Sudden Visual Loss

Question 1

what 5 questions should you ask on presentation of sudden visual loss

Answer 1

headache? GCA

eye movements hurt? optic neuritis

light/flashes preceding visual loss? retinal detachment

like a curtain descending over vision? amaurosis fugax may precede permanent visual loss

poorly controlled DM?

Question 2

what supplies the retina

Answer 2

CRA supplies the inner 2/3 and ciliary body the outer 1/3

Question 3

presentation of CRAO

Answer 3

dramatic visual loss within seconds of occlusion

no pain

relative afferent pupillary defect occurs within seconds

Question 4

describe the extent of vision loss in CRAO

Answer 4

in 90% acuity is finger counting or worse

Question 5

CRAO fundoscopy

Answer 5

retina is pale and yellow due to oedema and there is a cherry red spot macula

Question 6

causes of occlusion in CRAO

Answer 6

carotid artery disease or thrombo-embolic (clot, tumour, infective)

look for signs of atherosclerosis, heart valve disease, smoking etc

Question 7

managment of CRAO

Answer 7

• if it presents within 24 hours the aim is to increase the retinal blood flow by reducing IOP by ocular massage
• vascular management is used to establish the source of the embolus (carotid doppler (US))
• risk factors must be managed and assessed

Question 8

BRAO

Answer 8

retinal and visual changes relate only to the part of the retina supplied by the occluded artery

Question 9

amaurosis fugax

Answer 9

transient CRAO

painless temporary loss of vision described to be like a curtain falling down. usually lasts around 5 minutes with full recovery

Question 10

fundoscopy of Amaurosis Fugax

Answer 10

nothing abnormal seen usually

Question 11

what can cause Amaurosis Fugax

Answer 11

can be due to the passage of emboli through the retinal arteries

a TIA causing Amaurosis Fugax is an early sign of internal carotid artery stenosis

Question 12

management of Amaurosis Fugax

Answer 12

urgent referral to stroke clinic

aspirin

Question 13

name some other causes of transient visual loss

Answer 13

migraine (visual loss usually followed by headache)

Always think of vascular causes such as platelet-fibrin/cholesterol micro-emboli from atherosclerotic plaques in the heart or carotid arteries

Question 14

compare the appearance of veins and arteries on fundoscopy

Answer 14

veins appear thicker than arteries, which are pale inside due to muscle

Question 15

CRVO

Answer 15

venous stasis - blood is going in but is not able to leave

Question 16

describe the venous drainage of the eye

Answer 16

SOV drains into cavernous sinus via the superior orbital fissure

Question 17

incidence of CRVO

Answer 17

increases with age

more common than CRAO

Question 18

causes of CRVO

Answer 18

Blockage in veins cause by pressure from nearby artery or blood clot forming in the vein. This leads to bleeding and leakage of fluid from blood vessels.

virchow’s triad: stasis, hypercoagulability, hypertension

arteriosclerosis, hypertension, hyperviscosity

diabetes and polycythaemia

glaucoma

associated with heart disease, smoking etc

Question 19

presentation of CRVO

Answer 19

if the whole central retinal vein is occluded there is blurring and visual loss, less sudden than CRAO.

it may be perceived as sudden by the patient but the mechanisms of visual loss are due to development of ischaemia and macular oedema

Question 20

macular oedema in CRVO

Answer 20

Question 21

describe the appearance of CRVO on fundoscopy

Answer 21

stormy sunset appearance - hyperaemia and haemorrhages

Question 22

ischaemic CRVO

Answer 22

decreased perfusion, capillary closure and retinal hypoxia

marked RAPD

fundoscopy: cotton wool spots (infarcts), swollen optic nerve, macular oedema, risk of neovascularization (ischaemia leads to release of VEGF)

Question 23

non-ischaemic CRVO

Answer 23

have better acuity and prognosis, but may progress to ischaemic forms, hence the need for follow up

Question 24

managment of CRVO

Answer 24

monitor as complications may occur due to the formation of new vessels - laser photocoagulation treatment may be required

Anti-VEGFs

assess underlying risk factors eg hypertension, diabetes

Question 25

anterior ischaemic optic neuropathy

Answer 25

*occlusion of optic nerve head circulation* the optic nerve is damaged if the **posterior ciliary arteries are blocked** by inflammation or atheroma

Question 26

2 types of AION

Answer 26

arteritic - due to inflammation (GCA) non-arteritic - due to atherosclerosis

Question 27

signs and symptoms of AION

Answer 27

sudden, profound visual loss swollen pale optic disc is seen on fundoscopy

Question 28

Vitreous Haemorrhage

Answer 28

haemorrhage often occurs into the vitreous cavity bleeding can occur from new retinal vessels, retinal tears, retinal detachment or trauma

Question 29

signs of Vitreous Haemorrhage

Answer 29

small extravasations of blood produce vitreous **floaters** (seen as small black dots or tiny ring like forms with clear centres) large enough bleed may **obscure vision and cause a loss of red reflex**

Question 30

what may be seen on fundoscopy of Vitreous Haemorrhage

Answer 30

haemorrhage

Question 31

managment of Vitreous Haemorrhage

Answer 31

identify cause a **vitrectomy** is done to remove the blood in the vitreous if the retina is torn/detached or the patient needs treatment of new vessels

Question 32

optic neuritis

Answer 32

*inflammation of the optic nerve* subacute unilateral loss of acuity occurs over hours or days **colour vision** is affected more than acuity: red desaturation **pain on eye movement** swelling of optic disc

Question 33

in optic neuritis will the pupillary defect be afferent or efferet

Answer 33

afferent

Question 34

dyschromatopsia

Answer 34

ability to perceive colours is not fully normal

Question 35

why does optic neuritis cause pain on eye movement

Answer 35

the sheath of the optic nerve is attached to the common tendinous ring where the rectus muscles of the eye attach

Question 36

Answer 36

optic neuritis

Question 37

what is the chief cause of registrable blindness in patients over 65

Answer 37

age related macular degeneration

Question 38

cause of ARMD

Answer 38

unknown and multifactorial risk factors include increasing age, smoking, positive family history, poor nutrition etc

Question 39

pathophysiology of wet ARMD

Answer 39

abberant vessels grow from the choroid into the neuro-sensory retina and leak this causes a build up of fluid/blood and eventually scarring

Question 40

symptoms of wet ARMD

Answer 40

rapid central vision loss and distortion (metamorphopsia)

Question 41

signs of wet ARMD

Answer 41

haemorrhage and exudate

Question 42

Answer 42

wet ARMD

Question 43

treatment of wet ARMD

Answer 43

injection of anti-VEGF into vitreous cavity