What is glaucoma always due to in the most basic terms?

• A. Increased production of aqueous humor
• B. Obstruction of lens capsule
• C. Decreased tear production
• D. IMPAIRED OUTFLOW of aqueous humor

Answer: (D)

Glaucoma is driven by impaired drainage of aqueous humor, which raises intraocular pressure and damages the optic nerve. Aqueous humor is produced by the ciliary body, flows into the anterior chamber, and normally exits mainly through the trabecular meshwork into Schlemm's canal (with a secondary route via the uveoscleral pathway). When outflow is hindered—whether the drainage pathways become resistant in open-angle glaucoma or are physically blocked in angle-closure glaucoma—pressure climbs. The crucial idea is the resistance to outflow, not how much fluid is produced. Increased production of aqueous humor is not the typical cause, and decreased tear production or obstruction of the lens capsule are unrelated to the core mechanism.