Function
The cornea functions like a camera lens, helping to focus light coming into the eye onto the retina. The cornea is also filled with nerves that alert us to irritations that could potentially harm our vision and eye health.
What Is It Made Of?
The cornea is a remarkable piece of tissue made up of specialized cells. One thing unique to the cornea is that there are no blood vessels in the cornea to provide it nourishment.
The corneal tissue is arranged in six different layers, with the final layer discovered in 2013:
Each layer serves a different purpose. The first five layers below are described in full in the Indian Journal of Opthalmology. The last layer is defined in the journal Opthalmology.
Epithelium: This layer acts as a barrier to prevent chemicals, water, and microbes from entering the eye. It also provides a smooth optical surface as an internal part of tear film-cornea interface contributing to the refractive power of the eye, and has Langerhans cells thatperform immunological functions. Bowman’s Layer: This layer maintaitns the corneal shape. Stroma: This layer gives the cornea mechanical strength and is the main refracting lens and transparency of the cornea. Descemet’s Membrane: This layer is the resting layer for the endothelial cells. Endothelium: This layer maintains corneal clarity by removing water from the corneal stroma. Dua’s Layer: Its recognition impacts the future of posterior corneal surgery and the understanding of corneal biomechanics, posterior corneal pathology such as acute hyrops, Descematocele, and pre-Descemet’s dystrophies.
Measurement and Examination
Eye doctors can view the cornea under a slit lamp biomicroscope. A slit lamp is basically an upright microscope. A special slit beam is used to illuminate the different layers of the cornea. To measure the thickness of the cornea, doctors perform pachymetry. Pachymetry can be performed using an ultrasonic pachymeter. The power and the curvature of the cornea can be measured by a corneal topographer. This may have implications for prescription contact lenses, corneal surgery, cataract surgery and corneal disease monitoring and management.
