low vision assessment Flashcards

1
Q

name 3 things that you observe about a patient in your lv clinic

A
  • postural abnormalities
  • mobility
  • appearance
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2
Q

what is the most important part of a low vision assessment

A

history taking

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3
Q

how is a lv history taking different to a pcc history taking

A

more follow up questions are asked and more time is spent on it

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4
Q

list 9 things you will ask about in history taking of your lv assessment

A
  • the duration of condition and onset
  • stability of condition and differences between the eyes
  • patients knowledge of the condition and prognosis
  • ongoing hospital monitoring and or treatment
  • registration status
  • education and or employment
  • present aids and spectacles
  • general health and medications
  • reason for making the appointment
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5
Q

why will you ask the patient about their knowledge of the condition and prognosis, during history taking

A

as the patient needs to understand the eye condition to know how to deal with it and they will know if the condition will deteriorate so they can adjust to it well

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6
Q

why will you need to know if a lv patient is on any ongoing hospital monitoring and or treatment

A

to know if you should prescribe glasses or not
and you dont want to dilate the patient unless they’re having a new symptom, because if they’re at the hospital then they are getting dilated already, but if they’re not then you must dilate

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7
Q

why will you want to know about a patients registration status during history taking

A

to know if they’re SI or SSI
and you want to know if they have access to any benefits e.g. social services
if not you may need to follow up with them or refer them to be registered

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8
Q

why will you want to know about a patients education status during history taking

A

if its a child, you want to know if they’re in an ordinary or a specialist school

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9
Q

why will you want to know about a patients employment status during history taking

A

incase you need to tell them about the access to work scheme

if they’re employed they can use lv aids at work

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10
Q

why will you want to know about present aids and spectacles during history taking

A

to know if the aids/spectacles have been working in order to avoid wasting your patients time

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11
Q

why will you want to know about a patients general health and medications during history taking

A

to know which aid to give e.g. patient may have arthritis or Parkinson’s therefore they cannot hold a magnifier and you will want to give glasses instead etc

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12
Q

why will you want to know about a patients reason for making the appointment during history taking

A

you don’t want to assume that the px made the appointment themselves
sometimes they don’t know why they have made the appointment, as in the UK, the patient will be referred by the ophthalmologist and they don’t know why they came to the clinic

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13
Q

why do you want to ask about distance vision to your lv patient during history taking

A
  • difficulty seeing: faces, buildings, cars, street signs, road signals, bus numbers and steps
  • vision fluctuates or not
  • eccentric viewing status
  • problems with glare: wears tinted glasses
  • vision better outdoors/indoors
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14
Q

which type of eye conditions will a lv px have if they have difficulty seeing faces

A

AMD or stargart’s / any macula problem

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15
Q

why would you want to know if a patients distance vision fluctuates or not during history taking

A

because you want to be aware, incase you give the wrong lv aid or glasses

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16
Q

why would you want to know about a patients eccentric viewing status during history taking

A

because if they dont use this technique, then you can give advice on how to use it for e.g. AMD or stargart’s patient management

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17
Q

why would you want to know if vision is better outdoor or indoor during history taking

A

as this can cause a fluctuation in vision and this can impact on what LVA you give to the px

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18
Q

what do you want to know about a patients mobility in the lv clinic

A

does the patient walk alone, or accompanied in new/familiar environments

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19
Q

give an example of a px who will have problems with mobility in unfamiliar environments

A

px who’s had a stroke and got a hemianopia

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20
Q

list 4 things you want to ask about a patients home situations during history taking

A
  • if the patient lives alone or with family
  • if they have difficulty getting around the house
  • if they have difficulty watching tv
  • if they have difficulties with colours
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21
Q

why would you want to ask a lv patient is they live alone or with family in your history taking

A
  • if lives alone, they may need additional help e.g. with reading letters etc
  • if lives with family, you know that support is easier for them
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22
Q

what 3 things will you ask your lv px during history taking about reading, close work and hobbies

A
  • do they have difficulties seeing books, newspapers, headlines, large print, own writing
  • is vision better in dim light or bright light
  • do they have difficulties with hobbies such as sewing, bingo etc
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23
Q

why would you want to ask your lv px about their reading during history taking

A

it is one of the main problems a lv px faces, especially the elderly as they tend to stay at home and read

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24
Q

why would you want to ask your lv px about their hobbies during history taking

A

to know how to best help the px

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25
Q

whats a good idea to do at the end of history taking

A

make a list of the patients priorities in order to know what help the patients wants
then summarise your findings to the patient and offer help by asking the patient

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26
Q

what is the next thing to do in your lv assessment after history taking

A

measure visual acuity

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27
Q

record visual acuity ____________ then ___________ ______ and ___________ aid

A

record visual acuity monocularly then binocularly with and without aid

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28
Q

where is it best to start testing va’s

A

a close distances and then modify

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29
Q

what must you never resort to when measuring va’s and why

A

contain fingers

because if the px can read 6/60 at 1m then they can definitely see counting fingers at 1m, so don’t resort to it

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30
Q

give an example of how precisely va should be recorded

A

3/60 instead of

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31
Q

if a lv patient does not have a previous va history, how must you start

A

start at 3 metres as this is a positive start and the patient is most likely to read

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32
Q

when measuring near vision on your lv px, what 2 things must you do/record

A
  • distance at which near vision assessment was made

- measure reading speed if possible

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33
Q

why must you measure the distance at which near vision assessment was made

A

because for example, N40 at 40cm can be different to N40 at 20cm
so must record working distance

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34
Q

what must you make sure of when measuring near vision of your lv px

A

that field of illumination is uniform and glare free

reading charts should not be laminated

35
Q

give an example of how you will record distance VA unaided

A

if px wears glasses then record their unaided va’s with glasses
RE: 3/60 LE: 2/60 BE: 3/60

36
Q

give an example of how you will record distance VA with an lv aid

A

distance va with (Eschenbach telescope, 6x) used with RE

RE: 6/9

37
Q

give an example of how you will record near VA unaided

A
Near va (reading glasses)/MNREAD charts 
RE: N36 LE: N36 BE: N36@ 40cm
38
Q

give an example of how you will record near VA with an lv aid

A

near va with (Eschenbach HM, 6x)

N6 at 12cm

39
Q

after measuring visual acuity, what is the next step to your lv assessment

A

determine refractive error

40
Q

when may you observe a dull reflex on your lv px during retinoscopy and what will you need to do

A

if the px has cataract

you need to move closer

41
Q

what can you do in difficult cases of retinoscopy when you can see the reflex at all

A

use old glasses as a guide, but be careful

42
Q

why is it a good idea to use a trial frame and full aperture lenses when determining refractive correction on your lc px

A

it is easier to see their facial expressions while testing, which you can’t with a phoropter

43
Q

what can you use for high refractive errors whilst determining your refractive correction

A

Harlberg clips
where you refract over the patients glasses
used if can’t see ret reflex and want an idea of px’s rx and then do subjective that way

44
Q

what steps of spheres and cross cyls should you use when refining your rx when determining the refractive correction of your lv px

A

+/- 2DS spheres
+/-1DC JCC

px has low va’s so can’t appreciate small steps

45
Q

how and when will you check the binocular status of your lv px when determining they refractive correction

A
  • by doing CT or EOM if required

- only check if px has diplopia or you see a squint, as VI px will usually have one very bad eye

46
Q

what must you remember to take into account when prescribing

A

the working distance used for subjective acceptance. it is important if the px’s working distance is 3m or less

47
Q

what must be in place in order to determine near acuity on your lv px

A

distance correction and appropriate addition

48
Q

what add should you always check with for what a px can read when determining a lv px’s near vision and at what distance should this be

A

+4.00D add at 25cm

49
Q

what type of near chart us best to use on your lv px when checking their near acuity and why

A

a word chart

because the px can guess the next word in the sentence and this is not a good estimation of near va

50
Q

as well as near acuity, what else must you record when measuring near vision

A

record what type of illumination was preferred

51
Q

name 2 additional tests you can carry out after determining the refractive error of your lv px

A
  • visual field test: area of distortion/defect

- contrast sensitivity: if you feel theres a need to that

52
Q

which three things can you use to measure visual fields on your lv px

A
  • amsler grid: for central vf
  • arc perimeter
  • tangent screen
53
Q

what 2 things do 10-20% of lv patients only need

A

a good refraction and advice on lighting

so don’t need a full lv examination

54
Q

what is required in va of an lv px to appreciate subjective improvement

A

an increase of at least 2 lines

so only change glasses if theres that much of an difference

55
Q

what may not all lv px’s benefit with

A

an LVA

they may need sensory substitution e.g. braille or convert text to speech

56
Q

what must you need to determine when prescribing magnification

A

whether monocular or binocular correction would be preferable

57
Q

how is magnification for distance calculated

A

mag = required va/present va
e.g.
required va = 6/6 (to watch tv)
present va = 6/18

mag = (6/6) / (6/18) = 3x…..18/6 = 3x (dist lv aid)

58
Q

how is magnification for distance calculated using a LogMAR chart

A
magnification = (1.25)n 
n = number of steps 
e.g.
required va = 0.1 
present va = 0.5 

mag required = (1.25)4 = 2.5x
n = 4 steps

59
Q

what is the rule of thumb when predicting near magnification from distance vision

A

always divide by 3
e.g.
if distance va = 6/18 then near va = 18/3 = N6

but it is better not to predict near vision from distance vision

60
Q

what are three disadvantages to predicting near magnification from distance va

A
  • crowding effects with words (as with distance va you’re measuring isolated letters on a chart)
  • increased va with sentences (can guess whats coming up next)
  • cataracts (e.g. nuclear sclerosis makes px more myopic, bad dv but good nv, so can’t use the divided by 3 rule)
61
Q

at what distance should you measure patients current near va

A

25cm

62
Q

how do you use the LogMAR chart to measure a patients near magnification

A

same as for distance mag

magnification = (1.25)n 
n = number of steps 
e.g.
required va = 0.1 
present va = 0.5 at 25cm  

mag required = (1.25)4 = 2.5x
n = 4 steps

63
Q

how do you use N notation to measure a patients near magnification

A

magnification = present va/required va

present va = N16 @ 25cm
required va = N8 @ 25cm

magnification = 16/8 = 2x

64
Q

what are the 2 ways to calculate near magnification

A
  • LogMAR chart

- N notation

65
Q

what will a lv px require for each task that they wish to perform

A

a separate lv aid

66
Q

what will a lv patients ability to read for leisure depend on

A

their acuity and contrast reserve

67
Q

what type of magnifier is available for distance tasks

A

telescope: monocular or binocular

68
Q

what 4 types of magnifiers are available for near tasks

A
  • spectacle mounted magnifier
  • hand magnifier
  • stand magnifier
  • near vision telescope
69
Q

when trialling a predicted magnification, what should you assess

A

the patients visual acuity with the selected aid

70
Q

what should you increase or decrease the magnification go the aid depending on

A

the acuity achieved and task requirement

always give minimal magnification that gives you best acuity

71
Q

which rx does a distance telescope need to be used with

A

distance rx

72
Q

which rx does a hand magnifier need to be used with and why

A

distance rx

as the rays of light leaving the HM are parallel so the patient does not accommodate when using this aid

73
Q

which rx does a stand magnifier need to be used with and why

A

near rx
as the rays of light diverge, the px needs the rays of light to converge, whereas older patients can’t accommodate so they need a near rx

74
Q

what can you do with a lv aid if its under the nhs

A

loan the aid for home trial

75
Q

what must you mention when explaining to the patient how to use the lv aid

A
  • which rx the aid should be used with

- how to clean the aid and charge the batteries if required

76
Q

what is the next step after dispensing a lv aid

A

a follow up visit

77
Q

after how long is a follow up visit after dispensing a lv aid

A

usually 3 weeks (to check that they know how to use the LVA)

78
Q

after the first 3 weeks visit of dispensing a lv aid, how often should subsequent visits be

A

either yearly or whenever the patient experiences difficulties

79
Q

name 3 reasons why an lv aid may not be successful at a follow up visit

A
  • deterioration in va 9 (e.g. wet AMD)
  • aid is used incorrectly e.g. too far away from the eye or inappropriate lighting
  • using the aid for a different task than what is was intended for
80
Q

what should you do with the LVA if it isn’t successful due to deterioration in va

A

select a different possible stronger aid

81
Q

what should you do with the LVA if it isn’t successful due to the aid being used incorrectly

A

give appropriate training/advice

82
Q

what should you do with the LVA if it isn’t successful due to using the aid for a different task than what it was intended for

A

explain the intended use of the aid

83
Q

what 4 final things should you do upon completing the lv assessment visit

A
  • give patient the contact details of the practice and encourage the patient to call if a problem arises
  • encourage the patient to implement practical tips that were suggested e.g. the use of felt tip pens etc
  • give the px useful contacts such as: RNIB, macular degeneration society, social services department
  • report to the: GP/optometrist/ophthalmologist where appropriate