Ocular abnormalities in amyotrophic lateral sclerosis.

It has long been known that the oculomotor system is not involved in amyotrophic lateral sclerosis (ALS). In early stages. Some authors suggest oculomotor abnormalities in some patients. In the present study, quantitative analysis of ocular movements including smooth pursuit eye movements, optokinetic nystagmus (OKN), visual suppression of vestibular nystagmus (VS), and horizontal saccades were investigated in 9 patients with ALS. These patients were neurologically diagnosed as having ALS in the early stage. The results were as follows: The velocity of saccade was markedly reduced in 4 patients. In addition, there were abnormalities of smooth pursuit (one patient), OKN (one patient) and visual suppression (2 patients). Furthermore, these abnormalities were observed more often in patients with bulbar signs. In conclusion, the results suggest a existence of ocular abnormalities in ALS, even at early stages.