Learning Objective: By the end of this session, the learner should be able to describe the anatomy, layers, vasculature, innervation, and clinical relevance of the eyelids and apply this knowledge to basic clinical scenarios.
The eyelids are thin, mobile folds that protect the anterior eye from excessive light and injury while maintaining lubrication by spreading tears over the ocular surface. Each eyelid—upper and lower—meets at the medial and lateral canthi, forming the palpebral aperture. This article reviews the layers, neurovascular supply, and functions of the eyelids.
Layers of the Eyelid
The eyelid is composed of five layers (superficial → deep):
- Skin & subcutaneous tissue
- Orbicularis oculi
- Tarsal plates
- Levator apparatus
- Conjunctiva
Skin and Subcutaneous Tissue
This outermost layer contains the thinnest skin in the body and loose connective tissue without fat, making it prone to swelling.
It contains:
- Eyelashes with ciliary glands of Moll (modified sweat glands)
- Glands of Zeis (sebaceous glands)
Orbicularis Oculi
A facial expression muscle with three parts:
- Palpebral part: gently closes the eyelids
- Orbital part: tightly closes the eyelids
- Lacrimal part: assists in tear drainage
Innervation: Facial nerve (CN VII)
Tarsal Plates
Dense connective tissue structures forming the framework of the eyelids:
- Superior tarsus
- Inferior tarsus
They contain Meibomian glands, which secrete an oily layer that prevents tear evaporation and keeps lids from sticking.
Clinical Relevance: Styes & Chalazia
- Stye (hordeolum): Painful infection of eyelash follicles or Meibomian glands
- Chalazion: Painless granulomatous obstruction of a Meibomian gland
Levator Apparatus
Responsible for elevating the upper eyelid.
| Structure | Attachments | Action | Innervation |
|---|---|---|---|
| Levator palpebrae superioris (LPS) | Lesser wing of sphenoid → upper eyelid + superior tarsal plate | Opens eyelid | CN III |
| Superior tarsal muscle | From LPS → superior tarsal plate | Assists LPS | Sympathetic fibres |
Conjunctiva
The palpebral conjunctiva lines the inner eyelid and reflects onto the sclera as the bulbar conjunctiva. It is a thin, mucous membrane essential for lubrication.
ACTIVITY
Vasculature
Arterial supply:
- From the ophthalmic artery: lacrimal, medial palpebral, supraorbital, supratrochlear, dorsal nasal
- Facial artery (angular branch)
- Superficial temporal artery (transverse facial branch)
Venous drainage:
- Medially → angular + ophthalmic veins
- Laterally → superficial temporal vein
Innervation
Sensory innervation:
- V1 (ophthalmic division): upper eyelid
– Supraorbital, supratrochlear, lacrimal, infratrochlear branches - V2 (maxillary division): lower eyelid
– Infraorbital, zygomaticofacial branches
Motor innervation:
- CN VII: orbicularis oculi
- CN III: LPS
- Sympathetic fibres: superior tarsal muscle
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