Digoxin is used to treat Congestive Heart Failure. Which of the following is NOT a side effect associated with Digoxin?

• A. Retrobulbar optic neuritis
• B. Bull's eye maculopathy
• C. Blue/Yellow color defects
• D. Entoptic phenomenon

Answer: (B)

Ocular effects from digoxin are most characteristically color-vision disturbances, especially xanthopsia (yellow vision), and other color perception changes or blurred vision with toxicity. Bull's eye maculopathy, on the other hand, is a classic finding linked to chloroquine/hydroxychloroquine toxicity, not digoxin. So this option represents a side effect not associated with digoxin, making it the best choice for what is NOT a digoxin-related side effect. The other visual symptoms listed can occur with various ocular or retinal issues and aren’t the iconic digoxin toxicity signs, but the well-established digoxin-related visual change is yellow vision rather than a bull’s-eye maculopathy.