examination (pupils)

Last reviewed 01/2018

Pupils should be circular, central and equal in size. They should constrict to light and accommodation equally.

There are four steps in the examination of the pupils:

• inspection:
• look for irregularity, inequality in size or eccentricity

• light reaction:
• with one eye shielded from a pen torch beam observe the constriction of the illuminated pupil (the direct response) and the constriction in the shielded pupil (the consensual response)

• swinging light test:
• the pen torch beam should be passed rapidly from one eye to the other
• the normal response is sustained constriction of both pupils
• if one pupil dilates upon illumination there is an relative afferent pupillary defect (Marcus Gunn pupil) in that eye
• this is a simple test of optic nerve function

• accomodation reflex:
• the patient is asked to look at a distant object and then at an object close to his face
• both pupils should constrict and dilate again when distant gaze is resumed