Corneal reflex is a natural reaction of the cornea to irritation. With the normal functioning of the nerves when you touch the cornea, the eyelids of both eyes involuntarily close. Violation or total absence of reflex is a sign of lesion of the facial nerve or organic disease of the brain, as well as the disease of the cornea itself.
Corneal reflex is necessary to protect the eyeball. Therefore, nature has equipped the cornea with a host of extra-sensitive cells for instant eye protection.
This reflex is also called corneal from the Latin word cornea - cornea.
How does the
pass? An experienced doctor will perform this simple procedure without problems. Nevertheless, he must be careful, because he is in contact with one of the most delicate organs of the human body. To conduct an examination, a qualified specialist performs the following manipulations: the patient's
- is laid on the couch;
- the doctor raises the patient's eyelid;
- with a slightly moist piece of cotton wool, the doctor touches the cornea of the subject, revealing the presence of a reaction.
If everything is in order, the eyeball should instantly roll up, as during a healthy sleep. Verification of the corneal reflex is performed in order to know the condition of the trigeminal and facial nerves.
Absence of a reflex will tell the doctor and that the patient is probably in a deep coma. Anesthesiologists also perform the procedure in order to find out whether the depth of anesthesia is sufficient for the operation. As a rule, the absence of a reflex also indicates the introduction of a patient into a deep( general) anesthesia.
Causes of weakness or absence of corneal response
A weak or zero corneal response to an external effect can be caused by a variety of diseases and abnormal conditions of the body. It is impossible to diagnose only the result of one of these tests, but it is an important basis for an additional neurological examination. As a rule, after the study, depending on the results, the following pathologies can be assumed:
- In the absence of reaction, a specialist can make a preliminary diagnosis - deformation of the varioly bridge. The Varoliev Bridge is one of the parts of the brain that belongs( together with the cerebellum) to the hindbrain. Its function is to transmit information from the spinal cord to the head. He controls the facial and trigeminal nerves.
- With the decrease of the reflex towards the hearing organs, one can assume the presence of neurinoma of the auditory nerve .This is a benign tumor, which is manifested by a decrease in hearing in one of the half of the face, painful sensations and impaired swallowing function. The tumor is removed surgically or with the help of radiotherapy. Sometimes a neurinoma requires only observation.
- It is not necessary that the corneal reaction to touch interferes with internal pathologies. The corneal reflex can be reduced or even disappeared in the event that the patient in large quantities takes medications that have very powerful sedative properties of .These drugs include benzodiazepines, barbiturates, some antipsychotics and antidepressants, as well as alcohol. Also, the reflex may be affected by antiemetics and analgesics.
- With the brain injury , the physician can identify both the revitalization and the inhibition of the reaction. In the first case, there are improvements and an early exit from the coma is possible, the second case is more severe: usually oppression is observed with a fracture of the temporal bone.
Conductive pathways of pupillary and corneal reflexes
Any change in the normal response of the cornea to external irritation urgently requires the help of a doctor, as this may be a symptom of a serious illness. Do not hesitate with the help and conduct all necessary procedures as quickly as possible.
