Corneal sensation test= Corneal reflex test= Blinking reflex

Corneal sensation test= Corneal reflex test= Blinking reflex

Aim: to test the sensation of the cornea or blinking reflex

Steps:

1-Make the end of a piece of cotton in the form of a tapered thread(avoid to show it to the patient)

2-Ask the patient to look in the opposite direction to disturb his attention(e.g. ask him to look to his right side if you want to test his left eye & the reverse)

3-Try to touch the patient's left cornea by your right hand (& the reverse)

Results:

*Closure of eyelids(Blinking)à Intact corneal sensation or corneal reflex pathway

*No closure of eyelidsàlesions affecting any part of the reflex pathway

Reflex pathway:

Receptorsà touch receptors in the cornea

Afferent: long ciliary nsànasociliary nàophthalmic division of 5^th nerve

Center: area 18 in occipital lobe

Efferent: 7^th nerve

Effector: orbicularis oculi muscle

Action : blinking or lid closure

Oral questions:

*Pathway of corneal reflex

*Causes of lost corneal reflex

*Types of blinking:

-Spontaneous: center in basal ganglia

-Reflex: center in area 18(occipital lobe)

-Voluntary: center in area 8(frontal lobe)

*What are other reflexes which have their centers in area 18.