Differentiating between the complete optic tract lesion vs. Complete lesion of the right visual radiations (5+6 together)
Differentiating between the complete optic tract lesion that also results in left homonymous hemianopia vs. Complete lesion of the right visual radiations (5+6 together) which will also result in left homonymous hemianopia (not shown in the image)
Recall if there is a optic tract lesion it would present as slightly suppressed pupillary light reflex because the optic tract has optic nerve fibers that in addition to synapsing in LGB are also projecting to the pretectal area. On the contrary, patient with optic radiations lesion there will be no affect on the pupillary light reflex with homonymous hemianopia.