornea, sclera and vitreous body, corneal reflex

From WikiLectures

Cornea[edit | edit source]

Cornea is the clear covering that is present at the front of your eyes. It has a protective function. It keeps debris, dust, germs and other harmful substances out of your eye. Since they are located at the front of your eyes, corneas are very susceptible to injury or damage. The cornea is composed of 6 layers that work together.

The 6 layers -

  • Epithelium - Outermost layer.
  • Bowman’s layer - Mostly made of collagen. Helps hold the shape
  • Stroma - Bends light and focuses it onto the retina. It is the thickest layer of the cornea.
  • Pre-Descemet’s layer - Airtight layer
  • Descement’s layer - Protects the inside of your eye
  • Endothelium - Responsible for fluid balance

Common problems -

  • Dry eye
  • Infection
  • Inflammation

Sclera[edit | edit source]

It is the white part of the eye which extends from the cornea (front of the eye) to the optic nerve which is located in the back of the eye. The sclera is thin but it is quite strong. The sclera is made of collagen which makes it strong. Some muscles also attach to the sclera which help with the movement of the eyeball.

Vitreous body[edit | edit source]

Vitreous body is a gel-like substance that fills the area between the lens and retina. The substance is mostly made of water. It also has some salts, electrolytes and phagocytes.

Corneal Reflex[edit | edit source]

The corneal reflex ( corneal reflex ) is a spontaneous eyelid closure (blinking) after mechanical irritation of the cornea. However, apart from blinking a tear reflex can also occur. Hence, there are 2 types of the reflex.

The 2 types -

  • Blink - The automatic blinking that occurs when something touches the cornea of the eye
  • Tear - When the tear system flood your eye when something is stuck in there

The blink reflex is mediated by a reflex arc formed by corneal exteroreceptors, the afferent n. ophthalmicus (1st branch of n. V. ) and the efferent n. VII innervating the m. orbicularis oculi.


References[edit | edit source]

AMBLER, Zdeněk – BEDNAŘÍK, Josef. Clinical Neurology. 2. edition. Triton, 2008. ISBN 9788073871574.


https://my.clevelandclinic.org/health/body/21562-cornea

https://my.clevelandclinic.org/health/body/22088-sclera

https://my.clevelandclinic.org/health/body/24611-aqueous-humor-vitreous-humor

https://my.clevelandclinic.org/health/articles/24674-reflexes-of-the-eye

Retrieved from "https://www.wikilectures.eu/index.php?title=Cornea,_sclera_and_vitreous_body,_corneal_reflex&oldid=93315"