Summary eye conditions: Retinal Flashcards
common retinal problems
- Age related macula degeneration (most common cause of sight loss in UK)
- Diabetic retinopathy
- Hypertensive retinopathy
- Retinal artery occlusion
- Retinal vein occlusion
- Posterior vitreous detachment
- Retinal tear/ detachment
diabetic retinopathy background
High glucose content over a long period of time can cause damage to the retinal blood vessels, which causes haemorrhage and subsequent ischaemia to the retina.
Pathophysiology
- Hyperglycaemia causes increased vascular permeability of the blood vessels
- This causes leakage from the blood vessels including blot haemorrhage and hard exudates (lipids- yellow)
- Ischaemia to the nerve fibres in the retina due to microaneursyms causes cotton wool spots (fluffy white patches)
- Overtime due to chronic ischaemia neovasculisation occurs due to release of VEGF by the retina
- Vitrous Haemorrhage can occur which can cause changes to vision (think blood blocking vision)
- Over time diabetic retinopathy can lead to retinal detachment due to ischaemia of the retina
classification of diabetic retinopathy
- Background
- Pre-proliferative
- Proliferative
- Advanced
presentation of diabetic retinopathy
Asymptomatic
Symptoms
- Floaters -> small haemorhrages obscuring vision
- Blurred vision if maculopathy
- Decreased visual acuity
- Loss of vision
- Blindness
Key findings on fundoscopy: Diabetic retinopathy
- Dot and blot haemorrhages
- Hard exudates
- Cotton wool spots
- Venous beading
- Microaneurysms
- Neovascularisation
fundoscopy: background diabetic retinopathy
Microanerysms
Dot and blot haemorrhage
fundscopy: Pre-proliferative diabetic retinopathy
Cotton wool spots
- Accumulations of dead nerve cells from ischaemic damage
Fundoscopy: proliferative diabetic retinopathy
Neovascularisation (due to VEGF)
Advanced diabetic retinopathy can result in
- Recurrent vitreous haemorrhage from bleeding areas of neovascularisation
- Tractional retinal detachments as areas of neovascularisation grow into the vitreous and form fibrous bands suspending the retina
- Rubeosis as neovascularisation occurs at the iris and drainage angle resulting in increased intraocular pressure and progressive glaucoma
management of diabetic retinopathy
- Pan-retinal photocoagulation
- Anti-VEGF medications such as ranibizumab and bevacizumab
- Vitreoretinal surgery (keyhole surgery on the eye) may be required in severe disease
Pan-retinal photocoagulation
is the primary treatment for proliferative diabetic retinopathy.
The rationale behind the treatment is to reduce the production of VEGF by reducing the oxygen demand from the peripheral retina.
Clinically it is seen as clusters of burn marks on the retina which have been created by the laser used in the treatment process.
hypertensive retinopathy background
Damage to retinal vessels caused by systemic hypertension
- Chronic hypertension
- Malignant hypertension (acute)
Hypertensive retinopathy is graded as follows:
Keith-Wagner Classification
Stage 1: Mild narrowing of the arterioles
Stage 2: Focal constriction of blood vessels and AV nicking
Stage 3: Cotton-wool patches, exudates and haemorrhages (similar to diabetic)
Stage 4: Papilloedema (malignant hypertension)
Key findings on fundoscopy: Hypertensive retinopathy
- Silver/copper wiring (arterioles thickeed and sclerosed)
- Arteriovenous nipping
- Cotton wool spots (ischaemia to nerve fibres)
- Hard exudates (damaged vessels leaking lipids into retina)
- Retinal haemorrhage (damaged vessels rupture)
- Papilloedema - ischameia to optic nerve leading to oedema
Malignant hypertension
Ggrade 4 hypertensive eye disease
- Which includes all the features of grade 3, with the addition of optic disc swelling.
- Other features include headaches, eye pain, reduced visual acuity and focal neurological deficits.
**Initial management **typically involves antihypertensives and emergency hospital admission.
general management of hypertensive retinopathy
Management is focused on controlling the blood pressure and other risk factors such as smoking and blood lipid levels.
age related macular degeneration background
Most common cause of vision loss in UK
Two types
- Wet (more acute and worse prognosis)
- Dry (90%) - no exudation or neovascularisation
pathophysiology of ARMD
Disease starting with the choroid layer (blood vessels), which affects all layers above: Bruchs membrane, retinal pigement epithleium and photoreceptors
Due to disrutpion of these layers Drusen form between the retinal pigment layer and Brich membrane
- found in both wet and dry AMD
Key findings on fundoscopy: both wet and dry
- Drusen (yellow depsotis of protein and lipids)
- Atrophy of the retinal epithelium
- Degeneration of photoreceptors
Wet AMD pathophysiology
- New vessels growing from the choroid layer into the retina.
- These vessels can leak fluid or blood and cause oedema and more rapid loss of vision.
- Fluid can be seen on OCT
- A key chemical that stimulates the development of new vessels is **vascular endothelial growth factor (VEGF) **and this is the target of medications to treat wet AMD.