Ophthalmology - General Medicine and the Eye Flashcards
What is diabetic retinopathy?
In patients with diabetes mellitus, poor glycaemic control can lead to vascular occlusion and vascular leakage of the capillaries supplying the retina.
What is the result of hyperglycaemia in diabetic retinopathy?
Leads to damage to the retinal small vessels and endothelial cells
What is the result of increased vascular permeability in diabetic retinopathy?
Leads to leakage from the blood vessels, blot haemorrhages and the formation of hard exudates (yellow/white deposits of lipids in the retina)
What is the result of damage to the blood vessels in diabetic retinopathy?
Microaneurysm and venous beading
What are microaneurysms?
where weakness in the wall causes small bulges
What is venous beading?
Where the walls of veins are no longer straight and parallel and look more like a string of beans/sausages
What is the result of damage to the nerve fibres in the retina in diabetic retinopathy?
causes fluffy white patches to form on retina called cotton wool spots
What is the most common cause of severe sight impairment in working-age people in England, Wales and Scotland?
Diabetic retinopathy
Give some complications of diabetic retinopathy
- Retinal ischaemia
- Retinal detachment
- Vitreous haemorrhage (bleeding into vitreous humour)
- Optic neuropathy (? vision loss)
- Cataracts
Give some risk factors for diabetic retinopathy
- Duration of diabetes
- Poor diabetic control (hyperglycaemia)
- Hypertension
- Hyperlipidaemia
- Smoking
What are the 2 types of diabetic retinopathy?
- Non-proliferative diabetic retinopathy (NPDR)
- Proliferative diabetic retinopathy (PDR)
What does PDR involve?
Neovascularisation
Give some fundoscopy signs seen in diabetic retinopathy
- Microaneurysms - ‘dots’
- Hard exudates - lipid deposits
- Haemorrhages - ‘blots’
- Engorged tortuous veins
- Cotton wool spots
- Large ‘blot’ haemorrhages
- In PDR neovascularisation can be found on retina or optic disc
Describe the grading system of diabetic retinopathy
- Background diabetic retinopathy
- Pre-proliferative diabetic retinopathy
- Proliferative diabetic retinopathy
- Advanced diabetic retinopathy
Give some signs seen in each stage of diabetic retinopathy
- Background diabetic retinopathy → microaneurysms & dot and blot haemorrhages
- Pre-proliferative diabetic retinopathy → Cotton wool spots
- Proliferative diabetic retinopathy → neovascularisation
- Advanced diabetic retinopathy → recurrent vitreous haemorrhage from bleeding areas of neovascularization & retinal detachments
What are cotton wool spots?
Small, fluffy, whitish superficial lesions (accumulations of dead nerve cells from ischaemic damage)
Management of diabetic retinopathy?
- Laser photocoagulation
- Anti-VEGF medications e.g. ranibizumab
What is diabetic maculopathy?
Macular oedema caused by leakage of vessels close to macula. This can significantly threaten vision and should be treated with urgency.
What is hypertensive retinopathy?
Hypertension can cause damage to the retina through arteriolar** **vasoconstriction** and **leakage.
What is malignant hypertension?
Malignant hypertension is defined as grade III hypertensive retinopathy in the presence of swollen optic discs (grade IV hypertensive retinopathy).
- All features of Grade III + optic disc welling
- Headaches, eye pain, reduced visual acuity and focal neurological deficits
Describe the different grades of hypertensive retinopathy
- Grade I – Vascular attenuation (narrowing of retinal arteries)
- Grade II – Above + compression of venules at sides of arteriovenous crossing (AV nipping)
- Grade III – Above + retinal haemorrhage, hard exudates, and cotton wool spots (similar to those of diabetic retinopathy)
- Grade IV – Above + optic disc swelling
- This is malignant hypertension
What is thyroid eye disease?
Grave’s disease is an autoimmune hyperthyroidism which often affected the eyes.
Describe what happens in thyroid eye disease
Autoantibodies target the extraocular muscles, causing lymphocytic infiltrate of the orbit. This results in muscle and fatty tissues to become inflamed, causing swelling behind the eye and proptosis of the eyeballs.
What are the 2 main risk factors for thyroid eye disease?
- FH of Grave’s disease and other autoimmune disease
- Smoking – worsens thyroid eye disease
Presentation of thyroid eye disease?
- Lid retraction (eyelids can also be red and swollen)
- Proptosis (bulging eyes)
- Lid lag
-
Corneal irritation due to proptosis causes:
- Eyes feeling dry and gritting
- Sensitivity to light
- Red and watering eyes
- Extraocular muscle compression and inflammation can cause diplopia/restricted eye movement
- Optic nerve compromise can cause vision loss/blurred vision/reduced colour vision
Corneal irritation can result from proptosis in thyroid eye disease. How can this present?
- Eyes feeling dry and gritting
- Sensitivity to light
- Red and watering eyes
Investigation in thyroid eye disease?
TFTs - important to note that patient can be euthyroid with evidence of TED (patient will likely have been hyperthyroid at some point in past)
Complications of thyroid eye disease?
- Exposure keratopathy
- Compressive optic neuropathy
- Double vision
What is exposure kertopathy?
Corneal damage and infection occurs as patient unable to close eyes
How can thyroid eye disease lead to compressive optic neuropathy? What is the result of this?
Retro-orbital swelling begins to compress optic nerve:
- Reduced visual fields
- Reduced colour vision
- Reduced vision acuity
- Relative afferent pupillary defect
Why can thyroid eye disease cause double vision?
Due to fibrosis of extraocular muscles
Management of thyroid eye disease?
- Symptomatic:
- Ocular lubricants
- Prisms for diplopia
- Good thyroid hormone control
- Lifestyle – stop smoking, selenium supplements
