Is Double Vision a Side Effect of Medium/High Dose Ivermectin Use?
Yes, double vision (diplopia) can occur as a neurologic manifestation of ivermectin toxicity, particularly at supratherapeutic doses, though it is not among the most commonly reported visual symptoms.
Evidence for Visual Disturbances with Ivermectin
The available evidence demonstrates that ivermectin toxicity primarily manifests with neurotoxicity rather than diplopia specifically:
- Neurotoxicity is the predominant clinical effect in ivermectin overdose, occurring in 81% (30 of 37 cases) of patients who required healthcare visits for ivermectin toxicity during the COVID-19 pandemic 1
- Patients taking veterinary formulations at higher doses developed more severe altered mental status compared to those taking prescription tablets 1
- Visual hallucinations have been documented as a neurologic manifestation of supratherapeutic ivermectin doses 2
Specific Visual Complaints Documented
The most robust evidence for ivermectin-related visual problems comes from controlled trials:
- Transitory subjective visual problems were significantly more frequent in groups treated with high doses (800 mcg/kg) compared to standard doses (150 mcg/kg annually) 3
- These visual complaints were of an unexpected type and could not be fully explained by ophthalmological examination findings 3
- Bilateral blindness has been reported in severe post-ivermectin encephalopathy, though this represents an extreme complication 4
Why Diplopia Is Not Prominently Featured
The literature does not specifically identify diplopia as a characteristic feature of ivermectin toxicity, unlike the well-documented diplopia associated with other medications 5. The visual disturbances reported with ivermectin appear to be:
- Non-specific and transitory in nature 3
- More likely related to central nervous system effects (altered mental status, visual hallucinations) rather than extraocular muscle dysfunction 1, 2
- Associated with inflammatory processes in severe encephalopathy cases 4
Clinical Context and Dosing Patterns
Toxicity patterns differ based on formulation and dosing:
- Acute toxicity from veterinary formulations involves large single doses causing rapid-onset neurotoxicity 1
- Chronic toxicity from smaller daily doses (median 13.5 mg) over prolonged periods (median 3.8 weeks) produces milder symptoms 1
- Patients developing toxicity were predominantly male, over 60 years old, taking higher than recommended doses 1
Clinical Recommendation
If a patient reports double vision while taking medium to high doses of ivermectin, consider it a potential neurologic manifestation of toxicity requiring immediate evaluation, though diplopia is not a hallmark feature. The more characteristic presentations include altered mental status, confusion, and non-specific visual disturbances rather than true binocular diplopia 1, 3, 2. Discontinue ivermectin and evaluate for other causes of diplopia using standard ophthalmologic assessment, as the strabismus guidelines emphasize numerous other etiologies that are far more common 6.