A patient with cataract exhibits polychromatic lustre of reds, greens and blues. He is having the following type of cataract:
**Core Concept**
The polychromatic lustre of reds, greens, and blues in a patient with cataract indicates the presence of a specific type of cataract that affects the way light is scattered within the lens. This phenomenon is a result of the irregular distribution of refractive indices within the lens.
**Why the Correct Answer is Right**
The polychromatic lustre observed in this patient is characteristic of a cataract with a high degree of cortical spillover into the nuclear region, leading to the scattering of light. This type of cataract is known as a **Cortical Cataract with Nuclear Spillover**. The scattering of light is due to the irregular distribution of refractive indices within the lens, which is a result of the loss of lens fibers and the accumulation of fluid within the lens cortex. This type of cataract is more common in older adults and can cause significant visual disturbances.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because a **Nuclear Sclerosis Cataract** would exhibit a yellowish or brownish coloration due to the accumulation of lipofuscin within the lens nucleus, rather than a polychromatic lustre.
* **Option B:** This option is incorrect because a **Posterior Subcapsular Cataract (PSC)** would typically exhibit a white or grayish opacification in the posterior subcapsular region of the lens, rather than a polychromatic lustre.
* **Option C:** This option is incorrect because a **Snowflake Cataract** would exhibit a characteristic "snowflake" pattern of opacities within the lens cortex, rather than a polychromatic lustre.
**Clinical Pearl / High-Yield Fact**
It's essential to note that the type of cataract can be influenced by the patient's age, diabetes status, and exposure to UV radiation, among other factors. A thorough examination of the lens and the patient's medical history is crucial in determining the underlying cause of the cataract.
**Correct Answer:** C. Cortical Cataract with Nuclear Spillover. Cortical Cataract with Nuclear Spillover.