**Core Concept**
Lanatoprost is a prostaglandin analog used in the management of glaucoma, a group of eye conditions characterized by increased intraocular pressure (IOP). The goal of glaucoma treatment is to reduce IOP to prevent optic nerve damage and vision loss. The mode of action of glaucoma medications involves either decreasing aqueous humor production or increasing its outflow.

**Why the Correct Answer is Right**
Lanatoprost works by increasing the uveoscleral outflow of aqueous humor. This is achieved through its action on the prostaglandin F2α receptor (PGF2α receptor), which is present in the ciliary body of the eye. Activation of this receptor leads to relaxation of the ciliary muscle and increased permeability of the uveoscleral pathway, resulting in increased outflow of aqueous humor. This mechanism is distinct from other glaucoma medications that increase trabecular outflow or decrease aqueous humor production.

**Why Each Wrong Option is Incorrect**
**Option A:** Increasing trabecular outflow is the mechanism of action of medications like latanoprost's close analog, Bimatoprost, but not Lanatoprost itself.

**Option B:** Releasing pupillary block is a mechanism associated with iridotomy procedures, not topical glaucoma medications like Lanatoprost.

**Option C:** Decreasing aqueous humour formation is the mechanism of action of medications like beta-blockers (e.g., Timolol) and carbonic anhydrase inhibitors (e.g., Acetazolamide), not Lanatoprost.

**Clinical Pearl / High-Yield Fact**
Lanatoprost is a member of the prostaglandin analog class of glaucoma medications, which are often associated with changes in iris pigmentation, particularly in patients with darker irises. This is an important consideration when prescribing these medications.

**✓ Correct Answer: D. Increasing uveoscleral outflow**