Good Hope, Heartlands, and Solihull Eye Clinics

Pupils, for professionals

David Kinshuck

To start

  • If smaller pupil normal, think Adie's on the other side
  • If the larger pupil normal, think Horner's on the other side
  • Wrong pupil stays big in light or small in dark
  • No reaction= ?trauma
  • If patient walks off street an isolated dilated pupil not third
  • Fixed dilated pupil neurosurgery, trauma, serious
  • Pharmacological: big or small
  • One skin cream contains phenylephrine like drug
examination of unequal pupils/anisocoria
React to light
Normal Abnormal
  1. Physiological
  2. Horners
Horners examine eye on slit lamp
  • Anisocoria increases in dark
  • takes along time to dilate
  • heterochromia
  • Constricts rapidly
normal abnormal

Neuronal level

  1. CVA M.S.
  2. neoplastic, trauma
  3. carotid..disection...hemifacial head pain
  • 111rd n palsy
  • drops

light: spiralling of iris fibres

accommodation: tonic
(take ages to dilate )



  • review, really excellent, Eye 2013
  • miosis..small pupil
  • ptosis..droopy lid
  • various other changes
  • lighter iris if long-standing (heterochromia)
  • sweating is reduced on the same side of the face
  • after CVP line Eye 16


  • Eye 2013
  • ptosis, 88%, sometimes lower lid might be elevated (upside down ptosis), enophthalmic appearance
  • anisocoria, more pronounced in dark: dilatation lag. Examine in room light, dim light, and as the light changes....the Horner's pupil dilates a lot more slowly as the light is dimmed: the difference is most obvious in the first 5 seconds
  • anhidrosis
  • After dissection and if longstanding no risk even if Horners remains: at time of dissection, discuss anticoagulation with stroke team

to test

  • Cocaine (or apraclonidine) separates normals: post cocaine ansiocoria >0.8mm, very likely Horners. 4% cocaine prevents nor-adrenaline dilates the normal pupil, but has no effect on a Horner's pupil. Iopidine 0.5% (apraclonidine and here) should dilate the Horner's pupil but not the normal pupil (unless the Horner's is very recent). Apraclonidine 40 minutes to work. Best to photograph before and after. (take 24 hours after horners starts to develop)
  • 1% phenylephrine will dilate/mydriais in post-ganglionic Horners due to denervation hypersensitivity (wont dilate others).
  • there are different causes depending whether 1st, 2nd or 3rd neurones affected.
  • 1st order CVA, demyelination..MRI brain/cervical spine, upper thoracic spine
  • 2nd order neoplasm, trauma..?CT angiogram
  • 3rd base of skull lesion, internal carotid dissection/aneurysm (e.g. after neck injury playing rugby)
  • apraclonidine..example JNO 15
  • hydroxyamphetamine localising JNO 17

Imaging in Horner's

  • an excellent review (adults)
  • Children: investigate unless trauma: Mri down to upper chest include spinal cord
  • Adults investigate all but long-standing third neurone.
  • generally (98%) the diagnosis was known at time of diagnosis of the Horner's. In 83% the diagnosis was made. Problems included previous neck/skull surgery, brainstem CVA, chest or skull base masses or trauma.
  • Carotid dissection was identified because the Horner's was PAINFUL (with/without trauma).
  • Cavernous sinus masses were related to other %5 or 6th) cranial nerve palsy.
  • Cervical spine mass (scapular pain/upper limb sensory problems).
  • None targeted imaging (no focal signs etc) was not that helpful.
  • One patient had a thyroid Ca.
  • Central Horners..MS/CVA/tumour
  • pre-ganglionic ...trauma, tumour
  • post ganglionic...carotid, trigeminal, cavernous sinus
  • HS (Horners syndrome) with localizing signs
    • 1st order. Brain/spine MRU
    • 2nd/3rd CT angiogram
  • HS (Horners syndrome) with NO localising sign
    • acute/painful, trauma, malignancy... CT angiogram same day
  • HS with no localizing signs and no pain/trauma, malignancy, urgent imaging not needed...?CT angiogram



  • no light response; sector palsy with slit lamp, spiralling or iris fibres, tonic to accommodation
  • initially pupil is larger than the normal pupil
  • normal near reflex
  • 66% reduced accommodation...difficult reading
  • pilocarpine 0.1% constricts an Adies pupil, not a normal pupil.
  • eventually the pupil becomes smaller
  • often called a 'tonic pupil': when trying to read pupil does become smaller, but takes much longer than the normal pupil to dilate, hence the term 'tonic'.
  • bilateral 4%/year
  • if part of Holme's-Adies ankle jerks reduced, no transillumination (HZO...transilluminates)
  • may have bilateral peripheral neuropathy
  • More common in women



  • part of Parinauds or
  • Argylle-Robertson pupil
  • absent light reflex, brisk near reflex



  • measure pupil in bright light
  • in dim light
  • check near reflex
  • examine iris & pupil on slit lamp...other disease?
  • if the light reflex is normal
  • <1.0mm difference, perhaps physiological (same all illumination)
  • otherwise, and if ptosis present, suspect Horner's (different according to illumination as above)
  • if the light reflex is abnormal, suspect Adies
  • pupils get smaller with age
  • constrict with light and accommodation


  • pupils dilate quickly after accommodation, but adies take ages to dilate 

Unequal pupils (Pane/Burden/Miller)


Do pupils react briskly?


Smaller pupil is abnormal.
Are the following present?

  • mild ptosis
  • dilation lag of the affected pupil in dark
  • anisocoria increased in dark

Larger pupil is abnormal

history of trauma, intraocular surgery (with iris damage visible on slit lamp)


possible Horner's
(?cocaine/apraclonidine test)

probably physiological likely traumatic no

are either of the following present

  1. ptosis on the side of the larger pupil
  2. diplopia or abnormal mobility?
    ?partial third nerve palsy

are both the following present?

  1. slow constriction to near?
  2. spiraling of the pupil on slit lamp exam
      arrow arrow
      yes no
      arrow arrow
      likely tonic pupil (Adies) Possible pharmacological dilation


Horner's tests (Pane/Burden/Miller)




site cocaine apraclonidine hydroxyamphetamine 1% phenylephrine
normal dilates no change dilates no change
central or preganglionic no/minor change dilates dilates no change
post-ganglionic no change dilates no change dilates


Pharmacologic and eye disease

  • many drugs dilate atrovent inhaler. Pilocaprine will constrict such a pupil and exclude 111n palsy
  • patient may have (?accidentally) instilled such drops
  • none-ophthalmologists should remember that many eye conditions cause unequal or unresponsive pupils: acute glaucoma. acute uveitis, chronic uveitis, surgery, trauma

Afferent..pupil response to light

  • even if there is an afferent defect there is no anisocoria
  • use a bight light in a dim rook and shine at fovea
  • swing the light from one eye to the other to identify an afferent defect
  • only need one working pupil
  • caused by optic nerve or severe retinal disease
  • animation (APD) .exe file  1 mb