Visual defects: a clinicans perspective Flashcards
what are the typical characteristics which are asked about in visual loss
character of visual loss out of focus glare distorted vision things look pale shadow floater timing associated factors
what causes blurred vision (what is the problem in the eye)
Refractive problem: cornea, lens, and shape of eye.
macular problem
what is one of the treatments for blurred vision
glasses to help correct the focusing problem.
what is glare and what causes glare.
difficulty seeing in bright light.
corneal lens problem- often due to cataract.
what is distortion of vision and why causes it
Things look wavy, jumbled up. Lines with kinks.
Affects retina
Wet macular degeneration- proliferation of blood vessels, which leads to fluid and protein leaking into the macula.
Macular hole- due to unequal distribution of fluid in eye.
Macular pucker- scar tissue on the retina especially macula
Retinal detachment
what causes things to look pale
Optic nerve disease
– Optic neuritis
– Compressive optic nerve disease- due to mass in orbit.
Condition affecting retina
– Wet macular degeneration
– Central serous retinopathy
if a visual field defect is homonymous where is the lesion
visual pathway
if the visual field pathway is not homonymous
retinal (retinal detach,ent)
optic nerve
what are the discs of a visual field defect.
Patient will not say they cannot see on one side.
They will say that bump into things on the right- then you have to test them and diagnose them
what causes floater
Problems with the gel behind the lens (vitreous)
vitreous floats around, and isn’t uniform.
Vitreous syneresis- older (gel behind the vitreous becomes more fluid.
Posterior vitreous detachment
Vitreous haemorrhage.
what is the slit lamp examination used to check
look at the surface of the eye.
what is cataracts
opacity of the lens.
what are the main signs and symptoms of cataracts
gradual onset
symptoms- blurred vison, glare ,change in refraction
what is the blood supply to the photoreceptor layer of the retina
choroid
what is the blood supply to the inner retinal layer of the eye
retinal artery.
what is the function of the retinal epithelium
maintains environment of photoreceptors remove waste products and reduced function leads to drusen (fatty yellow deposits under the retina)
define dry macular degeneration
Supporting cells have to survive a lifetime they are not replicated, and therefore they cannot protect photoreceptor- so they die
define wet macular degeneration.
fluid between photoreceptor and epithelium, photoreceptors no longer get blood supply from the choroid.
what are the signs if age related macula degeneration.
Drusen
RPE (retinal pigment epithelium) pigmentation
RPE atrophy
Gradual deterioration
which one of these is slow onset and which one is fast onset ; dry ARMD and wet ARMD.
dry-Slow
wet-Fast
why does a loss of small area leads to severe visual loss in dry ARMD
high density of photoreceptors in fovea
what is a phacoextraction
replacement of the lens of the eye.
what are the disadvantages of phacoextraction with lens implant.
Risk of serious complication leading to loss of vision (1-2%)
Visual recovery may be limited by ARMD in this case
Fear of operation – may request general anaesthetic
what normal and lifestyle changes can be made by a patient with cataracts
- No effective medical treatment
- Stop smoking
- Dark glasses to protect from bright sunshine
- Dietary changes / supplement
- Low visual aids.
- do not to drive until after the operation.
- Cataracts are likely to deterioarate.
what is involved in the premedical assessment
drugs patient may be taking - anticoagulants.
Counselled
Consented
Biometry to decide on power of lens implants.
what is the treatment after phacoextraction.
topical steroids for 2 weeks
what causes central retinal artery obstruction.
Carotid artery disease- Most common causes
Heart disease- Valve disease.
Giant cell arteritis- systemic vasculitis of head and neck
what are the symptoms of giant artery arteritis
- Headache
- Malaise
- Visual loss
what are the risk factors of carotid artery disease
Hypertension, Smoking, Diabetes, High Cholesterol
how is carotid artery disease managed
Antiplatelet agents- typical management.
Carotid endarectomy- remove clot.
what is the risk of visual loss in the second eye is patient has CRAO or AION (Anterior Ischemic Optic Neuropathy
30 days before sdond eye is affected
what is the treatment for CRAO or AION (Anterior Ischemic Optic Neuropathy
Nothing.
what symptom often predisposes to CRAO
frontal headache.
define metamorphosia
type of distorted vision in which a grid of straight lines appears wavy and parts of the grid may appear blank
where are the climcl presentation signs of metamorphosia
vision blurry
no changes in level of blurriness.
what treatment is used for choroidal neovascular membrane (new blood vessels in the retina cause visual disturbance)
antiVEGF binds to VEGF and prevents it acting on CNM
which part of the vision does macular hole affect
central vision
what is the treatment for a macular hole
closing hole but visual improvement variable
what are the disadvantages of the macular hole operation
Risk of not closing hole about 10%
Risk of serious complication leading to loss of vision (1%)
Will develop cataract
