2.5: Visual Loss and Blindness Flashcards Preview

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Flashcards in 2.5: Visual Loss and Blindness Deck (65):

What are the two types of visual loss?

Gradual Sudden


What are four causes of sudden visual loss?


Retinal Detachment

Age-Related Macular Degeneration

Closed Angle Glaucoma


Describe the arterial supply to the eye?

Internal carotid gives off the ophthalmic artery This has many branches that supply the eye Some of the branches include: - Central Retinal Artery - Posterior Ciliary Artery


Describe vascular causes of sudden vision loss?

Occlusion of the retinal circulation

Occlusion of the optic nerve head circulation Haemorrhage from abnormal blood vessels Haemorrhage from normal blood vessels (retinal tear)


Describe the blood supply to the retina?

Central retinal artery supplies inner 2/3rd of retina Posterior Ciliary Artery supplies outer 1/3rd of retina


Describe occlusion of the retinal circulation? (Where can be occluded?) There are three types

Central Retinal Artery Occlusion - affects all of retina

Branch Retinal Artery Occlusion - affects only the area supplied by the branch


Amaurosis Fugax - Transiet central retinal occlusion


Describe central retina artery occlusion? - Symptoms

This causes sudden visual loss Profound visual loss (Counting fingers or less)


Painless Central artery is end artery (no other supply) so can lead to blindness


Signs of central retina artery occlusion?

Relative Afferent Pupil Defect (RAPD) - eyes react differently


Pale, oedematous retina with thin, thready vessels


Describe what you see? Condition?

Small area in middle of normal retina (supplied by tiny blood vessel) Rest of retina is pale Thin, thready vessels Condition is central retinal artery occlusion


What can cause central retinal artery occlusion?

Carotid Artery Disease (Plaques in artery) Emboli from heart (clot/vegetation etc.) Less rare


Those who have a central retinal artery occlusion are at risk of developing...?

Stroke Central retinal artery occlusion is a type of mini-stroke and patients who have this are at risk of developing full blown stroke


Management of central retinal artery occlusion? - Present very early? - Present later?

Carotid Massage to try move occlusion from central to branch (minimise damage, save sight) Later: - Carotid doppler to establish site of occlusion - Assess and manage risk factors (for further stroke)


Describe branch retinal artery occlusion? - What does this look like on examination?

In central, entire retina is affected In branch, only the area supplied by that branch is affected Some vision is unaffected - Only some of the retina is pale on examination


Describe amaurosis fugax? - What does this look like on examination? - Treatment?

This is transient central retinal artery occlusion Like a curtain shutting/blind coming down Only lasts for a few minutes - Very little to see on examination - Treatment includes referral to TIA clinic (this is a sign that central occlusion or stroke may occur) and aspirin


Another cause of amaurosis fugax? How do you determine the cause?

Migraines Migraines are followed by a headache, amaurosis fugax is not


Describe central retinal vein occlusion? Causes?

This is when there is occlusion of the central vein that drains the retina Causes: Virchow's Triad (Hypercoagulable, Abnormal Blood Flow (Stasis) and Endothelial Injury) Raised IOP (Intraocular Pressure)


Symptoms of central retinal vein occlusion? Signs?

Sudden visual loss Moderate to severe (less than central artery occlusion)


Signs of central retinal vein occlusion?

Retinal Haemorrhages Tortous Veins Disc and Macular Swelling Cotton Wool Spots


Treatment of central retinal vein occlusion?

Based on cause (Treat underlying cause) Monitor - New vessels may form which may cause complications and require laser treatment Anti-VGEF to shrink back any new vessels


Describe why new vessels form in central retinal vein occlusion? Why do we treat them?

New vessels form to help get round the occlusion These are thin and weak and can bleed/rupture leading to more complications That is why we treat them with laser treatment and anti-VGEF (to prevent the complications)


 What do you see? What condition?

Tortous Veins Dark retina (haemorrhage) Central Retinal Vein Occlusion


What do you see? What condition?

One tortuous vein One patch of darkness and haemorrhage Branched Retinal Vein Occlusion


 What do you see? What condition?

One area of paleness One thready vessel Branched Central Artery Occlusion


Describe occlusion of optic head circulation? Describe arterial supply to optic nerve head and its relevance in this condition?

This is also called ischaemic optic neuropathy (ischaemic damage to the optic nerve) This is infarction of the optic nerve head due to obstruction of the posterior ciliary arteries Posterior ciliary arteries are not end arteries so patients may have severe visual loss but not complete


What are the two types of ischaemic optic neuropathy?

Arteritic Non-Arteritic


Describe the presentation of ischaemic optic neuropathy?

Sudden, profound visual loss with swollen discs


Describe arteritic ischaemic optic neuropathy (ION) - How does this occur?

This is damage to the optic nerve due to ischaemia of the optic nerve

Caused by Giant Cell Arteritis (GCA) or temporal arteritis This is inflammation of the medium to large arteries Inflammation blocks the lumen of the arteries Visual loss from ischaemia of optic nerve head


Describe the symptoms in arteritic ION

Sudden, vision loss Profound vision loss (counting fingers only or in some cases no perception of light) Temporal Headaches Jaw pain when chewing Scalp tenderness Enlarged scalp arteries Malaise


Describe the visual loss in arteritic ischaemic optic neuropathy

Sudden vision loss Profound vision loss - can be counting fingers or no perception of light Irreversible blindness Important to catch early to prevent both eyes becoming blind


What may help diagnosis of arteritic ischaemic optic neuropathy

Temporal Artery Biopsy

Shows up if there is Giant Cell Arteritis Disease present


Treatment in arteritic ischaemic optic neuropathy

Quick treatment High dose steroids to save the other eye from going blind


Complications of arteritic ION?

Blindness - one eye or both Can lead to death (if the arteritis affects coronary arteries)


One of the causes of sudden visual loss is haemorrhage - what the two types?

Haemorrhage of abnormal blood vessels Haemorrhage of normal blood vessels


Describe haemorrhage of abnormal blood vessels?

In ischaemia, the body responds by the formation of new vessels - often in the wrong place These vessels are very fragile and can rupture easily Can bleed and cause damage to the retina


Describe haemorrhage of normal blood vessels?

Retinal tears in areas that are supplied by blood vessels can lead to bleeding


Where does haemorrhage of the eye usually occur into?

The vitreous cavity


Describe the signs and symptoms of vitreous haemorrhage?

Symptoms: - Loss of vision - Floaters Signs: - Loss of red reflex - Haemorrhage on fundoscopy


Treatment/Management of vitreous haemorrhage?

Identify the cause Vitrectomy for non-resolving cases


Describe retinal detachment?

This is when the retina detaches from the supporting layer of soft tissue


Signs and symptoms of retinal detachment?

Symptoms: - Loss of vision - Sudden onset of flashes and floaters Symptoms: - May have relative afferent pupil defect - May see tear on ophthalmoscopy


Treatment/Management of retinal detachment?

Usually surgery


What are the two types of age related macular degeneration?

Wet = Sudden onset visual loss Dry = Gradual onset visual loss


Describe wet age related macular degeneration?

This is the formation of new blood vessels under the retina Leakage from these blood vessels causes accumulation of fluid and blood This causes scarring of the retina and vision loss


Symptoms of wet age related macular degeneration? Signs of wet age related macular degeneration?

Symptoms: Rapid central vision loss Distortion of straight lines (Metamorphosia) Signs: Haemorrhage or exudate


Treatment of wet age-related-macular degeneration?

Anti-VGEF Given by intravitreal injection


Describe gradual visual loss? When do people present?

Often bilateral Asymmetrical (one side worse) If they have reduced visual acuity --> Presents early If they have reduced visual field --> Presents late


Causes of gradual visual loss? Mnemonic for remembering this?

Cataracts Age Related Macular Degeneration (Dry) Refractive Error Diabetic Retinopathy Inherited Disease Glaucoma Access to eye clinic Non Urgent (Cardigan) but really just CARDIG


What is cataracts? Causes?

Cloudiness of the lens Very common Can be age related, congenital, traumatic, metabolic (Eg: Diabetes) or drug induced (Steroids) Many different types


Management of Cataracts?

Surgical Removal with intra-ocular lens implantation if patient is symptomatic


Describe dry age-related macular degeneration?

This is gradual loss of vision Missing of the central vision (Scotoma)


What is Scotoma?

This is a partial loss of vision/blind spot in an another wise normal field of vision


Symptoms of dry age related macular degeneration?

Symptoms: Loss of vision Loss of central vision (Scotoma) Signs: Drusen (Build up of lipid deposits) Atrophic Patches of retina


Treatment for dry age related macular degeneration?

No treatment available Supportive visual aids eg: Magnifiers


What is refractive error?

This is when the eye is unable to clearly focus an image


What is myopia?

Being short sighted Eye brings the light into focus too early


What is hypertropia?

Being long sighted Eye doesn't bring the light into focus early enough (focused behind retina)


What is astigmatism?

Abnormal curvature of the cornea Causes two focal points of light on the retina instead of one


What is Presbyopia?

This is the inability to see up close/read small print Happens to everyone with age


Describe the treatment for refractive error?



What is Glaucoma? Cause?

This is progressive optic neuropathy Progressive damage to optic nerve leading to progressive vision loss Cause of glaucoma is unknown - probably multifactorial. Raised IOP may be a factor


What are the types of glaucoma?

Closed angle glaucoma Open angle glaucoma Refers to angle between cornea and iris


Describe open angle glaucoma? Signs? Symptoms?

This is loss of peripheral vision Often picked up in screening - people don't notice it themselves (No symptoms) Signs: - Cupped disc - Visual field defect - Possible raised IOP


Treatment for open angle glaucoma? Follow up?

Aims to preserve vision - Lower IOP using drops Patients require regular monitoring in clinic


Describe closed angle glaucoma? Symptoms?

This is a medical emergency Symptoms: - Painful, red eye - Headache - Vision Loss - Nausea and vomiting


Treatment for closed angle glaucoma?

Need to lower IOP using drops to prevent patient going blind