Visual changes secondary to initiation of amiodarone: a case report and review involving ocular management in cardiac polypharmacy.
BACKGROUND: Amiodarone is a benzofuran derivative used to treat cardiac arrhythmias. The most-common ocular symptom is colored rings around lights. Common ocular findings include comeal micro-deposits and lens opacities. An amiodarone optic neuropathy has been described. Digoxin is a cardiac glycoside used to treat cardiac arrhythmias and heart failure. It is known to cause dyschromatopsia, visual disturbances, and visual-field defects. Digoxin serum levels and toxicity risks increase with the addition of amiodarone. CASE REPORT: Soon after initiation of amiodarone HCl (200 mg/day), a 76-year-old man came to us with symptoms of visual "shining," glare, color vision anomalies, and gradually decreased vision. Best-corrected visual acuity was 20/50 O.D. and 20/60 O.S. Ishihara color plates showed a marked, acquired color vision defect O.D., O.S. Biomicroscopy revealed amiodarone corneal deposits. The optic nerve appeared healthy, with no visible swelling in each eye. Amiodarone was discontinued after discussion with the cardiologist. On followup, the patient reported disappearance of symptoms. Visual acuity had improved to 20/30(+2) O.D. and 20/30 O.S. Ishihara color plates showed normal color vision. CONCLUSIONS: As the elderly population and the incidence of heart disease increase in the United States, more people will probably be using heart drug therapy. Our case presents some of the challenges involved with managing ocular toxicity of these cardiac drugs. While both amiodarone and digoxin can cause permanent visual changes, the ocular effects are often reversible. Therefore, ocular examination at baseline and every 6 months is indicated for patients receiving a regimen of amiodarone and/or digoxin therapy.