## **Core Concept**
The glands of Zeis are a type of sebaceous gland located at the base of an eyelash follicle. They play a crucial role in the eye's health by contributing to the lipid layer of the tear film, which helps prevent excessive tear evaporation.

## **Why the Correct Answer is Right**
The glands of Zeis are specifically associated with the eyelashes and are sebaceous in nature. They open directly into the follicles of the eyelashes, providing sebum that helps to keep the eyelashes supple and contributes to the ocular surface health. This association with eyelashes and their sebaceous nature helps distinguish them from other types of glands in the ocular adnexa.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not accurately describe the glands of Zeis or their relationship with eyelash follicles.
- **Option B:** This option might refer to other types of glands or structures not directly related to the glands of Zeis or their function.
- **Option C:** While there are various glands around the eye, this option does not specifically and accurately identify glands of Zeis or their association with eyelashes.
- **Option D:** This option might be incorrect because it does not accurately represent the type or function of the glands of Zeis.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that an infection of the glands of Zeis can lead to a condition known as **external hordeolum** or stye, which presents as a painful, localized swelling at the base of an eyelash. This condition often requires warm compresses and sometimes antibiotics for treatment.

## **Correct Answer:** B. Sebaceous glands.