lacrimal systems and dry eyes

Question 1

what are layers of the tear film and role

Answer 1

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

Question 2

what is the lacrimal system pathway

Answer 2

Lacrimal gland → puncta → canaliculi → Lacrimal sac → nasolacrimal duct → inferior nasal meatus.

Question 3

what is the lacrimal gland

Answer 3

tubule-alveolar gland consisting of acini and ducts. Acini are responsible for the production of watery secretions.

Question 4

what are the two parts of lacrimal gland

Answer 4

Orbital part: Lies in the frontal bone.

Palpebral part: Located superolaterally in the eyelids, inferior to the levator palpebrae muscle.

Question 5

what is the function of the lacrimal gland

Answer 5

Forms the aqueous layer of the tear film.

Question 6

what is the blood supply of the lacrimal gland

Answer 6

lacrimal artery - branch of the ophthalmic artery

Question 7

nerve supply of the lacrimal gland

Answer 7

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.

Question 8

what is the lacrimal reflex

Answer 8

CNV1 (afferent) and CNVII (efferent)

Question 9

what are the accessory lacrimal glands

Answer 9

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

Question 10

what is the krause gland

Answer 10

Situated adjacent to the conjunctival fornix. They are more numerous in the upper eyelid.

Question 11

what is the wolfring glands

Answer 11

Situated in the upper border of the tarsal plate. Although fewer in number, they are larger than Krause glands.

Question 12

what is the puncta

Answer 12

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.

Question 13

what is the canaliculi and what is it made of

Answer 13

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.

Question 14

what is the cannaliculus and what is the name of the valve between this and lacrimal sac

Answer 14

superior and inferior canaliculi join together at the canaliculus

Rosenmuller valve at the junction of the lacrimal sac and common canaliculus

Question 15

importance of the rosenmuller valve

Answer 15

preventing tear reflux

Question 16

what is the lacrimal sac

Answer 16

Situated in the lacrimal fossa, which is formed by the lacrimal bone and frontal process of the maxilla.

Question 17

what is the nasolacrimal duct

Answer 17

● 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

Question 18

role of the valve of Hasner

Answer 18

his valve

functions to prevent air entering the nasolacrimal system during nose blowing.

Question 19

main presentation of acquired obstruction in the nasolacrimal duct

Answer 19

epiphora

Question 20

causes of punctal stenosis and MX

Answer 20

idiopathic
chronic blepharitis
HSV or HZO

Mx

• dilatation of the punctum
• Punctoplasty

Question 21

causes of nasolacrimal obstruction and Mx

Answer 21

● Causes: Idiopathic, trauma, surgery or tumours.

● Treatment: Dacryocystorhinostomy (anastomosis of lacrimal sac with mucosa of middle meatus).

Question 22

in congenital nasolacrimal duct obstruction where is the obstruction usually

Answer 22

valve of Hasner

Question 23

features of congenital nasolacrimal duct obstruction

Answer 23

● Epiphora
- matting of lashes
● Mucopurulent discharge on pressure over lacrimal sac

Question 24

Mx of congenital nasolacrimal duct obstruction

Answer 24

● 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.

Question 25

what is canaliculitis and caused by which organism

Answer 25

infection of the canaliculi most commonly due to Actinomyces israelii. anaerobic filamentous gram +ve

Question 26

Sx of canaliculitis

Answer 26

• unilateral red eye
• epiphora
• swollen lump on medical eyelid margin
• Mucoid discharge when pressure applied over canaliculus
• sulfur granules at punctum, pouting

Question 27

RFs of canaliculitis

Answer 27

• obstruction of cancaliculus ie punctal plug

- typically occurs in adults over 40

Question 28

Mx of canaliculitis

Answer 28

• warm compress
• topical ABx - levofloxacin
• canaliculotomy for chronic cases

Question 29

what is dacryoadenitis and main RF and secondary cause

features

Answer 29

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.

Question 30

what is dacrocystitis

Answer 30

infection of lacrimal sac secondary to obstruction in nasolacrimal duct causing stagnation of tears

Question 31

bilateral dacryoadenitis should raise suspicion of what condition

Answer 31

sarcoidosis

Question 32

in dacryoadenitis persistence or presence of parasethesia should raise concern of what

Answer 32

carcinoma

Question 33

features of dacryoadenitis

Answer 33

● 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.

Question 34

common organisms that cause dacryocystitis

Answer 34

ADULTS - Staphylococcus aureus

CHILDREN - Haemophilus influenzae

• S. epidermidis (in adults)
• Streptococcus pneumoniae

Question 35

acute features of dacryocystitis and acute mx

Answer 35

• 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.

Question 36

chronic features of dacryocystitis and chronic Mx

Answer 36

Epiphora and recurrent unilateral conjunctivitis.

SIGNS

• painless swelling at the inner canthus caused by mucocele
• pressure - mucopurulent material

Treat with dacryocystorhinostomy.

Question 37

what is pleomorphic adenoma

Answer 37

Most common lacrimal gland tumour, occurring in middle-aged patients. Benign, but can transform into malignant.

Question 38

histopathology and Ix of pleomorphic adenoma

Answer 38

Epithelial and mesenchymal components.

CT scan

Question 39

features and Mx of pleomorphic adenoma

Answer 39

Progressive, painless enlargement of the upper eyelid with
inferonasal dystopia.

Mx
surgical excision

Question 40

histopathology of lacrimal gland carcinoma

Answer 40

The main type is adenoid cystic carcinoma, which exhibits a cribriform or ‘Swiss cheese’ growth pattern. Other types include pleomorphic adenocarcinoma and mucoepidermoid carcinoma.

Question 41

features of lacrimal gland carcinoma

Answer 41

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).

Question 42

Mx of lacrimal gland carcinoma

Answer 42

Biopsy, orbital exenteration (surgical removal of the globe and surrounding tissue), radical orbitectomy and/or radiotherapy.

Question 43

RFs for dacrocystitis

Answer 43

females
>40
rhinits
Wegner’s granulomatosis

Question 44

what is Sjogren

Answer 44

An autoimmune condition in which the salivary and lacrimal glands become infiltrated with lymphocytes and the acini are progressively destroyed.

Question 45

features of Sjogren

Answer 45

● 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).

Question 46

Ix for Sjoren

Answer 46

● 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.

Question 47

Mx of dry eye

Answer 47

● 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).

Question 48

what is xerophthalmia

Answer 48

Xerophthalmia is caused by severe vitamin A deficiency, which is a major cause of childhood blindness in Africa.

Question 49

features of xerophthalmia

Answer 49

● Nyctalopia
● Xerosis: Severe conjunctival dryness and keratinization
● Bitot’s spots: Triangular keratinized buildup on the conjunctiva
● Punctate corneal epithelial erosions
● Keratomalacia in severe cases

Question 50

Mx of xerophthalmia

Answer 50

Vitamin A supplementation and topical lubrication.

Question 51

Length of ampulla
canaliculus
lacrimal sac
nasolacrimal duct

Answer 51

ampulla 2mm
cannaliculus - 8mm
lacrimal sac - 10mm
nasolacrimal duct - 12mm

Question 52

what is dacryocystorhinostomy

indications

Answer 52

anastamosis between sac and the nasal mucosa to bypass an obstruction

Obstruction beyond the medial opening of the common canaliculus

Question 53

causes if a watering eye

Answer 53

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

Question 54

what is congenital dacryocele

signs
Mx

Answer 54

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

Question 55

what is the ‘giant fornix syndrome’

Answer 55

chronic relapsing purulent conjunctivitis

retained debris in the upper fornix colonised by S.aureus

Question 56

RFs of dacrocystitis

Answer 56

females
>40
rhinitis
wegner’s granulomatosis