QS Study

Argyll-Robertson Pupil

It is the condition in which light reflex is lost but accommodation reflex is intact. The size of the pupil is dictated by an interaction of sympathetic and parasympathetic nervous systems, which are involved in the constriction and dilation of the iris.

The pupil will respond to light through what is called a direct light reflex, and to some extent, it will respond to near somewhere to live. When there are interruptions of the elements of the pathways, it could result in the poor constraint of the pupil.

Causes: Syphilis is the most related cause for this occurrence, but there are other probable causes such as diabetes and alcoholism.

  • Diabetic pseudorabies
  • Neurosyphilis.

Fig: Argyll-Robertson Pupil


An absence of light reflex, Small irregular pupils, unequally sized pupils, Iris atrophy, Depigmentation, Loss of ciliospinal reflex etc.

The site of lesion:

  • Pretectum of the midbrain.
  • 3rd (oculomotor) nerve nucleus.