Orthoptics + Orbital disease

Question 1

What is binocular vision and what 3 things is it based on?

Answer 1

Brains ability to perceive a single image from each eye
Based on:
Simultaneous perception (good visual acuity in both)
Depth perception
Fusion (alignment of visual axes)

Question 2

Where are the different categories of squint?

Answer 2

Manifest (pathological) - Concomitant/Incomitant

Latent (physiological) - compensated/decompensated

Question 3

In the cover + alternate cover tests what is seen in convergent + divergent?

Answer 3

Convergent (esotropia) - eye moves away from nose after uncovering
Divergent (exotropia) - eye moves towards nose from uncovering

Question 4

In what cases in the cover tests may fixation not be able to occur? (2)
What sign use instead?

Answer 4

V poor visual acuity (can't fixate anyway)
Muscle paralysis (cannot fully take up fixation)

Use corneal reflections as guide

Question 5

Who are concomitant squints mostly seen in?

What conditions are they associated with?

Answer 5

Children (eso*/exo)

Convergents: Hypermetropia (child wears glasses) + Amblyopia

Question 6

What is amblyopia?

List 3 causes

Answer 6

Reduced acuity from failure of development of visual pathways (→ lazy eye)
Causes:
Stimulus deprivation e.g. severe ptosis, congenital cataracts (lack of sharp image on macula at critical stage of devel)
Strabismic (squint) (uncorrected myo/hypermetropia - brain suppresses deviated image)
Anisometropic (diff refractive powers + brain favours better eye)

Question 7

When should management of a squint be started?

What is the management? (OOO)

Answer 7

As soon as noticed (>7yrs too late)
Optical: correct refractive errors
Orthoptic: patch on good eye
Operation: resection/recession of rectus muscles (cosmetic) + Botox

Question 8

What is seen in a cover test of a manifest squint?

Answer 8

When normal eye covered → bad eye corrects itself (takes up fixation) (+good eye deviates)
When good eye uncovered → bad eye deviates again (+ good eye to normal)

Question 9

What is seen in an alternate cover test in a latent squint?

Answer 9

If eye moves (to take up fixation) when uncovered → latent squint

NB latent squint will have in both eyes

Question 10

What measures of visual acuity can be used in children?

Answer 10

Preferential looks (shows have some form of sight)
Cardiff cards / Kays pictures
LogMAR (reading age)

Question 11

What is an incomitant squint? List the causes (5)

Answer 11

Due to CN3/4/6 palsy/paralysis
Microvascular (BP/DM)
Nerve compression (direct - aneurysm; indirect - space occupying lesion raising ICP)
Head injury (esp CN4)
Mechanical (thyroid; orbit inflamm; orbit trauma)
Idiopathic

Question 12

What symptoms may be seen in orbital disease? (3)

What signs may be seen? (8)

Answer 12

Diplopia
Pain/discomfort
Reduced vision

Soft tissue involvement
Exophthalmos (proptosis)
Pseudoproptosis (high myopia/contralat endophthalmos)
Endophthalmos
Ophthalmoplegia
Visual dysfunction
Dynamic changes (pulsation)
Fundus changes

Question 13

What are some causes of soft tissue involvement in orbital disease? (3)

Answer 13

Lid/periorbital oedema
Ptosis
Conjunctival swelling

Question 14

What are some causes of proptosis/pseudo? (TIT)

Answer 14

Thyroid eye disease
Tumour
Inflamm/infection

Question 15

What are some causes of endophthalmos? (3)

Answer 15

Small globe
Structural abn (e.g. blow out)
Atrophy of orbit contents (irradiation/scleroderma)

Question 16

What are some causes of ophthalmoplegia? (5)

Answer 16

Tumour
Infection (cellulitis)
Trauma (blow out)
Restrictive myopathy
Ocular motor nn lesions

Question 17

What kinds of dynamic changes may be seen in orbital disease (2)
And give examples of conditions where these changes might arise (2/3 each)

Answer 17

Venous pressure increase: thyroid eye, vascular probs

Pulsation: AV communication, orbital floor defects, CSF pulsation

Question 18

What kinds of fundus changes may be seen in orbital disease (3)

Answer 18

Retinal/vascular changes
Disc changes
Choroidal folds

Question 19

What ocular manifestations are seen in thyroid eye disease? (2 main + 2 rare)

Answer 19

Soft tissue involvement (eyelid/periorbital oedema)
Exophthalmos (1/3rd)

Diplopia (restrictive myopathy/oedema/fibrosis)
Optic nn compression / neuropathy (open angle glaucoma)

Question 20

What can be given to patients with permanent diplopia?

Answer 20

Prisms (alleviate symptoms)

Question 21

What are some symptoms (2) and signs (4) of orbital cellulitis?

Answer 21

Severe malaise + fever
Pain

Painful ophthalmoplegia
Severe orbital oedema (+redness)
Ptosis
Optic nn dysfunction (advanced)

Question 22

What are some complications of periorbital oedema (2)

Answer 22

Optic neuropathy
Abscess formation (→ cranial if severe)

Question 23

What is idiopathic orbital inflammatory disease?
How does it usually present? (3)
Signs (4)

Answer 23

Any non-neoplastic / non-infectious orbital lesion (Dx of exclusion)

20-50yrs unilateral abrupt onset

Unilateral proptosis
Periorbital swelling
Ophthalmoplegia
Chemosis (irritation)

Question 24

What are the main vascular orbital disorders? (2)

Answer 24

Orbital varices

Carotid-canervous fistulas

Question 25

What causes orbital varicose?
What do they have a tendency to do?
How do they present/signs? (2)

Answer 25

Congenital
May bleed/thrombose
Unilateral, intermittent proptosis accentuated by valsalva manouvre

Question 26

Where is the (carotid-cavernous) fistula connection in direct + indirect?

Answer 26

Direct: B/wn carotid aa + cavernous sinus
Indirect: B/wn meningeal branches of internal carotids + cavernous sinus

Question 27

What are some causes of a direct carotid-cavernous fistula? (2)
And causes of indirect? (2)

Answer 27

Direct: Head trauma / spontaneous rupture
Indirect: Congenital / spontaneous rupture

Question 28

List some clinical features (signs) of a direct carotid-cavernous fistula? (6)

Answer 28

Ptosis
Chemosis / conjunctival infection
Ophthalmoplegia
Raised IOP
Pulsatile proptosis (w. bruit + thrill)
Retinal venous congestion + haemorrhage

Question 29

How is direct carotid-cavernous fistula treated?

Answer 29

Ipsilateral carotid compression

Question 30

List some clinical features of an indirect carotid-cavernous fistula? (4)

Answer 30

Dilated episcleral vessels
Raised IOP
Occasional ophthalmoplegia
Mild proptosis

Question 31

What are the different types of tumour that affect the orbit? (7)

Answer 31

Capillary haemangioma
Cavernous haemangioma

Pleomorphic lacrimal gland adenomas
Lacrimal gland carcinoma

Optic nerve glioma
Optic nerve sheath meningioma

Metastases

Question 32

What is the commonest orbital tumour in children?
+ in adults (benign)
What age do most orbital tumours present?

Answer 32

Children → capillary haemangioma
Adult (benign) → cavernous haemangioma
Most (except capillary haemangioma) middle around (40-70)

Question 33

How may a capillary haemangioma present

How is it treated?

Answer 33

Enlarge on coughing / straining
Assoc w. systemic conditions (high output cardiac failure)
Grow mainly in 1st yr

Tx: systemic/IM steroids + local resection (if poss)

Question 34

How may an optic nerve glioma present? (2)

How treated?

Answer 34

Young/teen girls
Assoc w. NF-1
Gradual visual loss (slow growing lesion)

Question 35

What is the treatment for:
pleomorphic lacrimal gland adenoma
lacrimal gland carcinoma
cavernous haemangioma
optic nerve sheath meningioma

Answer 35

Pleomorphic - surgical excision
Lacrimal carcinoma - radical surgery + radiotherapy (poor prog)
Cavernous - surgical excision
Optic nn sheath - excision + radio

Question 36

What are the common sites of tumour origin in orbital metastases? (6)

Answer 36

Prostate
breast
Bronchus
GI
Kidney
Skin melanoma

Question 37

How is orbital cellulitis managed?

What are the indications for surgery? (3)

Answer 37

Admit to hosp + IV Abx
Monitor optic nn func

(complications)
Abx resistance
Orbital/subperiosteal abscess
Optic neuropathy

Question 38

How is idiopathic orbital inflam disease managed? (3)

What is a complication if not treated?

Answer 38

Steroids
Radiotherapy
Cytotoxics

Severe prolonged activity → frozen orbit