Glands of Zeis are unilobar sebaceous gland

Sebaceous gland

The sebaceous glands are microscopic glands in the skin that secrete an oily/waxy matter, called sebum, to lubricate and waterproof the skin and hair of mammals...

s located on the margin of the eyelid

Eyelid

An eyelid is a thin fold of skin that covers and protects an eye. With the exception of the prepuce and the labia minora, it has the thinnest skin of the whole body. The levator palpebrae superioris muscle retracts the eyelid to "open" the eye. This can be either voluntarily or involuntarily...

. The glands of Zeis service the eyelash

Eyelash

An eyelash or simply lash is one of the hairs that grow at the edge of the eyelid. Eyelashes protect the eye from debris and perform some of the same function as whiskers do on a cat or a mouse in the sense that they are sensitive to being touched, thus providing a warning that an object is near...

. These glands produce an oily substance that is issued through the excretory ducts of the sebaceous lobule into the middle portion of the hair follicle

Hair follicle

A hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....

. In the same area of the eyelid, near the base of the eyelashes are sweat gland

Sweat gland

Sweat glands, or sudoriferous glands, are small tubular structures of the skin that produce sweat. There are two kinds of sweat glands:...

s called the glands of Moll

Glands of Moll

Glands of Moll, also known as ciliary glands, are modified apocrine sweat glands that are found on the margin of the eyelid. They are next to the base of the eyelashes, and anterior to the Meibomian glands within the distal eyelid margin. These glands are relatively large and tubular-shaped.Moll's...

.

If eyelashes are not kept clean, conditions such as folliculitis

Folliculitis

Folliculitis is the inflammation of one or more hair follicles. The condition may occur anywhere on the skin with the exception of the palms of the hands and soles of the feet.- Causes :...

 may take place, and if the sebaceous gland becomes infected, it can lead to abscess

Abscess

An abscess is a collection of pus that has accumulated in a cavity formed by the tissue in which the pus resides due to an infectious process or other foreign materials...

es and stye

Stye

An external stye or sty , also hordeolum , is an infection of the sebaceous glands of Zeis at the base of the eyelashes, or an infection of the apocrine sweat glands of Moll. External styes form on the outside of the lids and can be seen as small red bumps. Internal styes are infections of the...

s. The glands of Zeis are named after German ophthalmologist Eduard Zeis

Eduard Zeis

Eduard Zeis was a German surgeon and ophthalmologist who was a native of Dresden.He studied medicine at the Universities of Leipzig, Bonn and Munich, and received his doctorate at Leipzig in 1832. Afterwards he opened a general practice in his hometown of Dresden, and in 1844 became a professor of...

(1807–68).