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Ophthamology > 10. Dry and watery eyes > Flashcards

10. Dry and watery eyes Flashcards

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1
Q

What are the three main layers of the tear film, from outermost to innermost?

A

Lipid layer (outermost), Aqueous layer (middle), and Mucus layer (innermost).

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2
Q

What is the function of the lipid layer in the tear film?

A

It prevents evaporation of the underlying aqueous layer.

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3
Q

Where is the lipid layer of the tear film produced?

A

It is secreted by the meibomian glands.

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4
Q

What is the main role of the aqueous layer in the tear film?

A

It provides lubrication, nutrition, antiseptic protection, and maintains optical regularity.

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5
Q

Which gland produces the aqueous layer of the tear film?

A

The lacrimal gland.

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6
Q

What is the function of the mucus layer in the tear film?

A

It aids wetting of the corneal surface by allowing the tear film to spread evenly.

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7
Q

Where is the mucus layer of the tear film produced?

A

By goblet cells in the conjunctiva.

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8
Q

What is the role of the corneal epithelium in relation to the tear film?

A

It forms the base of the tear film and interacts with the mucus layer to help anchor the film to the eye surface.

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9
Q

What are common symptoms of a lipid layer disturbance in the tear film?

A

Gritty or dry eyes, symptoms worse in the morning, and eyelid crusting.

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10
Q

Why are symptoms of lipid disturbance typically worse in the morning?

A

Because the eyes are closed during sleep, leading to tear film instability and poor lipid layer function overnight.

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11
Q

What condition is associated with crusting in lipid disturbance?

A

Anterior blepharitis, which involves crusting at the base of the eyelashes.

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12
Q

What is a clinical sign of posterior blepharitis related to lipid disturbance?

A

Meibomian gland pouting, where the gland openings appear swollen or prominent.

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13
Q

How does lipid disturbance affect the tear film?

A

It leads to increased evaporation of the aqueous layer, causing dryness and irritation.

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14
Q

What is Tear Film Break-Up Time (TBUT)?

A

TBUT is the time between a blink and the first appearance of dry spots or streaks in the fluorescein-stained tear film.

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15
Q

How is TBUT measured?

A

By instilling fluorescein dye into the eye and observing the tear film under a cobalt blue light.

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16
Q

What does a TBUT of less than 10 seconds indicate?

A

Tear film instability, which may be due to either tear deficiency or lipid layer disturbance.

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17
Q

What is seen on examination when TBUT is reduced?

A

Streaks or dry spots appear quickly in the tear film after a blink, usually within less than 10 seconds.

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18
Q

Why does a lipid disturbance reduce TBUT?

A

Because the lipid layer normally prevents evaporation; its disruption causes rapid drying of the tear film.

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19
Q

What is the first-line long-term management for blepharitis-related gritty eyes?

A

Twice daily lid scrubs using a clean swab or cotton bud.

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20
Q

What can be added to lid scrubs to help remove crusting?

A

Diluted baby shampoo can be used during lid scrubs to help with crusting.

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21
Q

What additional treatment is useful if the eyelids appear greasy?

A

Warm compresses, which help to soften meibum and improve gland drainage.

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22
Q

Which topical antibiotic is commonly used for blepharitis with crusting?

A

Chloramphenicol ointment applied twice daily for one month.

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23
Q

What alternative topical antibiotic can be used for severe crusting in blepharitis?

A

Fucidic acid is an alternative for more severe cases.

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24
Q

What role do lubricants play in managing blepharitis?

A

Lubricants relieve dryness and irritation by supplementing the tear film.

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25
What systemic treatment is used if there is no improvement with topical measures?
Doxycycline 100 mg daily for 3 months, which improves meibomian gland function and reduces inflammation.
26
Causes of tear deficiency
Oral contraceptives Smoking Sympathomimetic drugs Sjogren’s HIV-associated dry eye
27
How do oral contraceptives contribute to tear deficiency?
They alter hormonal balance, which can reduce lacrimal gland secretion.
28
Why does smoking cause tear deficiency?
Smoking increases tear film evaporation and can impair lacrimal gland function.
29
How do sympathomimetic drugs lead to tear deficiency?
They reduce parasympathetic stimulation to the lacrimal gland, decreasing tear production.
30
What autoimmune condition is a major cause of tear deficiency?
Sjögren’s syndrome, which involves autoimmune destruction of lacrimal and salivary glands.
31
How is HIV associated with dry eye?
HIV can cause lacrimal gland inflammation or infiltration, reducing tear secretion.
32
What is a hallmark symptom of tear deficiency?
A burning sensation that worsens as the day goes on.
33
When are tear deficiency symptoms commonly aggravated?
During prolonged concentration (e.g., reading or watching TV), in dry, windy weather, and in air-conditioned environments
34
What morning symptom is suggestive of tear deficiency?
Eyelids stuck together upon waking.
35
What causes dry eye due to mucus deficiency?
Loss of conjunctival goblet cells, which are responsible for producing the mucus layer of the tear film.
36
What are some conditions that cause goblet cell loss?
Ocular cicatricial pemphigoid Post-Stevens-Johnson syndrome Vitamin A deficiency Chemical burns
37
What is the consequence of mucus layer deficiency in the tear film?
It leads to severe dry eye due to poor tear film stability and can result in vision-threatening complications or blindness.
38
Why is early referral to an ophthalmologist important in mucus deficiency?
To initiate intensive treatment early and prevent complications, including vision loss.
39
What treatments may an ophthalmologist consider for mucus deficiency dry eye?
Frequent lubricants (especially preservative-free) Punctal occlusion to conserve tears
40
Tear replacement
Use drops during the day and ointment at night Titrate frequency against patients’ symptoms If patients need drops more than 4 times a day, consider preservative-free alternatives
41
What are the two main categories of causes of a watery eye?
Hypersecretion of tears Impaired drainage of tears
42
What are common causes of tear hypersecretion?
Dry eye (reflex tearing due to irritation) Allergic conjunctivitis Infective conjunctivitis Corneal irritation (e.g., foreign body, trichiasis, entropion)
43
How does dry eye cause a watery eye?
Paradoxically, irritation from dryness triggers reflex tearing, leading to overflow
44
How do allergies cause watery eyes?
Allergens trigger histamine release, leading to irritation and increased tear production.
45
What are causes of impaired tear drainage leading to watery eye?
Ectropion (punctum turned outward) Punctal stenosis (narrowing) Nasolacrimal duct obstruction (congenital or acquired) Canaliculitis Tumor compressing nasolacrimal system
46
What is the most common congenital cause of watery eye in infants?
Congenital nasolacrimal duct obstruction
47
What age-related change can impair tear drainage?
Involutional ectropion, causing malposition of the lower lid and punctum.
48
How can infection cause impaired tear drainage?
Chronic infections like canaliculitis or dacryocystitis can block or inflame the lacrimal drainage system.
49
Ectropion
out- turned eyelid
50
entropion
in- turned eyelid Inturned lashes can abrade the cornea  causing trichiasis
51
What is a common cause of sticky eye in infants under 1 year of age?
Delayed canalisation of Hasner’s valve in the nasolacrimal duct.
52
Until what age is benign sticky eye typically considered normal?
Up to 1 year of age.
53
How can parents help speed up the canalisation of Hasner’s valve at home?
By performing gentle downward massage of the nasolacrimal sac towards the nose at each feed.
54
When should antibiotics be prescribed for sticky eye in infants?
Only if the baby’s eye becomes red, indicating possible infection.
55
What is the next step if the sticky eye persists after 1 year of age?
Therapeutic probing of the nasolacrimal duct to open Hasner’s valve.
56
What do you not want to miss in watery eye in infancy
Congenital glaucoma
57
Signs of congenital glaucoma
Watering eye Photophobia Cloudy cornea Buphthalmos (ox eye)  Refer urgently
58
Syringing drainage system
Saline is injected into th canaliculus using a blunt cannula If patient tastes salty water, there is no obstruction If saline refluxes through the puncti, there is a blockage
59
Complications of nasolacrimal obstruction
Acute dacrocystitis Chronic dacrocystitis with fistula
60
What is the definitive surgical treatment for nasolacrimal duct obstruction?
Dacryocystorhinostomy (DCR), which creates a new passage between the lacrimal sac and nasal mucosa.
61
How does a DCR work?
It bypasses the blocked nasolacrimal duct by removing bone between the lacrimal sac and nasal cavity to form a new drainage route.
62
What are the two main approaches to performing a DCR?
External DCR, performed by an ophthalmologist Endoscopic DCR, performed by an ENT surgeon
63
What is used postoperatively to maintain the new passage created by DCR?
Silastic tubes are inserted and left in place for about 6 months to keep the ostium open.
64
When is DCR typically considered?
In cases of chronic nasolacrimal duct obstruction or recurrent dacryocystitis, especially if conservative management fails.

Ophthamology (12 decks)

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