pupils Flashcards
what is the target for pupils?
letter/ spotlight if va worse than 6/18b in poorer eye
procedure
1) with room light on - check size, shape and location of both pupils // if unequal sizes measure with ruler in mm
2)dim lights and measure size again
3) direct - observe speed and extent of constriction
4) consensual
CHECK SEVERALK TIMES
4) swinging flash light checks for rapid
normal - both pupils constrict
raid - eye will dilate as light is shone on it
1) what Is normal pupil size
2-6mm
<2
miotic due to pathology, drugs (pilocarpine) or physiology
> 6
midriatic- due to drugs( tropicamid´, cyclopentolate) , glaucoma iris injury
RAPD
Marcus Gunn pupil.
palsy o Defect in the afferent pathway (indicated within name).
o Causes: asymmetric glaucoma, optic neuritis, MS, RD, CRAO/CRVO, AAION.
o Effect: pupil dilation in affected eye on ‘swinging light test’
ANISOCORIA
Seen in about 20% of normal patients and is generally the same in bright and dim light.
o Pathological anisocoria is due to an abnormality in the efferent or motor pupil pathway.
o Anisocoria that is greatest in bright light will generally show an abnormal direct and
consensual light reflex.
This indicates a problem in the motor leg of the light reflex pathway, such as 3rd nerve palsy, Adie’s or could be drug induced.
AMAUROTIC PUPIL = blind eye
light is shone in the affected eye, both pupils do not respond due to being blind in affected
eye.
o If light is shone in the unaffected eye, both pupils respond normally and equally.
o Pupillary diameter is equal in both eyes.
o Near reflex (accommodative) normal.
o Caused by a complete unilateral optic nerve lesion.
symptoms of aides pupil
Mild blurring of vision,especially near(fromparalysisoftheciliarymuscle,whichfocusesthe lens).
o Glare(fromthedilatedpupil).
signs of Adie pupil
Dilated pupil with very poor constriction to light but which constricts slowly when the patient is asked to look at a near target (‘light-near dissociation’).
o No ptosis, normal eye movements.
adies pupil
ossibly a viral infection of the orbital ciliary ganglion causing lack of parasympathetic supply
to the eye. the iris sphincter muscle (which causes pupil constriction) is paralysed, resulting in
a dilated pupil.
o Unilateral(lesscommonlybilateral).
o Occurs in otherwise well patients.
o Commoninyoungerwomen.
o Adie’s in younger people – then concerned but with elderly people it’s common due to
damage within pupil pathway caused by viruses and infections throughout life.
management of aides pupil
Ophthalmic referral to confirm diagnosis.
- Elderly patient = routine referral
- Young patient = urgent referral, in case of neurological origin.
o Reading glasses might be necessary (especially if young patient due to paralysis of iris sphincter); sunglasses should be worn outside.
- How do you know the difference between a RAPD and an amaurotic pupil?
No direct and consensual reflex in Amaurotic
- Anisocoria vs. Adie’s?
Adie’s is unresponsive to light
Anisocoria is responsive to light, just difference in pupil sizes
ARGYLL-ROBERTSON PUPIL (miotic pupils)
Due to CNS disorder.
o Both pupils are affected – appear constricted.
o Neither pupil react to light(or react poorly)but they both have a near response=light-near
dissociation.
o The pupils are unequal in size, small and irregularly shaped.
o Caused by diabetes, alcoholism and neurosyphilis.
o Parasympathetic defect.
HORNER’S SYNDROME
Interruption of the sympathetic nerve supply to the eye and upper lid at any point in the head, neck or upper chest.
o Lack of sympathetic supply to the smooth muscle of the upper lid(Muller’smuscle)causes the mild ptosis; lack of supply to the iris dilator muscle causes the small pupil.
oCauses include head or neck tumour,trauma brainstemstroke,apical lung tumour,dissecting aneurysm of the internal carotid artery.
symptoms of Horners syndrome
o Usually asymptomatic: the eyelid and pupil changes are usually noticed by a relative or examining practitioner.
o If the patient has neck pain or a recent history of head or neck trauma,suspect internal carotid artery dissection as the cause.
signs of Horners syndrome
Often subtle but difficult to detect
o If unilateral: mild ptosis and miosis
3np
