Impaired saccadic eye movement in diabetic patients: the relationship with visual pathways function.

The aim of this study was to evaluate whether a correlation existed between saccadic eye movements and visual pathways function in diabetic patients. Saccadic or fast Eye Movement System (EMS) and Visual Evoked Potentials (VEPs) were assessed in 20 insulin-dependent diabetic mellitus (IDDM) patients without long-term complications and in stable metabolic control and in 21 age-matched control subjects. In IDDM patients we observed significantly (p<0.01) longer EMS latency, while EMS velocity and accuracy were similar to those of controls; VEPs showed a significant delay in N75, P100, N145 latencies and significant reduction of N75-P100 and P100-N145 amplitudes. In IDDM patients no relationships between EMS and VEP parameters were found. In conclusion, EMS latency delay suggests an impairment of the saccadic eye movement system, while impaired VEPs may be ascribed to a dysfunction of the visual pathways. The lack of correlation between VEPs impairment and EMS latency delay suggests that in our IDDM patients the delay of saccadic latency cannot be exclusively related to a visual pathways dysfunction and could be ascribed to a diffuse neuronal involvement.