New insights into amiodarone induced retinal and optic nerve toxicity: functional and structural changes

Area of Science:

• Ophthalmology
• Cardiology
• Neuroscience

Background:

• Amiodarone is a common antiarrhythmic drug for cardiac arrhythmias.
• Previous research suggests a potential link between chronic amiodarone use and optic neuropathy.
• The current study investigates subclinical ocular effects of amiodarone.

Purpose of the Study:

• To detect subtle structural or functional alterations in the retina and optic nerve.
• To evaluate patients on long-term amiodarone therapy who have no visual complaints.
• To compare ocular findings in amiodarone users with a healthy control group.

Main Methods:

• An observational study involving 15 patients on chronic amiodarone and 15 healthy controls.
• Electrophysiological testing included pattern visual evoked potential (PVEP), pattern electroretinogram (PERG), and multifocal electroretinogram (mfERG).
• Optical coherence tomography (OCT) and OCT angiography (OCTA) were performed to assess retinal and optic nerve structure.

Main Results:

• No significant differences were found in PVEP, PERG, or mfERG between the amiodarone and control groups.
• OCT and OCTA revealed no significant structural or functional changes in the macula or optic nerve head.
• Minor statistically significant differences were noted in optic disc morphology, specifically cup/disc ratio and rim area.

Conclusions:

• Chronic amiodarone therapy, in the absence of visual symptoms, did not lead to evident structural or functional changes in the retina or optic nerve.
• Electrophysiological tests and advanced imaging (OCT, OCTA) did not reveal significant ocular toxicity.
• The subtle optic disc changes warrant further investigation but do not indicate significant visual impairment.