Lacrimal System

Question 1

Tear flow

Answer 1

1. Secretion by the lacrimal gland onto the ocular surface
2. Channeled medially by the orbicularis pump mechanism
3. Drainage into the nasolacrimal system via the upper and lower puncta
4. Flow through the upper and lower canaliculi into the common canaliculus
5. Common canaliculus → Nasolacrimal sac → Nasolacrimal duct → inferior nasal meatus

Question 2

Thinnest and most superficial layer of the tear film

Answer 2

lipid layer
prevents evaporation of the tear film
produced by meibomian gland

Question 3

thickest layer of the tear film

Answer 3

aqueous layer
Produced by lacrimal gland
has an immune function

Question 4

Deepest layer of the tear film

Answer 4

Mucin layer
Produced by conjunctival goblet cells
Spreads film evenly and keeps it stable

Question 5

Lacrimal gland innervation

Answer 5

Sensory innervation → lacrimal nerve (branch of CNV1)
Lacrimation (secretomotor) → Parasympathetic (CN7)

Question 6

accessory lacrimal glands

Answer 6

krause and wolfring

Question 7

Krause glands

Answer 7

found at the conjunctival fornices and are more abundant in the upper fornix

Question 8

Wolfring glands

Answer 8

less numerous but bigger. They are found at the tarsal plate.

Question 9

Eyelash associated glands

Answer 9

The glands of Moll and Zeis

Question 10

Moll galnds

Answer 10

apocrine (modified sweat glands)

Question 11

Zeis glands

Answer 11

holocrine (sebaceous)

Question 12

Schrimers test description

Answer 12

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

Question 13

TBUT test description

Answer 13

Eye is stained with fluorescein dye and the time taken for the first dry spot to appear on the cornea is measured

Question 14

Jones test description

Answer 14

Jones 1 -
Dye squirted onto the conjunctiva and cotton bud placed in the inferior meatus.
Jones 2 -
Dye syringed into the nasolacrimal system and cotton bud placed in the inferior meatus.

Question 15

Dacryocystography

Answer 15

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

Question 16

Dacryoscintigraphy

Answer 16

Radiological evaluation of nasolacrimal system drainage using radiopharmaceutical eyedrops

Question 17

schirmer test interpretation

Answer 17

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

Question 18

TBUT test interpretation

Answer 18

<5 seconds → abnormal tear film
10-30 seconds → normal

Question 19

Treatment ladder of dry eye

Answer 19

1. Lubrication and artificial tears
2. Topical steroids and pilocarpine
3. Punctal plugs
4. Autologous serum drops
5. Bandage contact lenses
6. Tarsorrhaphy (sewing the lids shut, this is typically a temporary measure)

Question 20

pathology of Sjogren’s syndrome

Answer 20

associated with rheumatoid arthritis and SLE
anti-ro and anti-la autoantibodies

Question 21

triad of sjogren’s

Answer 21

dry eye, dry mouth and parotid gland swelling