Introduction and Anatomy

The eyelid is important for ensuring physical protection of the eye and maintaining lubrication over the surface of the eyeball.

It is composed of five main layers (superficial to deep): skin and subcutaneous tissue, orbicularis oculi, tarsal plate, levator apparatus and conjunctiva. The meibomian glands are modified sebaceous glands that sit within the tarsal plates; they secrete oily substances onto the surface of the eye, reducing evaporation of the tear film.

Eyelid problems are frequently encountered in primary care and within the ophthalmology department – this article aims to provide an overview of the most common ones that you may come across in your clinical practice.

Eyelid anatomy

Image from https://www.futurelearn.com/info/courses/eliminating-trachoma/0/steps/21659

Abnormalities in Eyelid Position

Entropion

• Entropion is when the eyelid turns inwards towards the eyeball.
• It usually affects the lower eyelid, and occurs with increasing age where the orbicularis oculi muscle becomes weaker.
• It can also occur due to infection and conjunctival scarring, which pull the lids inwards.
• As the eyelashes brush against the cornea, this can cause irritation and corneal abrasions.
• Short term management of entropion involves regular eye lubrication or taping of the lid to direct eyelashes away from the eye.
• Injection of botulinum toxin into the orbicularis oculi muscle may also temporarily improve symptoms, but surgical correction is the definitive treatment.

Entropion of the right lower lid

Image from Medscape https://emedicine.medscape.com/article/1212456-overview

Ectropion

• Ectropion is when the lower eyelid droops downwards and outwards.
• The majority of cases are caused by laxity of the orbicularis oculi muscle with increasing age.
• It can also be caused by a facial nerve (Bell’s) palsy or stroke.
• Constant exposure of the conjunctiva and cornea can result in exposure keratopathy, which requires urgent ophthalmology review.
• Eversion of the puncta (which are responsible for draining tears) can also lead to excess tearing (epiphora). Similar to entropion, the definitive treatment for ectropion is surgery.

Ectropion of the right lower lid

Image from Medscape https://emedicine.medscape.com/article/1212398-overview

Inflammation of the Eyelid

Blepharitis

• Blepharitis is inflammation of the eyelid margin that is often chronic with recurrent exacerbations.
• There are two types: posterior blepharitis (commonest, caused by meibomian gland dysfunction) and anterior blepharitis (associated with chronic staphylococcal infection).
• Both are strongly associated with rosacea, seborrhoeic dermatitis and atopic eczema.
• Symptoms include bilateral red, sore and itchy eyes upon waking with crusting of the lid margins.
• On examination, there may be red, scaly and thickened lid margins, conjunctival injection and plugging of the meibomian orifices.
• Management involves lid hygiene measures (warm compresses for 5-10 mins twice daily, eyelid massages, removal of debris from the lid margins using soaked cotton buds) and artificial tears.
• A short course of a topical corticosteroid/antibiotic may also be considered if there is poor response to initial eye hygiene measures.

Blepharitis – note greasy crusting at the lid margin and lash bases

Image from American Academy of Ophthalmology https://www.aao.org/education/image/blepharitis

Benign Eyelid Lumps and Bumps

Hordeolum

• Hordeolum is caused by an acute, painful, localised infection of the eyelid margin, of which there are two types:
  • External hordeolum (also known as a stye) originate from the glands of Zeis (sebum-producing) or glands of Moll (sweat glands), which are located superficial at the eyelash base. Most self-resolve with warm compresses but some cases may require oral antibiotics if surrounding cellulitis is present.
  • Internal hordeolum originate from the deeper situated meibomian glands within the tarsal plate. Topical antibiotics and/or incision and drainage may be required.
  • If left untreated, internal hordeolum may develop into a chalazion or preseptal cellulitis.

L image from https://www.reviewofoptometry.com/article/stye-vs-stye

R image from https://webeye.ophth.uiowa.edu/eyeforum/atlas/pages/internal-hordeolum-a-meibomian-abscess.html

Chalazion

• Chalazion is a painless granuloma that forms within the eyelid as a result of an obstructed meibomian gland.
  • Although unsightly, the majority resolve within six months with good lid hygiene measures (warm compresses and eyelid massage).
  • Incision and curettage can be considered if the chalazion persists.

Chalazion

Image from American Academy of Ophthalmology https://www.aao.org/education/image/chalazion-12

Abnormalities of the Eyelashes

Trichiasis

• Not to be confused with entropion, trichiasis is where eyelashes are directed inwards towards the eyeball.
• As the lashes rub against the cornea, corneal irritation and abrasion occur, which may result in blindness if left untreated.
• Causes of trichiasis include chronic lid margin inflammation (e.g., blepharitis) and trachoma in developing countries.
• Treatment is with epilation of the problematic lashes; recurrence is common and can be managed with electrolysis or cryotherapy.
• Surgical correction is required if there are abnormalities in eyelid position. 

Trichiasis

Image from American Academy of Ophthalmology https://www.aao.org/eye-health/diseases/what-is-trichiasis

References

Written by Dr Alice Wang (FY2) and reviewed by Mr Chris Ashton (Ophthalmology TSC External Fellow)