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Duke Elder > Lacrimal System > Flashcards

Lacrimal System Flashcards

1
Q

Tear Flow

A

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

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2
Q
A

A) lacrimal gland B) Superior punctum C) Superior lacrimal canal D) Lacrimal sac E) Inferior punctum F) Inferior lacrimal canal G)Nasolacrimal canal

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3
Q

Layers of Tear Film

A
  1. Lipid layer
    * Thinnest and most superficial layer
    * Produced by the meibomian gland (Sebaceous).
    * Prevents evaporation of the tear film.
  2. Aqueous layer
    * Produced by the lacrimal gland.
    * Thickest layer
    * Has an immune function
  3. Mucin layer
    * Deepest layer
    * Produced by conjunctival goblet cells.
    * Spreads the film evenly and keeps it stable on the ocular surface.
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4
Q

What is Reflex tearing?

A

A common cause of hypersecretion.

It is caused by irritation of the ocular surface.

A good quality tear film reduces reflex tearing.

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5
Q

Glands of Lacrimation

A
  1. Lacrimal Gland (main)
    Sensory innervation → lacrimal nerve (branch of CNV1)
    Lacrimation (secretomotor) → PNS (CN7)
  2. 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.
  3. 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)
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6
Q

Schirmer’s test

A

Filter paper placed under the lower lid. Amount of moisture measured after 5 mins

> 10mm → normal (Schirmer negative)
<5mm → tear deficiency (Schirmer positive)

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7
Q

Tear film break-up time

A

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

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8
Q

Jones 1 test and Jones 2 test

A
  1. Dye squirted onto the conjunctiva and cotton bud placed in the inferior meatus - No dye on cotton bud → do jones 2
  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
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9
Q

Dacryocystography

A

Radiological evaluation using injected fluorescent contrast to evaluate the nasolacrimal system morphology

Excellent anatomical detail for evaluation
Invasive and painful

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10
Q

Dacryoscintigraphy

A

Radiological evaluation of nasolacrimal system drainage using radiopharmaceutical eyedrops

Evaluation of tear flow but provides poor anatomical detail
Painless

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11
Q

Pathology of dry eyes

A

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

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12
Q

Eye conditions which predispose to dryness

A

Ectropion and lagophthalmos

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13
Q

Presentation of dry eyes

A

More common in the elderly and women of post-menopausal age
Gritty, irritated red eyes

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14
Q

Investigations for dry eyes

A

Schirmer’s test positive (<5mm)
Tear film breakup time <5 seconds
Ocular surface staining (fluorescein, rose bengal, lissamine green)

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15
Q

Treatment ladder for dry eyes

A

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)

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16
Q

How does pilocarpine help dry eyes

A

promotes lacrimation

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17
Q

Sjogren Syndrome

A

Autoimmune destruction of the salivary and lacrimal glands

Commonly associated with rheumatoid arthritis and SLE

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18
Q

Sjogren sydrome presentation

A

TRIAD: dry eye, dry mouth and parotid gland swelling

+Gritty, burning eyes

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19
Q

Dry eyes can lead to erosions of the ocular surface

Which dyes can be used to visualise these?

A

Fluorescein (cornea) and lissamine (conjunctiva)

20
Q

Management of Sjogren

A

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)

21
Q

Xerophthalmia

A

A major cause of childhood blindness in Africa

Severe Vitamin A deficiency → lack of tear production → dry eyes

22
Q

Presentation of Xerophthalmia

A

Characteristic Bitot’s spots - triangular conjunctival keratin buildups

23
Q

Investigations for Xerophthalmia

A

Standard findings in dry eye:

Tear film break up time is reduced (<5)
Schirmer’s test is positive
Ocular surface staining

24
Q

Management of Xerophthalmia

A

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)

25
Q

Mechanisms of epiphora

A

Nasolacrimal drainage failure and hyper-secretion.

26
Q

Causes of nasolacrimal drainage failure

A

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

27
Q

Causes of hyper-secretion

A

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.

28
Q

Management of Hypersecretion

A

Lubricants and other drops (steroids/antibiotics) to manage specific causes of irritation

29
Q

Congenital Nasolacrimal Duct Obstruction

A

Imperforate membrane over the valve of Hasner (between the nasolacrimal duct and inferior nasal meatus)

30
Q

Presentation of Congenital Nasolacrimal Duct Obstruction

A

Infant
Epiphora
Discharge when the lacrimal sac is squeezed

31
Q

Management of Congenital Nasolacrimal Duct Obstruction

A

<12 months of age
Massage + topical antibiotics + observation

> 12 months of age
1. Syringing and probing
2. Silicone stent intubation
3. Dacryocystorhinostomy (DCR)

32
Q

Acquired Lacrimal System Obstruction

+ Management

A
33
Q

Population affected by Dermatochalasis

A

Elderly and obese

34
Q

Population affected by orbicularis pump failure?

A

Seen in neuropathies such as Bell’s palsy

35
Q

What is Dacryoadenitis?

A

Inflammation of the lacrimal glands

36
Q

Pathology of Dacryoadenitis

A

Often idiopathic
Secondary causes include viral infections like mumps

37
Q

Presentation of Dacryoadenitis

A

Acutely painful upper lateral lid
Swollen lacrimal gland
Hypoglobus (medially)
Enophthalmos
S-shaped eyelid deformity

38
Q

Investigatins for Dacryoadenitis

A

Only if recurrent or suspicious

Orbital MRI/CT
Biopsy

39
Q

Bilateral dacryoadenitis should raise suspicion of?

A

sarcoidosis

40
Q

Management of dacryoadenitis

A

Oral NSAIDs or steroids
Resolution can take months

41
Q

Canaliculitis

A

Often caused by infection, most commonly by Actinomyces

42
Q

Presentation of Canaliculitis

A

Unilateral epiphora and discharge

43
Q

Management of Canaliculitis

A

Topical antibiotics and canaliculotomy

Canalicular repair following canalicular trauma is with a Mini Monoka tube for 3 months

44
Q

Dacryocystitis

A

Inflammation of the lacrimal sac. It requires urgent management to prevent the spread of cellulitis.

Caused by nasolacrimal duct obstruction, usually by Staphylococcus species

45
Q

Presentation of Dacryocystitis

A

Presents acutely with epiphora and a tender lacrimal sac.

46
Q

Management of Dacryocystitis

A

Acute - Warm compress and oral antibiotics

Chronic/recurrent
Dacryocystorhinostomy (open connection between the nasolacrimal duct and middle nasal meatus)

Duke Elder (12 decks)

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