**Core Concept:** Angle recession glaucoma is a type of primary open-angle glaucoma where there is a decrease in the anterior chamber angle, leading to an impaired outflow of aqueous humor and increased intraocular pressure. In this case, the trabecular meshwork and the uveoscleral outflow pathways are affected, causing the characteristic damage to the optic nerve and visual field defects.

**Why the Correct Answer is Right:** The correct answer, **D**, refers to the concept that angle recession glaucoma is a secondary cause of glaucoma. This type is typically associated with other ocular or systemic conditions, such as inflammatory diseases, trauma, or surgery. In contrast, the question is asking about true characteristics of primary open-angle glaucoma, not those secondary causes.

**Why Each Wrong Option is Incorrect:**

**A:** False - Angle recession glaucoma is a type of primary open-angle glaucoma, not a secondary cause. It is characterized by a decreased anterior chamber angle, leading to impaired outflow and increased intraocular pressure.

**B:** False - Angle recession glaucoma is a primary cause of glaucoma, not a secondary cause. It is related to a decreased anterior chamber angle and impaired aqueous humor outflow.

**C:** False - Angle recession glaucoma is a primary cause of glaucoma, not a characteristic of secondary causes. It involves a decreased anterior chamber angle and impaired aqueous humor outflow, leading to increased intraocular pressure.

**Clinical Pearl:** It is essential for medical students and healthcare professionals to differentiate between primary and secondary glaucoma, as this understanding influences diagnosis, management, and prognosis. A thorough history, examination, and appropriate investigations are necessary for accurate diagnosis and appropriate treatment of glaucoma cases.