Ophthalmology Conditions

Question 1

Dry eye syndrome can result from a deficiency in? (3)

Answer 1

Any of the three components of the tear film i.e.:

1. Outer lipid layer.
2. Middle aqueous layer.
3. Inner mucin layer.

Question 2

How does aqueous tear deficiency (aka Keratoconjunctivitis sicca) cause severely dry eyes?

Answer 2

Lacrimal gland dysfunction.

Question 3

Causes of lacrimal gland dysfunction?

Answer 3

1. Inflammation - especially autoimmune.
2. Scarring of secretory ducts.
3. Excision of lacrimal gland.

Question 4

How does keratoconjunctivitis sicca differ from Primary Sjogren’s syndrome?

Answer 4

Pure keratoconjuctivitis sicca only involves the lacrimal gland.

Sjogen’s - involves other gland e.g. salivary.

Question 5

How does secondary Sjogren’s differ from primary?

Answer 5

Secondary occurs in conjunction with a systemic autoimmune disorder e.g. RA.

Question 6

How does mucin deficiency i.e. xeropthalmia occur?

Answer 6

Large numbers of goblet cells are damaged by extensive conjunctival scarring e.g. alkali burns, cicatrising conjunctival disease), hypovitaminosis A.

Question 7

Consequences of severe dry eyes?

Answer 7

• Corneal epithelial loss.
• Scarring.
• Vascularisation.
• Corneal thinning (melt) - rare.
• Corneal perforation - rare.

Question 8

How is dry eye syndrome managed?

Answer 8

• Humidifying environment/ reducing tear evaporation by altering glasses.
• Tear supplements.
• Lacrimal punctal occlusion - temporary (silicone plugs) or permanent (cautery).

Question 9

How might inappropriate watering of the eye arise?

Answer 9

1. Failure of lacrimal drainage system - epiphora.

2. Oversecretion of tears - lacrimation.

Question 10

Failure of the lacrimal pump to allow drainage is usually due to?

Answer 10

• Facial nerve palsy.

- Ectropion.

Question 11

Causes of inadequate lacrimal drainage?

Answer 11

• Obstruction.

- Lacrimal pump failure.

Question 12

Signs of nasolacrimal duct obstruction?

Answer 12

• Mucocele of lacrimal sac.
• Dacrocystits.
  Both of which appear at medial canthus.

Question 13

What is a mucocele of the lacrimal sac?

Answer 13

Non-infected swelling of the lacrimal sac.

Question 14

What is dacrocystitis?

Answer 14

Lacrimal sac infection.

Question 15

Causes of watering eyes?

Answer 15

• Blepharitis.
• Dry eyes (paradoxically).
• Entropion, ectropion and ingrowing eyelashes.
• Congenital or acquired nasolacrimal duct obstruction (e.g. dacrocystitis, mucocele).

Question 16

What is proptosis?

Answer 16

Forward displacement of the eye due to a space occupying effect.

Question 17

Lesions where would cause axial proptosis?

Answer 17

Behind the eyeball.

Question 18

Lesions where would cause non-axial proptosis?

Answer 18

Lesions not behind the eyeball (e.g. lacrimal gland tumour, mucocele).

Question 19

Thyroid eye disease is usually associated with which conditions?

Answer 19

Hyperactive thyroid e.g. Graves disease or Graves ophthalmopathy.

Question 20

What causes thyroid eye disease?

Answer 20

infiltration of orbital tissues by inflammatory cells and oedema.

Question 21

What are the main symptoms of thyroid eye disease?

Answer 21

• Proptosis.
• Diplopia.
• Lid lag and retraction.

Question 22

More severe consequences of thyroid eye disease?

Answer 22

• Corneal exposure leading to vision loss.

- Optic nerve compression leading to vision loss.

Question 23

Management of thyroid eye disease?

Answer 23

TREATMENT OF UNDERLYING THYROID DYSFUNCTION DOES NOT INFLUENCE THE COURSE OF OCULAR DISEASE.

• Lubrication.
• Diplopia: prisms, surgery.
• Retraction: surgery.
• Severe proptosis and optic nerve compression (-> vision loss): Systemic immunosuppression, orbital RTx, surgical orbital decompression.

Question 24

Infection within the orbit is usually associated with infection where?

Answer 24

Paranasl sinus.

Question 25

symptoms/ signs of orbital cellulitis?

Answer 25

- Proptosis. - Reduced ocular movement. - Redness and swelling of eyelid. - Conjunctival injection. - Systemic signs of infection e.g. pyrexia, malaise.

Question 26

What are the most likely causative organisms of orbital cellulitis?

Answer 26

- Haemophilus influenzae (young children esp.). - Strep. pneumoniae. - Anaerobes.

Question 27

How is orbital cellulitis treated?

Answer 27

IV ABx immediately to prevent intracranial spread and sight loss.

Question 28

Failure to respond to IV antibiotics in orbital cellulitis likely indicates what?

Answer 28

Development of an orbital abscess - CT.

Question 29

Eye displacement backwards is known as?

Answer 29

Enophthalmos.

Question 30

Entrapment of orbital tissues within a fracture site (floor) leads to double vision, worse on?

Answer 30

Up- and down-gaze.

Question 31

Signs of orbital wall fracture and entrapment of orbital tissues?

Answer 31

- Hx of trauma e.g. squash ball. - Diplopia worse on up- and down-gaze. - Initial haematoma. - Enophthalmos. - Altered cheek sensation if infraorbital nerve damaged.

Question 32

Why should systemic antibiotics be given for orbital wall fractures?

Answer 32

They are essentially compound fractures.