We studied the prevalence, type and severity of vigabatrin (VGB)-attributed visual field defects (VFDs), and used these data to assess the associated risk factors in pediatric patients. Medical records were retrospectively reviewed for 67 pediatric patients who received VGB alone or in combination with other antiepileptic drugs, and who had undergone visual field examinations using a Humphrey visual field analyzer. Of the 67 patients, 15 had VGB-attributed VFDs: 13 had nasal arcuate type, 1 had nasal and temporal constricted type and 1 had nasal constricted type. In terms of severity, 7 patients had Grade I VGB-attributed VFDs, 5 had Grade II, 2 had Grade III, and 1 had Grade IV. Although there were no significant differences between the VFD and non-VFD groups with regards to all tested parameters, there were no cases of VGB-attributed VFDs in patients with total treatment durations <2 yr and cumulative doses <10 g/kg. In conclusion, the prevalence of VGB-attributed VFDs in VGB-treated pediatric epilepsy patients was 22%. The high frequency of VGB-attributed VFDs indicates that physicians should inform all patients of this risk prior to VGB treatment and perform periodic visual field examinations.
Visual Fields/drug effects ; Vision Disorders/*chemically induced ; Vigabatrin/adverse effects/*therapeutic use ; Time Factors ; Risk Factors ; Retrospective Studies ; Male ; Humans ; Female ; Epilepsy/*drug therapy ; Drug Therapy, Combination ; Drug Monitoring/statistics & numerical data ; Child ; Anticonvulsants/adverse effects/*therapeutic use ; Adult

The methanol poisoning by oral intake or skin contact occurs occasionally, which may have serious consequences including blindness and/or death. Methanol and its metabolites, formaldehyde and formic acid, are associated with metabolic acidosis, visual dysfunction and neurological symptoms. At present, the mechanism of methanol poisoning primarily focuses on the cell hypoxia, the alteration of structure and biological activity induced by free radical and lactic acid. Meanwhile, methanol poisoning causes changes in the balance between the production of free radicals and antioxidant capacity and in the proteases-protease inhibitors system, which lead to a series of disturbances.
Acidosis/chemically induced* ; Animals ; Formaldehyde/poisoning* ; Formates/poisoning* ; Free Radicals/metabolism* ; Humans ; Methanol/poisoning* ; Nervous System/pathology* ; Oxidoreductases Acting on CH-NH Group Donors/metabolism* ; Proteins/metabolism* ; Vision Disorders/pathology*