Lacrimal system and dry eyes Flashcards
Function of lacrimal gland
Forms the aqueous layer of the tear film
Pathway of lacrimal system
Lacrimal gland → puncta → canaliculi → Lacrimal sac → nasolacrimal
duct → inferior nasal meatus
See picture
Parts of lacrimal gland?
-Orbital part: Lies in the frontal bone.
-Palpebral part: Located superolaterally in the eyelids, inferior to the levator palpebrae muscle
Blood supply lacrimal gland
Lacrimal artery, a branch of the ophthalmic artery
Nerve supply lacrimal gland
Sensory: Lacrimal nerve (CNV1).
● Parasympathetic secretomotor: CNVII. Pathway: preganglionic
parasympathetic fibres originate from the superior salivatory nucleus
in the pons and travel with the greater petrosal nerve (a branch of the
CNVII) to synapse at the pterygopalatine ganglion. Postganglionic fibres
then joins the lacrimal branch of CNV1 to supply the lacrimal gland
Acquired obstruction
Punctal stenosis
Nasolacrimal obstruction
Punctal stenosis causes and treatment
- Causes: Idiopathic or chronic blepharitis.
- Treatment: Punctoplasty.
Nasolacrimal obstruction
- Causes: Idiopathic, trauma, surgery or tumours.
- Treatment: Dacryocystorhinostomy (anastomosis of lacrimal sac with
mucosa of middle meatus).
Congenital nasolacrimal duct obstruction
Can occur in newborns
90% of cases resolve within the first 12 months of life. Typically occurs at valve of Hasner
Congenital nasolacrimal duct obstruction features and treatment
Features: Epiphora, Mucopurulent discharge on pressure over lacrimal sac
Treatment:
1st line - Observation and massaging of the lacrimal sac for the first 12 months of life
2nd line - Nasolacrimal duct probing
3rd line - Nasolacrimal duct stent insertion, balloon dilatation, or dacrycystorhinostomy
What is canaliculitis?
This is an infection of the canaliculi most commonly due to Actinomyces israelii.
Usually presents unilaterally with epiphora, red eye and discharge on pressure
over the canaliculus.
Management: Topical antibiotics
What is dacryoadenitis?
Idiopathic lacrimal gland inflammation
Causes of dacryoadenitis
Tear stasis
Viral infections e.g mumps
Sarcoidosis (cause bilateral)
Features of dacryoadenitis
- Painful, tender, erythematous and swollen lacrimal gland (superolateral
upper eyelid). - Disturbed tear production.
- S-shaped ptosis of the upper eyelid.
- Downward and inward displacement of the globe
What is dacryocystitis?
Infection of the lacrimal sac due to an obstruction in the nasolacrimal duct. Most
commonly due to Staphylococcus aureus, S. epidermidis (in adults), Streptococcus
pneumoniae or Haemophilus influenzae (in children).
Features and mx of dacrocystitis?
Acute
● Erythematous, tender swelling over the lacrimal sac with associated
epiphora.
● Treat with warm compresses, systemic antibiotics and
dacryocystorhinostomy after the acute phase has completely resolved to
reduce the risk of recurrence.
Chronic
● Epiphora and recurrent unilateral conjunctivitis.
● Treat with dacryocystorhinostomy
Pleomorphic adenoma of lacrimal gland
Most common lacrimal gland tumour, occurring in middle-aged patients. Benign,
but can transform into malignant.
● Histopathology: Epithelial and mesenchymal components.
● Features: Progressive, painless enlargement of the upper eyelid with
inferonasal dystopia.
● Investigation: CT scan.
● Treatment: Surgical excision
Lacrimal gland carcinoma
A rare, malignant tumour of the lacrimal gland.
● Histopathology: The main type is adenoid cystic carcinoma, which
exhibits a cribriform or ‘Swiss cheese’ growth pattern. Other types include
pleomorphic adenocarcinoma and mucoepidermoid carcinoma.
● Features: Rapidly growing and painful lacrimal gland mass,
inferonasal dystopia, optic disc swelling, choroidal folds and may cause
perineural invasion (spreading of a cancer around a nerve causing
neurological deficits).
● Management: Biopsy, orbital exenteration (surgical removal of the globe and
surrounding tissue), radical orbitectomy and/or radiotherapy.
Xeropthalmia
Xerophthalmia is caused by severe vitamin A deficiency, which is a major cause
of childhood blindness in Africa.
FEATURES
● Nyctalopia
● Xerosis: Severe conjunctival dryness and keratinization
● Bitot’s spots: Triangular keratinized buildup on the conjunctiva
● Punctate corneal epithelial erosions
● Keratomalacia in severe cases
MANAGEMENT
Vitamin A supplementation and topical lubrication
What is Sjorgen syndrome
An autoimmune condition in which the salivary and lacrimal glands become
infiltrated with lymphocytes and the acini are progressively destroyed
Features of sjorgen syndrome
Triad: Xerostomia, keratoconjunctivitis sicca and parotid gland enlargement.
● Posterior blepharitis is commonly present.
● Corneal punctate epithelial erosions (stains with fluorescein).
● Strands of filaments containing mucus or debris (stains with rose bengal)
Investigations for Sjorgen syndrome
Anti-Ro and anti-La antibodies.
● Reduced tear film breakup time.
● Schirmer test: Determines whether the eye produces enough tears to keep it
moist.
● Ocular staining: Showing interpalpebral staining of cornea and conjunctiva,
rather than a superior or inferior stain pattern seen in superior limbic
keratoconjunctivitis or exposure keratopathy, respectively.
Management of Sjorgens
● First line: Ocular lubricants and artificial tears: includes hypromellose
(lowest viscosity), carbomer and paraffins (highest viscosity).
● Second line: Topical corticosteroids and/or oral pilocarpine (increases
lacrimal gland secretion).
● Third line: Punctal occlusion or low-water content bandage contact lenses
(e.g. silicone hydrogel)
