## Core Concept
Vigabatrin is an antiepileptic medication that works by inhibiting the action of **gamma-aminobutyric acid transaminase (GABA-T)**, the enzyme responsible for the breakdown of **gamma-aminobutyric acid (GABA)**, an inhibitory neurotransmitter in the brain. By preventing GABA degradation, vigabatrin increases GABA levels, which helps to reduce neuronal excitability and prevent seizures.

## Why the Correct Answer is Right
The correct mechanism of action of vigabatrin involves the selective and irreversible inhibition of **GABA-T**. This results in an increase in the concentration of **GABA** in the brain, enhancing inhibitory neurotransmission and contributing to its antiepileptic effects. This action is specific to vigabatrin and distinguishes it from other antiepileptic drugs.

## Why Each Wrong Option is Incorrect
- **Option A:** Incorrect because it does not accurately describe the mechanism of action of vigabatrin.
- **Option B:** Incorrect as it does not relate to the known effects or mechanism of vigabatrin.
- **Option C:** This option is not provided, but based on the structure, it would be incorrect for similar reasons as A and B.
- **Option D:** Incorrect because, although not specified, any other mechanism not involving **GABA-T** inhibition would be incorrect.

## Clinical Pearl / High-Yield Fact
A significant clinical pearl regarding vigabatrin is its association with **permanent vision loss** (bilateral concentric visual field constriction) and **visual impairment**. This side effect is rare but significant, necessitating careful monitoring and discussion of risks with patients.

## Correct Answer Line
**Correct Answer: D.**