STUDY - Technical - New Dacian's Medicine
Corneal
reflex, absent (Classical / Allopathic Medicine)
The corneal reflex
is tested bilaterally by drawing a fine-pointed wisp of
sterile cotton from a corner of each eye to the cornea.
Normally, even though only one eye is tested at a time, the
patient blinks bilaterally each time either cornea is touched
- this is the corneal reflex. When this reflex is absent,
neither eyelid closes when the cornea of one eye is touched.
(See Eliciting the corneal reflex.)
The site of the
afferent fibers for this reflex is in the ophthalmic branch of
the trigeminal nerve (cranial nerve V); the efferent fibers
are located in the facial nerve (cranial nerve VII).
Unilateral or bilateral absence of the corneal reflex may
result from damage to these nerves.
HISTORY:
Ask the patient about associated symptoms, such as facial pain, dysphagia, and limb weakness.
Ask the patient if he has noticed hearing loss or tinnitus.
Ask the patient about associated symptoms, such as facial pain, dysphagia, and limb weakness.
Ask the patient if he has noticed hearing loss or tinnitus.
PHYSICAL
ASSESSMENT:
Assess the patient for signs and symptoms of increased intracranial pressure, such as decreased level of consciousness, headache, and vomiting.
Look for other signs of trigeminal nerve dysfunction. To test the three sensory portions of the nerve, touch each side of the patient's face on the brow, cheek, and jaw with a cotton wisp and ask him to compare the sensations.
If you suspect facial nerve involvement, note if the upper face (brow and eyes) and lower face (cheek, mouth, and chin) are weak bilaterally.
Assess the patient for signs and symptoms of increased intracranial pressure, such as decreased level of consciousness, headache, and vomiting.
Look for other signs of trigeminal nerve dysfunction. To test the three sensory portions of the nerve, touch each side of the patient's face on the brow, cheek, and jaw with a cotton wisp and ask him to compare the sensations.
If you suspect facial nerve involvement, note if the upper face (brow and eyes) and lower face (cheek, mouth, and chin) are weak bilaterally.
Eliciting the
corneal reflex
To elicit the corneal reflex, have the patient turn her eyes away from you to avoid involuntary blinking during the procedure. Then approach the patient from the opposite side, out of her line of vision, and brush the cornea lightly with a fine wisp of sterile cotton. Repeat the procedure on the other eye.
SPECIAL CONSIDERATIONS:
When the corneal reflex is absent, take measures to protect the patient's affected eye from injury, such as lubricating the eye with artificial tears to prevent drying.
To elicit the corneal reflex, have the patient turn her eyes away from you to avoid involuntary blinking during the procedure. Then approach the patient from the opposite side, out of her line of vision, and brush the cornea lightly with a fine wisp of sterile cotton. Repeat the procedure on the other eye.
SPECIAL CONSIDERATIONS:
When the corneal reflex is absent, take measures to protect the patient's affected eye from injury, such as lubricating the eye with artificial tears to prevent drying.
PEDIATRIC
POINTERS:
Brain stem lesions and injuries are the most common causes of absent corneal reflexes in children; Guillain-Barré syndrome and trigeminal neuralgia are less common.
Infants, especially those born prematurely, may have an absent corneal reflex due to anoxic damage to the brain stem.
Brain stem lesions and injuries are the most common causes of absent corneal reflexes in children; Guillain-Barré syndrome and trigeminal neuralgia are less common.
Infants, especially those born prematurely, may have an absent corneal reflex due to anoxic damage to the brain stem.
PATIENT
COUNSELING:
Provide emotional support. The cause of the absent corneal reflex may be disfiguring and cause anxiety over body image disturbances.
Provide emotional support. The cause of the absent corneal reflex may be disfiguring and cause anxiety over body image disturbances.
Bibliography:
1. Rapid Assessment, A
Flowchart Guide to Evaluating Signs & Symptoms, Lippincott
Williams & Wilkins, 2004.
2. Professional Guide to
Signs and symptoms, Edition V, Lippincott
Williams & Wilkins, 2007.
3. Guide to common
symptoms, Edition V, McGraw - Hill, 2002.
Dorin,
Merticaru (2010)