Lacrimal System Flashcards
Tear Flow
Secretion by the lacrimal gland onto the ocular surface
Channeled medially by the orbicularis pump mechanism
Drainage into the nasolacrimal system via the upper and lower puncta
Flow through the upper and lower canaliculi into the common canaliculus
Common canaliculus → Nasolacrimal sac → Nasolacrimal duct → inferior nasal meatus
A) lacrimal gland B) Superior punctum C) Superior lacrimal canal D) Lacrimal sac E) Inferior punctum F) Inferior lacrimal canal G)Nasolacrimal canal
Layers of Tear Film
- Lipid layer
* Thinnest and most superficial layer
* Produced by the meibomian gland (Sebaceous).
* Prevents evaporation of the tear film. - Aqueous layer
* Produced by the lacrimal gland.
* Thickest layer
* Has an immune function - Mucin layer
* Deepest layer
* Produced by conjunctival goblet cells.
* Spreads the film evenly and keeps it stable on the ocular surface.
What is Reflex tearing?
A common cause of hypersecretion.
It is caused by irritation of the ocular surface.
A good quality tear film reduces reflex tearing.
Glands of Lacrimation
- Lacrimal Gland (main)
Sensory innervation → lacrimal nerve (branch of CNV1)
Lacrimation (secretomotor) → PNS (CN7) - Accessory Lacrimal Glands
Krause and Wolfring glands are accessory lacrimal glands that maintain a basal aqueous layer
Krause glands are found at the conjunctival fornices and are more abundant in the upper fornix
Wolfring glands a less numerous but bigger. They are found at the tarsal plate. - Eyelash Associated Glands
The glands of Moll and Zeis both service eyelash follicles
Moll glands are apocrine (modified sweat glands)
Zeis (and Meibomian glands) are holocrine (sebaceous)
Schirmer’s test
Filter paper placed under the lower lid. Amount of moisture measured after 5 mins
> 10mm → normal (Schirmer negative)
<5mm → tear deficiency (Schirmer positive)
Tear film break-up time
Eye is stained with fluorescein dye and the time taken for the first dry spot to appear on the cornea is measured
<5 seconds → abnormal tear film
10-30 seconds → normal
Jones 1 test and Jones 2 test
- Dye squirted onto the conjunctiva and cotton bud placed in the inferior meatus - No dye on cotton bud → do jones 2
- Dye syringed into the nasolacrimal system and cotton bud placed in the inferior meatus
- No dye on cotton bud → nasolacrimal system obstruction
- Dye is now seen on cotton bud → pump/punctal problem
Dacryocystography
Radiological evaluation using injected fluorescent contrast to evaluate the nasolacrimal system morphology
Excellent anatomical detail for evaluation
Invasive and painful
Dacryoscintigraphy
Radiological evaluation of nasolacrimal system drainage using radiopharmaceutical eyedrops
Evaluation of tear flow but provides poor anatomical detail
Painless
Pathology of dry eyes
Caused by a problem in the tear film (hyposecretion/instability) or increased evaporation
Can lead to erosions of the ocular surface, which can be blinding
Eye conditions which predispose to dryness
Ectropion and lagophthalmos
Presentation of dry eyes
More common in the elderly and women of post-menopausal age
Gritty, irritated red eyes
Investigations for dry eyes
Schirmer’s test positive (<5mm)
Tear film breakup time <5 seconds
Ocular surface staining (fluorescein, rose bengal, lissamine green)
Treatment ladder for dry eyes
Lubrication and artificial tears
Topical steroids and pilocarpine
Punctal plugs
Autologous serum drops
Bandage contact lenses
Tarsorrhaphy (sewing the lids shut, this is typically a temporary measure)
How does pilocarpine help dry eyes
promotes lacrimation
Sjogren Syndrome
Autoimmune destruction of the salivary and lacrimal glands
Commonly associated with rheumatoid arthritis and SLE
Sjogren sydrome presentation
TRIAD: dry eye, dry mouth and parotid gland swelling
+Gritty, burning eyes
Dry eyes can lead to erosions of the ocular surface
Which dyes can be used to visualise these?
Fluorescein (cornea) and lissamine (conjunctiva)
Management of Sjogren
Lubrication and artificial tears
Topical steroids and pilocarpine
Punctal plugs
Autologous serum drops
Bandage contact lenses
Tarsorrhaphy (sewing the lids shut, this is typically a temporary measure)
Xerophthalmia
A major cause of childhood blindness in Africa
Severe Vitamin A deficiency → lack of tear production → dry eyes
Presentation of Xerophthalmia
Characteristic Bitot’s spots - triangular conjunctival keratin buildups
Investigations for Xerophthalmia
Standard findings in dry eye:
Tear film break up time is reduced (<5)
Schirmer’s test is positive
Ocular surface staining
Management of Xerophthalmia
Lubrication and artificial tears
Topical steroids and pilocarpine
Punctal plugs
Autologous serum drops
Bandage contact lenses
Tarsorrhaphy (sewing the lids shut, this is typically a temporary measure)
Mechanisms of epiphora
Nasolacrimal drainage failure and hyper-secretion.
Causes of nasolacrimal drainage failure
Obstruction of the nasolacrimal system
* Punctal eversion
* Canalicular fibrosis
* Lacrimal sac obstruction
Nasolacrimal duct obstruction
* Orbicularis pump failure
* Lid laxity
* CN7 palsy
* Lateral dermatochalasis
* Overzealous punctoplasty
Causes of hyper-secretion
Irritation hyper-secretion is typically caused by a foreign body on the ocular surface or lashes rubbing on the ocular surface as in trichiasis and entropion
Autonomic abnormalities and pro-secretory drugs like pilocarpine can also cause hypersecretion.
Management of Hypersecretion
Lubricants and other drops (steroids/antibiotics) to manage specific causes of irritation
Congenital Nasolacrimal Duct Obstruction
Imperforate membrane over the valve of Hasner (between the nasolacrimal duct and inferior nasal meatus)
Presentation of Congenital Nasolacrimal Duct Obstruction
Infant
Epiphora
Discharge when the lacrimal sac is squeezed
Management of Congenital Nasolacrimal Duct Obstruction
<12 months of age
Massage + topical antibiotics + observation
> 12 months of age
1. Syringing and probing
2. Silicone stent intubation
3. Dacryocystorhinostomy (DCR)
Acquired Lacrimal System Obstruction
+ Management
Population affected by Dermatochalasis
Elderly and obese
Population affected by orbicularis pump failure?
Seen in neuropathies such as Bell’s palsy
What is Dacryoadenitis?
Inflammation of the lacrimal glands
Pathology of Dacryoadenitis
Often idiopathic
Secondary causes include viral infections like mumps
Presentation of Dacryoadenitis
Acutely painful upper lateral lid
Swollen lacrimal gland
Hypoglobus (medially)
Enophthalmos
S-shaped eyelid deformity
Investigatins for Dacryoadenitis
Only if recurrent or suspicious
Orbital MRI/CT
Biopsy
Bilateral dacryoadenitis should raise suspicion of?
sarcoidosis
Management of dacryoadenitis
Oral NSAIDs or steroids
Resolution can take months
Canaliculitis
Often caused by infection, most commonly by Actinomyces
Presentation of Canaliculitis
Unilateral epiphora and discharge
Management of Canaliculitis
Topical antibiotics and canaliculotomy
Canalicular repair following canalicular trauma is with a Mini Monoka tube for 3 months
Dacryocystitis
Inflammation of the lacrimal sac. It requires urgent management to prevent the spread of cellulitis.
Caused by nasolacrimal duct obstruction, usually by Staphylococcus species
Presentation of Dacryocystitis
Presents acutely with epiphora and a tender lacrimal sac.
Management of Dacryocystitis
Acute - Warm compress and oral antibiotics
Chronic/recurrent
Dacryocystorhinostomy (open connection between the nasolacrimal duct and middle nasal meatus)
