Pupil Disorders

Question 1

What is the pupil formed by?

Answer 1

A hole in the centre of the iris

Question 2

How do pupils constrict?

Answer 2

There are circular muscles in the iris which cause pupil constriction, they are stimulated by the parasympathetic nervous system using acetylcholine as a neurotransmitter. The fibres of the parasympathetic system innervating the eye travel along the oculomotor nerve.

Question 3

How are the dilator muscles stimulated?

Answer 3

They are arranged like spokes on a bicycle and they travel straight from the inside to the outside of the iris
They are stimulated bu the sympathetic nervous system using adrenalin as a neurotransmitter

Question 4

If you saw a vertical oval pupil shape in someone with an acute red painful eye what would you be suspecting?

Answer 4

Acute angle closure glaucoma

Question 5

What can anterior uveitis lead to in terms of pupils?

Answer 5

Anterior uveitis can cause adhesions (scar tissue) in the iris that make the pupils misshapen.

Question 6

What is rubeosis iridis and what can it do to pupil shape?

Answer 6

Neovascularisation in the iris
Can distort the shape of the iris and the pupil
This is usually associated with poorly controlled diabetes and diabetic retinopathy

Question 7

What is coloboma?

Answer 7

Congenital malformation in the eye

This can cause a hole in the iris causing an irregular pupil shape

Question 8

What is tadpole pupil?

Answer 8

This is where there is a spasm in the segment of the iris causing a misshapen pupil, it is usually temporary and is associated with migraines.

Question 9

What are the causes of mydriasis (dilated pupil)?

Answer 9

3rd nerve palsy 
Anticholinergics 
Stimulants like cocaine 
Trauma
Congenital 
Raised intracranial pressure 
Holmes- adie syndrome

Question 10

What are the causes of miosis (constricted pupil)?

Answer 10

Horners syndrome
Cluster headaches
Argyll robertson pupil (in neurosyphilis)
Opiates
Nicotine
Pilocarpine (eye drops used for glaucoma)

Question 11

What is a holmes adie pupil?

Answer 11

Unilateral dilated pupil which is sluggish to react to light with slow dilation of the pupil following constriction
Caused by damage to the post ganglionic parasympathetic fibres, the exact cause is unkown but may be viral

Question 12

What is an argyll robertson pupil?

Answer 12

A specific finding in neurosyphilis

It is a constricted pupil which accommodates when focusing on a near object but does not react to light