Diabetic eye disease Flashcards
What is diabetic retinopathy?
Essentially a retinal vasculopathy- affects the retinal precapillary arterioles, capillaries and venules
Resulting retinal disease may be vascular leakage and/or closure and sequelae- sequelae are related to VEGF and other factors released into the retina
What are the risk factors for diabetic retinopathy?
Duration of DM Age Smoking Hypertension Poor DM control Hyperlipidemia Nephropathy Pregnancy
How is diabetic retinopathy graded?
R0: none
R1 (background): microaneurysms, intraretinal haemorrhage +- exudate
R2 (pre-proliferative): venous bleeding, venous looping or reduplication, intraretinal microvascular abnormality, multiple flame, round or blot haemorrhages, cotton wool spots
R3 (proliferative): neovascularisation of disc/elsewhere, pre-retinal or vitreous haemorrhage, pre-retinal fibrosis +- tractional retinal detachment
What is non-proliferative diabetic retinopathy?
Asymptomatic and occurs after 8-10 years of DM whether well controlled or not
Severity depends on other risk factors
How does non-proliferative diabetic retinopathy present?
Microaneurysms- focal dilatations of retinal capillaries which may leak and are usually temporal to the macula
Haemorrhages- dots or blots from the venous end of retinal capillaries, deep in the retina. Flame shaped (arterial side) located in the nerve fibre layer
Exudates- precipitation of leaking lipoproteins from diseased retinal vasculature
Cotton wool spots, microinfarcts in the retinal nerve fibres (axoplasmic accumulations)
How does severe non-proliferative diabetic retinopathy present?
large number of dark haemorrhages, irregular calibre variation (beading) and dilatation of retinal veins and intraretinal microvascular abnormalities (IRMA)
most patients with severe NPDR will progress to PDR within 12 months
How do neovascularisations appear?
Small tuffs of irregular ramifying vasculature arising from veins- they are initially flat but enlarge and move forward into the vitreous
fragile and likely to bleed with slight traction resulting in pre-retinal and/or vitreous haemorrhage
What are the late changes of PDR?
retinal fibrosis and traction retinal detachment
This will lead to VEGF entering the anterior segment of the eye and causing rubeosis iridis and neovascular glaucoma
What is diabetic maculopathy?
Can occur in proliferative or non- proliferative DR
More common with type 2, leads to visual loss if untreated
What are the types of diabetic maculopathy which can occur?
Focal leakage- retinal thickening & hard exudate
Diffuse- diffuse retinal thickening, but usually no exudate
Ischaemic- due to closure of the perifoveal capillary network, diffuse oedema with associated dark haemorrhages- fluorescein angiography is important to confirm
Mixed: ischaemia and exudate
How is diabetic maculopathy graded?
M1:
Exudate within 1 disc diameter (DD) of the centre of the fovea
Circinate or group of exudates within the macula
Retinal thickening within 1 DD of the centre of the fovea
Any microaneurysm or haemorrhage within 1 DD of the centre of the fovea only if
associated with a best VA of ≤ (if no stereo) 6/12
What other parts fo the eye can diabetes affect?
Increased incidence of eyelid infections and cataracts
Cranial nerve palsies of 3,4 and 6
Delayed healing of corneal abrasions and corneal ulcers
More severe post-operative intraocular inflammation
Abnormal wound healing
What are the treatment options for diabetic maculopathy?
Laser photocoagulation
Pharmacological treatment: intravitreal injections
Anti-VEGF drugs: ranibizumab, aflibercept, (bevacizumab, ziv-aflibercept are unlicensed for intravitreal injection)
Steroids: dexamethasone implant, triamcinolone, fluocinolone
Surgery: Vitrectomy –only if significant traction
What are the treatments for diabetic retinopathy?
Control of diabetes and other risk factors
Laser photocoagulation
Pharmacologic therapy: intravitreal injections of Anti-VEGFs, and or steroids as indicated
How do lasers treat DR?
Focal laser is useful in stopping focal leaks as occur in focal maculopathy
Grid laser is indicated in diffuse macular oedema; it is not recommended for ischaemic maculopathy
Mixed maculopathies require combined strategies
Pan-retinal photocoagulation (PRP) is recommended treatment for PDR
