Retinal Disorders Flashcards
How does fundus fluorescein angiography (FFA) show a defect/damage in the retina?
Inner and outer blood-retinal barriers are impermeable to fluorescein, and choriocapillaris is only permeable to free fluorescein (15%), therefore the majority is kept within the retina, so a leak is indicative of retinal defect/damage
How does optical coherence tomography (OCT) work?
Uses light waves to take cross-section pictures of the retina, allowing each layer to be mapped and measured
How does electroretinogram (ERG) work?
Measures retinal function by recording action potentials within the retina
How does electro-oculogram (EOG) work?
Measures function of RPE and photoreceptors by measuring resting potential difference between RPE and photoreceptors
How are visually evoked potentials (VEP) measures?
Records optic nerve function by measuring electrical activity in the visual cortex in response to a flashing light or a checker board patter
What does reduced amplitude of VEP indicate?
Reduced cell number - ischamic/traumatic optic neuropathy
What does latency in VEP indicate?
Reduced cell function - optic neuritis
Causes of central retinal vein occlusion
Hypertension
Glaucoma
Hyperviscosity
Inflammation
Presentation of central retinal vein occlusion
Macular oedema
Causes of central retinal artery occlusion
Emboli
Inflamamtion
Presentation of central retinal artery occlusion
Pale retina with cherry-red spots
Types of ischaemic optic neuropathy
Arteritic (AION)
Non-arteritic (NAION)
Cause and presentation of arteritic ischaemic optic neuropathy
Giant cell arteritis
Headaches, weight loss, lethargy
Sudden painless vision loss in one and then both eyes
How do you differentiate between arteritic and non-arteritic ischaemic optic neuropathy?
Using blood tests for inflammatory markers, particularly ESR and CRP, as non-arteritic is not related to inflammation
Sign of ischaemic optic neuropathy seen on examination of the eye
Swollen nerve
Indistinct margins
Pale if atrophy has occurred
Presentation of giant cell arteritis
Headache Scalp tenderness Jaw claudication Neck pain Nausea Anorexia Vision loss
Treatment of giant cell arteritis
High dose oral steroids
Presentation of optic neuritis
Pain on eye movements
Reduced vision
Central scotoma
Red desaturation
Signs of optic neuritis on eye examination
Relative afferent pupil defect
Swollen optic disc
Typical patient affected by optic neuritis
Middle-aged females
related to MS
Painless causes of sudden vision loss
Stroke
Vitreous haemorrhage
Retinal detachment
What is age-related macular degeneration?
Progressive loss of central vision
Risk factors for age-related macular degeneration
Age
Smoking
Poor diet
Typical presentation of age-related macular degeneration
People no longer able to read newspaper/computer screen
Treatment of dry-type age-related macular degeneration
No treatment - vitamins can be given to slow onset/progression
What happens in wet-type age-related macular degeneration?
Patients with dry-type will go on to develop blood or fluid in the retina, can lead to fibrous scarring
Presentation of diabetic neuropathy
Exudates and haemorrhage from the eyes, cotton wool spots seen on examination
Treatment of diabetic neuropathy
Controlling diabetes
Manage symptomatic features
Laser treatment to reduce vision loss
Cause of hypertensive retinopathy
Poor control of hypertension
Type of photoreceptor retinal dystrophies
Retinitis pigmnetosa
Cone dystrophy
Leber’s congenital amaurosis
Types of retinal pigment epithelium dystrophies
Best’s vitelliform macular dystrophy
Stargadt macular dystrophy
Sorsby macular dystrophy
North Carolina macular dystrophy
Types of choiroidal dystrophies
Choroideraemia
Gyrate atrophy
Types of vitreoretinal dystrophies
Stickler syndrome
Congenital retinoschisis
What structures of the eye are predominantly affected by retinitis pigmentosa?
Rods
Drug classes responsible for drug-induced retinopathy
Antimalarials
Phenothiazines
Tamoxifen
TB medications
Other causes of gradual painless loss of vision
Cataract
Refractive error
Open-angle glaucoma
Other acquired maculopathies
Central serous retinopathy Idiopathic macular hole Epiretinal membrane Cystoid macular oedema Myopic maculopathy Choroidal folds Angioid streaks
Method of gene therapy for retinal disease
Used to treat defective/missing gene
Use of a viral vector to insert replacement gene into host DNA
