## **Core Concept**
Diabetic cataract, also known as snowflake cataract, is a type of cataract that occurs in people with diabetes mellitus. It is associated with fluctuations in blood glucose levels, leading to the accumulation of certain substances in the lens of the eye.

## **Why the Correct Answer is Right**
The correct answer, **sorbitol**, is a sugar alcohol that accumulates in the lens of the eye in diabetic patients. This accumulation occurs due to the enzyme **aldose reductase**, which converts glucose into sorbitol. The sorbitol does not easily cross the lens capsule and its accumulation leads to osmotic changes, causing water to enter the lens, swelling, and ultimately cataract formation.

## **Why Each Wrong Option is Incorrect**
- **Option A: Fructose** - While fructose is related to glucose metabolism, it is not directly implicated in the pathogenesis of diabetic cataracts through accumulation in the lens.
- **Option B: Galactitol** - Galactitol is indeed a sugar alcohol involved in another type of cataract, specifically in galactosemia, a condition where the body is unable to properly break down galactose. It is not directly related to diabetic cataracts.
- **Option D: Glycogen** - Glycogen is a complex carbohydrate stored in the liver and muscles, not directly related to cataract formation in diabetes.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that rapid changes in blood glucose levels can lead to the development of cataracts in diabetic patients. This is often seen as a "snowflake" cataract, which can be reversible if blood glucose levels are stabilized.

## **Correct Answer: C. Sorbitol**