Visual disturbance Flashcards
What is blurred vision?
Loss of clarity or sharpness of vision
What are the main associated symptoms with blurred vision?
Visual loss
Double vision
Floaters
Main causes of blurred vision?
Refractive error: most common
Cataracts
Retinal detachment
Age related macular degeneration
Acute angle closure glaucoma
Optic neuritis
Amaurosis fugax
How do you assess for blurred vision?
Visual acuity with a snellen chart
- Pinhole occluders uses to check whether the blurring is due to refractive error. If blurring IMPROVES with pinhole, then likely due to refractive error
Visual Fields
Fundoscopy
Managment of blurred vision?
Depends on underlying cause.
If gradual onset and corrected with pinhole occluder–> optician review
Other pts seen by ophthalmology–> if associated sx such as visual loss or pain–> urgent
What is myopia?
Short sight
What is hypermetropia?
Long sight
What is astigmatism?
Refractive error characterised by a variation in the dioptric power of the eye from one meridian to another
Another definition: a defect in the eye or in a lens caused by a deviation from spherical curvature, which results in distorted images, as light rays are prevented from meeting at a common focus.
What causes myopia?
Long axial length and average cornea (most common)
OR
High power cornea with an average axial length
What causes hypermetropia?
Short axial length and average cornea
OR
low power cornea with an average axial length
What is asthenopia?
Frontal headache and intermittent blurry vision
What is presbyopia?
associated with older age
Declining amplitude of accommodation with age.
Better at focusing further away
How do you test visual acuity?
Snellen chart
6m test distance
6/6 is perfect vision.
Top number what pt can see vs what normal person can see at the bottom e.g 6/60 (pt can see at 6m what a normal person can see at 60m)
If pt can’t see at 6m, move them forward to 3m
What are cataracts?
Common eye condition where the lens of the eye gradually opacifies (cloudy)–> reduced/blurred vision
Who gets cataracts?
More common in women than men
Incidence increases with age
Causes of cataracts?
Normal ageing process- MOST COMMON
Other causes:
Smoking
increased alcohol consumption
Trauma
DM
Long-term corticosteroids
Radiation exposure
Myotonic dystropy
Metabolic disorders e.g. hypocalcaemia
Presentation of cataracts?
Gradual onset of:
Reduced vision
Fades colour vision- hard to distinguish
Glare
Halos around lights
Signs in a pt with cataracts?
Defect in red reflex. Cataracts prevent light getting to the retina–> defect
What is the red reflex?
Reddish- orange reflection seen through an ophthalmoscope when light in shone on the retina.
Investigations for cataracts?
Ophthalmoscopy: done after pupil dilation. Findings:normal fundus and optic nerve
Slit- lamp examination: visible cataracts
Classification of cataracts?
Nuclear: change lens refractive index, common in old age
Polar: localized, commonly inherited, lie in the visual axis
Subcapsular: due to steroid use, just deep to the lens capsule, in the visual axis
Dot opacities: common in normal lenses, also seen in diabetes and myotonic dystrophy
Management of cataracts?
Non-surgical:
Early stages- age-related cataracts can be managed conservatively by prescribing stronger glasses/contacts or by encouraging brighter lighting- will slow the progression
Surgical: only effective treatment for cataracts.
Removing cloudy lens and replacing it with an artificial one
What information do you need to give patients surrounding cataract surgery?
Prior: Information on refractive implications of various types of intraocular lenses
After: Patients should be advised on the use of eye drops and eyewear,, what to do if vision changes and the management of any other ocular problems.
What are the complications following cataract surgery?
Posterior capsule opacification: thickening of the lens capsule
Retinal detachment
Posterior capsule rupture
Endophthalmitis: inflammation of aqueous and/or vitreous humour
What is retinal detachment?
When the neurosensory tissue that lines the back of the eye comes away from its underlying pigment epithelium.
Prognosis of retinal detachment?
Reversible cause of visual loss as long as it is recognised and treated before macula is affected.
If left untreated and symptomatic, retinal detachment–> permanent visual loss
Children–> poor prognosis
What type of retinal detachment do diabetics face?
Tractional retinal detachment.
Breaks in retina due to traction by vitreous humour
RF for retinal detachment?
Age
Previous surgery for cataracts (accelerates posterior vitreous detachment)
Myopia
eye trauma (boxing)
Family history
Previous hx of retinal break/detachment in either eye
Presentation of retinal detachment?
New onset floaters (pigment cells entering the vitreous space) or flashers (traction in the retina)
Sudden onset, painless and progressive visual field loss–> curtain or shadow progressing to the centre of the visual field from the periphery
Retinal detachment in children presentation?
Squint or white pupillary reflex
Referral guidelines for ?retinal detachment?
Any pt with new onset flashes or floaters should be referred urgently (<24hrs) to an opphthalmologist for assessment
Investigations for retinal detachment?
Visual acuity: may not be reduced in peripheral RD but if vision it is decrease, central retina probably affected
Swinging light test: may highlight relative afferent pupillary defect if optic nerve is involved.
Fundoscopy: red reflex lost and retinal folds may appear pale, opaque or wrinkled.
Slit lamp exam: retinal detachment, retinal break, vitreoretinal pathology (traction or presence of pigment)
Indirect ophthalmoscopy: Vitreous haemorrhage may be present.
Causes of optic neuritis?
Multiple sclerosis
Diabetes
Syphilis
Features of optic neuritis?
Unilateral decrease in visual acuity over hours/days
Poor colour discrimination- red desaturation
Pain worse on eye movement
Relative afferent pupillary defect
Central scotoma
Management of optic neuritis?
IV methylprednisolone
Recovery usually takes 4-6 weeks
Features of central retinal vein occlusion?
sudden painless loss of vision, severe retinal haemorrhages on fundoscopy
RF for central retinal vein occlusion?
increasing age
hypertension
cardiovascular disease
glaucoma
polycythaemia
Management of central vein occlusion?
the majority of patients are managed conservatively
indications for treatment in patients with CRVO include:
macular oedema - intravitreal anti-vascular endothelial growth factor (VEGF) agents
retinal neovascularization - laser photocoagulation
Fundoscopy findings central retinal vein occlusion?
widespread hyperaemia
severe retinal haemorrhages - ‘stormy sunset’
When do you use dye for the slit lamp?
To look at the front of the eye, therefore shows any corneal or conjunctival abnormalities
types of retinal detachment?
Rhegmatogenous- separation due to a retinal discontinuity (break or tear)
Tractional- Proliferative membranes on the retinal surface or under it (less common). No break, but it may develop due to the traction
Serous/haemorrhagic- fluid/blood accumulates under the neuroretina and separates it
RF for central retinal artery occlusion?
Hypertension
Diabetes mellitus
coronary artery disease
peripheral vascular disease
Presentation of central retinal artery occlusion?
Acute monocular loss of portion of visual field (often inferior), likely to have central vision loss
Examination findings for central retinal artery occlusion?
afferent pupillary defect, ‘cherry red’ spot on a pale retina
What non-ophthalm investigations would you do for central retinal artery occlusion?
Lipid panel- elevated LDLs and triglycerides; reduced HDLs
Echo: valvular or intramural thrombi
PT time: elevated or normal
INR: elevated or normal
Clotting panel: may be abnormal in young patients
What is ‘transient monocular visual loss’
Sudden, transient loss of vision that lasts less than 24 hrs
What are the most common causes of sudden painless loss of vision?
Ischaemic/vasuclar
Vitreous haemorrhage
Retinal detachment
Retinal migraine
Describe ischaemic/vascular causes for sudden loss of vision
Large artery disease (atherothrombosis, embolus, dissection),
small artery occlusive disease (anterior ischaemic neuropathy, vasculitis e.g. GCA),
venous disease
hypo perfusion
May represent a form of TIA- 300mg aspirin
How does ischaemic neuropathy differ from central retinal artery occlusion?
Ischaemic neuropathy is due to occlusion of the short posterior ciliary arteries causing damage to the optic nerve
CRAO- central retinal artery occluded and no damage to the optic nerve but the aetiology may be the same (thromboembolism and arteritis)
Causes of vitreous haemorrhage?
Diabetes, bleeding disorders, anticoagulants
Features of vitreous haemorrhage?
Sudden visual loss, dark spots, may precede retinal detachment
What is vitreous haemorrhage?
bleeding into the vitreous humour. It is one of the most common causes of sudden painless loss of vision.
Causes of vitreous haemorrhage?
proliferative diabetic retinopathy (over 50%)
posterior vitreous detachment
ocular trauma: the most common cause in children and young adults
Presentation of vitreous haemorrhage?
painless visual loss or haze
red hue in the vision
floaters or shadows/dark spots in the vision
Signs in vitreous haemorrhage?
decreased visual acuity: variable depending on the location, size and degree of vitreous haemorrhage
visual field defect if severe haemorrhage
Investigations in vitreous haemorrhage?
dilated fundoscopy: may show haemorrhage in the vitreous cavity
slit-lamp examination: red blood cells in the anterior vitreous
ultrasound: useful to rule out retinal tear/detachment and if haemorrhage obscures the retina
fluorescein angiography: to identify neovascularization
orbital CT: used if open globe injury
Ddx sudden painless loss of vision?
Vitreous haemorrhage
Retinal detachment
Central retinal artery occlusion
Central retinal vein occlusion
