**Core Concept**
Glaucomatous optic atrophy is a progressive damage to the optic nerve, often due to elevated intraocular pressure (IOP) that causes retinal ganglion cell loss. This condition eventually leads to visual field defects and blindness.

**Why the Correct Answer is Right**
The retinal ganglion cells are the primary neurons affected in glaucomatous optic atrophy. These cells are responsible for transmitting visual information from the retina to the brain. Elevated IOP, typically greater than 21 mmHg, causes mechanical damage to these cells, leading to their degeneration and eventual loss.

**Why Each Wrong Option is Incorrect**
**Option A:**
The retinal pigment epithelium (RPE) is a layer of cells at the back of the retina, but it is not directly affected in glaucomatous optic atrophy. The RPE plays a crucial role in photoreceptor maintenance and vitamin A metabolism, but it is not the primary site of damage in glaucoma.

**Option B:**
The optic nerve itself is affected in glaucomatous optic atrophy, but the primary cells of concern are the retinal ganglion cells, not the glial cells. Glial cells, such as astrocytes and oligodendrocytes, provide support and maintenance functions to neurons, but they are not the primary site of damage in glaucoma.

**Option C:**
The retinal bipolar cells are involved in transmitting visual information from photoreceptors to ganglion cells, but they are not the primary cells affected in glaucomatous optic atrophy. The bipolar cells are more closely related to the visual pathway, but they are not the main site of damage in glaucoma.

**Clinical Pearl / High-Yield Fact**
In glaucomatous optic atrophy, the loss of retinal ganglion cells is often irreversible, making early detection and treatment crucial to prevent progression of the disease.

**Correct Answer: C. Retinal ganglion cells.**