**Core Concept**
Betaxolol is a selective beta-1 adrenergic receptor blocker that is used topically in the treatment of glaucoma. Its prolonged duration of action makes it an effective option for managing intraocular pressure.

**Why the Correct Answer is Right**
Betaxolol has a longer duration of action compared to other beta-blockers due to its high lipophilicity, which allows it to penetrate the cornea and bind to beta-1 receptors in the ciliary body. This binding prevents the release of aqueous humor, thereby reducing intraocular pressure. Betaxolol's selective beta-1 activity also minimizes systemic side effects, making it a preferred choice for ocular use.

**Why Each Wrong Option is Incorrect**
**Option B:** Timolol is a non-selective beta-blocker with a shorter duration of action compared to betaxolol. Although it is commonly used in glaucoma treatment, its non-selective activity can lead to systemic side effects.
**Option C:** Carteolol is a non-selective beta-blocker with intrinsic sympathomimetic activity, which allows it to stimulate beta-2 receptors and increase heart rate. Its pharmacological profile is not as favorable as betaxolol for ocular use.
**Option D:** Metoprolol is a selective beta-1 blocker, but it is primarily used orally for systemic hypertension and heart failure. Its pharmacokinetic properties are not suitable for ocular administration.

**Clinical Pearl / High-Yield Fact**
When choosing an ocular beta-blocker, it's essential to consider the patient's systemic cardiovascular status. Selective beta-1 blockers like betaxolol are generally safer for patients with asthma or chronic obstructive pulmonary disease (COPD), as they are less likely to cause bronchoconstriction.

✓ Correct Answer: A. Betaxolol.