Visual loss Flashcards
What are the causes of sudden visual loss?
Vascular (central retinal artery/ vein occlusion) Vitreous haemorrhage Retinal detachment ARMD - wet Closed angle glaucoma Optic neuritis Stroke
What is the arterial supply to the eye?
All arises from the ophthalmic artery
Posterior ciliary artery supplies the optic nerve head
Central retinal artery supplies the retina
What are the symptoms of central retinal artery occlusion (CRAO)?
Sudden visual loss
Painless
What are the signs of CRAO?
RAPD
Pale, edematous retina
Thread like retinal vessels
Cannot see top letter on snellen chart
What are the common causes for CRAO?
Carotid artery disease
Emboli from heart due to vegetations on heart valve
What will branch retinal artery occlusion cause?
A section of the retina will be pale and ischaemic
What are the symptoms of amaurosis fugax?
Transient painless visual loss
“Like a curtain coming down”
Lasts 5 mons
What should be done if someone presents with a history of amaurosis fugax?
Urgent referral to stroke clinic as it can be a pre-warning to a stroke
What is central retinal vein occlusion (CRVO) associated with?
Endothelial damage e.g. diabetes
Abnormal blood flow e.g. hypertension
Hypercoagulable state e.g. cancer
What are the symptoms of CRVO?
Sudden visual loss if there is ischaemia
What are the signs of CRVO?
Retinal haemorrhages
Dilated tortuous vessel
Disc swelling and macular swelling
Cotton wool spots (small infarcts of the nerve fiber layer)
What can cause ischaemic optic neuropathy?
Occluded posterior ciliary artery
Giant cell arteritis
What causes ION in GCA?
Posterior ciliary arteries become inflamed with multinucleated giant cells causing a gross thickening of artery wall resulting in visual loss due to ischaemia of the optic nerve head
What are the symptoms of ION?
Sudden severe visual loss
Irreversible blindness
What is the sign of ION?
Swollen optic nerve
Pale disc
What are the symptoms of GCA?
Temporal headache Jaw claudication Scalp tenderness Amaurosis fugax Malaise
What is vitreous haemorrhage?
Bleeding from abnormal neovascularization bleeds into vitreous causing floaters
When will neovascularization occur in the retina?
Retinal ischaemia in diabetes or retinal vein occlusion sends out VEGF resulting in abnormal, fragile blood vessels to form which are susceptible to bleeding
What are the symptoms of vitreous haemorrhage?
Loss of vision
Floaters
What are the signs of vitreous haemorrhage?
Loss of red reflex
Haemorrhage on fundoscopy
What are the symptoms of retinal detachment?
Painless loss of vision
Sudden onset of flashes/ floaters
What are the signs of retinal detachment?
RAPD
Tear on ophthalmoscopy
What is wet ARMD?
New blood vessels grow under the retina resulting in leakage causing a build up of fluid/ blood and eventual scarring
What are the symptoms of wet ARMD?
Rapid central vision loss
Distortion (metamorphopsia)
What are the signs of wet ARMD?
Pale macula
Exudates at the periphery of macula
Small haemorrhages
What is glaucoma?
Progressive optic neuropathy mostly due to high IOP
2 different types
End result is optic nerve damage and visual loss
What causes closed angle glaucoma?
Aqueous humour has increased resistance through iridocorneal angle which results in an increase pressure pusing iris forward obstructing the trabecular meshwork
What are the symptoms of acute closed angle glaucoma?
Painful Red eye Sudden visual loss Headache Nausea and vomiting
What are the signs of acute closed angle glaucoma?
Red eye
Cloudy cornea
Dilated pupil
When will gradual visual loss present early and late?
Presents early if reduction in visual acuity
Presents late if decreased visual field
What are the causes of gradual visual loss?
Cataract ARMD - dry Refractive error Glaucoma Diabetic retinopathy
What is cataracts?
Cloudiness of the lens - abnormal changes in lens proteins (crystalline) results in their chemical and structure alteration, leading to loss of transparency
What can cause cataracts?
Age related Congenital (intrauterine infection) Traumatic Metabolic (diabetes) Drug-induced (steroids)
What are the different types of cataract?
Nuclear
Posterior subcapsular
Christmas tree
Congenital
What are the symptoms of cataracts?
Gradual decline in vision (hazy/blurred) that cannot be fixed with glasses
Glare
What is the management of cataracts?
Surgical removal with intraocular lens implant if symptomatic
What causes dry ARMD?
Build up of drusen under the retina which will stop nutrients from diffusing from the choroid to the retina
The retina will become atrophic and thin
What are the symptoms of dry ARMD?
Gradual decline in vision
Central vision missing - scotoma
What are the signs of dry ARMD?
Drusen - waste products below the RPE
Atrophic patches of retina - scotoma
What is myopia?
Short sighted
What is hypermetropia?
Long sighted
What is astigmatism?
Irregular corneal curvature
What is presbyopia?
Loss of accommodation with aging (pupil dilation, medial convergence and parasympathetic fattening of lens)
What are the symptoms of open angle glaucoma?
NONE
Optician may discover
What are the signs of open angle glaucoma?
Cupped disc
Visual field defect
May/ may not have high IOP
What is a swollen disc?
Any disc swelling secondary to any cause
What is papilloedema?
Swollen optic disc secondary to raised ICP
What is the golden rule with bilateral optic disc swelling?
All patients with bilateral optic disc swelling should be suspected of having raised ICP due to SOL until proven otherwise
RAISED ICP IS A MEDICAL EMERGENCY
What is included in the optic nerve examination?
Ophthalmoscopy Visual acuity - snellen chart Pupil exam - direct, consensual and RAPD Visual field assessment Colour vision - ishihara test
Where is the CSF fluid in papilloedema?
Subarachnoid space of the meninges
What are the three components of ICP?
Brain 80%
Blood 10%
CSF 10%
What is the monro-kellie hypothesis?
An increase in one variable of ICP will result in a decrease of one/both other variables as the cranium is rigid and cannot expand
What will occur with an increase in CSF fluid?
Blood vessels compressed causing global brain ischaemia
Swelling with herniation through foramen magnum, brainstem compression and death
CASE:
70yr old male, blurred vision, headaches, VA 6/6 R and L
Bilateral swollen discs
Meningioma
CASE: 55yr old Smoker Obese C/o blurred vision for 1 week Bilateral grossly swollen discs
ALWAYS CHECK BP
He has a BP of 240/140 mmHg
Malignant hypertension
What are the functions of CSF?
Maintains stable extracellular environment for the brain Buoyancy Mechanical protection Waste removal Nutrition
What can cause a rise in ICP?
Obstruction to CSF circulation
Overproduction of CSF
Inadequate absorption
CASE: 25 y/o female 6 mnth headaches BMI 40 VA 6/6 R&L Bilateral disc swelling Normal BP Normal head MRI
Lumbar puncture showed raised CSF opening pressure
Idiopathic intracranial hypertension
What causes idiopathic intracranial hypertension?
Stenosis of transverse cerebral sinuses
Increased abdo pressure, increased cardiac pressure resulting in obstructed venous return from cranium
Microemboli in sagittal sinus
What happens if the disc swelling becomes chronic?
Atrophic and pale disc
Loss of visual function
Blindness
What are the causes of RAPD?
Optic neuritis Ischaemic optic disease Severe glaucoma resulting in trauma to the optic nerve Direct optic nerve damage Retinal detachment Severe macular degeneration Retinal infection
Symptoms of horners sydrome
Ptosis - loss of innervation to superior tarsal muscle
Miosis - loss of symp output to ciliary muscles
Anhidrosis
What can cause horner’s syndrome?
Carotid artery dissection
Pancoast tumour
Brachial plexus injury
Cavernous sinus thrombosis
