[9] Diabetic Retinopathy Flashcards
What eye problems can be associated with diabetes mellitus (DM)?
- Diabetic retinopathy (most common)
- Cataracts
- Rubeosis iridis and glaucoma
- Oculomotor nerve palsies
What is diabetic retinopathy?
A chronic progressive, potentially sight-threatening disease of the retinal microvasculature
What is diabetic retinopathy associated with?
Prolonged hyperglycaemia of DM and other diabetes-linked conditions such as hypertension
How is diabetic retinopathy classified?
Based on the ares of the retina affected and the degree of pathology seen on slit lamp examination
What are the two broad types of diabetic retinopathy?
- Diabetic retinopathy
- Diabetic maculopathy (I think this is potentially a separate thing thats closely related but idk so lets roll with it)
What are the classifications of diabetic retinopathy (DR)?
- Background (mild) non-proliferative DR
- Moderate non-proliferative DR
- Severe to very severe non-proliferative DR
- Non-high risk proliferative DR
- High-risk proliferative DR
What is background non-proliferative diabetic retinopathy?
1 microaneurysm seen on slit lamp examination on background of DM
What is moderate non-proliferative diabetic retinopathy?
Moderate amount of micro-aneurysms and intra-retinal haemorrhages with or without cotton wool spots, venous beading or other intra-retinal micro-vascular abnormalities
What is severe to very severe non-proliferative diabetic retinopathy?
Like moderate but more severe (obvs)
What is non-high risk proliferative diabetic retinopathy?
Where there are new vessels on the disc (or within 1 disc diameter) or elsewhere
What is high risk proliferative diabetic retinopathy?
- Large new vessels on the disc or elsewhere
- Potentially pre-retinal haemorrhages
- Potentially retinal detachment in advanced disease
What are the types of diabetic maculopathy?
- Focal or diffuse macular oedema
- Ischaemic maculopathy
- Clinically significant macular oedema
What are the features of focal or diffuse macular oedema diabetic maculopathy?
What are the features of focal or diffuse macular oedema diabetic maculopathy?
What are the features of ischaemic diabetic maculopathy?
- Clinically appear relatively normal
- Visual acuity is dropped
- Ischaemia seen on fluorescein angiography
What are the features of clinically significant macular oedema?
- Thickening of the retina
- Hard exudates around the fovea or above a certain size
What causes diabetic retinopathy?
Diabetes mellitus
What is the mechanism behind diabetic retinopathy?
Microvascular occlusions cause retinal ischaemia leading to arteriovenous shunting, neovascularisation, intra retinal haemorrhages and oedema
What are the characteristic features that can be seen at different stages of diabetic retinopathy?
- Micro-aneurysms
- Hard exudates
- Haemorrhages
- Cotton wool spots
- Neovascularisation
What are micro-aneurysms in diabetic retinopathy?
Physical weakening of the capillary walls that predispose them to leakages
What are hard exudates in diabetic retinopathy?
Precipitates of lipoproteins/other proteins leaking from the retinal blood vessels
What are the haemorrhages seen in diabetic retinopathy?
Rupturing of weakened capillaries, appearing as small dots/larger blots or ‘flame’ haemorrhages that track along nerve-fibre bundles in superficial retinal layers
What are cotton wool spots seen in diabetic retinopathy?
Build up of axonal debris due to poor axonal metabolism in the margins of ischaemic infarcts
What is neovascularisation in diabetic retinopathy?
An attempt by residual healthy retina to revascularise hypoxic retinal tissue
What is progression of diabetic retinopathy mainly associated with?
Severity and length of hyperglycaemia
What are some other risk factors that influence onset and progression of diabetic retinopathy?
- Hypertension
- Other cardiovascular risk factors
- Pregnancy
- Minority ethnic community
- Intraocular surgery
What are some excellent predictors of the presence of diabetic retinopathy?
- Renal disease evidenced by proteinuria and elevated serum urea/creatinine
When should eye screening be performed in patients with diabetes?
At or around the time of diagnosis and then repeated annually
How is diabetic retinopathy screening conducted?
Via photographing the dilated retina
When should standard (4 week) referral to an ophthalmologist be made following diabetic retinopathy screening?
- Referable maculopathy
- Referable pre-proliferative retinopathy
- Any large, sudden drop in visual acuity
When should an urgent referral to an ophthalmologist be made following diabetic retinopathy screening?
When there is new vessel formation
When should an emergency referral to an ophthalmologist be made following diabetic retinopathy screening?
- Sudden loss of vision
- Rubeosis iridis
- Pre-retinal or vitreous haemorrhage
- Retinal detachment
Do all patients present with major symptoms in diabetic retinopathy?
No
If patients with diabetic retinopathy present with symptoms what can they include?
- Painless reduction of central vision
- Dark, painless floaters that may resolve over several days
- Painless visual loss
What are floaters in diabetic retinopathy associated with?
Haemorrhages
When may a patient with diabetic retinopathy get painless visual loss?
If haemorrhage obscures the vitreous
Is the severity of symptoms in diabetic retinopathy always in correlation with the threat of the disease to sight?
No
If assessing without a slit lamp, what steps should be taken when examining a patient for diabetic retinopathy?
- Check acuity
- Check red reflex
- Assess each arterial branch from the optic disc outwards
- End with assessing the macula
What may be seen when checking the red reflex of a patient with diabetic retinopathy?
Spots suggestive of vitreous haemorrhage
When assessing blood vessels in diabetic retinopathy what should be noted?
- Little red dots (dot haemorrhages or small aneurysms)
- Irregular notching (venous beading)
- New vessels
How can new vessels in the retina be identified in diabetic retinopathy?
Tend to be thinner and more disorganised than pre-existing vessels
What else (extra-vascular signs) may be noted when following along the blood vessels in diabetic retinopathy?
- Hard exudates
- Cotton wool spots
How do hard exudates appear in diabetic retinopathy?
Creamy/yellow lesions often in clusters
How do cotton wool spots appear in diabetic retinopathy?
Pale lesions with poorly defined edges
What is the gold standard for diagnosing diabetic retinopathy?
Dilated retinal photography with accompanying ophthalmoscopy
When may further investigation be required in diabetic retinopathy?
To refine the diagnosis and plan management
What further investigations can be used in diabetic retinopathy?
- Optical coherence tomography
- Fluorescein angiography
What are the differentials for diabetic retinopathy?
- Ocular ischaemic syndrome
- Radiation therapy
- Retinal venous occlusion
- Hypertension
What is involved in primary prevention of diabetic retinopathy?
- Glycaemic control
- Blood pressure control
- Lipid control
- Healthy diet
- Exercise
- Smoking cessation
What is the aimed for HbA1c in patients with diabetes to try and prevent diabetic retinopathy?
<7%
What is optimal glycaemic control associated with in terms of diabetic retinopathy?
Improved long-term outcomes and delayed progression
What blood pressure should be aimed for in patients to prevent diabetic retinopathy?
≤140/80mmHg
What does good blood pressure control do in relation to diabetic retinopathy?
Reduces progression
What does lipid control do in relation to diabetic retinopathy?
Reduces the risk of progression, particularly macular oedema and exudation
Do all patients with diabetic retinopathy require treatment?
No, most do not
What options are available for treating diabetic retinopathy?
- Laser treatment (laser photocoagulation)
- Intravitreal steroids
- Surgery
What is the aim of laser photocoagulation in treating diabetic retinopathy?
To induce regression of new blood vessels and reduce central macular thickening
How is laser photocoagulation thought to work?
Reduces the release of vasoproliferative mediators by hypoxic retinal vessels and allows easier direct diffusion of oxygen from the choroid blood supply
How can laser photocoagulation be targeted?
- Can target specific areas (focal)
- Can target entire retinal periphery (panretinal)
What does the choice of the area targeted by laser photocoagulation depend on?
The nature of the diabetic retinopathy
What type of diabetic retinopathy is treated with panretinal laser treatment?
Retinopathy
What type of diabetic retinopathy is treated with focal laser treatment?
Macular oedema
How is laser photocoagulation therapy carried out?
In a clinic on an outpatient basis
How can areas of laser treatment for diabetic retinopathy be identified at a later date?
As well-demarcated pale spots with dark brown centres
What are the complications of focal laser photocoagulation?
- Impaired central vision
- Paracentral scotoma
- Choroidal neovascularisation
What are the complications of panretinal laser photocoagulation?
- Constriction of visual field
- Nocturnal diminution of vision
- Worsening macular oedema
- Ocular pain
What intravitreal steroid can be given as a primary or adjunctive therapy for diabetic retinopathy?
Intravitreal triamcinolone
Over what period is intravitreal steroid therapy more effective than laser photocoagulation at treating diabetic retinopathy?
The first 2 years
In what way is laser photocoagulation better than intravitreal steroids at treating diabetic retinopathy?
It provides better visual acuity and less maculopathy after 2 years
What are the complications of intravitreal steroids in diabetic retinopathy?
- Cataract formation
- Raised intraocular pressure
What is the main complication of diabetic retinopathy?
Visual loss
What is visual loss in diabetic retinopathy often secondary to?
- Macular oedema
- Macular ischaemia
- Vitreous haemorrhage
- Tractional retinal detachment
