**Core Concept**
Keratomalacia is a serious ocular condition characterized by the softening of the cornea due to a lack of nutrients, primarily vitamin A. This condition can lead to corneal ulcers, perforation, and ultimately, blindness if left untreated.

**Why the Correct Answer is Right**
Keratomalacia occurs due to vitamin A deficiency, which impairs the synthesis of rhodopsin, a pigment essential for night vision. Vitamin A plays a crucial role in maintaining the integrity of the cornea by promoting the production of mucopolysaccharides, which maintain corneal hydration and prevent its softening. The deficiency of vitamin A also affects the integrity of the epithelial layer of the cornea, making it more susceptible to damage.

**Why Each Wrong Option is Incorrect**
**Option B:** Keratomalacia is a severe and potentially blinding condition that requires prompt medical attention, making it anything but "relative benign."
**Option C:** While keratomalacia is a feature of vitamin A deficiency, it is not the first feature. The initial symptoms of vitamin A deficiency include night blindness, followed by xerophthalmia, and then keratomalacia.
**Option D:** Retinitis pigmentosa is a group of genetic disorders that affect the retina, leading to progressive vision loss. While vitamin A deficiency can exacerbate retinitis pigmentosa, keratomalacia is not a direct feature of this condition.

**Clinical Pearl / High-Yield Fact**
Keratomalacia is often associated with other forms of malnutrition, particularly in children. Recognizing the importance of vitamin A in maintaining ocular health is crucial in preventing this condition, especially in regions with high prevalence of malnutrition.

**✓ Correct Answer: A. Occurs due to Vitamin A deficiency**