Pupil abnormalities Flashcards
(16 cards)
What can cause an irregular pupil shape during cataract surgery?
Trauma to the sphincter muscles in the iris
This can lead to abnormal pupil shapes due to damage to the iris.
What condition can cause adhesions in the iris leading to an irregular pupil shape?
Anterior uveitis
Adhesions can form scar tissue in the iris.
What is a common pupil shape resulting from acute angle-closure glaucoma?
Vertical oval
This condition causes ischaemic damage to the muscles of the iris.
What is rubeosis iridis and its association?
Neovascularisation in the iris, usually associated with poorly controlled diabetes and diabetic retinopathy
It can distort the shape of the iris and pupil.
What congenital malformation can cause a hole in the iris?
Coloboma
This malformation can lead to an irregular pupil shape.
What are some causes of mydriasis (dilated pupil)?
- Congenital
- Trauma
- Third nerve palsy
- Holmes-Adie syndrome
- Raised intracranial pressure
- Acute angle-closure glaucoma
These factors can lead to pupil dilation.
What are some causes of miosis (constricted pupil)?
- Horner syndrome
- Cluster headaches
- Argyll-Robertson pupil (neurosyphilis)
- Opiates
- Pilocarpine
These conditions or substances can cause pupil constriction.
What are the symptoms of third nerve palsy?
- Ptosis (drooping upper eyelid)
- Dilated non-reactive pupil
- Divergent strabismus (squint)
The affected eye typically has a “down and out” position.
What muscle does the oculomotor nerve supply that is responsible for lifting the upper eyelid?
Levator palpebrae superioris
Damage to the oculomotor nerve affects this muscle, leading to ptosis.
What does a third nerve palsy cause in relation to the pupil?
A dilated, non-reactive pupil
This occurs due to the loss of parasympathetic innervation to the iris.
What conditions can cause a third nerve palsy that spares the pupil?
- Diabetes
- Hypertension
- Ischaemia
These conditions suggest a microvascular cause.
What can cause a full third nerve palsy?
- Tumour
- Trauma
- Cavernous sinus thrombosis
- Posterior communicating artery aneurysm
- Raised intracranial pressure
These factors compress the oculomotor nerve.
What triad of symptoms is associated with Horner syndrome?
- Ptosis
- Miosis
- Anhidrosis (loss of sweating)
The presence of anhidrosis helps locate the lesion.
How does the location of a lesion affect anhidrosis in Horner syndrome?
- Central lesions: Anhidrosis of arm, trunk, and face
- Pre-ganglionic lesions: Anhidrosis of the face
- Post-ganglionic lesions: No anhidrosis
The specific type of lesion determines the pattern of sweating loss.
What characterizes a Holmes-Adie pupil?
- Dilated
- Sluggish to react to light
- Responsive to accommodation
This pupil reacts well when focusing on a near object.
What is an Argyll-Robertson pupil and its significance?
A constricted pupil that accommodates but does not react to light
It is a specific finding in neurosyphilis.
