Referral to emergency

If any of the following are present or suspected, please refer the patient to the emergency department (via ambulance if necessary) or seek emergent medical advice if in a remote region.

  • acute onset pupil asymmetry with associated neurological features
  • acute onset pupil asymmetry without other neurological signs (may be associated with changes in eye movements or eyelid position)

For urgent referrals, please contact the on-call registrar to discuss your concerns prior to referral.

For clinical advice, please telephone the relevant metropolitan Local Health Network switchboard and ask to speak to the relevant specialty service.

Southern Adelaide Local Health Network

Women's and Children's Health Network

Exclusions

  • second opinions

Triage categories

Category 1 (appointment clinically indicated within 30 days)

  • asymmetry of pupil size or reaction with ptosis (less than 6 weeks onset)
  • unexplained neurological visual field impairment
  • recent onset diplopia

Category 2 (appointment clinically indicated within 90 days)

  • pre-literate child with greater than 6 weeks asymmetry of pupil size or reaction without significant changes
  • pre-literate child with greater than 6 weeks asymmetry of pupil size or reaction without ptosis

Category 3 (appointment clinically indicated within 365 days)

  • literate child with greater than 6 weeks asymmetry of pupil size or reaction without ptosis

For information on referral forms and how to import them, please view general referral information.

Essential referral information

Completion required before first appointment to ensure patients are ready for care. Please indicate in the referral if the patient is unable to access mandatory tests or investigations as they incur a cost or are unavailable locally.

  • identifies as Aboriginal and/or Torres Strait Islander
  • identify within your referral if you feel your patient is from a vulnerable population, under guardianship/out-of-home care arrangements and/or requires a third party to receive correspondence on their behalf
  • interpreter required
  • antenatal, birth, developmental, medical, family history
    • note any developmental or behavioural issues such as autism spectrum disorder (ASD), and attention deficit disorder (ADD), or attention deficit hyperactivity disorder (ADHD)
  • ocular history, including:
    • length of time asymmetry of pupil size or reaction has been noted, compare with previous photos for chronicity
    • other eye conditions and associated treatments e.g. eye drops
    • eye trauma
    • surgery and medical management, including glasses and/or amblyopia therapy
  • eye and vision examination in both eyes:
    • pupil sizes and assessment including reactions to light
    • eyelid position
    • uniocular visions
    • ocular motility: ask child to follow a toy or a light in all directions of gaze
    • asymmetry of eye colour – suggestive of congenital Horner’s syndrome
    • optometrist report within the last 3 months - category 3 only
    • literate children use a visual acuity chart
    • preschool children use a letter or picture optotype matching
    • pre-literate children use a visual behaviour e.g. ability to fix and follow an object of interest

Clinical management advice

Pupil size asymmetry is a common occurrence in the general population and can be caused by either harmless or serious factors. Benign causes of asymmetry can include:

  • essential anisocoria, which is present from birth and usually results in less than a 1mm difference in pupil size in light and dark conditions, affecting up to 10% of individuals.
  • contact with certain medications or poisons can impact pupil reactions and size, as can eye trauma or surgery, which can result in dilation, constriction, or abnormal shaping of the pupil.

Important causes of asymmetry can include:

  • third nerve palsy, where sudden onset leads to reduced pupil constriction to bright light and may be accompanied by limited eye movement or ptosis,
  • Horner's syndrome, which causes reduced pupil dilation in low light and may also be accompanied by ptosis

Clinical resources