Visual Loss and Blindness Flashcards
What vascular problems can cause sudden visual loss?
- Occlusion of either retinal or optic nerve circulation
- Haemorrhage
What symptoms present when the central artery of the retina is occluded?
Sudden visual loss with no PAIN
What signs can show a central retinal artery occlusion
- RAPD (relative afferent pupil defect - slight dilatation)
- Pale oedematous retina
- thread-like retinal vessels
Emboli from where can cause Central Retinal Artery Occlusions (CRAO)?
- Carotid artery disease
- Emboli from the heart (unusual)
**type of stroke
Occlusion of a branch of the retinal artery can cause what?
Amaurosis fugax - transient occlusion
“curtain coming down”
What symptoms present in an occlusion of a branch of the retinal artery?
- transient painless visual loss
- ‘like a curtain coming down’
- lasts around 5mins with full recovery
Any transient CRAO requires urgent referral to the stroke clinic. TRUE/FALSE?
TRUE
How is a central retinal vein occlusion commonly caused?
Endothelial damage e.g. diabetes
Abnormal blood flow e.g. hypertension
Hypercoaguable state e.g. cancer
A central retinal vein occlusion presents with variable sudden vision loss. TRUE/FALSE?
TRUE
What signs are present on fundoscopy when there has been a central retinal vein occlusion?
- Retinal haemorrhages
- Dilated tortuous veins
- Disc and macular swelling
Describe the main difference on fundoscopy for CRAO and CRVO?
CRAO = pale with thin vessels CRVO = dark with tortuous vessels
Infarction of the head of the optic nerve is caused by an occlusion in which artery?
Posterior ciliary arteries
Infarction of the optic nerve head is known as what condition?
Ischaemic optic neuropathy
What other condition can cause ischaemic optic neuropathy?
Giant Cell/ Temporal Arteritis
causes lumen of posterior ciliary arteries to become occluded
The sudden visual loss caused in ischaemic optic neuropathy is irreversible. TRUE/FALSE?
TRUE
What other symptoms may be present in giant cell arteritis?
- Headache (usually temporal)
- Jaw claudication
- Scalp tenderness (painful to comb hair)
- Tender/enlarged scalp arteries
- Amaurosis fugax
- Malaise
Why do abnormal vessels haemorrhage into the vitreous cavity?
Retinal ischaemia in diabetes OR retinal vein occlusion => abnormal, fragile new blood vessels form and leak
When would normal blood vessels haemorrhage into the vitreous cavity?
When bridging a retinal tear
What symptoms and signs indicate a vitreous haemorrhage
- Loss of vision
- ‘Floaters
- Loss of red reflex
What are the common symptoms of retinal detachment
- Painless loss of vision
- Sudden onset of flashes/floaters (mechanical - separation of sensory retina from retinal pigment epithelium)
How does a detached retina appear on fundoscopy
pale
curled up
oedematous
What type or age related macular degeneration can cause sudden visual loss?
Wet
dry type causes gradual sight loss
Describe the pathogenesis of wet ARMD
- New blood vessels grow under retina
- Leakage causes build up of fluid/blood
- eventually scarring develops
What symptoms do patients with wet ARMD experience?
- Rapid central visual loss
- Distortion (metamorphopsia)
What can be seen on a fundoscopy when a patient has wet ARMD?
- haemorrhage
- exudate
What type of glaucoma is responsible for sudden visual loss?
Closed-angle glaucoma
What symptoms are experienced in closed-angle glaucoma?
- painful, red eye
- sudden visual loss
- headache
- nausea/vomiting
What signs can be seen in closed-angle glaucoma?
- red eye
- cloudy cornea
- dilated pupil (cant move due to optic nerve ischaemia)
What are the main differences between sudden and gradual visual loss?
Bilateral
Often asymmetrical
How does gradual visual loss present early vs late?
Presents early with reduced Visual Acuity
May present late with decreased field
What are the main causes of gradual visual loss?
- Cataract
- Age related macular degeneration (dry type)
- Refractive error
- Glaucoma
- Diabetic retinopathy
Describe the pathogenesis of lens clouding in cataracts
abnormal changes in lens proteins (crystallins)
=> changes their structure
=> leading to loss of transparency
What are the main causes of cataracts?
- age related
- congenital (intrauterine infection)
- traumatic
- metabolic (diabetes)
- drug-induced (steroids)
What visual symptoms may patients with cataracts experience?
- decline in vision (‘hazy’ / ‘blurred’) that cannot be corrected with glasses
- May get glare from sunshine
What surgery is used for cataracts and is it always useD?
intra-ocular lens implant
only completed if patient is symptomatic
What part of the vision is lost in dry type ARMD?
Central vision ‘missing’ (scotoma)
What signs can be seen on fundoscopy that indicate dry type ARMD?
- Drusen – build up of waste
- Atrophic patches of retina
Explain the role of magnifiers in dry type ARMD
Scotoma stays in same place
=> magnifier allows font or object to get larger and more to be viewed around missing part of vision
What is required if patients have a refractive error?
Glasses
What is the correct term for “short-sighted”?
Myopia
What is the correct term for “long-sighted”?
Hypermetropia
What is an astigmatism?
irregular corneal curvature
Older patients can lose the ability to accommodate, what is this called?
Presbyopia
Patients with open-angle glaucoma often have no symptoms. TRUE/FALSE?
TRUE
picked up by optometrist
What signs can open-angle glaucoma cause?
Cupped disc
Visual field defect
High Intra-ocular pressure
