Visual Loss and Blindness Flashcards
Sudden visual loss can have a vascular aetiology. Whhich two things does this include?
- Occlusion
- Haemorrhage
Occlusion of which two circulations may induce sudden visual loss?
- Retinal circulation
- Optic nerve head circulation
Haemorrhage from which causes may induce sudden visual loss?
- Abnormal new blood vessels
- Retinal tears
Which common conditions can cause the development of abnormal new vessle growth?
- Wet macular degeneration
- Diabetic retinopathy
The retina has a vascualr supply from which two sources?
- Central retinal artery
- Choroid (outer 1/3rd)
What are the classic symptoms of a central retinal artery occlusion (CRAO)?
- Sudden profound visual loss
- Painless
Which classic sign of a CRAO can be seen in the pupils?
Relative afferent pupil defect
How can a CRAO be identified on a fundoscopy?
- Pale oedematous retina
- Thread-like retinal vessels
- Cherry red spot
What may induce a CRAO?
- Carotid artery disease
- Emboli from heart (rare)
How can a CRAO be treated?
If presents within 24hrs ocular massage
Transient CRAO is known by which other name?
Amaurosis fugax
What should happen with a patient who presents with amaurosis fugax?
- Urgent referral to stroke clinic
- Aspirin
How is the vision loss associated with a transient CRAO different from that associated with a migraine?
It is painless
What are the different causes for a central retinal vein occlusion?
- Systemic - Atherosclerosis, hypertension, hyperviscosity (Virchow’s triad)
- Ocular - Raised IOP
What are the symtoms of of a CRVO?
- Sudden, moderate/severe visual loss
- Painless
What signs on a fundoscopy are characteristic of a CRVO?
- Retinal “flame” haemorrhages
- Dilated tortuous veins
- Disc and macular swelling
What are the treatments for a CRVO?
- Anti-VEGF therapies
- Address underlying risk factors such as diabetes or hypertension
- Laser therapies to target new vessel growth
Which arteries become occluded in ischaemic optic neuropathy?
Posterior ciliary arteries
What are the two forms of ischaemic optic neuropathy?
- Arteritic (inflammation)
- Non-arteritic (atherosclerosis)
Which condition causes arteritic ischaemic optic neuropathy?
Giant cell arteritis
How does the optic disc present in a patient with ischaemic optic neuropathy?
Swollen
What are the symptoms associated with arteritic ischaemic optic neuropathy?
- Sudden profound vision loss
- Irreversible blindness
Which symptoms are closely associated with giant cell arteritis?
- Tender enlarged temporal artery
- Headache
- Jaw claudication
- Scalp tenderness
- Amaurosis fugax
- Malaise
What are the symptoms of a vitreous haemorrhage?
- Loss of vision
- Floaters
What are the signs of vitreous haemorrhage?
- Loss of red reflex
- Haemorrhage seen on fundoscopy
How are non-resolving cases of vitreous haemorrhage managed?
Vitrectomy
What are the symptoms of a retinal detachment?
- Painless loss of vision
- Sudden onset of flashes and floaters
What are the signs of retinal detachment?
- May have relative afferent pupil defect
- May see tear on opthmaloscopy
Which type of treatment is usually required in a retinal detachment?
Surgical
What is the most common cause of blindness in the western world?
Age related macular degeneration
What are the two types of macular degeneration?
- Wet type
- Dry type
What is the most common form of macular degeneration?
Dry type
Which type of macular degeneration is associated with sudden visual loss?
Wet type
What is the main issue with wet macular degeneration?
Development of new vessels which haemorrhage
What are the classical symptoms of wet macular degeneration?
- Rapid central vision loss
- Distortion (metamorphopsia)
What are the signs of wet ARMD?
- Haemorrhage
- Exudate
What are the treatment options for wet ARMD?
- Anti-VEGF
- Laser
- Photodynamic therapy
Which common condition can be described as a progressive optic neuropathy?
Glaucoma
What is the pathophysiology of closed angle glaucoma?
Aqueous humour encounters increased resistance through the iris/lens channel (at the iridocornel angle)
The associated increase in pressure causes the peripheral iris to bow forward obstructing the trabecular meshwork and drainage system
How does a patient with acute closed angle glaucoma often present?
- Severe pain
- Nausea and vomiting
- Red eye
- Visual loss
What is the required treatment for acute closed angle glaucoma?
- Lower IOP with drops or oral medication
- Laser iridotomy
What can be causes of gradual visual loss?
- Cataract
- ARMD (dry type)
- Refractive error
- Glaucoma
- Diabetic retinopathy
What are the main causes for cataracts?
- Age
- Congenital
- Traumatic
- Metabolic (diabetes)
- Drug induced (steroids)
What are the main symtpoms of cataracts?
- Gradual decline in vision
- Hazy/blurred vision uncorrected by glasses
- Glare
What is the management for cataracts?
Surgical removal of lens and insertion of intra-ocular lens implant
What are the symptoms of ARMD dry type?
- Gradual decline in vision
- Loss of central vision (scotoma)
What are the signs for dry type macular degeneration?
- Drusen - build up of waste products below the retinal pigment epithelium
- Atrophic patches on the retina
What is the cure for dry type ARMD?
No cure
Only supportive therapy e.g. magnifiers
What is the term used to describe short sightedness?
Myopia
What is the term used to describe long sightedness?
Hypermetropia
What is astigmatism?
Error in the shape of the cornea
Lens of the eye or the cornea has an irregular curve
This can change the way light passes, or refracts, to the retina causing blurry, fuzzy, or distorted vision
What is presbyopia?
Loss of accomodation associated with ageing
What is open angle glaucoma?
Glaucoma due to resistance to outflow of aqueous humour in the trabecular meshwork
(pressure gradient across the trabecular meshwork is increased, causing stress to the lamina cribrosa and retinal ganglion cells and their eventual destruction)
What are the symptoms of open angle glaucoma?
Often none
(frequently picked up coincidentally by opticians)
What are the signs for a open angle glaucoma?
- Cupped disc
- Visual field defect
- High IOP (not always)
What is the treatment for open angle glaucoma?
- Lower IOP with eyedrops, surgery or laser
- Regular eye clinic monitoring
