Flashcards in Common medical retinal diseases (AMD + DR) Deck (22):
Briefly describe the pathology in dry macular degeneration (MD).
atrophy of the photoreceptors in the retinal pigment epithelium due to age
leads to death of the photoreceptros
This is all caused by Drusens (soft thickenings of Bruch’s membrane) as Drusens separate the photoreceptors from the choroid and hence their blood supply.
Drusens are made of extracellular material and are white or yellow in colour
Briefly describe the pathology in wet macular degeneration (MD).
Abnormal vessels growing from the choroid (neovascularisation) and underneath the retina.
These vessels bleed and leak fluid which subsequently leaks and result in scar formation.
What is seen on the fundus in dry MD?
What is seen on the fundus in wet MD
abnormal blood vessel growth
fibrous scar formation
haemorrhage from abnormal vessels
What are the effects of visual fields due to MD?
A blind spot in the central vision and a distortion of vision
What is diabetic retinopathy?
essentially a retinal vasculopathy
and affects the retinal precapillary arterioles, capillaries and venules
What are the two types of diabetic retinopathy (DR)?
What is the factors that causes a case of background DR to become proliferative DR?
In proliferative DR there is new blood vessel growth
What is maculopathy?
Can occur with background and proliferative DR and is just when it affects the macula.
What are the symptoms of non-proiferative diabetic retinopathy (aka background DR)
It is asymptomatic
What can be seen on the fundus in background DR?
retinal haemorrhages (dots, blots or flames)
cotton wool spots
intraretinal microvascular abnormalities (IRMA)
Which vessels do dot, blot and flame haemorrhages come from?
dots + blots come from retinal venules
flames come from retinal arterioles
What are exudates
yellowish-white deposits with well-defined edges
they represent precipitation of leaking lipoproteins from diseased retinal vasculature
What are cotton wool spots (CWS)?
greyish white poorly defined fluffy edged lesions in the nerve fibre layer.
They represent microinfarcts in the retinal nerve fibres (axoplasmic accumulations)
Where do blood vessels grow in proliferative DR?
On the optic disc or surface of the retina.
What is a particular concern with neovascularisations in proliferative DR?
neovascularisations are fragile and are likely to bleed with slight traction
resulting in pre-retinal and/or vitreous haemorrhage
The development of rubeosis glaucoma
What symptoms occur in diabetic maculopathy?
visual loss if not treated
What are the three types of diabetic maculopathy?
What causes focal diabetic maculopathy and what signs can be seen?
It is caused by focal leakage from microaneurysms or dilated capillaries
focal retinal thickening
and surrounding exudates
What causes diffuse diabetic maculopathy and what signs can be seen?
It is caused by leaking from dilated capillaries which results in a diffuse retinal oedema
which may be associated with:
some retinal haemorrhages
but usually no exudates.
What causes ischemic diabetic maculopathy and what signs can be seen?
It is caused by closure of the perifoveal capillary network and manifests as:
a diffuse oedema plus associated dark haemorrhages.
Fluorescein angiography is important in confirming ischemia.