title: Patterns of peripapillary retinal nerve fiber layer thinning in vigabatrin-exposed individuals.
abstract: OBJECTIVE
  To explore the relationship of peripapillary retinal nerve fiber layer (ppRNFL) thinning in individuals exposed to the antiepileptic drug vigabatrin with respect to 2 separate variables: cumulative vigabatrin exposure and severity of vigabatrin-associated visual field loss (VAVFL).
  
  
  METHODS
  Cross-sectional observational study.
  
  
  METHODS
  Subjects were older than 18 years, 129 with vigabatrin-treated epilepsy (vigabatrin-exposed group) and 87 individuals with epilepsy never treated with vigabatrin (nonexposed group).
  
  
  METHODS
  All subjects underwent ppRNFL imaging using spectral-domain optical coherence tomography. Eighty-four vigabatrin-exposed individuals underwent Goldmann kinetic perimetry. The visual field examined from the right eye was categorized as normal (n = 47), mildly abnormal (n = 18), or moderately to severely abnormal (n = 19). In 91 vigabatrin-exposed individuals, the cumulative vigabatrin exposure could be ascertained: 41 subjects received 1000 g or less, 23 subjects received more than 1000 g but equal to or less than 2500 g, 16 subjects received more than 2500 g but equal to or less than 5000 g or less, and 11 subjects received more than 5000 g.
  
  
  METHODS
  Differences in ppRNFL thickness across the twelve 30° sectors: (1) among all nonexposed individuals and all vigabatrin-exposed individuals, (2) between each vigabatrin-exposed group, according to cumulative vigabatrin exposure, and the nonexposed group, (3) among different vigabatrin-exposed subjects grouped according to cumulative vigabatrin exposure, and (4) among vigabatrin-exposed subjects grouped according to severity of VAVFL.
  
  
  RESULTS
  The ppRNFL was significantly thinner in vigabatrin-exposed compared with nonexposed individuals in most 30° sectors (P<0.004). The temporal, temporal superior, and temporal inferior 30° sectors, as well as the nasal 30° sector, were not affected. There was a trend for increasing ppRNFL thinning with increasing cumulative vigabatrin exposure. The nasal-superior 30° sector was significantly thinner in group 1 (≤1000 g) compared with nonexposed individuals (P<0.05) and in vigabatrin-exposed individuals with normal visual fields compared with nonexposed individuals (P<0.05).
  
  
  CONCLUSIONS
  After vigabatrin exposure in individuals receiving cumulative doses of 1000 g or less or in the presence of normal visual fields, ppRNFL thinning in the nasal superior 30° sector may occur. With higher cumulative doses of vigabatrin exposure, additional ppRNFL thinning was observed. The temporal aspects of the ppRNFL are spared, even in individuals with large cumulative vigabatrin exposures and moderate or severe VAVFL.
authors.affiliation: Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, London, United Kingdom.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Clayton
authors.forename: Marita
authors.initials: M
authors.lastname: Devile
authors.forename: Trusjen
authors.initials: T
authors.lastname: Punte
authors.forename: Gerrit-Jan
authors.initials: GJ
authors.lastname: de Haan
authors.forename: Josemir W
authors.initials: JW
authors.lastname: Sander
authors.forename: James F
authors.initials: JF
authors.lastname: Acheson
authors.forename: Sanjay M
authors.initials: SM
authors.lastname: Sisodiya
mesh_terms: D000328:Adult; D000927:Anticonvulsants / Q000009:adverse effects*; D003430:Cross-Sectional Studies; D004827:Epilepsy / Q000188:drug therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000187:drug effects / Q000473:pathology*; D009898:Optic Disk / Q000187:drug effects / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000139:chemically induced / Q000175:diagnosis*; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000473:pathology*; D041623:Tomography, Optical Coherence; D020888:Vigabatrin / Q000009:adverse effects*; D014786:Vision Disorders / Q000139:chemically induced / Q000175:diagnosis; D058609:Visual Field Tests; D014794:Visual Fields
chemical_list: D000927:Anticonvulsants; D020888:Vigabatrin