A Study of the Structure and Function of the Retina in Adult Patients With Refractory Complex Partial Seizures Treated With Vigabatrin (Sabril®)

Multicenter, prospective open-label study with approximately 25 sites in the US that specialize in caring for adult patients with refractory CPS * Sites must have access to Humphrey static perimetry and to Spectralis SD-OCT. * All vision test results will be sent to the central readers for evaluation. * Additional study tests: * The Columbia Suicide Severity Rating Scale (C-SSRS) * The National Eye Institute Visual Field Questionnaire-39 (NEI VFQ-39) * A whole blood sample for specific analysis of DNA characteristics * An optional whole blood sample for exploratory analysis of DNA characteristics * Plasma samples for bioanalytical analysis of vigabatrin and blood samples for taurine biomarker analysis