The only intact eye movement in one and a half syndrome is
One-and-a-half syndrome is due to a lesion of MLF combined with PPRF of same side. Loss of all horizontal movements except contralateral abduction, which shows abduction nystagmus. One and One half syndrome (right sided lesion) Eight and half syndrome consists of one and half syndrome with 7th nerve palsy.
Abduction of Ipsilateral eye
Abduction of contralateral eye
Adduction of Ipsilateral eye
Adduction of contralateral eye
Neuro Ophthalmology