**Core Concept**
Galactosemic cataract is a type of cataract that occurs due to the accumulation of galactose in the lens of the eye, leading to opacification and vision loss. This condition is often seen in infants and children with galactosemia, a genetic disorder that affects the body's ability to metabolize galactose.

**Why the Correct Answer is Right**
Galactosemic cataract is caused by the accumulation of galactitol, a sugar alcohol that is formed when galactose is converted to glucose in the lens. This accumulation of galactitol leads to the formation of osmotic gradients, causing water to enter the lens and leading to swelling and opacification. The enzyme aldose reductase is responsible for the conversion of galactose to galactitol.

**Why Each Wrong Option is Incorrect**
**Option A:** This statement is incorrect because galactosemic cataract is not caused by a deficiency of galactokinase, but rather by the accumulation of galactitol due to the action of aldose reductase.

**Option B:** This statement is incorrect because galactosemic cataract is not a result of galactosemia being caused by a deficiency of galactose-1-phosphate uridyltransferase, but rather by the accumulation of galactitol in the lens.

**Option C:** This statement is incorrect because galactosemic cataract is not caused by the direct toxicity of galactose to the lens fibers, but rather by the accumulation of galactitol and the resulting osmotic gradients.

**Option D:** This statement is incorrect because galactosemic cataract is not a result of the lens being unable to import glucose, but rather by the accumulation of galactitol and the resulting osmotic gradients.

**Clinical Pearl / High-Yield Fact**
Galactosemic cataract is a classic example of a secondary cataract, which occurs as a result of a systemic metabolic disorder. It is essential for clinicians to be aware of the association between galactosemia and cataract formation in infants and children.

**Correct Answer:** D.