What piece of equipment allows a slit lamp to see the back of the eye?
A condensing lens
What is a disadvantage of an opthalmoscope that doesn’t affect the slit lamp?
narrow field of view
sense of depth missing
What is visible upon fluorescein angiography in a healthy eye?
Green colour in venules and arterioles.
Clouding in the background as it leaks out of the choriocapillaris
What is a similarity between the brain and the eye with regard to vascularity?
Blood retinal barrier similar to blood brain barrier
What is Optical coherence tomography used to look for?
Fluid around the fovea
What is the most common condition in which you would expect to see fluid under membrane around fovea?
Macular degeneration
What is the function of the RPE (retinal pigment epithelium)?
Phagocytoses the cells above it to keep turnover high.
What imaging cell type are concentrated at the fovea? and their function?
Cones - colour vision
What is electrophysiology?
Investigations that record electrical signals in the eye and brain in response to visual stimuli
What does an Electroretinogram (ERG) do?
Measures retinal function by recording action potentials from retina.
What does an electrooculogram do? (EOG)
Measures function of RPE and photoreceptors
What test can give away when someone is feigning blindness?
VEP (visually evoked potentials measured in the visual cortex)
What is RAPD a measure of?
Objective measure of optic nerve function
4 vascular causes of sudden vision loss?
Central retinal vein occlusion
Central retinal artery occlusion
Ischaemic optic neuropathy
Stroke
Roughly what happens in Central retinal vein occlusion?
Blood comes in but cannot leave so pools in the eye
Common causes of CRVO?
hypertension
glaucoma
hyperviscosity (leukaemia/lymphoma)
Inflammation
What would be seen on Fluorescein angiography with CRVO?
A masked choroid due to blood
What is noticed upon examination of an eye with CRAO?
Pale fundus and cherry red spot (fovea)
Common causes of CRAO
Emboli
Inflammation
How does the optic disk look in ischaemic optic neuropathy?
Pale with poorly defined borders
Some cases can look quite normal
High levels of what are a giveaway to Giant cell arteritis?
Inflammatory markers
What artery is used in biopsy for Giant cell arteritis and why?
Temporal artery - it isn’t 100% necessary and is quite accessible
What type of vision is usually the first to be lost in optic neuritis?
colour, particularly red
What optical condition can be the first presentation of MS?
Optic neuritis - check should be done after diagnosis
What are the risk factors for Age related macular degeneration?
Age
smoking
poor diet
What are the two types of AR macular degeneration? Which is more aggressive?
Dry type (atrophy) Wet Type (blood/fluid in membrane) - most aggressive
What does VEGF do?
drives the growth of new blood vessels.
Is released after ischaemia.
How can Wet type macular degeneration be treated?
Anti VEGF injections
What would be seen on OCT in age related mac degen?
Fluid blister in the retina
What are pericytes and what disease are they involved in?
Cells that line the walls of the eye epithelium
Diabetic retinopathy.
How does diabetes lead to retinopathy?
Excess sugar damages pericytes
These either occlude or anneurism.
Leakage follows of either blood from weak vessels or lipid from the sugar imbalance in the cells.
Is type 1 or 2 diabetes more likely to suffer blindness?
Type 1
What is a complication of vessels growing in the iris?
Block trabecular network, which increases IOP
What treatment is prefered in diabetic retinopathy?
antiVEGF, laser used to be used but significant vision loss occurred
What condition would you test for BP and sugar levels?
Hypertensive retinopathy
What are the two main groups of retinal dystrophy?
Choroidal
Vitreoretinal
What is a telltale sign of retinitis?
bone spicules on retina
Which forms of reinitis pigmentosa are the most common?
Dominant inherited
Sporadic mutations
Both of these are also the least severe types
What photoreceptors are primarily affected in Retinits pigmentosa?
Rods - progressive tunnel vision as the rods die off. Eventually all the cones will go as well, but later.
Drugs for what conditions can cause retinopathy?
TB
Rheumatoid arthritis
Breast cancer