Reversible blindness in a patient with closantel toxicity

Area of Science:

• Ophthalmology
• Toxicology
• Neuroscience

Background:

• Closantel, an anthelmintic drug, can cause ocular toxicity.
• Ocular toxicity from closantel is rare and not well-documented.
• Understanding the ocular effects of closantel is crucial for diagnosis and management.

Observation:

• A 25-year-old patient experienced sudden, painless vision loss after ingesting closantel.
• Ophthalmic examination revealed significantly reduced visual acuity (counting fingers at 5m).
• Optical coherence tomography (OCT) showed outer retinal layer disruption, and electroretinogram (ERG) and visual evoked potential (VEP) tests indicated subnormal responses.

Findings:

• Systemic corticosteroid treatment led to a marked improvement in visual acuity to 6/9.
• Post-treatment OCT scans demonstrated preservation of central outer retinal layers.
• ERG and VEP responses showed significant improvement following corticosteroid therapy.

Implications:

• This case highlights the potential for reversible blindness due to closantel toxicity.
• Systemic corticosteroids may be an effective treatment for closantel-induced ocular toxicity.
• Early diagnosis and intervention are key to restoring vision in such cases.