3.1 Anatomy of the eye

There are two components of the human body that are of particular interest to the lash artist: the eyelid and the eyelash. You would be forgiven for assuming we might jump straight into an examination of the eyelash, given the fact we are studying a course in lash lift and tints! However, as you’ll soon learn, it is the skin within which the eyelash is housed that provides for some of the eyelash’s most defining characteristics.

Defining the eyelid

In basic terms, the eyelids are folds of skin and tissue connected to a muscle (called the orbicularis occuli) that open and close either voluntarily (i.e. to sleep) or involuntarily (blinking or reflex). The upper eyelid is defined as starting at the eyelid margin (the very edge of the eyelid where the eyelashes grow) and extending to the base of the eyebrow. The lower eyelid again starts at the eyelid margin, and extends to the crease in the skin at the top of the cheek. The primary role of the eyelid is to keep the surface of the eye (cornea) moist, which is achieved by the spreading of tears (a film discharged from the tear duct) every time we blink. Secondary to this, when closed, the eyelids protect the eye from from foreign objects and light.

Fun fact: The hairs on your top lid are much fuller than your lower lash line. In fact, they’re almost twice as full with about 200 to 300 lashes. (Your lower lid has about 100.)

Structures of the eye

Without going into a full-blown science lesson, the main structure of the eye is the eyelids, sclera, iris, pupil and the tear duct. A diagram of the structures of the eye is shown below:

When performing lash lifts and tints correctly, the service is completely safe. However, if any of the lifting solutions enters a client’s eyes, they are at risk of developing a chemical burn or a corneal ulcer. You need to take great care when applying any chemicals to a client’s eyes and must also be on the lookout for any signs of irritation. Patch tests are a great way to prevent any nasty surprises, and we go into more detail about how to do these later in this module.

Fun fact: The average person blinks 12 times a minute (bet you just blinked!).

Eyelid skin: the thick and thin of it

To understand the peculiarities of the skin of the eyelids, it is helpful to compare it with the skin of the scalp (which is similar to the skin on much of the remainder of the body). The skin on the scalp contains three layers: the epidermis (external), the dermis (middle) and the hypodermis (internal), as you can see in the below diagram.

Anatomy of scalp hair consisting of three layers: the epidermis, the dermis, and the hypodermis

The skin of the eyelids, however, consists of only two layers: the epidermis (which is much thinner than the epidermis of the scalp) and the dermis. As a result, the skin of the eyelid is much thinner than that on the scalp, and the thinnest of any region of the body at lass than 1mm in thickness.

In terms of how this affects the eyelash (your canvas!), all hair follicles on the human body are rooted in their deepest skin layer, notably the hypodermis on the scalp and the dermis within the eyelid. Consequently, the eyelash follicle is shorter than the scalp hair follicle, resulting in a much shorter and finer hair shaft.

In addition to their relatively short length and fine composition, another defining property of an eyelash is its curved shape, a characteristic present in all ethnicities. The science behind exactly what causes this phenomenon is far too in depth for a lash mastery course (even the most comprehensive and educational course on the net!). However, in basic terms, this curvature is a result of asymmetric (or uneven) cell development in the hair root within the dermis of the eyelid, resulting in the concave (or inner) side of the hair being thicker and the convex (or outer) side of the hair being thinner. The eyelash therefore essentially grows ‘around’ the thicker, more tightly-packed cells on the inside of the curve (or curl).

Sense and sensitivity

The relative thinness of the skin layer in itself would suggest that the eyelids are a particularly delicate area of the human body. However, the skin of the eyelid also contains a relatively high amount of blood vessels and very little fat compared with other areas of skin. All of these characteristics combined equate to the skin of the eyelids being extremely susceptible to irritation and more prone to allergic reactions. We’ll explore irritations and reactions later in this module.

Fun fact: Early eyelash tools have been found in Ancient Egypt, but the modern mascara as we know it was created in 1913 in France by Rimmel. However, mascara didn’t become popular in America until Maybelline debuted its first formula, which was a mixture of coal and Vaseline.

Overview of eye shapes

When we start to look at the wide range of eye shapes you will work with, you will need to consider three distinct categories – physical shape, dimension and anatomy. The diagram below provides a good visual representation of these categories:

All of us will have features from the categories above. You may have a client who has small, almond and downturned eyes, and then your next client might have average almond eyes, which are hooded! The first distinction will always be between round and almond:

As you can see from the comparison above, round eyes tend more circular, and the height in the centre is larger, whereas almond eyes have a more distinct taper on each end – much like the shape of almonds! Oval shaped eyes are somewhere in the middle of round and almond. From there, we can determine the size of the eyes. If your clients’ eyes are a similar size to their mouth and nose, then they are average; if they are smaller or bigger than the mouth and nose, then they can be categorised as small or big.

Once you have determined the physical shape and the dimension, the next step is to look closer at the anatomy of each eye shape. Let’s take a look at each in more detail:


A person with wide-set eyes will have a space between their eyes that is more than the width of their eyeball.


As the name suggests, deep-set eyes are set deeper into the skill and will usually make the brown bone appear more prominent.


In contrast to wide-set eyes, a person with close-set eyes will have a smaller gap between their eyes, usually a smaller width than their eyeball.


Protruding eyes project outward in the eye socket area and are usually larger and round in shape.


Hooded eyes are where the eyelid appears smaller, and there is usually an extra layer of skin that is over the crease. The skin may droop down and give the appearance that there is no visible eyelid.


On the surface, monolid eyes are flat and will have little to no crease. These types of lids are common amongst Asian clients.


Downturned eyes can be determined by a slight drop in the outer corners.


Upturned eyes can be determined by a natural lift in the outer corners.

The eye shapes explained are very broad categories, and you and your clients may have features of a few!

If you are interested in learning more about eye shapes and types, read the articles linked:

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