corneal reflex examination

Corneal reflexes are divided into direct corneal reflexes and indirect corneal reflexes. Normally, the eyelid of the examinee is quickly closed, which is called direct corneal reflex. If the cornea is stimulated on one side, the eyelid closure reaction also occurs on the contralateral side, which is called indirect corneal reflex. An examination that stimulates the response of the cornea is called a corneal reflex examination. The patient is asked to look at one side. The examiner gently touches the outer and lower sides of the contralateral cornea with a thin bundle of cotton bristles, from the outside to the inside, so that the patient is not seen. Basic Information Specialist classification: neurological examination classification: neuroelectrophysiology Applicable gender: whether men and women apply fasting: not fasting Tips: Patients with eye pain or inflammation are not suitable for this test. Normal value The examiner contracted the bilateral orbicularis oculi muscles with a soft tweezer into a thin bundle of cotton bristles. Clinical significance Abnormal results: Corneal reflexes can be affected by a variety of lesions. There are three common situations in which corneal reflex disappears. (1) Reflex arc afferent neuropathy The lesion of the trigeminal ocular branch, except for the sensory area of ​​the facial (the forehead skin), is accompanied by a decrease or disappearance of corneal reflex. When the lateral trigeminal nerve damage causes corneal paralysis, there is no reaction on both sides, and the bilateral reaction can still be caused when the contralateral corneal reflex is performed. The common cause of attenuated corneal reflex is the early symptoms of the first damage of the trigeminal nerve. As the lesion progresses, the corneal reflex disappears. Since the cerebellum is also distributed by the first branch of the trigeminal nerve, corneal reflexes may be weakened in the early stage of the cranial fossa, such as cerebellar hemorrhage, cerebellopontine angle cholesteatoma. It has been reported that ipsilateral corneal reflexes are weakened and/or disappeared, which is an important indication for localization diagnosis. (2) Efferent neuropathy of the corneal reflex (peripheral facial paralysis) The efferent nerve of the corneal reflex is the facial nerve. When the peripheral facial neuropathy occurs, the cornea can not be closed after being stimulated (blinking). In view of it, the corneal reflex disappears. When the lateral nerve is paralyzed, the ipsilateral corneal reflex disappears and the contralateral reflex exists. (3) One side of the cerebral hemisphere lesions unilateral corneal reflexes weakened or disappeared, often part of partial numbness, and in many cases of hemiplegia, the cornea may be the only numb area. Some people think that there is a corneal reflex center in the parietal lobe, which may be explained. If the bilateral corneal reflexes weaken or disappear, it indicates extensive damage on both sides of the brain (such as deep coma, cerebral edema, cerebral hypoxia), and invades the intracerebral reflex arc of corneal reflex. People who need to be examined: patients with facial pain and lateral nerve spasms. Positive results may be disease: Theodore upper limbal keratoconjunctivitis, Thygeson superficial punctate keratopathy, brain edema, corneal disease considerations Taboo before inspection: The cotton wool to be used for inspection, the texture of the cotton wool should be soft and cut into thin bundles. Requirements for inspection: Do not rub your eyes during the inspection so as not to obstruct the examiner's observation. Inspection process The patient is asked to look at one side. The examiner gently touches the outer and lower sides of the contralateral cornea with a thin bundle of cotton bristles, from the outside to the inside, so that the patient is not seen. The reflex is caused by contraction of the bilateral orbicularis oculi muscles, and bilateral blinking action occurs. The same side is called direct corneal reflection, and the opposite side is called indirect corneal reflection. Reflex arc cornea - trigeminal nerve branch - middle cerebral trigeminal sensory nucleus - reticular structure - thalamus - cerebral cortex - cortical medullary bundle - bilateral lateral nucleus - bilateral lateral nerve - bilateral orbicularis oculi muscle. Not suitable for the crowd Inappropriate people: patients with eye pain or inflammation. Adverse reactions and risks Nothing.