Patients treated with vigabatrin exhibit central visual function loss.
OBJECTIVE
To investigate visual function in the central 10 degrees in patients who have undergone vigabatrin (VGB) antiepileptic drug (AED) therapy with the aim of identifying a clinical regimen for assessing central visual function.


METHODS
The sample comprised 12 epilepsy patients (mean age, 38.6 +/- 11.7 years) who had been treated with VGB (either as monotherapy or polytherapy). A number of central visual-function tests were carried out for each eye, including high-contrast LogMAR visual acuity, short-wavelength automated perimetry (SWAP 10-2), spatial contrast sensitivity (CSV-1000), and Farnsworth-Munsell (FM) 100-hue colour discrimination.


RESULTS
The group mean cumulative VGB dose was 5,086 +/- 3,245 g. The average SWAP 10-2 mean deviation (MD) for the group was -3.24 +/- 3.23 dB; 14 eyes of eight patients showed defects (range, -1.62 to -9.46 dB). The square root of the group mean total error score for FM 100-hue was 7.42 +/- 3.84; nine eyes of five patients were classified as abnormal with an unsolved colour axis suggestive of complex drug interactions. For contrast sensitivity, 15 eyes of eight patients yielded abnormal results in one or more spatial frequencies. Defects were more prominent at higher spatial frequencies. Overall, four patients had defects in all three visual-function tests, six patients had mixed defects, and two patients were normal.


CONCLUSIONS
Visual-function deficits in epilepsy patients treated with VGB are present in the central 10 degrees of the retina. We recommend a battery of investigations, including SWAP 10-2 and spatial contrast sensitivity testing, to assess central visual function.
Hilton
Emma J Roff
EJ
Neurosciences Research Institute, Aston University, and Queen Elizabeth Psychiatric Hospital, Birmingham, United Kingdom.
Cubbidge
Robert P
RP
Hosking
Sarah L
SL
Betts
Tim
T
Comaish
Ian F
IF
D000328:Adult; D000927:Anticonvulsants / Q000009:adverse effects*; D015331:Cohort Studies; D003118:Color Perception / Q000187:drug effects; D015350:Contrast Sensitivity / Q000187:drug effects; D004192:Discrimination, Psychological / Q000187:drug effects; D006801:Humans; D020888:Vigabatrin / Q000009:adverse effects*; D014786:Vision Disorders / Q000139:chemically induced* / Q000503:physiopathology; D014785:Vision, Ocular / Q000187:drug effects; D014792:Visual Acuity / Q000187:drug effects; D058609:Visual Field Tests; D014794:Visual Fields / Q000187:drug effects
D000927:Anticonvulsants; D020888:Vigabatrin