Week 2 Flashcards
Mechanisms of ocular trauma
Blunt trauma
Penetrating trauma
Burns (chemical / physical)
What can blunt trauma lead to
Blowout fractures
Subconjunctival haemorrhage
Globe rupture
Hyphaemia
Traumatic uveitis
What injury mechanism can cause blowout fracture
Direct blow to the central orbit by fist/ ball
What can happen as a result of blowout fracture
Herniation
Trapdoor fracture
Which structure is likely to herniate in a blowout fracture
Inferior rectus muscle
Orbital fat
Where does the herniates go into
Maxillary sinus
Inferior rectus muscle herniation can cause
Diplopia
when ask the patient to look up, one eye cannot move up
But when ask the patient to look down, both eyes can
What is subconjunctival haemorrhage
Rupture of blood vessels in conjunctiva, releasing the blood into the space between conjunctiva and sclera
Besides from trauma, what else can cause subconjunctival haemorrhage
Heavy coughing
Strenuous exercise
Straining when constipated
What is hyphaemia
Blood in anterior chamber
What is traumatic uveitis
Inflammation of iris due to eye trauma
What is the urea
Layer behind the conjunctiva and sclera, containing iris, choroid and ciliary body
Why are corneal abrasions very sore
Due to dense sensory innervation of the cornea
What can be used to check for corneal lacerations
Fluorescein stain drops
Management of corneal laceration
Remove the foreign body causing it
Ocular lubricants
Analgesia
chloramphenicol if risk of infection
What is myotonic dystrophy
Group of inherited conditions that show muscle weakness and myotonia
What is myotonia
inability to relax after muscle contraction
types of myotonic dystrophy
Classic dystrophia myotonica 1 (DM1)
Type 2 myotonic dystophy (DM2)
Which type of myotonic dystrophy is more common
Classic dystrophia myotonica 1 (DM1)
Myotonic dystrophia most commonly present at
20 years old
Cause of classic dystrophia myotonic 1
Mutation in DMPK gene
Presentation of myotonic dystrophia
Frontal balding in males
Long and thin face
Bilateral ptosis
Cataracts
Slurred speech
Loose jaw (mournful facial expression)
Muscle wasting and weakness
What causes slurred speech in myotonic dystrophia
Myotonic tongue and pharyngeal muscles
What cataracts are seen in myotonic dystrophia
Stellate posterior cortical cataract
Polychromatic cataract (Christmas tree)
What physical test can be done to identify myotonic dystrophia
Shake the patient’s hand - the patient will be unable to release their hand due to myotonia
What is neurofibromatosis type 1
Genetic condition that causes tumours along the nervous system
Cause of neurofibromatosis type 1
NF1 gene mutation
Presentation of neurofibromatosis type 1
> 6 cafe au last spots that are >5mm (pre puberty) or >15mm (post puberty)
Axillary or inguinal freckling
2 neurofibromas of any type on skin
Optic glioma
2 Lisch nodules
What is optic glioma
slow-growing brain tumor that arises in or around the optic nerve
What are Lisch nodules
Iris hamartomas (benign) that are seen as brown patches on the iris
What can optic glioma result in
Afferent pupillary defect
Globe proptosis (the tumour is pushing the eyeball out)
What is afferent pupillary defect
pupils respond differently to light stimuli
Which thyroid disease causes eye disease
Grave’s - hyperthyroidism
How does thyroid eye disease occur
Autoimmune disease caused by the activation of orbital fibroblasts by autoantibodies directed against thyroid receptors
Presentation of thyroid eye disease
Proptosis (unilateral / bilateral)
Lid retraction
Red, watery eyes
Optic neuropathy (as the swelling worsens and compresses the optic nerve)
How does proptosis occur in thyroid eye disease
The autoantibodies target the extra ocular muscles and orbital fat which causes swelling behind the eye hence pushes the eyeball out
What habit can worsen thyroid eye disease
Smoking
Complications of thyroid eye disease
Optic neuropathy
Exposure keratopathy
Double vision
What is exposure keratopathy
corneal damage and infection occurs as the patient is unable to close their eyes
What causes double vision in thyroid eye disease
Fibrosis of the extra-ocular muscles limiting the gaze in certain directions
