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Opthalmology > Eyelid and pupil disorders > Flashcards

Eyelid and pupil disorders Flashcards

1
Q

What causes constriction of the pupil

A
  • Circular muscles in the iris are stimulated by the parasympathetic nervous system using acetylcholine as a neurotransmitter.
  • The fibres of the parasympathetic system innervating the eye travel along the oculomotor (third cranial) nerve.
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2
Q

What causes dilatation of the pupil

A
  • dilator muscles of the pupil arranged like spokes on a bicycle wheel travelling straight from the inside to the outside of the iris.
  • stimulated by the sympathetic nervous system using adrenalin as a neurotransmitter.
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3
Q

What can lead to abnormal pupil shape

A
  • Trauma to the sphincter muscles in the iris (surgery)
  • Anterior uveitis can cause adhesions (scar tissue) in the iris that make the pupils misshapen.
  • Acute angle closure glaucoma
  • Rubeosis iridis (neovascularisation in the iris)
  • Coloboma
  • Tadpole pupil
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4
Q

What is Rubeosis iridis

A

(neovascularisation in the iris) can distort the shape of the iris and pupil. This is usually associated with poorly controlled diabetes and diabetic retinopathy.

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5
Q

What is Coloboma

A

congenital malformation in the eye. This can cause a hole in the iris causing an irregular pupil shape.

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6
Q

How can acute angle closure glaucome cause a mishapen pupil

A

can cause ischaemic damage to the muscles of the iris causing an abnormal pupil shape, usually a vertical oval.

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7
Q

What is tadpole pupil

A

there is spasm in a segment of the iris causing a misshapen pupil. This is usually temporary and associated with migraines.

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8
Q

Causes of Mydriasis (Dilated Pupil)

A 
Third nerve palsy
Holmes-Adie syndrome
Raised intracranial pressure
Congenital
Trauma
Stimulants such as cocaine
Anticholinergics
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9
Q

Causes of Miosis (Constricted Pupil)

A 
Horners syndrome
Cluster headaches
Argyll-Robertson pupil (in neurosyphilis)
Opiates
Nicotine
Pilocarpine
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10
Q

What is the presentation of a third nerve palsy

A

Ptosis (drooping upper eyelid)
Dilated non-reactive pupil
Divergent strabismus (squint) in the affected eye. It causes a “down and out” position of the eye.

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11
Q

Which extraoccular muscles are NOT supplied by the occulomotor nerve

A

lateral rectus and superior oblique

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12
Q

Causes of a full third nerve palsy

A 
Idiopathic
Tumour
Trauma
Cavernous sinus thrombosis
Posterior communicating artery aneurysm
Raised intracranial pressure
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13
Q

What is the pathophysiology behind a full third nerve palsy

A

compression of the nerve, including the parasympathetic fibres. This is called a “surgical third” due to the physical compression:

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14
Q

Why may a third nerve palsy spare the pupil

A

suggests a microvascular cause as the parasympathetic fibres are spared. This may be due to:

  • Diabetes
  • Hypertension
  • Ischaemia
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15
Q

What is the triad of Horner’s syndrome

A 
Ptosis
Miosis
Anhidrosis (loss of sweating)
(enopthalmos)
( Light and accommodation reflex not affected)
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16
Q

What is enopthalmos

A

sunken eye

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17
Q

What causes horners syndrome

A
  • Damage to the sympathetic nervous supply to the face

- Damage can be in the pregnanglionic nerve, in the central nervous system or in the post ganglionic nerve

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18
Q

How can we tell where the lesion is causing Horner’s syndrome

A
  • Central lesions cause anhidrosis of the arm and trunk as well as the face.
  • Pre-ganglionic lesions cause anhidrosis of the face.
  • Post-ganglionic lesions do not cause anhidrosis.
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19
Q

What causes the central lesions in Horner’s SYndrome

A

S – Stroke
S – Multiple Sclerosis
S – Swelling (tumours)
S – Syringomyelia (cyst in the spinal cord)

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20
Q

What causes the Pre-ganglionic lesions in Horner’s Syndrome

A

T – Tumour (Pancoast’s tumour)
T – Trauma
T – Thyroidectomy
T – Top rib (a cervical rib growing above the first rib above the clavicle)

21
Q

What causes the Post-ganglionic lesion in Horner’s syndrome

A

C – Carotid aneurysm
C – Carotid artery dissection
C – Cavernous sinus thrombosis
C – Cluster headache

22
Q

How can you test for Horner’s Syndrome

A
  • cocaine eye drops: No reaction to pupil in Horner’s syndrome
  • low concentration adrenalin eye drop: Won’t dilate a normal eye but will dilate a Horner’s eye
23
Q

What is Holmes Adie Pupil

A
  • unilateral dilated pupil that is sluggish to react to light with slow dilation of the pupil following constriction due to damage to the post-ganglionic parasympathetic fibres
  • exact cause unknown, possibly viral
24
Q

What is Holmes Adie Syndrome

A

Holmes Adie pupil with absent ankle and knee reflexes.

25
Q

What is Argyll-Robertson Pupil

A
  • Specific finding in neurosyphilis
  • constricted pupil that accommodates when focusing on a near object but does not react to light.
  • They are often irregularly shaped
  • ‘Prostitutes pupil’
26
Q

What is Blepharitis

A
  • inflammation of the eyelid margins
  • Can be associated with dysfunction of the Meibomian glands, which are responsible for secreting oil onto the surface of the eye
  • Can lead to styes and chalazions
27
Q

What is the presentation of Blepharitis

A

gritty, itchy, dry sensation in the eyes.

28
Q

What is the management of Blepharitis

A
  • hot compresses and gentle cleaning of the eyelid margins
  • Sterile water and baby shampoo
  • Lubricating eye drops
29
Q

Examples of lubricating eye drops

A

( Least to most viscous)
Hypromellose
Polyvinyl alcohol
Carbomer

30
Q

What is Hordeolum externum (Stye)

A
  • infection of the glands of Zeis or glands of Moll. (sebaceous gland and sweat gland at the base of the eyelashes, respectively)
31
Q

What is the presentation of a Hordeolum externum (Stye)

A

tender red lump along the eyelid that may contain pus

32
Q

What is a Hordeolum internum

A
  • infection of the Meibomian glands

- deeper, tend to be more painful and may point inwards towards the eyeball underneath the eyelid.

33
Q

What is the management of a stye

A
  • hot compresses
  • analgesia
  • Consider topic antibiotics (i.e. chloramphenicol) if assoc. with conjunctivitis or persistent
34
Q

What is a Chalazion

A
  • Meibomian gland becomes blocked and swells up.

- It is often called a Meibomian cyst.

35
Q

What is the presentation of a Chalazion

A
  • swelling in the eyelid that is typically not tender

- (can be tender and red)

36
Q

What is the management of a chalazion

A
  • hot compress
  • analgesia.
  • Consider topic antibiotics (i.e. chloramphenicol) if acutely inflamed.
  • Rarely if conservative management fails then surgical drainage may be required.
37
Q

What is Entropion

A
  • where the eyelid turns inwards with the lashes against the eyebal
  • results in pain and can result in corneal damage and ulceration.
38
Q

What is the management of entropion

A
  • Same day referral to opthal. to assess risk to sight
  • taping the eyelid down to prevent it turning inwards.
  • Lubricating eye drops
  • Definitive management is surgical
39
Q

What is Ectropion

A
  • where the eyelid turns outwards with the inner aspect of the eyelid exposed
  • usually affects the bottom lid
  • can result in exposure keratopathy as the eyeball is exposed and not adequately lubricated and protected
40
Q

What is the management of ectropion

A
  • Same day referral to opthal. to assess risk to sight
  • Mild cases may not require treatment.
  • Regular lubricating eye drops
  • More significant cases may require surgery to correct the defect.
41
Q

What is Trichiasis

A
  • inward growth of the eyelashes

- results in pain and can result in corneal damage and ulceration.

42
Q

What is the management of trichiasis

A
  • Same day referral to opthal. to assess risk to sight
  • specialist is to remove the eyelash (epilation).
  • Recurrent cases may require electrolysis, cryotherapy or laser treatment to prevent the lash regrowing.
43
Q

What is Periorbital Cellulitis (pre-orbital)

A

eyelid and skin infection in front of the orbital septum (in front of the eye)

44
Q

What is the presentation of periorbital cellulitis

A
  • Swelling,
  • redness
  • hot skin around the eyelids and eye.
  • essential to differentiate it from orbital cellulitis
45
Q

What is the management of periorbital cellulitis

A
  • systemic antibiotics (oral or IV).
  • Preorbital cellulitis can develop into orbital cellulitis so vulnerable patients (e.g. children) or severe cases may require admission for observation while they are treated.
46
Q

What is orbital cellulitis

A
  • infection around the eyeball that involves tissues behind the orbital septum.
  • MEDICAL EMERGENCY!
47
Q

How do you differentiate orbital cellulitis from periorbital cellulitis

A
  • pain on eye movement
  • reduced eye movements
  • changes in vision
  • abnormal pupil reactions
  • forward movement of the eyeball (proptosis).
48
Q

What is the management of orbital cellulitis

A
  • Medical emergency
  • Head CT
  • IV antibiotics + admission
  • May require surgical drainage if abscess

Opthalmology (4 decks)

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