Refractive errors and visual field defects Flashcards

1
Q

Emmetropia

A

No refractive errors

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2
Q

Myopia

A

Short sightedness

Vision is better for near than for further away

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3
Q

Myopia - positive/negative lens

A

Negative lens

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4
Q

Myopia - concave/convex lens

A

Concave lens

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5
Q

Myopia - relationship with the retina

A

Visual images come in to focus in front of the retina

- images focus too early

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6
Q

Myopia - converges/diverges light?

A

Diverges

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7
Q

Hypermetropia

A

Long sightedness

Vision is better for further away than near objects

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8
Q

Hypermetropia - positive/negative lens

A

Positive lens

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9
Q

Hypermetropia - concave/convex lens

A

Convex lens

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10
Q

Hypermetropia - relationship with the retina

A

Visual images come into focus behind the retina

- images focus too late

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11
Q

Hypermetropia - converges/diverges light

A

Converges

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12
Q

Presbyopia - definition

A

Power loss due to age

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13
Q

Presbyopia - positive/negative lens

A

Positive lens

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14
Q

Presbyopia - concave/convex lens

A

Convex lens

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15
Q

Accomodative esotropia

A

Patient with hypermetropia with a manifest squint in which the eye is turned in

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16
Q

Astigmatism - definition

A

Eye does not focus evenly on the retina
Eye has 2 surfaces to correct
There is shape correction needed

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17
Q

Astigmatism - clinical features

A

Constant blurred vision at all distances

18
Q

Diplopia

A

Double vision

19
Q

Horizontal diplopia

A

Images are side by side

Problem with LR or MR

20
Q

Vertical diplopia

A

Images are one on top of the other

Problem with SO, SR, IR, IO

21
Q

Esotropia - definition

A

Inward squint, convergent squint

22
Q

Esotropia - what movement do you see when covering good eye

A

Outward movement

23
Q

Exotropia - definition

A

Outward squint, divergent squint

24
Q

Exotropia - what movement do you see when covering good eye

A

Inward movement

25
Q

Hypertropia - definition

A

High eye

26
Q

Hypertropia - what do you see when covering good eye

A

Downward movement

27
Q

Hypotropia - definition

A

Low eye

28
Q

Hypotropia - what do you see when covering good eye

A

Upward movement

29
Q

Visual field pathway

A
Optic nerve -> 
Optic chiasm -> 
Optic tracts -> 
Optic radiations -> 
Occipital cortex
30
Q

Visual field defect

A

A lesion anywhere along the visual field pathway which results in a visual field defect

31
Q

Optic nerve defect - cause

A

Ischaemic optic neuropathy
Optic neuritis
Tumours

32
Q

Optic chiasm defect - cause

A

Pituitary tumour

33
Q

Optic tracts and optic radiation defect - cause

A

Tumours

Demyelination

34
Q

Occipital cortex - cause

A
Vascular disease (CVA)
Demyelination
35
Q

Optic nerve problem - patients vision

A

Can’t see at all in the affected eye

36
Q

Optic chiasm problem - patients vision

A

Loss of temporal vision in both eyes (as temporal vision hits nasal retina and this crosses at optic chiasma)

37
Q

Optic tract / optic radiation problem - patients vision

A

Visual field loss on the same side of both eyes (e.g. temporal vision lost on right eye, nasal vision lost on left eye)

38
Q

Occipital cortex problem - patients vision

A

Visual field loss on the same side of both eyes (e.g. temporal vision lost on right eye, nasal vision lost on left eye) but macula is not affected

39
Q

Sudden vision loss - causes

A
Vascular aetiology 
- CRAO
- CRVO
Vitreous haemorrhage
Retinal detachment 
Wet ARMD 
Closed angle glaucoma
40
Q

Gradual visual loss - causes

A
Cataract 
Dry ARMD
Refractive error 
Open angle glaucoma 
Diabetic retinopathy