Lecture ILO’s Flashcards
What causes the pupil to constrict and dilate?
Constrict - parasympathetic
Dilate - sympathetic
What muscles control extra-ocular movements and what nerves innervate them?
Third cranial nerve (oculomotor) moves the superior rectus, inferior rectus, medial rectus
Fourth cranial nerve (trochlear) moves the superior oblique
Sixth cranial nerve (abducens) moves the lateral rectus
What muscles causes eye elevation?
Levator palpebrae superioris - innervated by 3rd cranial nerve
Superior tarsal plate - innovated by sympathetic fibres
Role of sympathetic system to the eye, where does it run and what happens if this is damaged?
Dilates eye and prevents ptosis
Runs from cervical to lumbar region of spine
Damaged = horners syndrome - constricted eye and ptosis
What is ptosis?
Ptosis= >2mm of cornea covered by eyelid
Unilateral causes of ptosis
Involutional changes - ageing - muscle degeneration
Congenital
3rd nerve palsy
Horner’s Syndrome - sympathetic problem
Trauma to levator muscle
Bilateral causes of ptosis
Involutional changes
Congenital
Myasthenia gravis (one side can be more affected)
Myotonic dystrophy
Mitochondrial myopathies
Dermatochalasis
Trauma to levator muscle
Dermatochalasis
Excessive skin on upper / lower eye Lid
Presents with recurrent blepharitis which have now resolved (edges of your eyelids become red and swollen)
Involutional Ptosis
Connections to levator palpabrae superioris break down
• Diagnose by excluding other causes (only history and examination usually required)
• Surgical repair required if obscuring vision
Myotonic dystrophy clinical features
• Autosomal dominant
• Trinucleotide repeats (DM1); tetranucleotide repeats (DM2)→anticipation through generations
• Cause muscular dystrophy
Clinical features:
• Muscle weakness and wasting (lower motor neurone)
– Bilateral ptosis
– Wasted SCM
– Wasted temporalis
– Little lines on forehead
– Hatchet jaw
• Prolonged contraction/delayed relaxation
– Percussion myotonia (thumb flexes with a tendon hammer)
– Difficulty relaxing muscles-grip (muscle spasms following contraction)
• Male pattern balding
• Cataracts
• Diabetes
• Gynaecomastia
• Low IQ - learning disability
• Heart conduction defects - heart block
Horners syndrome causes and common symptoms
• Sympathetic supply to eye interrupted (parasympathetic overrides to affected side):
– Ptosis - drooping of the upper eye lid
– Meiosis - constricted pupils
– Enophthalmos - eye sinks deeper into eye socket
– Anhydrosis - inability to sweat
Horners syndrome causes
Central
Pre ganglionic
Post ganglionic
Central
- CVA
- Syringomyelia
- Multiple sclerosis
- Meningitis & Encephalitis
- Brain or spinal cord tumour
- Trauma (central)
Preganglionic
- Cervical rib
- Lymphadenopathy
- Thyroid mass (goitre, tumour, surgery)
- Lung apex pathology (tumour)
- Thoracic aorta, subclavian aneurysm
- Trauma (chest)
Postganglionic
- Carotid artery dissection/aneurysm
- Cavernous sinus thrombosis
- Middle ear infection
- Cluster headaches
- Trauma (neck and head)
• Myasthenia gravis is caused by antibodies against which receptors:
A. Acetylcholine
B. Adrenaline
C. Glutamate
D. GABA
E. Dopamine
A
Myasthenia gravis is associated with enlargement of which organ
A. Hypothalamus
B. Pituitary gland
C. Spleen
D. Thyroid
E. Thymus
E
Third nerve palsy
• Ptosis (levator palpebrae superioris)
• Mydriasis (parasympathetic supply via oculomotor nerve→short cilliary nerves)
• Eye= down and out (unopposed effect of lateral rectus and inf. oblique)
• Enophthalmos
Causes- Diabetes, atherosclerosis, posterior communicating artery aneurysm, space occupying lesion, brain infection/inflammation, cavernous sinus thrombosis, multiple sclerosis
Blepharitis of the eyelid
Blepharitis of the eyelid
• Blepharitis is a chronic inflammation of the lid margin
• The condition is common and more severe in the elderly
• Two types - Blepharitis staphylococcal and also seborrheic type
• May predispose to blepharoconjunctivis and loss of lashes
• Characteristic symptoms (often intermittent, with exacerbations and remissions occurring over long periods):
• Burning, itching and/ or crusting of the eyelid.
• Symptoms are worse in the mornings.
• Both eyes are affected.
• Recurrent hordeolum (stye)
• Contact lens intolerance.
Blepharitis management
• Requires ongoing maintenance treatment,self-care measures such eyelid hygiene and warm compresses continued even when symptoms are well controlled to minimise number and severity of relapses.
• Baby shampoo diluted1:10 with warm water and gently wiping along the lid margins to clear any lid debris.
• If self- care measures are ineffective consider prescribing a topical antibiotic (chloramphenicol) to be rubbed into the lid margin - can get OTC.
Chalazion (meibomian cyst)
• Ameibomiancyst/chalazionisasterile,inflammatory granuloma caused by the obstruction of a sebaceous gland.
• Obstruction of the gland duct causes the gland to enlarge and to rupture spontaneously or persist as a chronic nodule.
• Ameibomian cyst may develop acutely with anoedematous, erythematous eyelid or arise insidiously as a firm, painless nodule.
• If there is secondary infection it can spread to preseptal cellulitis requiring oral or sometime IV antibiotics.
• Rarely, a meibomian cyst may become secondarily infected. If the infection spreads to other ocular glands or neighbouring tissues this may lead to periorbital or orbital cellulitis.
Management of Meibomian Cyst
•Meibomian cyst is usually self- limiting and rarely causes serious complication
• Warm compress then gently massage (don’t massage in circles, massage towards lid margin)
If the mebomium cyst is persistent (>4/52), recurrent, causing significant astigmatism, cosmetically unacceptable, or there is uncertainty about the diagnosis, refer the person to an ophthalmologist for further management.
• Incision and curettage
No treatment — if the meibomian cyst is small and asymptomatic.
Stye or hordeolum
Stye or hordeolum
Acute localized infection or inflammation of the eyelid margin. bacterial infection usually caused by staphylococcal infection
External stye
• Appears on the eyelid margin.
• infection of an eyelash follicle and its associated sebaceous or apocrine gland.
• Internal stye
• Occurs on the conjunctival surface of the eyelid.
• infection of a Meibomian gland (situated within the tarsal plate).