Visual Loss Flashcards

1
Q

7 causes of sudden visual loss?

A
Central retinal artery occlusion
Central retinal vein occlusion 
Occlusion of optic nerve circulation
Vitreous haemorrhage
Retinal Detachment
Wet ARMD
Closed angle glaucoma
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2
Q

4 causes of gradual visual loss?

A

Cataracts
Dry ARMD
Open angle glaucoma
Refractive errors

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3
Q

What does a positive RAPD mean?

A

A positive RAPD means there are differences between the two eyes in the afferent pathway due to retinal or optic nerve disease.

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4
Q

How is a RAPD test done?

A

Swinging-flashlight test whereupon the patient’s pupils dilate when a bright light is swung from the unaffected eye to the affected eye. As to affected eye less light is perceived so the pupils need to constrict less.

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5
Q

What is virchows triad? How does this relate to retinal vein occlusion?

A

Three broad categories of factors that are thought to contribute to thrombosis. Hypercoagulability. Hemodynamic changes (stasis, turbulence) Endothelial injury/dysfunction.

Endothelial damage in diabetes
Abnormal blood flow in hypertension
Hypercoaguable state in cancer

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6
Q

Central retinal artery occlusion is a form of _____

A

stroke and patients may have carotid artery disease

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7
Q

Central retinal artery occlusion is associated with _____________________

A

Atherosclerosis and hypertension

Occasionally GCA but this is more likely to effect blood supply to the optic nerve

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8
Q

Presentation of central retinal artery occlusion?

A

Sudden painless loss of vision
Positive RAPD test
On exam may see pale oedematous retina due to ischaemia and a cherry red spot

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9
Q

What is amaurosis fugax?

A

A form of retinal artery occlusion that causes transient painless visual loss and lasts 5 mins with a full recovery, need referred to the stroke clinic

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10
Q

Management of central retinal artery occlusion?

A

Ophthalmic emergency
Need to find cause
Ocular massage to dislodge emboli, paracentesis, dilation of arteries, acetazolamide
Unfortunately rarely recovers

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11
Q

What happens in central retinal vein occlusion?

A

Occlusion of central retinal vein causes obstruction in outflow of blood and get a rise in intravascular pressure

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12
Q

Predisposing factors to central retinal vein occlusion?

A

Age, hypertension, CV disease, glaucoma, blood disorders

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13
Q

Presentation of central retinal vein occlusion?

A

Sudden, painless visual loss

On exam: retinal haemorrhages, dilated torturous veins, swollen disc and macula

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14
Q

Contrast appearance of eye in CRVO and CRAO?

A

Vein: retinal haemorrhages, dialled torturous veins, swollen disc and macula > BACK-FLOW OF BLOOD AND RISE IN PRESSURE
Artery: pale oedematous retina and cherry red spot > ISCHAEMIA

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15
Q

Management of CRVO?

A

Find underlying cause

If neovascularisation can do photocoagulation or anti-VEGF intravitreal injection

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16
Q

What is more common CRVO or CRAO?

A

CRVO by far

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17
Q

What is ischaemic optic neuropathy?

A

Occlusion of the optic nerve head circulation

Get occlusion of the posterior ciliary arteries by GCA or atherosclerotic/ hypertensive disease

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18
Q

2 causes of ischaemic optic neuropathy?

A

GCA

Atherosclerosis/ hypertension

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19
Q

Presentation of ischaemic optic neuropathy?

A

Sudden visual loss usually painless
Pale swollen optic disc > may be splinter haemorrhages
RAPD test positive

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20
Q

Management of ischaemic optic neuropathy?

A

Prednisolone 40-60 mg in GCA

No exact treatment for non GCA type

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21
Q

What is the red reflex?

A

Pupil goes red when light shone as lights up blood rich retina. Pathologies that effect vitreous, cornea or retina can cause loss e.g. haemorrhage as covering the retina

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22
Q

What is vitreous haemorrhage and the causes?

A

Bleeding from the retinal blood vessel into the vitreous gel due to:

  • proliferative diabetic retinopathy
  • any other cause of retinal or optic disc neovascularisation e.g. branch RVO
  • spontaneous tearing of retina (may precede retinal detachment)
  • systemic hypertension
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23
Q

Presentation of vitreous haemorrhage?

A

Painless loss of vision, may get floaters

On exam: partial or total loss of red reflex, haemorrhage visible

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24
Q

Management of vitreous haemorrhage?

A

Identify underlying cause

May resolve spontaneously, may need vitrectomy

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25
What is a scotoma?
a partial loss of vision or blind spot in an otherwise normal visual field
26
What happens in retinal detachment?
Separation of the 2 embryonic layers of the retina (the neuroretina from the pigment epithelium). Pigment epithelium layer is the layer that nourishes the retinal visual cells. Neuroretina contains the photoreceptors. Retina is classed as neuroretina.
27
Predisposing factors to retinal detachment?
Increasing age Myopia Lattice degeneration of the retina Mechanical trauma
28
Presentation of a retinal detachment?
Painless loss of vision > depends on where the detachment affects. Primary shadow that increases. Sudden onset of floaters as the separation occurs or flashes of light. On exam the detached retina is elevated and grey in colour.
29
Management of retinal detachment?
Surgery | Needs quick treatment
30
What is Age related macular degeneration?
Commonest cause of blindness, multifactorial (age, hypertension, smoking, UV) and causes degeneration of the macula and therefore central vision
31
Wet/ Neovascular Macular degeneration causes sudden or gradual visual loss?
Sudden
32
Dry/ atrophic macular degeneration causes sudden or gradual visual loss?
Gradual
33
Describe what happens in Wet ARMD? What will eye look like?
New blood vessels grow and leakage causes build up of fluid and scarring may see haemorrhages and exudates on exam
34
Presentation of wet ARMD?
Rapid central visual loss and distortion
35
Treatment of wet ARMD?
Anti VEGF intravitreal injections aims to convert wet ARMD to dry ARMD which will cause more gradual visual loss.
36
Describe what happens in Dry ARMD? What will the eye look like?
Build up of druse (lipid deposits) behind the retina. Drusen can be hard or soft and may be focal RPE detachment, can get atrophic patches of the retina
37
Macular degeneration causes central or peripheral visual loss?
Central
38
Treatment of ARMD?
No cure | Treatment is supportive with low vision aids, magnifiers and social support
39
What is glaucoma?
Condition caused by increased pressure inside the eye that is sufficiently elevated to cause optic nerve damage and result in visual field defects with loss of sight.
40
What are some risk factors for primary open angle glaucoma?
Age, Race (black africans more at risk), positive family history, myopia
41
What angle is being referred to in glaucoma?
Angle between the cornea and iris
42
Primary open angle glaucoma causes gradual or sudden visual loss?
Gradual loss of peripheral vision (central vision is preserved until late on)
43
What happens in primary open angle glaucoma?
High intraocular pressure resulting from reduced outflow of aqueous humour through the trabecular meshwork
44
Presentation of primary open angle glaucoma?
Gradual, insidious painless loss of peripheral vision Initially asymptomatic and identified during ophthalmic exam Optic disc shows enlarged cup with a thin neuroretinal rim (increased cup to disc ratio) Visual fields show a normal blind spot with scotomas
45
What does treatment for POAG aim to do?
Reduce aqueous production or increase drainage
46
5 examples of drugs for POAG?
Beta blockers reduce aqueous production (end in lol) Prostaglandin analogues increase aqueous outflow (end in prost) Carbonic anhydrase inhibitors reduce aqueous production (amide) Alpha 2 adrenergic agonists reduce production and increase drainage (brimonidine) Parasympathomimetics (pilocarpine) increase drainage
47
What causes acute angle closure glaucoma?
Sudden rise in intraocular pressure due to reduced aqueous drainage when the lens pushes the iris forward against the trabecular meshwork
48
Acute angle closure glaucoma causes sudden or gradual visual loss?
Sudden
49
Presentation of acute angle closure glaucoma?
Painful, red eye, sudden visual loss, headache, nausea, vomiting, cloudy cornea (due to water logging), dilated pupil (iris sphincter can't work properly), long sighted
50
Long sighted person, cloudy cornea, dilated pupil, visual loss, painful eye?
Acute angle closure glaucoma
51
Treatment of acute angle closure glaucoma?
Refer to ophthalmologist, pilocarpine eye drops and oral acetazolamide (carbonic anhydrase inhibitor) to reduce production of aqueous humour. Definitive treatment involves making a whole in the periphery of the iris by lazer or surgical means.
52
What is a cataract?
Opacification of the lens due to abnormal changes in lens proteins.
53
Causes of cataracts?
Many different causes, can be congenital but majority are age related
54
Presentation of cataract?
Gradual visual loss/ blurring Cloudy lens Partial or full loss of red reflex
55
Treatment of cataracts?
Early changes are correctable by glasses by eventually need surgical intervention Small-incision extra capsular or phacoemulsification cataract extraction with insertion of an intraocular lens is treatment of choice
56
Define a refractive error?
Any abnormality in the focusing mechanism of the eye as opposed to an opacity of the system
57
Define emmetropic?
Eye with no refractive errors | Point of focus is on the retina
58
Define myopia?
Short sighted | Eye point of focus is in front of the retina so objects far away looked blurred
59
How is myopia corrected?
Using a concave negative lens (causes divergence of light so hits a point further away)
60
Define hypermetropia?
Eye point of focus is behind the rent so objects up close appear blurred
61
How is hypermetropia corrected?
Corrected using a convex (positive lens) (causes convergence of lights so hits a point closer)
62
What happens in presbyopia?
Ageing of the lens, it becomes less able to alter its curvature causing difficulty with near vision. Need reading glasses.
63
What is astigmatism?
Error where there are different degrees of refraction in different meridians of curvature. So can be myopic in one plane, hypermetropic or emmetropic in the other plane. Eye has multiple focal points.
64
Treatment of astigmatism?
Treat with contact lens or surgery
65
What type of investigation can be used to look at macular disease?
OCT optical coherence tomography - helps distinguish between wet and dry ARMD and other pathologies
66
Red flag for someone with optic neuritis?
loss of colour vision in a young patient as sign of MS
67
What are synechiae?
Synechiae are adhesions between the pupil and iris and can lead to a small/irregular pupil.
68
What is a hypopyon?
Inflammatory cells in anterior chamber usually a sign of significant intraocular inflammation
69
What is a hyphaema? Causes?
Collection of blood in the anterior chamber of the eye usually caused by trauma