Amiodarone and optic neuropathy.
OBJECTIVE
To investigate the clinical, perimetric, contrast sensitivity and visual evoked potentials findings in patients on longterm treatment with amiodarone.


METHODS
We enrolled 14 patients (age range 47-78 years, mean age 62.7 years) on chronic amiodarone therapy (mean cumulative dose of 519 g), and 14 age-matched control subjects. Participants were submitted to ophthalmological examination, kinetic visual field testing (Goldmann), standard achromatic automated perimetry (central 30-2, Humphrey), computerized isoluminant chromatic contrast sensitivity (CCS) and pattern visual evoked potentials evaluation (VEP). Data from baseline, 6-month and 1-year follow-up examinations were analysed. The main outcome measures were: initial and final corrected visual acuity; corneal, optic disc and fundus abnormalities; mean deviation (MD) and pattern standard deviation (PSD) central 30-2 perimetry parameters; visual field loss on kinetic perimetry; indices of CCS (tritan, protan and deutan axes), and pattern VEP latency (L-VEP) and VEP amplitude (a-VEP).


RESULTS
We found a statistically significant difference between the patients and controls' baseline L-VEP and a-VEP measurements (p < 0.001). We found no significant correlation between prolonged L-VEP and duration of amiodarone use (r = 0.07). After a 1-year follow-up, we evidenced an average increment in L-VEP of 1.96 ms and a-VEP measurements showed a decline of 0.69 micro V. In cumulative dose-specific analyses, mean differences between baseline and 12-month L-VEP measurements were more evident in those taking higher than 200 g cumulative amiodarone doses (p = 0.03). We found abnormal tritan CCS results in 19 eyes (68%). Of these, four eyes belonged to patients with no ocular disease (diabetes, cataracts). No significant differences were observed between the baseline and 12-month clinical eye examinations, central 30-2 perimetry and CCS results.


CONCLUSIONS
We found a significant prolongation in pattern L-VEP and a significant reduction in pattern a-VEP in patients on longterm treatment with amiodarone compared to control subjects. Nevertheless, current data are insufficient to recommend appropriate methods of visual screening.
Domingues
M F
MF
Ophthalmology Department, Hospital São João, University of Porto Medical School, Porto, Portugal. mfdomingues@netcabo.pt
Barros
H
H
Falcão-Reis
F M
FM
D000368:Aged; D000638:Amiodarone / Q000009:adverse effects*; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects*; D016022:Case-Control Studies; D015350:Contrast Sensitivity / Q000187:drug effects; D005074:Evoked Potentials, Visual / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009901:Optic Nerve Diseases / Q000139:chemically induced* / Q000175:diagnosis; D014786:Vision Disorders / Q000139:chemically induced / Q000175:diagnosis; D015351:Vision Screening / Q000379:methods; D014792:Visual Acuity / Q000187:drug effects; D058609:Visual Field Tests; D014794:Visual Fields / Q000187:drug effects
D000889:Anti-Arrhythmia Agents; D000638:Amiodarone