Pupillary Examination | Diabetic Exam - MedSchool
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Diabetic Exam
 

Pupillary Examination

 
 

Inspection of Pupils

    • Look For

    • The size of the pupils (dilated, normal, constricted) and equality of size bilaterally.
    • Normal Pupillary Size

    • In the dark - 4-8mm
    • Under bright light - 2-4mm
    • Causes of Bilateral Pupillary Dilation

    • Cerebral lesion - herniation, encephalitis, visual cortex infarct, tumour, trauma, MS
    • Drugs - anticholinergics, SSRIs / SNaRIs, stimulants, barbiturates, methanol
    • Brain stem death
    • Causes of Bilateral Pupillary Constriction

    • Drugs - opiates, antipsychotics, acetylcholine, clonidine
    • Intracranial haemorrhage
    • Horner’s syndrome (bilateral) - autonomic failure, amyloidosis, diabetes
    • Causes of Unequal Pupils (Anisocoria)

    • Physiological (20% of the population - compare with an old photo)
    • Migraine
    • Post-ictal
    • Horner’s syndrome (unilateral)
    • Drugs applied to one eye - pilocarpine, tropicamide, cocaine
    • Intraocular conditions - glaucoma, retinal detachment
    • Optic (II) or oculomotor (III) nerve lesion - trauma, compression, optic neuritis, Guillain barré
    • CNS lesion - trauma, tumour, haemorrhage, infarct, MS

Pupillary Light Reflexes

    • How to Elicit

    • Shine a light into each pupil. Watch to see that both the ipsilateral (direct response) and contralateral (consensual response) pupils constrict as a result of the stimulus.
    • Causes of Absent Pupillary Reflexes

    • Intraocular conditions - glaucoma, retinal detachment
    • Optic (II) nerve lesion - trauma, compression, optic neuritis
    • Midbrain lesion - encephalitis, tumour, trauma, haemorrhage, MS, midbrain infarct
    • Oculomotor (III) nerve lesion - trauma, compression, small vessel ischaemia, Guillain barré
    • Medications - sympathomimetic, parasympatholytic (anticholinergics), barbiturates, methanol
    • Interpretation

    • No direct response - absent reflex in the tested eyeIpsilateral oculomotor nerve (III) lesion
    • No consensual response - absent reflex in opposite eyeContralateral oculomotor nerve (III) lesion
    • No afferent response - absent reflex in one eye when testing either eyeIpsilateral optic nerve (II) lesion
    • No response - absent reflex in both eyes when testing either eyeMidbrain lesion, medications

Swinging Light Test

    • How to Perform

    • Shine a light into one eye, swing it into the other eye, and so on back and forth.
    • Interpretation

    • A relative afferent pupillary defect (RAPD) is present if the affected eye dilates, or constricts briefly followed by dilatation.
    • Causes of RAPD

    • Intraocular haemorrhage
    • Retinal detachment
    • Optic or oculomotor nerve lesion
    • Midbrain lesion

Accommodation

    • How to Assess

    • Ask the patient to focus on a distant object, such as the back wall of the room. Place a finger in front of their field of view and ask them to look at it.
    • Causes of Impaired Accommodation

    • Optic (II) nerve lesion - trauma, compression, optic neuritis
    • Thalamic / occipital / midbrain lesion - encephalitis, tumour, trauma, MS, midbrain infarct
    • Oculomotor (III) nerve lesion - trauma, compression, small vessel ischaemia, Guillain barré
Last updated on November 28th, 2019
 
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