The human eye is made up of several different parts that are designed to enable clear and complete vision. The eyelids are designed to continuously wipe and clean the cornea. The cornea is the outer layer of the eyeball. The eye contains structures such as the pupils and various internal parts of the eye. The pupils direct light to the lens which then refracts the light to the back of the eye where it is sensed. This process of sensing light is used to actually transmit information to the brain which computes what has been seen. The outer layer of the eye, the cornea, is continuously lubricated. Tear glands produce a saline fluid that coats the eye. This fluid is constantly replaced in the eye with the fluid draining into the nasal canal. If an individual cries or is suffering from watering in the eyes, the tears will not be able to drain as the quantity of fluid is excessive. This will cause tear drops to fall down the face.
The cornea, being the external layer of the eye is prone to damage. Damage may be caused by scratching, the presence of a foreign object, or by infections. The medical test to determine the nature of the damage to the cornea is known as the fluorescein dye test. The fluorescein dye test is conducted using the dye substance known as fluorescein which is placed on the eye. A blotting paper may be used to place the fluorescein dye on the cornea. The individual then needs to blink to spread the dye around. The eye is then examined under a special light that will illuminate the dye. Judging by its pattern of spreading, the doctor will be able to notice areas where the dye has accumulated. This happens if there is damage in that area of the cornea. The fluorescein dye test can therefore be used to determine physical and infection based damage to the eye. The fluorescein dye analysis would be interpreted by your doctor and the results made clear to you quickly.
There is not much preparation required on the part of the patient for a fluorescein dye exam. Patients who wear contact lenses will need to remove these lenses before the test. The fluorescein dye test for the cornea usually takes just a minute or two for each eye.
The patient can wash the eye with cool water after the test to ensure that there is no stinging or burning sensation in the eye once the procedure has been completed.