Bimatoprost, a prostaglandin analogue used for glaucoma, primarily reduces intraocular pressure by:
- A Reducing aqueous humor production by ciliary body epithelium
- B Increasing uveoscleral (unconventional) outflow via FP receptor-mediated remodeling of ciliary muscle extracellular matrix ✓
- C Increasing trabecular meshwork outflow (conventional pathway) only
- D Reducing episcleral venous pressure
Correct answer: B. Increasing uveoscleral (unconventional) outflow via FP receptor-mediated remodeling of ciliary muscle extracellular matrix
Explanation
Prostaglandin analogues (latanoprost, bimatoprost, travoprost) lower IOP primarily by increasing uveoscleral (unconventional) outflow. They act on FP (prostanoid) receptors in the ciliary muscle, stimulating remodeling of the extracellular matrix (decreased collagen and increased MMP expression), which widens the spaces in the ciliary muscle and enhances uveoscleral drainage. They do not reduce aqueous production (unlike beta-blockers) or primarily increase trabecular outflow.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.