Most characteristic finding of retinitis pigmentosa –a) Ring scotomab) Peripheral field defectc) Central scotomad) Diplopia

**Core Concept**
Retinitis pigmentosa (RP) is a group of genetic disorders affecting the retina's ability to respond to light, leading to progressive vision loss. The degeneration of photoreceptor cells in the retina results in characteristic clinical findings.

**Why the Correct Answer is Right**
The most characteristic finding of retinitis pigmentosa is a **ring scotoma**, which is a circular area of vision loss in the central visual field. This occurs due to the degeneration of the macula, the part of the retina responsible for central vision. The ring scotoma is often accompanied by night blindness, which is a common symptom of RP.

**Why Each Wrong Option is Incorrect**
**Option A:** Ring scotoma is the correct answer, so this option is incorrect.
**Option B:** Peripheral field defect is not the most characteristic finding of RP, although it may occur in advanced cases.
**Option C:** Central scotoma is not a typical finding in RP, as the disease primarily affects the peripheral retina.
**Option D:** Diplopia (double vision) is not a direct consequence of RP, which primarily affects vision and not extraocular muscle function.

**Clinical Pearl / High-Yield Fact**
A classic clinical sign of RP is the "bone-spicule" appearance of the retina, which is visible on fundoscopic examination. This is caused by the accumulation of pigment in the retina due to the degeneration of photoreceptor cells.

**Correct Answer:** A. Ring scotoma