In the refraction discussion, we learned how important the cornea is to the quality of vision perception. Here we will look at some problems with the cornea and the resulting vision. The condition called Astigmatism deals with the shape of the cornea and is discussed in its own section. Here we mostly focus on the quality of the cornea although some affect the shape also.
Keratitis includes a wide variety of inflammation, infection, or irritation conditions of the cornea. Usually these are caused by bacteria or fungus after scraps or cuts on the cornea. Eye injury or other severe eye irritations are common factors leading to this. If due to an eye injury, the condition can likely be treated. If other problems exist which led to the situation, they must also be dealt with.
Reactions to contact lenses, allergies, and cosmetics can also play a role in the formation of Keratitis. Many contact lenses trap any particles between the contact and the conjunctiva. If any scratch or abrasion occurs, infections may follow. Cosmetic supplies might also lead to infections if particles come in contact with scratches or small cuts.
Infections usually are accompanied by pain or sensitivity. However, nerve damage or underdevelopment may reduce or eliminate the pain. Dryness and the reflex of needing to rub the eye usually also occur.
In some cases, these conditions are caused by abnormal development of the eye. Cornea problems often occur along with other conditions such as Aniridia, Astigmatism, and many eyelid related diseases. Underdevelopment of parts of the eye are usually due to genetics and often affect the development of corneal tissue also.
It is very important to keep the surface of the eye clean and free of unwanted particles, moreso with the presence of cosmetics on the eye lids and lashes. Avoid touching or rubbing the eyes with the fingers. Avoid touching the inner side of contact lenses or any handling without freshly washed hands. During times of illness, avoid touching or rubbing of the eye areas altogether as this might spread germs from the hands to the eyes.
Severe eye trauma, such as a deep scrap or cut, can cause the corneal tissue to be damaged beyond normal cell replacement repair. It becomes scar tissue and is rarely transparent. Depending on the degree of scarring, vision can be any degree of blurred or as severe as causing total blindness.
Burns can also lead to formation of scar tissue. Acids, boiling water, chemicals, and excessive heat (as from fire) are some things which can damage the tissue. The impact relates to the degree of severity.
Corneal scarring can also result from disease. A condition called vascularization is where blood vessels form in the normally clear cornea to promote healing. Such causing conditions include herpes simplex, syphilis, and keratitis.
When the scarring is a result of disease, it may continue to advance while the disease is still present. Even if the disease is being treated, the damage can move forward. Again, the amount of vision impact will coincide with the severity.
Scar tissue damage cannot be reversed or healed. If there is little vision loss, usually nothing is done for treatment. But if it yields an unreasonable vision impact, surgery might offer a solution. There are currently two forms of corneal surgery that I know, corneal transplant and corneal stem cell grafting.
You may read about the cell grafting process on my personal webpage (Terrys Place) under personal vision. The discussion covers some information on corneal transplants also. This KLAL surgery link opens a new browser window for convenience.
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