Sudden visual loss Flashcards
What is retinal detachment
- the retina separates from the choroid underneath
- Sight threatening condition
Why do retinal detachments usually occur
This is usually due to a retinal tear that allows vitreous fluid to get under the retina and fill the space between the retina and the choroid. The outer retina relies on the blood vessels of the choroid for its blood supply
What are the risk factors for retinal detachment
Posterior vitreous detachment Diabetic retinopathy Trauma to the eye Retinal malignancy Older age Family history
What is the presentation of retinal detachment
- Peripheral vision loss. This is often sudden and like a shadow coming across the vision.
- Blurred or distorted vision
- Flashes and floaters
What is the management of retinal detachment
- Urgent opthalmology review
- Treat retinal tears
- reattach the retina and reduce any traction or pressure that may cause it to detach again
What is the management of retinal tears
Laser therapy
Cryotherapy
How can you reattach the retina
- Vitrectomy
- Scleral buckling
- Pneumatic retinopexy
What is pneumatic retinopexy
involves injecting a gas bubble into the vitreous body and positioning the patient so the gas bubble creates pressure that flattens the retina against the choroid and close the detachment.
What is a vitrectomy
involves removing the relevant parts of the vitreous body and replacing it with oil or gas.
What is a Central retinal vein occlusion
occurs when a blood clot (thrombus) forms in the retinal veins and blocks the drainage of blood from the retina. There are four branched veins that come together to form the central retinal vein. Blockage of one of the branch veins causes problems in the area drained by that branch whereas blockage in the central vein causes problems with the whole retina.
What is the pathophysiolgoy behind a retinal vein occlusion
- Blockage of a retinal vein causes pooling of blood in the retina.
- This results in leakage of fluid and blood causing macular oedema and retinal haemorrhages.
- This results in damage to the tissue in the retina and loss of vision.
- It also leads to the release of VEGF, which stimulates the development of new blood vessels (neovascularisation).
What are the risk factors for central vein occlusion
Hypertension High cholesterol Diabetes Smoking Glaucoma Systemic inflammatory conditions such as systemic lupus erythematosus
What is the presentation of central retinal vein occlusion
Blockage of one of these retinal veins causes sudden painless loss of vision.
what will you see on fundoscopy of a central retinal vein occlusion
Flame and blot haemorrhages
Optic disc oedema
Macula oedema
What are the risk factors for central vein occlusion
Hypertension High cholesterol Diabetes Smoking Glaucoma Systemic inflammatory conditions such as systemic lupus erythematosus
What is the presentation of central retinal vein occlusion
Blockage of one of these retinal veins causes sudden painless loss of vision.
what will you see on fundoscopy of a central retinal vein occlusion
Flame and blot haemorrhages
Optic disc oedema
Macula oedema
Other investigations that should be compelted for a patient with ? retinal vein occlusion
Full medical history FBC for leukaemia ESR for inflammatory disorders Blood pressure for hypertension Serum glucose for diabetes
Management of central retinal vein occlusion
- referred immediately to an ophthalmologist
- Management in secondary care aims to treat macular oedema
- prevent complications
- Laser photocoagulation
- Intravitreal steroids (e.g. a dexamethasone intravitreal
implant) - Anti-VEGF therapies (e.g. ranibizumab, aflibercept or
bevacizumab)
What are the complications of central retinal vein occlusion
- neovascularisation of retina and iris
- glaucoma
What is central retinal artery occlusion
- something blocks the flow of blood through the central retinal artery.
- The central retinal artery supplies the blood to the retina. - It is a branch of the ophthalmic artery, which is a branch of the internal carotid artery.
What are the causes of central retinal artery occlusion
- Atherosclerosis
2. giant cell arteritis
What are the risk factors for central retinal artery occlusion
Older age Family history Smoking Alcohol consumption Hypertension Diabetes Poor diet Inactivity Obesity giant cell arteritis polymyalgia rheumatica.
Presentation of a patient with central retinal artery occlusion
- sudden painless loss of vision
- relative afferent pupillary defect.
What is a relative afferent pupillary defect.
the pupil in the affected eye constricts more when light is shone in the other eye compared when it is shone in the affected eye. This occurs because the input is not being sensed by the ischaemic retina when testing the direct light reflex but is being sensed by the normal retina during the consensual light reflex.
What will be seen on fundoscopy in a patient with a central retinal artery occlusion
- pale retina: lack of perfusion with blood
- cherry red spot: the macula, which has a thinner surface that shows the red coloured choroid below and contrasts with the pale retina.
What is the immediate management of central retinal arterty occlusion
- Ocular massage
- Removing fluid from the anterior chamber to reduce intraocular pressure.
- Inhaling carbogen (a mixture of 5% carbon dioxide and 95% oxygen) to dilate the artery
- Sublingual isosorbide dinitrate to dilate the artery
What is the long term management of central retinal artery occlusion
treating reversible risk factors and secondary prevention of cardiovascular disease.
