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Ocular Hypotonia and Transient Decrease of Vision as a Consequence of Exposure to a Common Toad Poison.
Renato Pejic1, Marija Simic Prskalo1, Josip Simic2
1University Clinical Hospital Mostar, Department of Ophthalmology, Bosnia and Herzegovina.
Case Reports in Ophthalmological Medicine
|February 5, 2020
Summary
Toad venom (bufotoxin) can cause sudden vision loss by inhibiting Na+/K+-ATPase in the eye. This case report details a patient
Area of Science:
- Ophthalmology
- Toxicology
- Pharmacology
Background:
- Common toads produce bufotoxin, a potent Na+/K+-ATPase inhibitor.
- Bufotoxin's physiological effects mimic digitalis, impacting heart rate and muscle contractions.
- Ocular toxicity from bufotoxin exposure is rarely described.
Observation:
- A 67-year-old female presented with sudden vision loss and eye burning after toad poison exposure.
- Examination revealed conjunctival hyperemia and ocular hypotonia.
- Topical antibiotic treatment led to remission of corneal edema and ocular hypotonia within 24 hours.
Findings:
- Bufotoxin inhibits Na+/K+-ATPase, crucial for corneal endothelial cells, ciliary body, and iris.
- Inhibition disrupts corneal function, causing vision decrease and ocular hypotonia.
- Bufadienolides demonstrate potent and rapid effects in lowering ocular pressure.
Implications:
- This case highlights a rare ocular effect of bufotoxin.
- Toad venom's potential for developing ocular hypotensive agents warrants further research.
- Understanding bufotoxin's mechanism may inform treatments for certain eye conditions.
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