Pupillary Light Reflexes

Question 1

What is the afferent pupillary nerve pathway?

Answer 1

Light is detected by the retina and transmitted via the optic nerve (CN2) to the lateral geniculate body in the midbrain.

Question 2

What is the efferent pupillary nerve pathway?

Answer 2

The Edinger Westphal nucleus in the midbrain stimulates pupil constriction through parasympathetic CN 3 oculomotor fibres

Question 3

What is an afferent pupillary defect?

Answer 3

When there is no pupil response to light shone on the retina, but when light is shone in the other eye (swinging light test) pupil constricts due to a consensual response.

Question 4

What causes afferent pupillary defects?

Answer 4

Optic Neuritis
Optic Atrophy
Retinal disease

Question 5

What is an efferent pupillary defect?

Answer 5

Pupil totally unresponsive to light due to total 3rd nerve palsy.
Fixed dilated with ptosis and a down and out eye.

Question 6

What are causes of efferent pupillary defects?

Answer 6

Coning
Cavernous Sinus Lesions
Diabetes