A 51-year-old woman was seen in the neuro-ophthalmology clinic. She reported difficulties with night vision dating back to approximately age 10 and an abnormal gait since childhood, which was described as unsteady and hesitant with stiffness of both legs. Ten years previously she was noted to have nystagmus by her family practitioner and was referred to an ophthalmologist, who diagnosed her with probable retinitis pigmentosa (RP). At that time, visual evoked potentials showed delayed P100 responses bilaterally.