Cornea
The cornea is the transparent circular part of the front of the human eyeball.
It has the important optical function of refracting light entering the eye through the pupil and onto the lens (which then focuses the light onto the retina).
The degree of curvature of the cornea varies between individuals and also throughout a person's life. It is more prominent in youth than later in life, when it can become flatter in shape.
The cornea has a complex structure that specialist texts describe in terms of the following layers - from the outside inwards:
- Several strata of epithelial cells, continuous with those of the conjunctiva
- A thick central fibrous structure called the substantia propria
- A homogeneous elastic lamina
- A single layer of endothelial cells forming part of the lining membrane of the anterior chamber of the eyeball
The cornea is a non-vascular structure (which means that it does not contain any blood vessels) because the capillaries that supply it with nutrients terminate in loops at its circumerfence. It is supplied by many nerves derived from the ciliary nerves. These enter the laminated tissue of the cornea. It is therefore extemely sensitive.
More about Ophthalmology:
This section includes short definitions and descriptions of the parts of the eye.
For other descriptions in this category, choose from the list
to the left (but note that this is not a complete / exhaustive list).
Other related sections include:
- A labelled diagram of the eye
- A concise description of the human retina with brief descriptions of the parts of the retina
- Diseases and disorders of the human eye and the human visual system
- Clinical and surgical procedures re. eyes and human visual system
For further information see also our pages of books about ophthalmology.
