**Core Concept**
Retinitis pigmentosa (RP) is a group of rare, genetic disorders that primarily affect the retina's ability to respond to light, leading to progressive vision loss. It is characterized by degeneration of the photoreceptor cells (rods and cones) in the retina.

**Why the Correct Answer is Right**
The correct answer, "Early loss of central vision," is incorrect in the context of retinitis pigmentosa. RP typically presents with night blindness and peripheral visual field loss, progressing to central vision loss later in the disease course. This is because the degeneration of photoreceptors starts in the periphery and gradually moves towards the center of the retina. The loss of central vision is a relatively late feature of RP.

**Why Each Wrong Option is Incorrect**
**Option A:** Night blindness is a characteristic symptom of retinitis pigmentosa, resulting from the degeneration of rod photoreceptors, which are primarily responsible for peripheral and night vision.
**Option B:** A waxy disc is a common finding in RP due to the secondary degeneration of the optic disc, which can occur as a result of the disease's progression.
**Option D:** Attenuation of retinal vessels is seen in RP due to the disease's effects on the retinal vasculature, leading to changes in the caliber and tortuosity of the vessels.

**Clinical Pearl / High-Yield Fact**
A key feature of retinitis pigmentosa is the "bone-spicule" appearance on fundoscopic examination, which is a result of the accumulation of pigmentary changes in the retina. This is a classic finding that can help differentiate RP from other retinal disorders.

**✓ Correct Answer:** C. Early loss of central vision