Involuntary oscillations of the eyes (nystagmus) impairs vision so that affected patients, who have neurological disorders such as Multiple Sclerosis (MS) , cannot read or watch TV. Two medicines have been reported to suppress nystagmus and improve vision in such patients: gabapentin and memantine. The investigators set out to test which of these two drug was more effective by carrying out a double-blind cross-over study. In this way, we could determine which drug worked best in each patient.
The study entails careful measurements of visual acuity and precise measurements of eye movements, using a contact lens device (magnetic search coil method). In this way, it is possible to make objective and reliable measurements of the effect of each drug, which are unbiased by the investigator or the patient.
Adult (18 years or older) males or females with acquired nystagmus that is degrading their vision
Exclusion Criteria:
Pregnant women Individuals who cannot describe their visual symptoms, cooperate with testing, or give informed consent Individuals with intolerance of gabapentin or memantine
