**Core Concept:** Hypersecretory glaucoma is a subtype of open-angle glaucoma characterized by an excessively high intraocular pressure (IOP) due to increased aqueous humor production.

**Why the Correct Answer is Right:** Hypersecretory glaucoma is caused by an overproduction of aqueous humor, the clear fluid that fills the anterior chamber of the eye. This excess production leads to an elevated intraocular pressure, damaging the optic nerve and potentially causing vision loss if left untreated.

**Why Each Wrong Option is Incorrect:**
A. Primary open-angle glaucoma (POAG) is a different type of glaucoma characterized by an open angle between the cornea and the iris, not related to aqueous humor production.
B. Angle-closure glaucoma, also known as narrow-angle glaucoma, is caused by a narrowed angle between the cornea and iris, not due to excessive aqueous humor production.
C. Normal-tension glaucoma is a variant of POAG where intraocular pressure remains within the normal range, but optic nerve damage occurs due to other factors unrelated to aqueous humor production.
D. Trauma-induced glaucoma is caused by physical injury to the eye, not related to aqueous humor production.

**Clinical Pearl:** Hypersecretory glaucoma is a rare condition, often associated with medications or other systemic conditions, thereby increasing awareness of its existence and appropriate diagnosis is crucial to prevent irreversible vision loss.

**Correct Answer:** C. Normal-tension glaucoma (NTHG)

**Explanation:** Normal-tension glaucoma (NTHG) refers to POAG where intraocular pressure remains within the normal range (IOP between 10-21 mmHg), but optic nerve damage occurs due to other factors unrelated to aqueous humor production. NTHG is a subtype of POAG, and its diagnosis is essential for timely treatment and preservation of vision.