**Core Concept**
Distichiasis is a rare congenital anomaly characterized by the abnormal growth of eyelashes from the meibomian gland orifices. This condition is distinct from the normal growth of eyelashes from the lash line.

**Why the Correct Answer is Right**
The meibomian glands are located within the tarsal plates of the eyelids and produce meibum, an oily substance that helps to lubricate the eye. In distichiasis, the meibomian gland orifices become abnormally located or develop in an abnormal position, leading to the growth of eyelashes from these sites. This can cause irritation, dryness, and discomfort to the eye. The growth of eyelashes from the meibomian gland orifices is a hallmark of distichiasis, distinguishing it from other conditions that affect the eyelashes.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because distichiasis is not characterized by an increased number of lashes in the lower eyelid. The condition is typically associated with abnormal lash growth from the meibomian gland orifices, not an increase in the number of lashes.

**Option C:** This option is incorrect because hyperpigmentation of eyelashes is not a feature of distichiasis. Hyperpigmentation refers to an increase in melanin, which is not typically associated with this condition.

**Option D:** This option is incorrect because increased thickness of eyelashes is not a defining characteristic of distichiasis. While the lashes may appear abnormal, the primary issue is the abnormal location of the lash growth, not the thickness of the lashes.

**Clinical Pearl / High-Yield Fact**
Distichiasis is often associated with other congenital anomalies and can be a component of certain syndromes, such as blepharophimosis, ptosis, and epicanthus inversus syndrome (BPES). This knowledge can help clinicians suspect and diagnose distichiasis in patients with multiple congenital anomalies.

**✓ Correct Answer: B. Growth of eyelashes from Meibomian Orifices**