lacrimal systems and dry eyes Flashcards
what are layers of the tear film and role
lipid (superficial)
- meiobian glands
- prevent aqueous layer evaporation
- 0.1um
aqueous
- lacrimal gland (reflex secretion) and accessory lacrimal glands (basal secretion)
- antibacterial activity
washing out debris and supplying cornea with nutrients
- 7um
mucous (deep)
- conjunctival goblet cells
- aids in spreading tears and stabilising the tear film
- 0.2um
what is the lacrimal system pathway
Lacrimal gland → puncta → canaliculi → Lacrimal sac → nasolacrimal duct → inferior nasal meatus.
what is the lacrimal gland
tubule-alveolar gland consisting of acini and ducts. Acini are responsible for the production of watery secretions.
what are the two parts of lacrimal gland
Orbital part: Lies in the frontal bone.
Palpebral part: Located superolaterally in the eyelids, inferior to the levator palpebrae muscle.
what is the function of the lacrimal gland
Forms the aqueous layer of the tear film.
what is the blood supply of the lacrimal gland
lacrimal artery - branch of the ophthalmic artery
nerve supply of the 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.
what is the lacrimal reflex
CNV1 (afferent) and CNVII (efferent)
what are the accessory lacrimal glands
These glands are histologically similar to the lacrimal gland. They sustain the basal secretory level of the aqueous layer of the tear film.
krause
wolfring
what is the krause gland
Situated adjacent to the conjunctival fornix. They are more numerous in the upper eyelid.
what is the wolfring glands
Situated in the upper border of the tarsal plate. Although fewer in number, they are larger than Krause glands.
what is the puncta
A small, round opening located medially at the posterior edge of the upper and lower lid margins at the junction of the lid’s ciliated and non-ciliated parts.
what is the canaliculi and what is it made of
composed of superior and inferior canaliculi
● A vertical part, the ampulla (2 mm long).
● A second horizontal part, about 8 mm long, after the vertical part.
what is the cannaliculus and what is the name of the valve between this and lacrimal sac
superior and inferior canaliculi join together at the canaliculus
Rosenmuller valve at the junction of the lacrimal sac and common canaliculus
importance of the rosenmuller valve
preventing tear reflux
what is the lacrimal sac
Situated in the lacrimal fossa, which is formed by the lacrimal bone and frontal process of the maxilla.
what is the nasolacrimal duct
● Continuation of the lacrimal sac.
● Opens into the inferior meatus in the nose.
● The opening contains a fold of mucous called the valve of Hasner. T
role of the valve of Hasner
his valve
functions to prevent air entering the nasolacrimal system during nose blowing.
main presentation of acquired obstruction in the nasolacrimal duct
epiphora
causes of punctal stenosis and MX
idiopathic
chronic blepharitis
HSV or HZO
Mx
- dilatation of the punctum
- Punctoplasty
causes of nasolacrimal obstruction and Mx
● Causes: Idiopathic, trauma, surgery or tumours.
● Treatment: Dacryocystorhinostomy (anastomosis of lacrimal sac with mucosa of middle meatus).
in congenital nasolacrimal duct obstruction where is the obstruction usually
valve of Hasner
features of congenital nasolacrimal duct obstruction
● Epiphora
- matting of lashes
● Mucopurulent discharge on pressure over lacrimal sac
Mx of congenital nasolacrimal duct obstruction
● First line: Observation and massaging of the lacrimal sac for the first 12 months of life.
● Second line: Nasolacrimal duct probing.
● Third line: Nasolacrimal duct stent insertion, balloon dilatation or
dacryocystorhinostomy.
what is canaliculitis and caused by which organism
infection of the canaliculi most commonly due to Actinomyces israelii. anaerobic filamentous gram +ve
Sx of canaliculitis
- unilateral red eye
- epiphora
- swollen lump on medical eyelid margin
- Mucoid discharge when pressure applied over canaliculus
- sulfur granules at punctum, pouting
RFs of canaliculitis
- obstruction of cancaliculus ie punctal plug
- typically occurs in adults over 40
Mx of canaliculitis
- warm compress
- topical ABx - levofloxacin
- canaliculotomy for chronic cases
what is dacryoadenitis and main RF and secondary cause
features
idiopathic lacrimal gland inflammation.
tear stasis
viral infections (mumps)
● 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 dacrocystitis
infection of lacrimal sac secondary to obstruction in nasolacrimal duct causing stagnation of tears
bilateral dacryoadenitis should raise suspicion of what condition
sarcoidosis
in dacryoadenitis persistence or presence of parasethesia should raise concern of what
carcinoma
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.
common organisms that cause dacryocystitis
ADULTS - Staphylococcus aureus
CHILDREN - Haemophilus influenzae
- S. epidermidis (in adults)
- Streptococcus pneumoniae
acute features of dacryocystitis and acute mx
- subacute onset of pain in medial canthal area
- epiphora
SIGNS
Erythematous
tender swelling over the lacrimal sac
ass w preseptal cellulitis
Mx
Treat with warm compresses, systemic antibiotics and dacryocystorhinostomy after the acute phase has completely resolved to reduce the risk of recurrence.
chronic features of dacryocystitis and chronic Mx
Epiphora and recurrent unilateral conjunctivitis.
SIGNS
- painless swelling at the inner canthus caused by mucocele
- pressure - mucopurulent material
Treat with dacryocystorhinostomy.
what is pleomorphic adenoma
Most common lacrimal gland tumour, occurring in middle-aged patients. Benign, but can transform into malignant.
histopathology and Ix of pleomorphic adenoma
Epithelial and mesenchymal components.
CT scan
features and Mx of pleomorphic adenoma
Progressive, painless enlargement of the upper eyelid with
inferonasal dystopia.
Mx
surgical excision
histopathology of lacrimal gland carcinoma
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 of lacrimal gland carcinoma
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).
Mx of lacrimal gland carcinoma
Biopsy, orbital exenteration (surgical removal of the globe and surrounding tissue), radical orbitectomy and/or radiotherapy.
RFs for dacrocystitis
females
>40
rhinits
Wegner’s granulomatosis
what is Sjogren
An autoimmune condition in which the salivary and lacrimal glands become infiltrated with lymphocytes and the acini are progressively destroyed.
features of Sjogren
● 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).
Ix for Sjoren
● 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.
Mx of dry eye
● 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).
what is xerophthalmia
Xerophthalmia is caused by severe vitamin A deficiency, which is a major cause of childhood blindness in Africa.
features of xerophthalmia
● Nyctalopia
● Xerosis: Severe conjunctival dryness and keratinization
● Bitot’s spots: Triangular keratinized buildup on the conjunctiva
● Punctate corneal epithelial erosions
● Keratomalacia in severe cases
Mx of xerophthalmia
Vitamin A supplementation and topical lubrication.
Length of ampulla
canaliculus
lacrimal sac
nasolacrimal duct
ampulla 2mm
cannaliculus - 8mm
lacrimal sac - 10mm
nasolacrimal duct - 12mm
what is dacryocystorhinostomy
indications
anastamosis between sac and the nasal mucosa to bypass an obstruction
Obstruction beyond the medial opening of the common canaliculus
causes if a watering eye
1) hypersecretion - inflammation or surface disease
2) defective drainage
a. malposition of the lacrimal puncta ie secondary ectropion
b. obstruction along lacrimal drainage
c. lacrimal pump failure - lower lid laxity or weakness of the orbicularis muscle
what is congenital dacryocele
signs
Mx
collection of amniotic fluid or mucus in the lacrimal sac caused by an imperforate hasner valve
signs - bluish cystic swelling at or below medial canthus
what is the ‘giant fornix syndrome’
chronic relapsing purulent conjunctivitis
retained debris in the upper fornix colonised by S.aureus
RFs of dacrocystitis
females
>40
rhinitis
wegner’s granulomatosis
