Function of the eyelids

The eyelids are part of the ocular appendages and their main functions are the protection of the eyeball from external agents and the maintenance of the tear film.

The eyelids have four main layers:

·         The outermost layer is made up of a very thin skin with little subcutaneous cellular tissue.

·         The muscular layer is made up of the orbicularis oculi, the levator palpebrae superioris, and the superior and inferior tarsal muscles.

·         In the fibrous layer are the palpebral tarsi with the meibomian glands, the orbital septa, and the external and internal palpebral ligaments.

·         The innermost layer is the palpebral or tarsal conjunctiva. Is in contact with the eyeball.

Eyelid disorders

There are different disorders of the eyelids, among them we can highlight:

·         Alterations in the position of the eyelids:

o   Ectropion

o   Entropion

o   Ptosis

o   Eyelid retraction

·         Alterations of the eyelashes

o   Trichiasis / distichiasis.

·         Cysts of the eyelids:

o   Moll’s cyst: A non-painful, round lesion with a translucent content, which appears on the eyelid margin due to the blockage of the excretory duct.

o   Zeiss cyst: Similar to Moll’s cyst, but coming from the sebaceous glands, its content is yellowish.

·         Inflammatory pathology of the eyelids:

o   Stye: Produced by an infection. It can be internal (it comes from the meibomian glands) or external (due to infection of a hair follicle or the Zeiss or Moll glands). Its most common location is the upper eyelid and it can be accompanied by eyelid edema, conjunctival hyperemia (redness), and tearing. External styes are generally self-limited and can disappear spontaneously within 7 days. Those that require treatment, the application of local heat (preferably dry), massage of the nodule and an ointment with antibiotics / corticosteroids will be indicated. In large styes it may be necessary to drain them.

o   Chalazion: It is an inflammation of the Meibomian or Zeiss glands. It presents as a nodular lesion (nodule appearance), slow growing, and painless on pressure. Initially, it can be treated with dry heat. If it does not improve, it may require treatment with a corticosteroid ointment. Those cases that do not improve can be treated with intralesional corticosteroid injections (inside the chalazion) or even surgery (opening and cleaning the chalazion).

o   Blepharitis: It is a diffuse inflammation of the eyelid margin. It is usually of chronic course, with occasional exacerbations. Two types are distinguished, although many times they overlap each other and the clinical distinction is complicated:

§  Chronic posterior or marginal blepharitis, the most common subtype. It affects the exit orifices of the meibomian glands. It can appear alone or associated with acne rosacea or other dermatitis (psoriasis, atopy); in which case it tends to be more severe.

§  Anterior chronic blepharitis affecting the base of the eyelashes. It is more common in women and younger patients. It can be of infectious or seborrheic etiology (patients with seborrheic dermatitis).

Su tratamiento se basa en la limpieza de las costras con toallitas o bastoncillos empapados en champú infantil suave (mañana y noche) y el empleo de compresas calientes (15 minutos, tres veces al día). En casos con sintomatología grave o refractaria, se aplicará pomada antibiótica (eritromicina, bacitracina) con o sin corticoide, de 1 a 3 veces al día, durante 10-15 días.

Eyelid tumors

The Verruga vulgaris is the most common benign tumor, while basal cell carcinoma is the most common malignant one.

Benign tumors:

·         Xanthelasmas: yellow patches on the skin. They are associated with high cholesterol levels.

·         Verruga vulgaris: The most common benign tumor. Associated with a human papillomavirus infection.

·         Seborrheic keratosis: It appears on an actinic keratosis (sun lesion) or a squamous carcinoma. It is a keratinized lesion, raised and hard in consistency.

·         Actinic keratosis: It is a premalignant lesion with a dry, scaly appearance, and an erythematous base (with an erythema appearance).

Malignant tumors:

·         Basal cell carcinoma: It is the most common malignant tumor. Its growth is slow, locally invasive and without distant metastasis.

·         Squamous cell carcinoma: Its appearance is that of a plaque or nodule with everted edges (outward) and crusts on its surface.

·         Sebaceous cell carcinoma: Slow-growing, painless, firm mass. It affects the meibomian glands.

·         Melanoma: The superficial type is more frequent, while the nodular type is more aggressive. It can affect the conjunctiva, so the eyelid must always be everted.

·         Keratoacanthoma: Fast growing hyperkeratotic nodule. It is a raised lesion, with prominent edges, with a large central ulcer filled with keratin.

Most of the eyelid disorders are relatively trivial processes. However, they must be evaluated by a specialist.