## Core Concept
The question tests knowledge on the etiology and risk factors associated with cataract formation. A cataract is a clouding of the eye's lens that affects vision. Various factors can contribute to cataract development, including aging, certain medications, and systemic diseases.

## Why the Correct Answer is Right
Option is the correct answer because it is not a known cause of cataracts. Typically, causes of cataracts include aging, diabetes mellitus, prolonged steroid use, trauma, and certain metabolic disorders.

## Why Each Wrong Option is Incorrect
* **Option A:** is a known risk factor for cataract formation. For instance, diabetes mellitus can lead to the development of cataracts due to the accumulation of sorbitol in the lens, which causes osmotic changes and lens opacification.
* **Option B:** is associated with cataract formation. Long-term use of corticosteroids can cause posterior subcapsular cataracts.
* **Option C:** can also contribute to cataract formation. Ocular trauma can directly damage the lens, leading to cataract formation.

## Clinical Pearl / High-Yield Fact
A key point to remember is that corticosteroid use, both topical and systemic, is a well-known risk factor for cataract development, particularly posterior subcapsular cataracts.

## Correct Answer Line
**Correct Answer: D.**