Anatomy of the eyelid
- A – On the outside of the eyelid is skin which meets the palpebral (also known as the tarsal) conjunctiva (E) at the lid margin (B)
- B – The eyelashes are at the lid margin. They point forward, away from the eye.
- C – Underneath the skin is a layer of muscle called the orbicularis oculi. This is important for closing the eyelid.
- D – Behind the orbicularis oculi muscle is a layer of dense connective tissue called the tarsal plate. This gives the eyelid its shape and rigidity.
- E – The palpebral (or tarsal) conjunctiva lines the inner surface of the eyelid. It provides a moist smooth surface to rest against, and protect, the surface of the eye.
Changes to eyelid anatomy caused by trachomaIn trachoma the posterior lamella and lid margin become scarred and contract. This mostly affects the upper eyelid. The lid margin and eyelashes can be pulled and turn inwards so that they touch the eyeball. This is known as trachomatous trichiasis (TT). As the person blinks, their inturned eyelashes can rub against the cornea causing pain and eventually damaging the cornea, making it opaque and causing vision loss. This is known as corneal opacity (CO).
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