NV - Eyelid Disorders - Week 3 Flashcards
What muscle forms the eyelid crease?
Levator palpebrae superioris
What three factors contribute to eyelid position?
Mechanical aspects of the orbit
Innervation
Anatomical
What generally happens to eyelid position with age?
It lowers
Define entropion.
Eyelid is turned in
Define ectropion.
eyelid is turned out
How can entropion be confirmed and what should you look for?
Have the patient squeezze their eyes shut, will cause it to turn further inward
Look for corneal staining from eyelash scratching
What would you expect the lid margin to look like with ectropion and why?
Red lower margin due to excessive drying of the conjunctiva
How can ectropion be confirmed?
Pull the eyelid downward, then let it retract
If it is slow, or remains stretched out, ectropion is present
What is the surgical treatment for entropion and ectropion?
Blepharoplasty
What muscle closes the eyelids and what cranial nerve is responsible. Is this the only force responsible for closing the lids?
CN7 activates orbicularis oculi
Also gravity on the tarsus
What three muscles are responsible for opening the eyelids? Note the cranial nerve, if applicable (2).
Frontalis muscle CN7
Levator palpebrae superioris CN3
Mullers muscle
What kind of information do lid/brow positions and lid crease locations give (2)?
Lid/brow position - information on neural/muscular activity
Lid crease location - identiying common disorders
From external appearance, what structure should be clear of the eyelids?
The pupil
What is the normal superior lid position and what happens to it with age? What about inferior?
Normal - 11 to 1 o’clock
With age - 10 to 2 o’clock
6 o’clock inferiorly
Is scleral show common?
Yes, as long as its symmetric
What are three key measures of lid position?
Palpebral fissure
Margin to reflex distance
-superior = MRD1
-inferior = MRD2
What is the normal range for palpebral fissure?
9-11mm
-normally 10
What are normal MRD1 and MRD2 values?
MRD1 - 4mm
MRD2 - 5 to 6mm
What is an abnormal MRD1 value (2)?
≤2mm or
>2mm symmetry between eyes
What is the main lid retracting muscle?
Levator palpebrae superioris
How is levator palepbrae superioris function measured? What values do you expect to see?
Eye excursion - 45 degrees down from primary gaze
Excursion should be ≥13mm
-typically 15mm, <4mm asymmetry
What would you suspect if you do not get normal values for levator paelpbrae superioris function (3)?
Neurological cause (CN3)
Mechanical failure (ligament)
Proptosis
What ligament is responsible for the eyelid crease?
Whitnall’s ligament
In what percentage of asian eyes is a single crease present and why is this so?
35%
Diffuse lower insertion of whitnalls ligament
Why do eyelids droop with age? What is this called?
Whitnalls ligament can stretch/break with age
-dehiscence
-causes loss of LPS function
What generally happens as a consequence of LPS function loss and what is a symptom?
Frontalis action keeps the eyes open giving a high brow and high crease
Common cause of headaches
Why does the crease rise with loss of LPS function?
Loss of whitnalls ligament and loss of LPS function means the frontalis muscle is used to keep eyes open
Creates a new crease where frontalis inserts
List three causes of pseudo-ptosis.
Muscle spasm
Excess skin (dermatochalasis)
Small hypotropia
Spasm of what muscle can cause pseudo-ptosis? What can cause this spasm? What is often the trigger?
Orbicularis occuli
Higher order CNS misfiring of CN7 blink-reflex
Trigger is often stress
What age and gender does pseudo-ptosis due to muscle spasm often occur?
Middle-aged women
What is the management of pseudo-ptosis due to muscle spasm (2)?
Stress management/antidepressants
Botulinum toxin injections around the eye
List three differential diagnoses for ptosis if lid deformity is present.
Trauma
Infection/inflammation
Tumour
List three differential diagnoses for ptosis if lid deformity is not present.
Congenital
Myopathy
Acquired
List three myopathies that can cause ptosis.
Myasthenia gravis
Muscular dystrophy
CPEO
What may often casue congenital ptosis and what is it associated with?
Due to aberrant neural innervation
-associated with eye movement anomaly
What is the likely cause of ptosis with pupil involvement (2)?
Horners or loss of CN3
What does loss of CN3 give (3)?
Total lid closure
Dilated pupil
EOM palsy (down+out)
What should you do if you see a down and out eye?
Hospital emergency - possibly intracranial aneurysm
What ocular signs would you generally see with horner’s syndrome (2)?
1/3rd eyelid closure and miotic pupil
If you see ptosis with pupils involved, is this considered an emergency?
Yes
What is duanes retraction syndrome, how many types are there, and what appearance does it cause?
Aberrant innervation of L and M recti
3 types
Gives head tilt due to vertical muscle problem
What do all types of duanes retraction syndrome manifest and why?
Retraction of the globe due to bilateral innervation which gives apparent ptosis
Does duanes retraction syndrome result in abduction or adduction?
Adduction
Why does head tilt occur in duanes retraction syndrome?
Excess innervation to contralateral vertical muscles on adduction
Describe each type of duanes retraction syndrome (3, 1, 2).
Type 1 - narrowing, limited abduction, vertical uscle overshoot
Type 2 - limited adduction
Type 3 - limited abduction with vertical muscle undershoot
