Diplopia, or double vision, is the perception of two images of a single object. This visual disturbance can be a troubling side effect of many different types of medications. The mechanisms vary widely, from impacting the intricate network of eye muscles to affecting the optic nerve or having an effect on the central nervous system. While some medication-induced diplopia is temporary and resolves when the drug is stopped, other cases can signify more serious, long-term issues.
Anticonvulsants and other neurological medications
Several medications used to manage neurological conditions like seizures and migraines are known to cause diplopia and other visual disturbances. These drugs often work by influencing nerve and muscle function, which can, at high doses, interfere with the coordinated movement of the eyes.
Notable examples from this category include:
- Topiramate (Topamax): Used for seizures and migraines, this medication can cause a range of eye complications, including diplopia, blurred vision, and even acute glaucoma.
- Carbamazepine: High doses of this anticonvulsant can lead to blurred vision, nystagmus (involuntary eye movements), and diplopia.
- Cenobamate (XCOPRI): This seizure medication lists double vision as a common side effect.
- Phenytoin (Dilantin): Another anticonvulsant, phenytoin, has been reported to cause nystagmus and diplopia, and acute visual loss in rare cases.
Antibiotics
Certain antibiotics, including some commonly prescribed for infections, have been linked to diplopia. The visual side effects often depend on the specific drug and dosage. The mechanism in some cases involves an effect on the tendons or muscles controlling eye movement, or an increase in intracranial pressure.
Examples of antibiotics affecting vision:
- Fluoroquinolones (e.g., Ciprofloxacin, Levofloxacin): Studies have linked this class of broad-spectrum antibiotics to cases of double vision, potentially due to tendinitis affecting the extraocular muscles.
- Tetracyclines (e.g., Doxycycline, Minocycline): Long-term use of these antibiotics can lead to idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, which can cause double vision and headaches due to increased pressure inside the skull.
- Azithromycin (Zithromax): Some case reports have noted rare occurrences of temporary diplopia with macrolide antibiotics like azithromycin.
Cardiovascular and cholesterol-lowering drugs
Medications used to treat heart conditions and manage cholesterol can also impact eye health, with diplopia being one possible side effect.
Cardiovascular and cholesterol drugs linked to diplopia:
- Amiodarone (Cordarone): This antiarrhythmic drug can cause corneal deposits and, more seriously, optic nerve damage, which can lead to vision changes including diplopia.
- Digoxin (Lanoxin): Used for various heart conditions, digoxin can cause visual disturbances including double vision, blurred vision, and a characteristic yellow-tinted vision.
- Statins (e.g., Atorvastatin, Simvastatin): While less common, some cholesterol-lowering medications can contribute to vision changes like double vision.
- Beta-blockers: Medications for high blood pressure, such as beta-blockers, can cause a range of visual side effects including blurred and double vision.
Psychiatric medications
Drugs affecting the central nervous system, including antidepressants and antipsychotics, can alter visual processing and eye muscle coordination.
Psychiatric drugs that may cause double vision:
- Antidepressants (e.g., Bupropion, Citalopram, SSRIs): Diplopia is a rare side effect, particularly with higher doses. Some effects may be related to central nervous system pathways.
- Benzodiazepines (e.g., Lorazepam, Alprazolam): These anti-anxiety drugs can cause diplopia, especially at higher doses, often linked to effects on eye movement and coordination.
- Antipsychotics (e.g., Chlorpromazine): Some antipsychotics can cause blurred vision and other eye movement disorders, which can lead to diplopia.
Other drug classes associated with diplopia
- Erectile Dysfunction Drugs (e.g., Sildenafil, Tadalafil): These drugs can cause visual side effects like color perception changes and blurred vision, and rarely, optic nerve damage that can present with diplopia.
- Osteoporosis Drugs (e.g., Alendronate): Bisphosphonates like alendronate can cause eye inflammation and subsequent visual disturbances, including double vision.
- Antihistamines (e.g., Diphenhydramine): Some antihistamines can cause dry eyes and dilated pupils, which may lead to visual disturbances.
- Corticosteroids (e.g., Prednisone): Long-term steroid use can cause cataracts and glaucoma, both of which can impact vision clarity and lead to diplopia.
When to see a doctor
Experiencing double vision can be disorienting and alarming. If you start a new medication and develop diplopia, it is crucial to consult your doctor or ophthalmologist immediately. They can help determine if the medication is the cause and recommend a dose adjustment or an alternative drug. It is important never to stop taking a prescribed medication abruptly without medical supervision, as this can have serious health consequences. In some cases, diplopia can signal a more serious underlying medical issue, such as a stroke, especially if it occurs suddenly and is accompanied by other neurological symptoms.
Comparing medication effects on vision
| Drug Class | Example Medications | How it can cause diplopia | Other Ocular Side Effects |
|---|---|---|---|
| Anticonvulsants | Topiramate, Carbamazepine, Cenobamate | Affects nerve signals and muscle coordination. | Blurred vision, nystagmus, acute glaucoma, fatigue |
| Antibiotics | Fluoroquinolones (Cipro), Tetracyclines | Tendon effects in eye muscles or increased intracranial pressure. | Light sensitivity, retinal detachment (rarely) |
| Cardiovascular Drugs | Amiodarone, Digoxin, Beta-blockers | Optic nerve toxicity, corneal deposits, effects on heart rhythm. | Corneal deposits, optic nerve damage, blurred vision |
| Psychiatric Drugs | Lorazepam, Bupropion, Chlorpromazine | Central nervous system effects impacting ocular motor function. | Dizziness, sedation, blurred vision |
| Erectile Dysfunction | Sildenafil (Viagra), Tadalafil (Cialis) | Optic nerve damage or color vision changes. | Blurred vision, light sensitivity, blue-tinged vision |
| Osteoporosis Drugs | Alendronate (Fosamax) | Eye inflammation affecting various parts of the eye. | Blurred vision, conjunctivitis |
Conclusion
Medication-induced diplopia is a significant but often treatable side effect that can arise from a wide range of drugs. By understanding which medications and drug classes are most likely to cause this condition, patients can be proactive in monitoring their health and communicating with their healthcare providers. A prompt and open discussion with a doctor or ophthalmologist is essential for proper diagnosis and management, ensuring a swift return to clear vision and preventing potential complications. The key takeaway is to never ignore a change in vision, especially when it coincides with starting or adjusting a new medication.
