vision loss Flashcards
causes of sudden vision loss
retinal detachment, vascular causes, WET ARMD, closed angle glucoma, optic neuritis, stroke
vision loss can happen due to occlusion of which 2 things?
retinal circulation
optic nerve circulation
vision loss can occur from haemorrhage from
abnormal formed vessels - diabetes, wet ARMD
retinal tear
symptoms of central retinal artery occlusion
sudden vision loss
Profound (Counting Fingers or less- remember CRA is ‘end artery’)
Painless
signs of central retinal artery occlusion
RAPD (relative afferent pupil defect)
Pale oedematous retina, thread-like retinal vessels
red dot on fovea
what are the causes of central retinal artery occlusion ?
Carotid artery disease
Emboli from the heart (unusual)
management of central retinal artery occlusion
in first 24 hours - ocular massage - increasing pressure of eye to try dislodge emboli to branch and increase retinal perfusion
Vascular management
Establish source of embolus – carotid doppler
Assess and manage risk factors
2 other types of retinal artery occlusion apart from CRAO
retinal artery branch occlusion
TRANSIENT CRAO–amaurosis fugax
signs and symptoms of amaurosis fugax
transient painless visual loss
curtain like blindness
vision restored fully around 5 minutes
nothing noramlly seen on examination
treatment of amaurosis fugax
Immediate referral TIA clinic
Aspirin
other cause of transient visual loss
migrane
causes of central retinal vein occlusion
Systemic causes
Atherosclerosis }
Hypertension } Virchow’s triad
Hyperviscosity }
Ocular causes raised IOP (venous stasis)
symptoms and signs of central retinal vein occlusion
Symptoms:
Sudden visual loss
Moderate to severe visual loss (6/9 – P of L)
Signs:
Retinal haemorrhages
Dilated tortuous veins
Disc swelling and macular swelling
treatment of central retinal vein occlusion
Based on treatment of systemic or ocular causes (eg hypertension, diabetes, glaucoma)
Monitor : may develop complications due to development of new vessels
- laser treatment may be required to avoid complications from these vessels eg vitreous haemorrhage)
- anti- VEGFs used (VEGF = vascular endothelial growth factor)
what colours do a central retinal vein and artery occlusion look like on fundoscopy?
artery occlusion - pale
vein occlusion - dark
what 2 types of ischemic optic neuropathy are there?
arteritic - GCA
non-arteritic - artherosclerosis
what do both types of ischemic optic neuropathy cause?
sudden, profund loss of vision with a swollen disc
how does giant cell arteritis cause ischemic optic neuropathy?
Lumen of artery becomes occluded (posterior ciliary arteries)
Visual loss from ischaemia of optic nerve head
symptoms of arteritic ischemic optic neuropathy
Visual symptoms Sudden visual loss Profound (CF – NPoL) Irreversible blindness swollen disc
why is arteritic ischemic optic neuropathy important to diagnose?
immediate treatment may prevent bilateral visual loss
what are the symptoms of giant cell arteritis?
Headache (usually temporal) Jaw claudication Scalp tenderness (painful to comb hair) Tender/enlarged scalp arteries Amaurosis fugax Malaise Very High ESR , PV and CRP Temporal artery biopsy may help diagnosis
what treatment must be started quickly to prevent visual loss in other eye for giant cell arteritis?
corticosteroids, starting at 40-60mg prednisolone and gradually reducing. Steroid sparing agents such as methotrexate and azathioprine may be added.
what can cause vitrous hamorrhage?
retinal tear
bleeding from abnormal vessels
signs and symptoms of vitrous haemorrhages
Symptoms
Sudden Loss of vision
‘Floaters’
Signs
Loss of red reflex
May see haemorrhage on fundoscopytreatment for vitrous haemorrhages
Management
Identify cause
Vitrectomy for non-resolving cases
cause for retinal detachment
Vitrous gel – when you get older the gel becomes more liquid based and then the vitrous can collapse and pull the retina with it – this causes the flashing
The floaters are due to epithelial cells getting pulled off by the retina and then you see these
symptoms and signs of retinal detachment
Symptoms
Painless loss of vision
Sudden onset of flashes/floaters (mechanical separation of sensory retina from retinal pigment epithelium)
Signs
May have RAPD - relative afferent pupillary defect
May see tear on ophthalmoscopy
management of retainal detachment
surgical
symptoms and signs of wet age related macular degeneration
Symptoms
Rapid central visual loss
Distortion (metamorphopsia)
Signs
haemorrhage/exudate
wet ARMD treatment
Previously:
Laser
Photodynamic therapy
Now:
Anti-VEGF treatment – injected into vitreous cavity. Stops new blood vessels growing by binding to VEGF (vascular endothelial growth factor)
cause of wet ARMD
new vessels begin to grow in choroid body and these vessels leak which cause scarring and retina to be displaced from choroid
causes of gradual visual loss
CARDIGAN Cataract Age related macular degeneration (dry type) Refractive error Diabetic retinopathy Inherited diseases e.g. retinitis pigmentosa Glaucoma Access (to eye clinic) Non-urgent
what is cataracts?
cloudiness of lens
causes of cataracts
Many different causes Age related Congenital – intrauterine infection (importance of checking red reflex in neonates) Traumatic Metabolic – diabetes Drug-induced (steroids)
cataracts management
Management is surgical removal with intra-ocular lens implant if patient is symptomatic
symptoms and signs of dry ARMD
Symptoms
Gradual decline in vision
Central vision ‘missing’ (scotoma)
Signs
Drusen – build up of waste
products below RPE - retinal pigment epithelium
Atrophic patches of retina
treatment of dry ARMD
No cure – treatment is supportive with low vision aids eg magnifiers
what is a refractive error?
the eye cannot focus clearly
what is myopia?
short sighted
cannot see far away as lens is too powerful and brings things to focus before the retina
what is hypermetropia?
long sighted
lens isnt powerful enough to focus close objects on the retina
What causes unilateral, sudden vision loss?
retinal artery embolisim
retinal vein thrombosis
vitreous haemorrhage (wet ARMD, retinal tear)
temporal arteritis
retinal detachment
optic neuritis
migraine
acute glaucomawhat causes bilateral, sudden vision loss?
bilateral occipital lobe ischaemia or infarction
bilateral occipital lobe trauma
severe bilateral papilloedema
rapidly progressive chiasmal compression
bilater optic nerve damage 3.g methyl alcohol poisoning
hysteria
what causes unilateral, gradual vision loss?
asymmetic cateract development
choiroiditis
inferior retinal detachment
malignant melanoma of the choroid
what causes bilateral, gragual visual loss?
diabetic maculopathy hypertensive retinopathy cateracts chronic glaucoma Chiasmal or bilateral optic nerve compression bilateral optic nerve damage
What causes diabetic retinopathy?
- retinal capillary microaneurysms and excessive vascular permeability
- vascular occlusion and proliferation of new blood vessels and accompanying fibrous tissue
- contraction of fibrovascular proliferations and vitreous
What are cotton wool spots?
cotton wool spots occur secondary to microvascular occlusion and represent retinal microinfarcts of the nerve fibre layer
Some pathology that occurs in diabetic retinopathy
retinal thickening, oedema and hard exudates occur as a result of leakage from capillaries; hard exudates are composed of lipoprotein and lipid filled macrophages
Flame-shaped haemorrhages occur when the rupture of microaneurysms occurs at nerve level blot haemorrhages occur if rupture of microaneurysms occur deep in the retina
how could proliferative diabetic retinopathy cause sudden visual loss?
In PDR, the fibrovascular proliferation extends beyond the internal limiting membrane. The new vessels are leaky, fragile, and often misdirected. They may grow off the retina and into the vitreous. As the vitreous shrinks with age, it pulls on these fragile vessels and can cause them to tear, resulting in a vitreous haemorrhage and sudden vision loss.
These vessels may also scar down, forming strong anchors between the retina and vitreous causing traction on the retina. If enough force is created, a tractional retinal detachment may occur. This is another mechanism by which PDR can cause sudden vision loss. If the retina is not re-attached soon, especially if the macula is involved, vision may be permanently compromised.
what is the most common cause of sudden vision loss in diabetic retinopathy?
macular oedema.
Macular oedema can occur in NPDR, but it is more common in more severe cases of DR due to the leakiness of the new blood vessels
What is astigmatism?
usually irregular corneal curvature
What is presbyopia?
weakening of the eye with age
What is glucoma?
progressive optic neuropathy
Fluid builds up behind the iris and pushes the iris forward – sometimes so much that it shuts off the angle – this is acute glaucoma
symptoms of acute glucoma
VERY painful, red eye/visual loss/headache/nausea/vomiting
treatment of acute glucoma
need to lower IOP with drops/oral medications to stop blindness
Symptoms and signs of open angle glucoma
symptoms
Often NONE
Optician may discover it
Signs
Cupped disc
Visual field defect
May/may not have high IOPTreatment of open angle glucoma
eye drops, lasers, surgery to reduce IOP
