Pupillary abnormalities
Most cases in pupil examination are straight forward. Very often observation alone will give you the clue to the most likely diagnosis, for example in the absence of ptosis and anisocoria the most likely diagnosis is relative afferent pupillary defect. Whereas presence of ptosis suggests either Horner's (partial ptosis with constricted pupil best seen in dim light and possibly lighter iris in congenital cases) or third nerve palsy (presence of a more significant ptosis with larger pupil and ocular misalignment). Anisocoria in the absence of ptosis should suggests the possibility of Adie's pupil.

Other possible cases include Argyll-Robertson's pupils and light-near dissociation but they are not as commonly seen as the four cases above.

Extra points will be gained if you could volunteer to elicit further physical signs without prompting. For example:

      • optic disc atrophy or old scar from previous temporal artery biopsy in a patient with relative afferent pupillary defect
      • neck scar in patient with Horner's syndrome
      • presence of neurosurgical scar in patients with third nerve palsy
      • absence ankle or knee jerk in Adie's pupil
Also remember to:
      • learn the differential diagnosis of a relative afferent pupillary defect,  unilateral large /  small pupil and  light/near dissociation
      • memorize the pharmacological testings for anisocoria
a
Click here to return to the main page