Diabetic Eye Disease Flashcards
5 RFs for progression of diabetic retinopathy
Lack of exercise
Not getting annual eye exam
Poor BP control
Poor glycaemic control
Pregnancy
What is the most common cause of blindness in adults aged 35-65?
Diabetic retinopathy
Describe pathophysiology of diabetic retinopathy
Hyperglycaemia increases retinal blood flow
Causes blood vessels to weaken/ rupture→ micro aneurysms + small haemorrhages
Endothelial dysfunction
→ increased vascular permeability
→ hard exudates on fundoscopy.
As blood flow increasingly compromised, hypoxia stimulates release of VEGF promoting neovasculization
What are the broad stages of diabetic retinopathy?
Background (Mild NPDR)
Pre-proliferative
Proliferative
Diabetic maculopathy
What is diabetic retinopathy?
Vascular disease of retina
Asymptomatic initially, progresses to visual impairment + blindness
What are the classes of diabetic retinopathy?
Non-proliferative diabetic retinopathy (NPDR)
Proliferative diabetic retinopathy (PDR)
What constitutes mild NPDR? (background retinopathy)
> ,1 microaneurysm
What constitutes moderate NPDR? (pre-proliferative)
Microaneurysms
Blot haemorrhages
Hard exudates
Cotton wool spots
Venous beading/ looping
Intraretinal microvascular abnormalities (IRMA)
What are cotton wool spots?
‘Soft exudates’
Areas of retinal infarction
What constitutes severe NPDR? (pre-proliferative)
4:2:1 rule
>20 blot haemorrhages in 4 quadrants
Venous beading in >, 2 quadrants
IRMA in >,1 quadrant
What is the hallmark feature of PDR?
Neovascularisation due to widespread retinal ischaemia
What are complications of PDR and why do these arise?
New vessels are fragile + prone to leaking
Complications: vitreous haemorrhage + tractional retinal detachment
In which patients is PDR more common?
T1DM
What is the prognosis of PDR?
If untreated, 50% blind in 2y
Describe early PDR
New vessels less than 1/3 of the disc area, no vitreous haemorrhage, and no tractional retinal detachment.
What characterises high-risk PDR?
Any of:
Neovascularization of the disc (NVD) >,1/3 of the disc area
NVD a/w vitreous or preretinal haemorrhage,
Neovascularization elsewhere (NVE) >,1/2 disc area with vitreous or preretinal haemorrhage.
What is diabetic macular oedema (DME)?
Complication of diabetic retinopathy + can occur at any stage
Most common cause of vision loss in those with diabetic retinopathy
How does DME arise?
Fluid + protein deposits collect on/ under the macula, causing it to thicken + swell (oedema)
How is DME classified?
Focal DME: foci of vascular abnormalities, primarily microaneurysms.
Diffuse DME: dilated capillaries in the retina.
When can diabetic macula oedema be detected? What is the GS Ix?
NOT on a 2D photo unless there are exudates in the macula
Exudates suggest there is/ has been fluid
GS: OCT
In which patients is diabetic maculopathy more common?
T2DM
What is optical coherence tomography?
OCT provides cross-sectional view of retina
Often used when examining DME
What investigations should be performed in diabetic eye disease?
HbA1c
Comprehensive dilated eye exam
Fundus photography
OCT
Fluorescein angiography
What is the gold-standard technique for visualising the vasculature of the retina?
Fluorescein angiography
Describe medical management of diabetic retinopathy
Glycemic control
BP control
Diet, exercise + smoking cessation
What is the primary intervention in management of PDR and severe NPDR?
Photocoagulation
Using laser to create numerous burns in the retina, destroying photoreceptors
Reduced O2 demand
Delays progression
What are the 2 methods of photocoagulation?
Focal photocoagulation
Pan-retinal photocoagulation
What occurs in focal photocoagulation?
Specific point of leakage identified + targeted with the laser.
What occurs in pan-retinal photocoagulation?
Periphery of retina targeted with aim of achieving a global reduction in O2 demand
Tx for proliferative diabetic retinopathy
Pan retinal laser photocoagulation (PRP)
Induces regression of new vessels before they bleed/ re-bleed causing vitreous haemorrhage
Following pan retinal photocoagulation for PDR, what do ~50% of patients develop?
Reduction in their visual fields due to scarring of peripheral retinal tissue
List 3 complications of panretinal photocoagulation other than reduction in visual fields
Decrease in night vision (majority of rods (responsible for low light conditions) are on periphery)
Decrease in visual acuity
Macular oedema
What intravitreal injections can be used in management of PDR?
Anti-VEGF: minimises neovascularisation
Corticosteroids: improve visual acuity + reduce maculopathy
Name 2 anti-VEGF injections used in PDR
Aflibercept (Eylea)
Ranibizumab (Lucentis)
Tx for diabetic macular oedema
Anti-VEGF Intravitreal injections
Macular laser (rarely) if allergy to drugs
When may a vitrectomy be performed in management of PDR?
Persistent haemorrhage
Central, sight-threatening tractional retinal detachment
List 3 complications of diabetic retinopathy
Neovascular glaucoma
Retinal detachment
Vitreous haemorrhage
What is diabetic maculopathy?
Any structural abnormality due to diabetes affecting macula
Often preceded by diabetic retinopathy
Ix for diabetic macular ischaemia
No fundal signs
Suspected in diabetic with unexplained poor vision (in absence of diabetic macular oedema)
How should diabetic maculopathy be managed?
If change in visual acuity: intravitreal VEGF inhibitors
How should NPDR be managed?
Regular observation
If severe: consider pan retinal photocoagulation
