Lids 1 - Lacrimal system + disorders

Question 1

Lacrimal System and tear film physiology?

Answer 1

•Produces tear film - three layers
- Lipid layer (0.1u), aqueous layer (8u), mucin layer (0.8u)
- Basal tear secretion - 1.2 ul/min
- Total basal tear production + drainage 10ml/day

Question 2

Outer lipid layer :

Answer 2

•Secreted by meibomian glands on eyelids
•Prevents tear evaporation
•Smooth eyelid movements on globe

Question 3

Middle aqueous layer:

Answer 3

•Secreted by lacrimal glands
•Supplies oxygen to avascular corneal epithelium
•Contains antibacterial enzymes
•Smooths corneal surface
•Washes away debris

Question 4

Inner mucin layer:

Answer 4

•Secereted by conjunctival goblet cells
•Converts corneal surface from hydrophobic to hydrophilic

Question 5

Lacrimal drainage:

Answer 5

•Eyelid closure (blink)
- Punctal opposition
- Lacrimal sac dilation
- Tears pushed into sac
•Eyelid opening
- Sac collapses (pushes tears into nasolacrimal duct)
- Canaliculi dilate (-ve pressure)

Question 6

Watery eye main causes:

Answer 6

•Hyperlacrimation
•Impaired drainage

Question 7

Hyperlacrimation (reflex epiphora) causes:

Answer 7

Trauma/inflammation
•Conjunctivitis/corneal FB
•Trichiasis
•Emotional stress
•Conjunctivitis
• Corneal ulcers
•Dry eye
•Blepharitis

Question 8

Dry eye :

Answer 8

•Commonest cause of reflex hyperlacrimation (5-30% of people over 50yrs are affected)
•Often not very obvious to examiner
- Unless think of it as cause of excess watering it is often misdiagnosed
•Dysfunction to any of the three layers of the pre-corneal tear film can lead to dry eye

Question 9

Dry eye symptoms

Answer 9

•Watering
• Ocular irritation
• Foreign body sensation
• Burning
• Photophobia
• Symptoms worse while reading, watching TV etc.(reduced blink reflex)
•Rarely complain of dry eyes

Question 10

Dry eyes - Signs

Answer 10

• Small marginal tear meniscus
• Mucous strands in conjunctiva
• Corneal filaments in severe cases
• Corneal punctate staining with flourescein
• Tear film break up
• Schirmer test
- 15mm normal:10mm borderline:5mm dry eye

Question 11

Filamentary keratitis

Answer 11

•Severe dry eye
•Thread like strands
- Degenerated epithelial cells + mucus adhering to corneal surface

Question 12

Management of dry eye

Answer 12

• General advice - avoid low humidity (air conditioning, warm room with too much heating, humidifiers etc)
• Tear substitutes
- hypromellose, carmellose (celluvisc)
- polyvinyl alcohol (liquifilm tears)
- carbomer gels (viscotears, gel tears)
- sodium hyaluronate based (hylo tears)
- petrolatum based ointments (lacrilube)
• Acetylcysteine for corneal filaments (lube)
Ciclosporin eye Drops (Ikervis)

Question 13

Punctal occlusion

Answer 13

•May be temporary or permanent
- Prevents drainage of tears, to help preserve what little tears

Question 14

Reduced tear drainage (epiphora) two categories :

Answer 14

•Obstruction to drainage
- Canalicular obstruction /inflammation
- Nasolacrimal duct blockage
- Lacrimal sac tumours

•Physiological dysfunction
- Eyelid malpositions (ectropion /entropion)
- Lacrimal pump failure (orbicularis weakness)
- Nasal pathology with normal lacrimal pathway

Question 15

History taking for Watery eye:

Answer 15

•Onset
• Any associated symptoms - red eye, photophobia, blurring, discharge, fb sensation, itchy eyes
• Lacrimal sac swelling
• History of medication - pilocarpine, chemo or radiotherapy (canalicular obstruction)
• Indoors or outdoors
• Inner or outer corner of eye

Question 16

Examination of watery eye:

Answer 16

• Eyelid position
• Dynamic eyelid closure
• Evaluate the puncta
• Lacrimal sac
• Tear meniscus (marginal tear strip)
• Flourescein dye disappearance test

Question 17

Eyelid laxity - lid distraction test

Answer 17

• Horizontal lid laxity is presumed if eyelid can be pulled >8mm from the cornea - Lacrimal pump failure

Question 18

Eyelid laxity - Snap-back test

Answer 18

• Pull the LL down with finger on centre of orbital rim and release to observe return of eyelid
• Spontaneous return
-Quick - Normal
- Slow - mild lid laxity
• Return with blink - moderate lid laxity
• Incomplete return - severe lid laxity

Question 19

What do we observe with lid closure?

Answer 19

• Normal - puncta well apposed when eyelids closed
• Abnormal - over riding of eyelid margins in lid laxity
• Abnormal - punctal eversion on eyelid closure

Question 20

Why do we examine the puncta?

Answer 20

• Slit lamp examination
• Normal - puncta directed posteriorly in contact with globe
• Look for punctal eversion, stenosis, abscess or foreign body,
• Canaliculitis

Question 21

Lacrimal sac examination:

Answer 21

•Check if sac is inflamed
•Fluorescein dye disappearance test

Question 22

History : Symptoms for obstructive epiphora:

Answer 22

•Watery
•Constant - both indoors and outdoors
•Tears run down the inner corner of the eye
•Lower lid skin changes

Question 23

Examinations: Signs for obstructive epiphora and techniques

Answer 23

• Rule out lid position abnormalities

• High tear meniscus
• Delayed FDDT

• Examine lacrimal puncta (stenosis, occlusion)
Techniques
• Syringing
•Imaging - Dacrocystogram

Question 24

Managements - two options for Blocked nasolacrimal duct?

Answer 24

• Dacryocystorhinostomy surgery
- Operation usually done under General
Anesthetic
- Lacrimal sac exposed
- Bony ostium created on lateral wall of nose
- Lacrimal sac connected to nasal mucosa to create alternate pathway for tear drainage into nose.

• Silicone intubation