Article 4 Pathway Differences in the Amblyopic Brain: A Review Based upon Pupillary Reflex Studies

Amblyopia is much more than decreased vision, it is a syndrome. The variety of deficits is a result of structural and functional differences in the visual pathway from the retina to the cortex. Historically, it was thought that amblyopia did not cause a relative afferent pupillary defect, but recent studies suggest otherwise. Research into the thalamic and cortical influences on the pupillary pathway has provided insight into some of the differences that occur in the amblyopic brain. Current research has cast light onto the complexity of the pupillary pathway, yet the exact mechanism is unknown. The neurological changes, which have long explained the visual deficits of amblyopia, may now also explain associated abnormal pupillary reactions. However, similar to some of the visual deficits of amblyopia, pupillary abnormalities have also been shown to be reversible with amblyopia treatment. This paper reviews research illustrating the increased awareness of pupillary involvement in those with amblyopia and the associated potential impact on optometric treatment of amblyopia.