Assessment of colour vision in epileptic patients exposed to single-drug therapy.
Diplopia, blurred vision and colour disturbances are well-known side effects associated with anti-epileptic drugs (AEDs). Farnsworth-Munsell 100-hue colour test (F-100) is an accepted and sensitive tool to detect changes in colour perception. To determine the impact of AEDs upon colour vision, we evaluated 37 consecutive patients with complex partial seizures exposed to monotherapy with phenytoin (PHT, carbamazepine (CBZ) or valproic acid (VPA). All had normal IQ and no congenital disturbances in colour vision or ocular diseases. Twenty normal controls were used for statistical analysis. Thirteen patients were exposed to PHT, 12 to CBZ and 12 to VPA. Visual colour perception was impaired in 30/37 (82%) of the study group. The most significant abnormality was detected in the blue-yellow axis in 10/13 patients exposed to PHT (p < 0.02) and in 8/12 treated with CBZ (p < 0.009). In 8/12 patients taking VPA, no significant abnormality was observed (p < 0.06). None of the studied patients complained of colour vision disturbances. Our findings strongly support the negative effect of AEDs upon colour vision discrimination, most likely due to changes at the retinal processing level. F-100 proved to be very useful to assess early toxicity due to AEDs.
López
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L
Neurology Department, Raúl Carrea Institute for Neurological Research, British Hospital, Buenos Aires, Argentina. llopez@roche.com .ar
Thomson
A
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Rabinowicz
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D000293:Adolescent; D000328:Adult; D000368:Aged; D000927:Anticonvulsants / Q000009:adverse effects* / Q000097:blood; D002220:Carbamazepine / Q000009:adverse effects* / Q000097:blood; D003118:Color Perception / Q000187:drug effects*; D003117:Color Vision Defects / Q000139:chemically induced* / Q000175:diagnosis*; D004172:Diplopia / Q000139:chemically induced* / Q000175:diagnosis*; D017029:Epilepsy, Complex Partial / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010672:Phenytoin / Q000009:adverse effects* / Q000097:blood; D012720:Severity of Illness Index; D016037:Single-Blind Method; D014635:Valproic Acid / Q000009:adverse effects* / Q000097:blood
D000927:Anticonvulsants; D002220:Carbamazepine; D014635:Valproic Acid; D010672:Phenytoin