Question

What does loss of the pupillary light reflex indicate? Explain what is occurring when unilateral loss becomes bilateral loss?

Answer 1

Main role of pupillary light reflex is to control diameter of the pupil, with change in light intensity. This helps the person adjust vision with change in light or darkness. Loss of pupillary light reflex will result in no response of pupil to light i.e. no constriction in bright light.

When there is loss of left pupillary light reflex, the right eye would constrict in light but left wouldn’t. However, when the loss is bilateral, both eyes can’t respond to change in light intensity. This would significantly diminish resolution of images formed on retina when light intensity is too bright or less.