2.5: Visual Loss and Blindness Flashcards Preview

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Flashcards in 2.5: Visual Loss and Blindness Deck (65)
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1

What are the two types of visual loss?

Gradual Sudden

2

What are four causes of sudden visual loss?

Vascular

Retinal Detachment

Age-Related Macular Degeneration

Closed Angle Glaucoma

3

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

4

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)

5

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

6

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

7

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

8

Signs of central retina artery occlusion?

Relative Afferent Pupil Defect (RAPD) - eyes react differently

 

Pale, oedematous retina with thin, thready vessels

9

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

10

What can cause central retinal artery occlusion?

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

11

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

12

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)

13

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

14

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

15

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

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

16

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)

17

Symptoms of central retinal vein occlusion? Signs?

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

18

Signs of central retinal vein occlusion?

Retinal Haemorrhages Tortous Veins Disc and Macular Swelling Cotton Wool Spots

19

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

20

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)

21

 What do you see? What condition?

Tortous Veins Dark retina (haemorrhage) Central Retinal Vein Occlusion

22

What do you see? What condition?

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

23

 What do you see? What condition?

One area of paleness One thready vessel Branched Central Artery Occlusion

24

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

25

What are the two types of ischaemic optic neuropathy?

Arteritic Non-Arteritic

26

Describe the presentation of ischaemic optic neuropathy?

Sudden, profound visual loss with swollen discs

27

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

28

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

29

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

30

What may help diagnosis of arteritic ischaemic optic neuropathy

Temporal Artery Biopsy

Shows up if there is Giant Cell Arteritis Disease present