Ophthalmology Conditions Flashcards
Dry eye syndrome can result from a deficiency in? (3)
Any of the three components of the tear film i.e.:
- Outer lipid layer.
- Middle aqueous layer.
- Inner mucin layer.
How does aqueous tear deficiency (aka Keratoconjunctivitis sicca) cause severely dry eyes?
Lacrimal gland dysfunction.
Causes of lacrimal gland dysfunction?
- Inflammation - especially autoimmune.
- Scarring of secretory ducts.
- Excision of lacrimal gland.
How does keratoconjunctivitis sicca differ from Primary Sjogren’s syndrome?
Pure keratoconjuctivitis sicca only involves the lacrimal gland.
Sjogen’s - involves other gland e.g. salivary.
How does secondary Sjogren’s differ from primary?
Secondary occurs in conjunction with a systemic autoimmune disorder e.g. RA.
How does mucin deficiency i.e. xeropthalmia occur?
Large numbers of goblet cells are damaged by extensive conjunctival scarring e.g. alkali burns, cicatrising conjunctival disease), hypovitaminosis A.
Consequences of severe dry eyes?
- Corneal epithelial loss.
- Scarring.
- Vascularisation.
- Corneal thinning (melt) - rare.
- Corneal perforation - rare.
How is dry eye syndrome managed?
- Humidifying environment/ reducing tear evaporation by altering glasses.
- Tear supplements.
- Lacrimal punctal occlusion - temporary (silicone plugs) or permanent (cautery).
How might inappropriate watering of the eye arise?
- Failure of lacrimal drainage system - epiphora.
2. Oversecretion of tears - lacrimation.
Failure of the lacrimal pump to allow drainage is usually due to?
- Facial nerve palsy.
- Ectropion.
Causes of inadequate lacrimal drainage?
- Obstruction.
- Lacrimal pump failure.
Signs of nasolacrimal duct obstruction?
- Mucocele of lacrimal sac.
- Dacrocystits.
Both of which appear at medial canthus.
What is a mucocele of the lacrimal sac?
Non-infected swelling of the lacrimal sac.
What is dacrocystitis?
Lacrimal sac infection.
Causes of watering eyes?
- Blepharitis.
- Dry eyes (paradoxically).
- Entropion, ectropion and ingrowing eyelashes.
- Congenital or acquired nasolacrimal duct obstruction (e.g. dacrocystitis, mucocele).
What is proptosis?
Forward displacement of the eye due to a space occupying effect.
Lesions where would cause axial proptosis?
Behind the eyeball.
Lesions where would cause non-axial proptosis?
Lesions not behind the eyeball (e.g. lacrimal gland tumour, mucocele).
Thyroid eye disease is usually associated with which conditions?
Hyperactive thyroid e.g. Graves disease or Graves ophthalmopathy.
What causes thyroid eye disease?
infiltration of orbital tissues by inflammatory cells and oedema.
What are the main symptoms of thyroid eye disease?
- Proptosis.
- Diplopia.
- Lid lag and retraction.
More severe consequences of thyroid eye disease?
- Corneal exposure leading to vision loss.
- Optic nerve compression leading to vision loss.
Management of thyroid eye disease?
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.
Infection within the orbit is usually associated with infection where?
Paranasl sinus.
symptoms/ signs of orbital cellulitis?
- Proptosis.
- Reduced ocular movement.
- Redness and swelling of eyelid.
- Conjunctival injection.
- Systemic signs of infection e.g. pyrexia, malaise.
What are the most likely causative organisms of orbital cellulitis?
- Haemophilus influenzae (young children esp.).
- Strep. pneumoniae.
- Anaerobes.
How is orbital cellulitis treated?
IV ABx immediately to prevent intracranial spread and sight loss.
Failure to respond to IV antibiotics in orbital cellulitis likely indicates what?
Development of an orbital abscess - CT.
Eye displacement backwards is known as?
Enophthalmos.
Entrapment of orbital tissues within a fracture site (floor) leads to double vision, worse on?
Up- and down-gaze.
Signs of orbital wall fracture and entrapment of orbital tissues?
- Hx of trauma e.g. squash ball.
- Diplopia worse on up- and down-gaze.
- Initial haematoma.
- Enophthalmos.
- Altered cheek sensation if infraorbital nerve damaged.
Why should systemic antibiotics be given for orbital wall fractures?
They are essentially compound fractures.
