Systemic eye diseases

What is diabetic retinopathy?

damage to the retinal blood vessels due to prolonged high blood sugar

What is the pathophysiology of diabetic retinopathy?

hyperglycaemia damages the retinal small vessels and endothelial cells. Increased vascular permeability leads to leaking vessels, blot haemorrhages and hard exudates.

Damage to the vessel walls leads to microaneurysms and venous bleeding.

Damage to nerve fibres causes cotton wool spots.

Intraretinal microvascular abnormalities refer to dilated and tortuous capillaries in the retina

neovascularisation involves release of growth factors stimulating new vessel development.

What does a fundoscopy look like in diabetic retinopathy?

What is background diabetic retinopathy?

microaneurysms, retinal haemorrhages, hard exudates and cotton wool spots

What is pre-proliferative diabetic retinopathy?

venous beading, multiple blot haemorrhages and intraretinal microvascular abnormality (IMRA)

What is proliferative retinopathy?

neovascularisation and vitreous haemorrhage

What are complication of diabetic retinopathy?

• vision loss

• retinal detachment

• vitreous haemorrhage

• rubeosis iridis- new blood vessel formation in the iris

• cataracts

• optic neuropathy

What is the epidemiology of diabetic retinopathy?

most common cause of blindness is adults aged 35-65

What is advice for diabetic retinopathy?

optimise glycaemic control, BP, and hyperlipidaemia

regular ophthalmology review

What is diabetic maculopathy?

has exudates in the macula and macula oedema

based on location rather than severity

check visual acuity

more common in T2

What is the management of non-proliferative diabetic retinopathy?

regular observation

if severe consider pan retinal laser photocoagulation

What is the management for diabetic maculopathy?

if there is a change in visual acuity, then intravitreal vascular endothelial growth factor

What is the management for proliferative diabetic retinopathy?

• pan retinal laser photocoagulation- this can cause a reduction in visual fields due to scarring, decrease in night vision due to decrease in rod cells located in the peripheral retina

• intravitreal VEGF inhibitors, eg: ranibizumab

• vitroretinal surgery

What is hypertensive retinopathy?

damage to the retinal blood vessels relating to hypertension. Changes can happen slowly with chronic HTN or quickly in response to malignant HTN

What are features of hypertensive retinopathy?

silver or copper wiring

arteriovenous nipping

cotton wool spots

hard exudates

retinal haemorrhages

papilloedema

What is silver/copper wiring?

where the walls of the arterioles become thickened and sclerosed and reflect more light on examination

What is Arteriovenous nipping (AV nipping)?

where arterioles cause compression of the veins where they cross due to sclerosis and hardening of the arteries

What are cotton wool spots?

caused by ischaemia and infarction causing damage to nerve fibres

What are exudates?

leakage of lipids from vessels

What are retinal haemorrhages?

caused by damage vessels rupturing and releasing blood to the retina

What is papilloedema?

ischaemia to the optic nerve causing optic nerve swelling

What is the Keith-Wagner classification of hypertensive retinopathy?

1- mild narrowing of arterioles

2- focal constriction of blood vessels and AV nicking

3- cotton-wool patches. exudates, and haemorrhages

4- papilloedema

What is the management of hypertensive retinopathy?

control of BP and manage risk factors (smoking, cholesterol)

What are clinical features of thyroid eye disease?

• swelling of the eyelids

• oedema and engorgement of vessels of the conjunctiva

• exposure of the cornea

• exophthalmos

• restricted eye movements

• optic neuropathy

What is the management of thyroid eye disease?

• lid retraction- guanethidine drops to relax smooth muscle

• artificial tears

• if corneal exposure threatens sight tarsorrhaphy (sewing the eyelids)

What are manifestations of RA on the eye?

• episcleritis

• scleritis

• corneal ulceration

• keratitis

How common are ocular manifestation of RA?

25% of patients with RA have eye problems

Which systemic infections can affect the eye?

syphilis

TB

toxoplasmosis

Covid

Ebola

these diseases can present with signs of intraocular inflammation

What haematological conditions can affect the eye?

sickle cell disease

What eye conditions can IBD cause?

episcleritis

uveitis

peripheral ulcerative keratitis

What eye manifestations can MS have?

optic neuritis

optic atrophy

Uhthoff’s phenomenon- worsening of vision following a rise in body temperature

internuclear ophthalmoplegia

What eye manifestations can myasthenia gravis have?

diplopia

ptosis

What dermatological conditions can affect the eye?

acne rosacea

pemphigoid

Steven’s-Johnson

atopic eczema

What can Horner’s present with?

miosis- small pupil

ptosis

enophthalmos- sunken eye

What is optic neuritis?

inflammation of the topic nerve

What are causes of optic neuritis?

multiple sclerosis

diabetes

syphilis

What are presenting features of optic neuritis?

• unilateral decrease in visual acuity over hours-days

• poor discrimination of colour with red desaturation

• pain worse on eye movement

• relative afferent pupillary defect

• central scotoma- area of depressed vision that interferes with central vision

What investigations are performed for optic neuritis?

MRI of the brain and orbits with gadolinium contrast (a clear colourless fluid used to make images clearer)

What is the management of optic neuritis?

high dose steroids

recovery can take 4-6 weeks

What is the prognosis of optic neuritis?

if >3 white matter lesions, the 5 year risk of developing MS is 50%