When there is erosion or sore formation on the cornea (outer layer) it is called corneal ulcer. This condition occurs due to infection on the eyes. The cornea is the protective covering of the eye which is made up of 5 layers. The outermost layer is called corneal epithelium; tough covering that protects the corneal stroma is called Bowman’s layer and the thick transparent layer in the middle made of collagen fibers is called corneal stroma. Next is the layer that serves as the basement membrane called Descemet’s membrane and finally a layer that contains sqamous cuboidal layer that manages the fluid level of the eye is called corneal endothelium.
Corneal Ulcer Causes :
The major cause of corneal ulcer is bacterial or viral infection. An amoebic infection (Acanthamoeba keratitis) develops on persons using contact lenses. Fungal infection can cause corneal ulcer causing corneal injury.
Infection can also happen in people with weakened immunity. Herpes simplex virus can also cause this type of infection. The virus would repeatedly attack the cornea causing continuous infection which is triggered by exposure to sunlight and stressful events. Overuse of corticosteroid eye drops can also lead to infection.
Corneal ulcers can also occur due to impairment of function of eyelids, when it does not close fully like Bell’s palsy. Presence of foreign particles like dust, hay, or tiny insects can cause irritation on the eyes causing ulcers. Eye injury or scratches on the surface of the eye can cause infection. Dryness on the eyes and allergic disorders can affect your eyes. If the person suffers from inflammatory disorders it can affect the eye causing infection.
In many cases, wearing contact lenses continuously and overnight can cause eye infection which may lead to ulcer. Contact lenses would slowly scrape the edges of the cornea causing ulcer which leads to the entry of bacteria. In addition, continuous wearing of lenses can disrupt normal blood flow on the corneal surface leading to ulcerous growth and infection.