**Core Concept**
Chronic simple glaucoma, also known as open-angle glaucoma, is a progressive optic neuropathy characterized by a gradual loss of retinal ganglion cells and their axons. The disease is associated with increased intraocular pressure (IOP) due to impaired aqueous humor outflow.

**Why the Correct Answer is Right**
The peripheral field of vision is last to be affected in chronic simple glaucoma because the retinal ganglion cells that innervate the peripheral retina are more resistant to damage from elevated IOP. The loss of these cells leads to a gradual deterioration of the visual field, starting from the nasal and superior areas and progressing towards the peripheral field. This is because the optic nerve fibers that carry information from the peripheral retina are more deeply located and protected by the retinal nerve fiber layer, making them more resistant to damage.

**Why Each Wrong Option is Incorrect**
**Option A:** **Temporal field of vision** - This is incorrect because the temporal field of vision is one of the first areas to be affected in chronic simple glaucoma, not the last.

**Option B:** **Central field of vision** - This is incorrect because the central field of vision is also one of the first areas to be affected in chronic simple glaucoma, due to the loss of parvocellular retinal ganglion cells that are responsible for high-acuity vision.

**Option D:** **Both nasal and superior fields** - This is incorrect because while these fields are indeed affected early in the disease, they are not the last to be affected.

**Clinical Pearl / High-Yield Fact**
The nasal and superior fields of vision are typically the first areas to be affected in chronic simple glaucoma, and a loss of these fields can be an early indicator of the disease.

**Correct Answer: C. Peripheral field of vision**