The external eye

Question 1

What is a stye?

Answer 1

Patient term for an inflammatory lid swelling

Question 2

What is hordeolum externum?

Answer 2

abcess or infection that is usually staphylococcal in a lash follicle

Question 3

What is the difference between the glands of moll and of zeis?

Answer 3

Moll are sweat glands and zeis are sebum producing glands attached directly to lash follicles

Question 4

How is hordeolum externum treated?

Answer 4

A warm compress should be applied for 5-10mins a day until stye resolves

Question 5

What is hordeolum internum?

Answer 5

Abscess of the meibomiam glands which points inwards towards to conjunctiva. Cause residual swelling. Can be treated if severe enough with incision and curettage

Question 6

What is blepharitis and how is it treated?

Answer 6

It is lid inflammation caused by staphs commonly. Treatment is good eyelid hygiene, use baby shampoo and cotton buds to clean lid margins.

Question 7

What is pinguecula and how is it treated?

Answer 7

Degenerative vascular yellow grey nodules on the conjunctiva. It typically affects adult males, if inflamed then steroids can be tried and then if invading the conjunctiva then surgery may be required.

Question 8

What is entropion and how is it treated?

Answer 8

This is an inturning of the lid typically due to degeneration of the lower lid fascial attachements. This can irritate the cornea and can be treated with botulinum toxin injection or surgery

Question 9

What is ectropion and how is it treated?

Answer 9

Lower lid eversion and causes eye irritation and watering. Plastic surgery can correct the abnormality or if facial palsy is the cause then surgical correction can be done with an implant in the lid

Question 10

What are the causes of upper lid malposition?

Answer 10

This results from globe hypertropic position e.g. ptosis

Can be congenital, mechanical (oedema, upper lid tumour), myogenic (muscular dystrophy), CNS (nerve palsys)

Question 11

What is lagophthalmos and what are the causes and treatment?

Answer 11

Difficulty in lid closure
Caused by:
-exophthalmos
-mechanical impairment of lid closure (burns etc)
-Paralysed orbicularis oculi
Treated with eye lubrication with liquid paraffin iontment
If corneal ulcers develop then temporary tarsorrhaphy (stitching together lids) may be required

Question 12

What is blepharospasm and how does it present?

Answer 12

It is involuntary contraction of orbicularis oculi and often as a result of ocular pain. This is a focal dystonia. It is often preced by exaggerated blinking and it usually starts unilaterally and becomes bilateral. Causes mostly unknown but can be caused by neuroleptic drugs.

Question 13

What is the treatment for blepharospasm?

Answer 13

Palliation is achieved by small injections of botulinum neurotoxin which produces a temporary flaccid paralysis. 3 monthly treatments are needed. Anticholinergics can be used alternatively but not as effective.

Question 14

What are tears made up of?

Answer 14

Lipid layer
Aqueous layer
Mucin layer

Question 15

What are the causes of dry eyes?

Answer 15

Decreased tear production:
-old age
-Sjogren's syndrome (associated with connective tissue disorders)
-sarcoidosis
-Leukaemia
-Haemochromatosis
Mucin deficiency

Question 16

How can you test for the cause of dry eyes?

Answer 16

Schirmer’s test
Can use a strip of filter pater to soak up the tears, should be greater than 15mm in 5 mins
This reveals a production problem

Question 17

How are dry eyes treated?

Answer 17

They can be treated with lubricating drops for symptomatic relief
The outflow of tears can be restricted with lubricating drops or by reducing the size of the punctum lacrimale with plugs or laser

Question 18

What are the three categories of watery eyes?

Answer 18

Decreased drainages from punctum lacrimale e.g. obstruction
Increased lactimations e.g. environmental or corneal injury
Pump failure - on blinking positive and negative pressure causes tears to be sucked into the lacrimal sack, pump failure can result from ectropion, entropion etc.

Question 19

What are the signs of retinoblastoma?

Answer 19

Strabismus (squint) and white pupil. Always suspect retinoblastoma when the red reflex is absent.

Question 20

What is the treatment for retinoblastoma?

Answer 20

Chemotherapy - can be used in bilateral tumours - carboplatin
Enucleation - removal of eye may be needed in large tumours
External beam radiotherapy - has a role but may cause secondary cancers
Ophthalmic plaque brachytherapy - more focal and shielded radiation field
Cryotherapy can be used for selected small tumours

Question 21

who is screened for retinoblastoma?

Answer 21

Screening is needed in parents and siblings to establish risk of having it and passing it on.

Question 22

What is shingles?

Answer 22

This is herpes zoster infection. It has two distinct forms. It occurs in childhood as chickenpox (varicella) then it can reactivate in 20% of individuals and present as shingles (zoster). Most commonly affects the thoracic nerves followed by the ophthalmic branch of the trigeminal nerve.

Question 23

How does ophthalmic shingles present?

Answer 23

Pain and neuralgia in the distribulation of V1 precedes a blistering inflamed rash. Post herpetic neuralgia is a common complication.

Question 24

How likely is it that the eye will be involved in herpes zoster and what indicates it to be more likely?

Answer 24

In 50% of herpes zoster cases the globe is affected with corneal signs and iritis. Nose tip involvement (Hutchinson’s sign) makes it more likely that the eye will be affected.

Question 25

How is ophthalmic shingles assessed and treated?

Answer 25

Assess for visual acuity and refer for more detailed examination if pain, redness or altered vision. Look for Hutchinson’s sign carefully.
Treated with oral antivirals (72 hours of rash onset) Famciclovir offers best dose schedule but more expensive than acyclovir. If Hutchinson’s sign then get specialist involved.

Question 26

What does a pulsatile exophthalmos indicate?

Answer 26

This may be a carotid aneurysm rupture into the cavernous sinus.

Question 27

How do lesions in the bony orbit typically present?

Answer 27

With proptosis regardless of the pathological origin

Question 28

How does orbital cellulitus typically present?

Answer 28

Child with inflammation in the orbit, fever, lid swelling and decreased eye mobility. Painful eye movements.

Question 29

How should orbital cellulitis be treated?

Answer 29

This is severe sight threatening emergency
Admit for prompt CT, ENT and ophthalmic opinion + antibiotics (metronidazole, ceftaxime)
If abscesses present than need surgical drainage.

Question 30

How does preseptal cellulitis differ in treatment to orbital cellulitis?

Answer 30

This is infection of soft tissues anterior to the orbital septum and more common than orbital cellulitis. Wont have painful eye movements just erythematous swelling of eye lid. Empirical treatment for cellulitis (amoxicillin)

Question 31

What are the names for a convergent and divergent squint?

Answer 31

Esotropia is convergent

Exotropia is divergent

Question 32

How is diagnosis of strabismus made?

Answer 32

Cornal reflection test and cover test (movement of weird eye takes up fixation when the good eye is covered)

Question 33

What is the management of strabismus?

Answer 33

3 Os
Optical - assess the refractive state after cyclopentolate (dilates and relaxes the eye)
Orthoptic - patching of the ye encourages use of the one that squints
Operations - resection and recession of rectus muscles