**Core Concept**
Pigmentary glaucoma is a type of secondary glaucoma caused by the dispersion of pigment from the iris into the anterior chamber, leading to inflammation, trabecular meshwork obstruction, and increased intraocular pressure.

**Why the Correct Answer is Right**
The dispersion of pigment from the iris is often associated with conditions that cause iris instability, such as pigment dispersion syndrome. The pigment, primarily melanin, accumulates on the trabecular meshwork and surrounding structures, causing chronic inflammation and scarring. This leads to a decrease in aqueous outflow and a subsequent increase in intraocular pressure.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because pigmentary glaucoma is not typically associated with a sudden, severe increase in intraocular pressure, which is more characteristic of acute angle-closure glaucoma.

**Option B:** This option is incorrect because pigmentary glaucoma is not primarily caused by a blockage of the trabecular meshwork by blood or debris, which is more characteristic of traumatic or neoplastic glaucoma.

**Option C:** This option is incorrect because pigmentary glaucoma is not typically associated with a decrease in aqueous production, which is more characteristic of primary open-angle glaucoma.

**Clinical Pearl / High-Yield Fact**
Pigmentary glaucoma often presents with asymptomatic mild to moderate increases in intraocular pressure, which may be exacerbated by exercise or activities that increase intraocular pressure, such as bending or heavy lifting.

**Correct Answer:** C. Decreased outflow due to trabecular meshwork obstruction.