The cornea is the eye’s outermost layer and acts as a window to the eye. It is made up of five delicate layers: the epithelium, bowman’s layer, stroma, descemet’s membrane and endothelium. The coloured iris and the pupil (the black dot in the centre of the iris) can be seen through the cornea.
The cornea helps to focus and transmit light as it is passed to the lens and on to the retina at the back of the eye. This ‘picture’ is in turn transmitted to the brain.
When the cornea is damaged it can lose its transparency or its shape can alter. This can prevent light from passing to the retina and causes the picture transmitted to the brain to be distorted or cloudy. When you can no longer see through it, a corneal transplant may be needed.
Corneal-related conditions may also be referred to as external eye diseases or ocular surface disease.
The cornea is a resilient part of the body and copes well with minor injuries and abrasions. However, there are many different types of diseases and disorders that could affect the cornea, a few of which are detailed below:
- Corneal infection – After an injury to the cornea has occurred it may become contaminated, causing painful inflammation and infections which may reduce the clarity of your vision.
- Dry Eye – this refers to those who produce too few, or low quality, tears and can are therefore unable to consistently lubricate the eye surface, to maintain a healthy eye. Symptoms of this condition include a ‘scratchy’ or ‘sandy’ feeling, as if something is in the eye. The sufferer may also experience stinging or burning f the eye, with excess tearing followed by a very dry sensation. Sometimes, you may experience blurred or decreased vision, although loss of vision is uncommon.
- Keratoconus – A degenerative disorder in which changes within the cornea cause it to thin and change into a more conical shape than normal. This involves a protrusion of the cornea that ultimately distorts vision in its sufferers.