The cornea is the diaphanous front part of the eye covering the anterior chamber, iris and pupil. Though being diaphanous and smooth, it is durable and strong. Function of cornea is to act as a shield and protect the eye from germs, dust and other malefic foreign matter. The other function of cornea is to control and focus the incoming light. It is responsible for the 65 to 75 % of the eyes total focusing power. Function of cornea is to reflect or bend the light that strikes on it to the lens.
The cornea also plays a protective role by serving as a filter and blocking some of the damaging ultraviolet rays of particular wavelength contained in the sunlight. Without the corneal protection, the retina and lens would become highly susceptible to injuries prone to UV radiation. The cornea also copes very well with abrasions and minor injuries. If the sensitive cornea gets scratched, healthy cells will then slide over it and patch the injury quickly before the infection occurs and vision might get affected.
- Study of Function of Cornea:
Whether the cornea is functioning properly or not can be diagnosed or studied by conducting few tests. The Hirschberg test is used to detect the corneal reflex function. The test is performed by striking light in the person’s eyes to observe the reflection of cornea. For people with normal ocular alignment, the reflex lies nasal from the cornea’s centre. The cornea’s function can also be altered due to the hazy deposit built on the cornea called as the Fuch’s dystrophy which can be studied by glare test, visual acuity, grade or guttata stage, corneal cell count and corneal pressure test. The cornea can also become dry due to continuous drainage of tears causing improper vision. The keratoconus disorder may be a reason for improper functioning of cornea and can be studied by evaluation of the cornea.