## Core Concept
Complicated cataract refers to the development of cataracts as a result of another intraocular disease, often due to inflammatory conditions or retinal diseases. It involves opacification of the lens that occurs secondary to another ocular condition.

## Why the Correct Answer is Right
The correct answer, ., implies that posterior subcapsular cataract (PSC) is a common feature of complicated cataract. Complicated cataracts often result from conditions like uveitis, retinitis pigmentosa, and high myopia. The posterior subcapsular region of the lens is particularly susceptible to damage from these conditions, leading to cataract formation.

## Why Each Wrong Option is Incorrect
* **Option A:** Snowflake cataract is more commonly associated with diabetes mellitus rather than being a direct complication of another intraocular disease.
* **Option B:** Cortical cataract, while common, is not specifically termed as a complicated cataract but rather as an age-related cataract type.
* **Option D:** Nuclear cataract is primarily age-related and not specifically referred to as a complicated cataract.

## Clinical Pearl / High-Yield Fact
A key clinical pearl is that complicated cataracts can be prevented or their progression delayed by treating the underlying condition. For example, controlling inflammation in uveitis can prevent cataract formation. Recognizing the association between intraocular diseases and cataract development is crucial for early intervention.

## Correct Answer: .