Eyelid and pupil disorders Flashcards
What causes constriction of the pupil
- 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.
What causes dilatation of the pupil
- 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.
What can lead to abnormal pupil shape
- 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
What is Rubeosis iridis
(neovascularisation in the iris) can distort the shape of the iris and pupil. This is usually associated with poorly controlled diabetes and diabetic retinopathy.
What is Coloboma
congenital malformation in the eye. This can cause a hole in the iris causing an irregular pupil shape.
How can acute angle closure glaucome cause a mishapen pupil
can cause ischaemic damage to the muscles of the iris causing an abnormal pupil shape, usually a vertical oval.
What is tadpole pupil
there is spasm in a segment of the iris causing a misshapen pupil. This is usually temporary and associated with migraines.
Causes of Mydriasis (Dilated Pupil)
Third nerve palsy Holmes-Adie syndrome Raised intracranial pressure Congenital Trauma Stimulants such as cocaine Anticholinergics
Causes of Miosis (Constricted Pupil)
Horners syndrome Cluster headaches Argyll-Robertson pupil (in neurosyphilis) Opiates Nicotine Pilocarpine
What is the presentation of a third nerve palsy
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.
Which extraoccular muscles are NOT supplied by the occulomotor nerve
lateral rectus and superior oblique
Causes of a full third nerve palsy
Idiopathic Tumour Trauma Cavernous sinus thrombosis Posterior communicating artery aneurysm Raised intracranial pressure
What is the pathophysiology behind a full third nerve palsy
compression of the nerve, including the parasympathetic fibres. This is called a “surgical third” due to the physical compression:
Why may a third nerve palsy spare the pupil
suggests a microvascular cause as the parasympathetic fibres are spared. This may be due to:
- Diabetes
- Hypertension
- Ischaemia
What is the triad of Horner’s syndrome
Ptosis Miosis Anhidrosis (loss of sweating) (enopthalmos) ( Light and accommodation reflex not affected)
What is enopthalmos
sunken eye
What causes horners syndrome
- 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
How can we tell where the lesion is causing Horner’s syndrome
- 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.
What causes the central lesions in Horner’s SYndrome
S – Stroke
S – Multiple Sclerosis
S – Swelling (tumours)
S – Syringomyelia (cyst in the spinal cord)
What causes the Pre-ganglionic lesions in Horner’s Syndrome
T – Tumour (Pancoast’s tumour)
T – Trauma
T – Thyroidectomy
T – Top rib (a cervical rib growing above the first rib above the clavicle)
What causes the Post-ganglionic lesion in Horner’s syndrome
C – Carotid aneurysm
C – Carotid artery dissection
C – Cavernous sinus thrombosis
C – Cluster headache
How can you test for Horner’s Syndrome
- 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
What is Holmes Adie Pupil
- 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
What is Holmes Adie Syndrome
Holmes Adie pupil with absent ankle and knee reflexes.
What is Argyll-Robertson Pupil
- 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’
What is Blepharitis
- 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
What is the presentation of Blepharitis
gritty, itchy, dry sensation in the eyes.
What is the management of Blepharitis
- hot compresses and gentle cleaning of the eyelid margins
- Sterile water and baby shampoo
- Lubricating eye drops
Examples of lubricating eye drops
( Least to most viscous)
Hypromellose
Polyvinyl alcohol
Carbomer
What is Hordeolum externum (Stye)
- infection of the glands of Zeis or glands of Moll. (sebaceous gland and sweat gland at the base of the eyelashes, respectively)
What is the presentation of a Hordeolum externum (Stye)
tender red lump along the eyelid that may contain pus
What is a Hordeolum internum
- infection of the Meibomian glands
- deeper, tend to be more painful and may point inwards towards the eyeball underneath the eyelid.
What is the management of a stye
- hot compresses
- analgesia
- Consider topic antibiotics (i.e. chloramphenicol) if assoc. with conjunctivitis or persistent
What is a Chalazion
- Meibomian gland becomes blocked and swells up.
- It is often called a Meibomian cyst.
What is the presentation of a Chalazion
- swelling in the eyelid that is typically not tender
- (can be tender and red)
What is the management of a chalazion
- hot compress
- analgesia.
- Consider topic antibiotics (i.e. chloramphenicol) if acutely inflamed.
- Rarely if conservative management fails then surgical drainage may be required.
What is Entropion
- where the eyelid turns inwards with the lashes against the eyebal
- results in pain and can result in corneal damage and ulceration.
What is the management of entropion
- 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
What is Ectropion
- 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
What is the management of ectropion
- 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.
What is Trichiasis
- inward growth of the eyelashes
- results in pain and can result in corneal damage and ulceration.
What is the management of trichiasis
- 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.
What is Periorbital Cellulitis (pre-orbital)
eyelid and skin infection in front of the orbital septum (in front of the eye)
What is the presentation of periorbital cellulitis
- Swelling,
- redness
- hot skin around the eyelids and eye.
- essential to differentiate it from orbital cellulitis
What is the management of periorbital cellulitis
- 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.
What is orbital cellulitis
- infection around the eyeball that involves tissues behind the orbital septum.
- MEDICAL EMERGENCY!
How do you differentiate orbital cellulitis from periorbital cellulitis
- pain on eye movement
- reduced eye movements
- changes in vision
- abnormal pupil reactions
- forward movement of the eyeball (proptosis).
What is the management of orbital cellulitis
- Medical emergency
- Head CT
- IV antibiotics + admission
- May require surgical drainage if abscess
