Visual Loss and Blindness Flashcards
what are the major branches of the ophthalmic artery?
- central optic artery
- posterior ciliary artery
what artery supplies the inner 2/3rds of the retina?
the central retina branch of ophthalmic artery
what artery supplies the outer 1/3rd of the retina?
posterior ciliary branch of ophthalmic
what are two types of basic vascular problems that can cause sudden visual loss?
occlusion or haemorrhage
what can become occluded that can cause sudden visual loss?
retinal circulation or optic nerve head circulation
what can haemorrhage to cause sudden visual loss?
abnormal blood vessels or a retinal tear
what kind of process/diseases can cause abnormal retinal blood vessels to haemorrhage?
diabetes , wet ARMD
what artery is occluded to cause an occlusion of the retinal circulation?
central retinal artery occlusion (CRAO)
is central retinal artery occlusion a painful vision loss?
no it is painless
symptoms of CRAO?
sudden profound vision loss
what would you expect a patient with a CRAO to be able to see on examination?
counting fingers a meter away from them or less
what clinical signs are present in a CRAO?
RAPD- relative afferent pupil defect
what is meant by RAPD? (relative afferent pupil defect)
showing that the message coming from one eye is weaker than the other. normal pupil will constrict to light, however affected pupil may dilate
how ill the retina appear in a CRAO?
pale oedematous retina with thread-like retinal vessels
in a CRAO, why can there sometimes be a small area of the retina that is preserved?
small area may contain a vessel from a choroidal artery that is supplying it
main cause of a CRAO?
carotid artery disease
what is a unusual and more rare cause of CRAO?
emboli from the heart
what is someone with a CRAO at risk of?
having a full-blown stroke
what is the ophthlamic managment of a CROA if they present within 24 hours and what is the aim of this managment?
ocular massage to try encourage blood flow though central retinal artery and reduce the occlusion to a BRAO (branch retinal artery occlusion)
what is the vascular management of a CRAO?
- establish source of emboli
- assess and manage risk factors
what is used to establish source of emboli in a CRAO?
carotid doppler
what is the other name for a transient CRAO?
amaurosis fugax
what are the classical symptoms of a transient CRAO?
- transient painless visual loss
- ‘like a curtain coming down over eyes’
- lasts about 5 mins with full recovery
what signs is there of a transient CRAO?
usually nothing abnormal to see on examination
what is the managment of a suspected transient CRAO?
- immediate referral to TIA clinic
- aspirin
what is another common cause of transient visual loss?
migraine
what other vessel can become occluded to cause sudden visual loss?
central retinal vein
what are the systemic causes of a central retinal vein occlusion (CRVO)
VIRCHOW’S TRIAD
- atherosclerosis
- hypertension
- hyperviscosity
ocular causes of CRVO?
raised intra-ocular pressure causing venous stasis
how severe is the visual loss in CRVO and what can patient normally still see?
- moderate to severe
- 6/9 - perception of light
signs when looking in the eye in a CRVO?
- retinal haemorrhages
- dialted tortous veins
- disc swelling and macular swelling
what is the treatment of a CRVO?
based on treatment of the systemic or ocular cause or more recently anti-VEGFs are being used
why is it important that CRVO is monitored?
may develop complications due to development of new vessels
what might be required to treat the development of new vessels in CRVO?
laser treatment
what is occlusion of optic nerve head circulation also known as?
ischaemic optic neuropathy
what artery is occluded that causes ischaemic optic neuropathy?
posterior ciliary arteries
what does occlusion of posterior ciliary arteries cause to infarct?
the optic nerve head
what are the 2 types of ischaemic optic neuropathy?
- arteritic
- non-arteritic
give an example of an arteritic ischaemic optic neuropathy?
GCA
give an example of a non-arteritic ischaemic optic neuropathy?
non-arteritic
signs of a arteritis ischaemic optic neuropathy?
pale, swollen disc
visual symptoms in ateritic ischaemic optic neuropathy? what is the range of what a patient may see?
sudden profound visual loss, range from counting fingers to no perception of light
is the blindness in GCA reversible?
no
how can GPA present?
-headache, jaw claudication, scalp tenderness, tender/enlarged scalp arteries, transient visual loss, malaise
what will be significant in a blood test in GCA?
very high ESR, PV and CRP
what is in important to recognise blindess is due to GCA early?
to prevent blindness in other eye
what is given to prevent blindness in GCA?
high dose steroids
-60-80mg prednisolone OD
where in the eye does a haemorrhage often occur and what is this known as?
into the vitreous cavity, called a vireous haemorrhage
if bleeding occurs from abnormal vessels what conditions is this normally associated with?
associated with retinal ischaemia and new vessel formation eg after CRVO or diabetic retinopathy
if bleeding occurs from normal retinal vessels, what is the usually associated with?
a retinal tear
symptoms of a vitreous haemorrhage?
loss of vision, ‘floaters’ in vision
clinical signs of vitreous haemorrhage?
loss of red reflex, may see haemorrhage on fundoscopy
what is the management for non-resolving cases of vitreous haemorrhage?
vitrectomy
symptoms of retinal detachment?
painless loss of vision, sudden onset of flashes/floaters
what 2 layer are separated in a retinal detachment?
sensory retinal from retinal pigmented epithelium
signs of retinal detachment?
- may have RAPD (relative afferent pupil defect)
- may see tear on ophthalmoscopy
managment of retinal detachment?
surgical correction
what is the commonest cause of blindness in western world in patients over 65?
age related macular degeneration (ARMD)
what are the 2 types of ARMD?
dry and wet
what does dry ARMD cause?
gradual reduction in vision
what does wet ARMD cause?
sudden reduction in vision
what is the pathological process behind wet ARMD?
new blood vessels grow under the retina- leakage of these vessels causes build up of fluid/blood and eventually scarring
symptoms of wet ARMD?
rapid central visual loss and distortion
what is the proper word for distortion in vision?
metamophopsia
signs in the retina in a wet ARMD?
haemorrhage/exudates
what test is done to assess wet ARMD?
the amsler grid
treatment of wet ARMD?
anti-VEGF treatment
how is anti-VEGF treatment given? and what does it do?
injected into vitreous cavity. stops new blood vessels growing by binding to VEGF
what does VEGF stand for?
vascular endothelial growth factor
is gradual visual loss usually bilateral or unilateral?
usually bilateral but can be asymetical
when does gradual visual loss tend to prevent early?
if there is a reduction in general visual ability
when may gradual visual loss present late? and why?
when there is decreased field vision as takes patient a while to notice this as central vision is unaffected
what does the acroynm ‘CARDIGAN’ stand for in relation to causes of gradual visual loss?
- Cataract
- ARMD (dry type)
- Refractive error
- Diabetic retinopathy
- Inherited diseases
- Glaucoma
- Access (to eye clinic)
- Non-urgent (gradual loss tends not to be urgent)
give an example of an inherited condition that can cause gradual visual loss?
retinitis pigmentosa
what is a cataract?
clouding of the lens
causes of cataract?
- age related
- congenital
- traumatic
- metabolic -diabetes
- drug induced (steroids)
what are the 4 main types of cataract?
- nuclear cataract
- posterior subcapsular cataract
- christmas tree cataract
- congenital cataract
what is the proper name for christmas tree cataract?
polychromatic cataract
what is the appearance of a congenital cataract?
solid white circle in the centre with a further ring of opacity around it
managment of cataract?
surgical removal with intra-ocular lens implant
what is the artificial lens in cataract surgery placed inside?
in the capsular bag that previously encased normal lens
what area of vision tends to affected in dry ARMD?
central vision
what is an area of vision that is missing refered to as?
a scotoma
what are the signs of dry ARMD when looking at the retina?
- drusen
- atrophic patches of retina
what is drusen?
a build up of waste products below the retinal pigmented epithelium
what sits underneath the retinal pigmented epithelium?
choroid
management of dry ARMD?
no cure - supportive treatment with low vision aids
what is meant by myopia?
‘short-sighted’
what is the word used to describe long-sighted?
hypermetropia
what is an astigmatism usually due to?
irregular corneal curvature
what is meant by presbyopia?
loss of accomodation of refractive power with aging
what is the treatment of a refractive error?
glasses
what happens in glaucoma?
progressive optic neuropathy
2 main types of glaucoma?
open-angle and closed-angle
what does the angle in ‘open-angle’ or ‘closed-angle’ refer to?
the angle between the cornea and the iris
what causes a closed angle glaucoma?
fluid builds up behind the iris and is pushes the iris forward so far that it can close the angle.
what type of glaucoma is an emergency?
closed-angle glaucoma
what can be used to treat a closed-angle glaucoma in an emergency and what is its purpose?
use a laser to zap a hole in the iris tissue to let fluid escape through the hole and into drainage channel
how does an acute closed-angle glaucoma present?
very painful, red eye, visual loss, headache, nausea, vomitting
what must be given straight away in an acute closed-angle glaucoma?
drops/oral medication to lower intra-ocular pressure
what are the symptoms of an open-angle glaucoma?
often there is none
signs of an open-angle glaucoma?
- cupped disc
- visual field defect
- may or may not have raised IOP
management of open angle glaucoma?
aim to preserve vision by lowering IOP with eye drops/laser/surgery. regular monitoring
