11.2 Eyelids & Lacrimal System

Question 1

Which muscle open the eye and by what nerve is it innervated?

Answer 1

Orbicularis - Cn7

Question 2

What muscles lifts the eyelid + innervation?

Answer 2

• Mullers muscle (Sympathetic, parasymphaletic)
• Levator (elevate) (Cn3)
• Frontalis (Cn7)

Question 3

Chronic Blephritis
General
Aetiology
Clinical features
Complications

Answer 3

GENERAL
- very common condition which is underdiagnosed.

Aetiological factors include the following:
- (1)Staphylococcal infection of the eyelash follicles.
- (2)Abnormal secretion from the eyelash or tarsal sebaceous glands.
- demodex folliculorum
- often associated with seborrhoeic dermatitis, acne rosacea, atopic eczema and dry eyes.

CLINICAL FEATURES
- early stages the condition is asymptomatic.
- Later chronic irritation develops, with eyes that burn, scratch and itch.
- Symptoms often appear to be out of proportion to the findings.
- Eyelid margin examination may reveal hyperaemia with flaking and crusting, but it may be difficult or impossible to see the clinical signs without a slit lamp.

Complications
- recurrent conjunctivitis,
- internal and external hordeola
- chalazia.

Question 4

Chalazion (meibomain cyst)
Affected site
Clinical features

Answer 4

Affected site
- Obstruction of a tarsal (Meibomian) gland duct results in retention of the sebaceous secretions and secondary swelling with low grade inflammation.
- not a true cyst because the walls consist of granulation tissue and not epithelium.

CLINICAL FEATURES
- It usually presents as a slowly enlarging round, firm swelling in the eyelid, with no signs of inflammation such as tenderness or redness of the skin.
- Occasionally it may develop from an internal hordeolum
- Eversion of the eyelid reveals a red, raised area of conjunctiva or a granuloma.

Question 5

Internal hordeolum (meibomain abscess)
Affected site
Clinical features

Answer 5

Affected site
- staphylococcal abscess of a tarsal (Meibomian) gland.

CLINICAL FEATURES
- Presents as a very tender inflamed swelling of the eyelid.
- Unlike an external hordeolum, the area of greatest swelling is away from the eyelid margin.
- The lesion may enlarge and resolve by draining posteriorly through the conjunctiva, or anteriorly through the skin.
- Occasionally it spontaneously becomes smaller to leave a small, hard nodule in the eyelid, and occasionally it spontaneously becomes quiescent to form a chalazion

Question 6

Molluscum contagiosum
General
Clinical features

Answer 6

GENERAL
- common viral skin disease caused by a member of the pox virus family.
- It occurs mainly in children and is spread by direct contact.

CLINICAL FEATURES
- A raised, shiny, pink to white nodule on the eyelid skin with characteristic central umbilication.
- Lesions may be single or multiple.
In patients with AIDS the lesions are often more confluent and disseminated disease may be present.
- Eyelid margin lesions may result in a toxic secondary keratoconjunctivitis.
- The lesions usually resolve spontaneously in 3-12 months.

Question 7

Entropion

Answer 7

• inversion of the eyelid margin.
• The retroverted eyelashes usually scratch the cornea, causing epithelial damage and irritation.
• Causes include involutional changes of ageing and scarring.

Question 8

Ectropion

Answer 8

• eversion of the eyelid margin.
• Because the lower lid no longer guides tear flow to the inferior punctum, it is often associated with epiphora.
• Causes include involutional changes of ageing and scarring.

Question 9

Ptosis
General
Aetiological classification

Answer 9

GENERAL
- abnormal drooping of the upper lid.
- Normally the upper lid covers only the superior 1-2 mm of the cornea.

AETIOLOGICAL CLASSIFICATION
1. NEUROGENIC
(a) Oculomotor (III) paralysis
(b) Horner’s syndrome: sympathetic denervation. (Small pupil, hanging eyelid)
2. INVOLUTIONAL
Involutional changes of ageing result in stretching of the levator aponeurosis or dehiscence of the aponeurosis from the tarsal plate.

Question 10

External Hordeolum (Style)
General
Clinical features

Answer 10

GENERAL
- staphylococcal abscess of an eyelash follicle.
- common in people with staphylococcal blepharitis

CLINICAL FEATURES
- Presents as a tender, inflamed swelling, maximal on the eyelid margin.
- always points anteriorly to the base of an eyelash.
- resolves spontaneously with or without draining onto the skin at the base of the eyelash.

Question 11

Dermatochalasis

Answer 11

• excessive loose skin on the upper lid as a result of involutional changes of ageing.
• When this begins to interfere with opening the eyes, surgical removal of the excess skin is indicated.

Question 12

Epicanthus

Answer 12

• may mimic esotropia (pseudostrabismus).
• eye condition that refers to either one or both of your eyes pointing inward.

Question 13

Xanthelasma

Answer 13

• flat or raised, yellowish lipid deposits under the skin
• common and occur mainly around the medial canthus.
• associated with hyperlipidemia.

Question 14

Different neoplasms

Answer 14

• basal cell carcinoma
• squamous cell carcinoma
• tarsal gland (meibomian) carcinoma
• Kaposi’s sarcoma

Question 15

Basal cell carcinoma

Answer 15

• commonest primary malignant tumour of the eyelids, with a peak incidence in the elderly
• many morphological types and it cannot reliably be distinguished clinically from the much rarer squamous carcinoma.

Question 16

Congenital conditions
Epicanthus
Epiblepharon

Answer 16

Epicanthus - looks like child is squinting but isn’t

Epiblepharon - Lower lid folds in and scrathes cornea

Question 17

Origin and function of the 3 layers of tear film

Answer 17

OUTER LIPID LAYER
- Secreted by the tarsal glands.
- Retards evaporation of the aqueous layer.
- Forms a lipid layer on the eyelid margin, preventing tears
from spilling over the edge of the eyelid.

MIDDLE AQUEOUS LAYER
- Secreted by the lacrimal gland.
- Constitutes 90% of the thickness of the tear film.

INNER MUCIN LAYER
- Secreted by conjunctival goblet cells.
- Adheres to the hydrophobic surface epithelium and acts as a hydrophilic surface on which the aqueous layer can be spread.

Question 18

Aqueous layer deficiency (Keratoconjunctivitis sicca)
Causes
Clinical features

Answer 18

Sicca = dry

CAUSES
1. Idiopathic
- no obvious cause it is primarily a disease of postmenopausal women
- may present in isolation, or as part of a more general condition including dryness of the mouth and genitalia.
2. Injury to the lacrimal gland
- Infection, surgery, autoimmune, with a strong association with connective tissue diseases, especially rheumatoid arthritis.
3. Occlusion of the lacrimal gland’s drainage ducts
- in cicatricial conjunctival diseases such as chemical burns, trachoma and Stevens-Johnson syndrome.

CLINICAL FEATURES
- burning and scratching eyes, especially when in an environment that promotes evaporation of tears, such as in the wind, or in air conditioning
- Macroscopic signs are minimal until the condition is sufficiently severe to produce corneal vascularisation, opacification and even keratinisation.
- Reduced antibacterial activity of the tear film and surface epithelial damage results in susceptibility to secondary infections.

Question 19

Lipid & Mucin layer deficiency
Causes
Clinical features

Answer 19

CAUSES
- Blepharitis may cause an abnormality of or decrease in the lipid layer secreted by the tarsal glands.
- Any condition that leads to extensive destruction of the mucous secreting conjunctival goblet cells will cause a mucin deficiency.
(a) Cicatricial conjunctival diseases such as chemical burns, trachoma and Stevens-Johnson
syndrome.
(b) Xerophthalmia (vitamin A deficiency).

CLINICAL FEATURES
- burning and scratching eyes
- paradoxical symptom of tearing.
- Tear film instability results in small dry spots on the ocular surface
- cause irritation and reflex aqueous tear secretion by the lacrimal gland to produce an excessive volume of fluid in the eye despite the dryness.
- macroscopic signs are minimal until the condition is sufficiently severe to produce corneal vascularisation, opacification and even keratinisation.

Question 20

Eyelid abnormalities
General
Causes

Answer 20

• result in inadequate wetting of parts of the cornea.
• resultant damage is known as exposure keratitis.
• damage is confined to the epithelium, but this is followed by vascularisation, opacification and eventually keratinisation.

CAUSES
1. ABNORMAL EYELID CONTOUR
- Trauma
- Trachoma
- Tumour
2. DISRUPTION OF EYELID MOVEMENTS
- Lagophthalmos (incomplete eyelid closure): VII paralysis.
- Symblepharon (adhesion between palpebral and bulbar conjunctiva): trauma, trachoma, Stevens-Johnson syndrome.

Question 21

Ocular surface abnormalities

Answer 21

• ocular surface may have an abnormal contour or abnormal epithelium as a result of pathology such as a pterygium or scarring.
• These areas may cause tear film turbulence or may resist mucin adhesion resulting in an unstable tear film and the formation of dry patches.

Question 22

Congenital epiphora

Answer 22

• Obstruction to tear outflow results in tears collecting in the conjunctival sac and flowing over the lid margin
• Obstruction causes stasis which predisposes to acute and chronic infections of the lacrimal sac.

Question 23

Lacrimal sac vs nasolacrimal duct

Answer 23

Nasolacrimal duct
- 5% of neonates
- thin membrane occludes the nasal orifice of the nasolacrimal duct.
- present with tearing and discharging eyes.
- Acute dacryocystitis may develop.

Lacrimal sac
- 90% of cases the tearing clears spontaneously by about 12 months of age
- Treatment consists of massaging the lacrimal sac twice a day, and the mother is taught to do this
- If the problem is not resolved by 12 months of age, probing must be considered.

Question 24

Acute dacryocystitis
Pathophysiology
Symptoms
Signs

Answer 24

PATHOPHYSIOLOGY
- Obstruction of tear flow distal to the lacrimal sac leads to stasis and predisposes to secondary infection.
- lacrimal sac fills with pus and a surrounding cellulitis occurs.

SYMPTOMS
- Epiphora (excessive tearing)
- Pain

SIGNS
- Epiphora
- Redness, swelling and tenderness over the lacrimal sac.
- The abscess may point and discharge onto the skin.

Question 25

Chronic Dacryocystitis
Pathophysiology
Symptoms
Signs

Answer 25

PATHOPHYSIOLOGY
- obstruction of tear flow distal to the lacrimal sac leads to stasis,
- remains low grade and the lacrimal sac fills with mucopurulent material instead of frank pus
- causes a chronic conjunctivitis with chronic irritation of the eye.
- no significant surrounding cellulitis, and consequently redness and tenderness over the lacrimal sac area are not prominent features, as they are in acute dacryocystitis.

SYMPTOMS
- Epiphora
- Mucopurulent discharge

SIGNS
- Epiphora
- Swelling over the lacrimal sac.
- Mucopurulent discharge.
- Pressure on the lacrimal sac results in mucopurulent material being expressed from the puncta.