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Clinical and professional practice > Optometric examination of cataract/examining specific groups of patients > Flashcards

Optometric examination of cataract/examining specific groups of patients Flashcards

1
Q

which 4 ways can you detect someone had a cataract in your eye examination

A
  • H and S
  • slit lamp
  • VA’s
  • retinoscopy/direct ophthalmoscopy
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2
Q

which type of slit lamp techniques allows you to detect a cataract

A
  • retroillumination

- lens section

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3
Q
  • how does a cataract show up in retroillumination on slit lamp and where do you need to look when doing this
A
  • Shows up black against orange/red fundus background

- Look behind iris

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4
Q

what are the 3 main types of cataract that you will detect in practice

A
  • cortical/cuniform
  • posterior sub capsular
  • nuclear sclerosis
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5
Q

list the 4 steps you need to do to detect a cataract on slit lamp with lens section
what is the advantage of using this technique
what is the disadvantage of using this technique

A
  • Very narrow beam
  • Very bright beam
  • Reduce height of beam to fill pupil
  • Narrow angle between the illumination and observation systems and move microscope towards patient to look at more posterior portion of lens
  • Allows depth of opacity to be assessed
  • But it is difficult to view lens behind iris
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6
Q

what does a lens section allow when viewing a nuclear sclerosis cataract

A

allows opacity and colour of the lens nucleus to be assessed

(opacity is usually described as something white, so describe the types of findings)

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7
Q

list 3 things you can do when doing retinoscopy on a patient with a cataract

A
  • Work closer than normal if the reflex is dim:
    • Note if you are working closer than normal
    • Make appropriate allowance for new working distance
  • Work off-axis if necessary
    • Note if you are working off-axis
    • May be easier to do ret post dilation as larger pupil allows to see the reflex
  • Note if reflex is poor or misleading
    • Central and spoke-like opacities can make the reflex very misleading
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8
Q

what 2 things do you need to make sure you do if you work closer than normal when doing ret on your cataract px because the reflex is dim

A
  • Note if you are working closer than normal

- Make appropriate allowance for new working distance

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9
Q

what do you need to make sure you do if you decide to work off axis during ret on a cataract px
and what can you do to make this easier

A
  • Note if you are working off-axis

- May be easier to do ret post dilation as larger pupil allows to see the reflex

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10
Q

what type of cataract opacity can make a ret reflex misleading

A

Central and spoke-like opacities

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11
Q

what 3 things can you do in your subjective refraction to help with a patient who has a cataract

A
  • Avoid the duochrome, because of preferential scattering of the short wavelength light - green light will always look blurrier than red
  • Use large dioptric intervals initially if VA is reduced
  • Use a pinhole, though it can be unreliable in some cases of cataract
    • Can pick out a tunnel of clear lens giving an acuity that cannot be achieved with the normal pupil diameter - gives less light scatter, improving VA
  • Moderate to severe cataract often results in very anomalous results when determining the near addition
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12
Q

what can a moderate to severe cataract result in with your subjective refraction results and hence whats best to do in this case

A
  • often results in very anomalous results when determining the near addition
  • best thing to look at previous glasses and take it from there
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13
Q

if the cataract is on the visual axis, what may you be able to improve and what may you not be able to improve

A
  • can improve DV
  • cannot improve NV

e.g. from a posterior sub capsular cataract

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14
Q

what 3 other tests/measurements must you carry on a cataract px to ensure that no other eye disease is ignored

A
  • Visual fields are particularly important
  • Most cataract patients are old and at greater risk of POAG, so IOPs should be taken
  • Motion detection is very insensitive to media opacities
    e.g. Moorfields Motion Displacement Threshold (MDT) test
    This is a test of hyperacuity (as is Vernier acuity)
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15
Q

how is a Moorfields Motion Displacement Threshold (MDT) test carried out on a patient with cataracts

A
  • The patient is asked to look at a central spot and to press the computer mouse each time a line on the screen is seen to move
  • The threshold is recorded as the minimum detectable displacement, which is measured in minutes of arc
  • Motion displacement sensitivity is greater than predicted from retinal ganglion cell spacing and therefore falls into the category of hyperacuity
  • The MDT test is insensitive to blur - so doesnt matter is px doesnt have good va, as long as everything else is normal in the eye
  • The MMDT task is to discriminate the positional change between two lines and may be regarded as a temporal form of vernier acuity
  • In certain pathologies the px won’t be able to detect the misalignment of the 2 lines on top of one another
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16
Q

what results will you find on a cataract patient’s visual fields

A
  • Cataract leads to a diffuse loss in threshold sensitivity
  • The effect is greater in the central field
  • But, you should still be able to obtain a field plot, and it does give very useful information as to the integrity of the retina and the visual pathway
  • Some instruments, notably the Humphrey Field Analyser allow you to adjust the threshold values obtained to correct for diffuse loss caused by cataract
    This allows the detection of localised loss
  • General reduction in sensitivity: the total deviation plot shows a vf defect but just by looking at that, you dont know if the vf defect is just because of the cataract or something else. so you then look at the PSD because the instrument accounts for the fact that someone can have a cataract, so it filters that information out.
    in the PSD - the inferior defect underneath the cataract still remains
  • High MD
  • Low PSD / CPSD
  • Large numbers of significant points on Total Deviation Map
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17
Q

what else can a patient with a cataract complain of even if their VA is adequate

A

of severe visual disability - often the problem is disability glare caused by a reduction in contrast of the retinal image due to light scatter within the eye

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18
Q

how will you measure a cataract patients’ disability glare clinically

A

generally involves recording the difference between VA or CS under normal conditions and when hindered by a nearby bright light source
to see if the cataract is causing the problem e.g. a brightness acuity tester

19
Q

what does the Actions on Cataract – good practice guidance (2000 NHS Executive) state about when an optometrist should refer a patient with a cataract

A

when the following three criteria are met:

  • Visual acuity is reduced as a result of the cataract
  • Visual symptoms, as a result of the cataract, are impacting on the individual’s lifestyle
  • The affected individual is willing to undergo surgery to remove the cataract
20
Q

what are the 2 ways which you can refer a patient with cataract

A
  • Via the GP in the usual way
    or
  • As part of a cataract direct referral scheme
21
Q

what is required in a direct referral scheme for cataract
what is the typical fee for this
what must you still do if you choose this route and not the conventional GP route

A
  • Participating optometrists need to be accredited (attend a course etc)
  • “Proforma” which can specifically ask for information on VA, effects on lifestyle and willingness for surgery
  • Typical fee for referral ranges from £15 - £35
  • The GP must still be kept informed
22
Q

what was found about whether optoms provide all the required information when referring for cataract
and what does this mean for the direct referral scheme

A
  • all the accredited optoms on the direct referral scheme fulfilled the 3 points for referring
  • but normal optoms didn’t touch on every point e.g:
  • only 10% gave full information
  • only 11% referred based on cataract affecting va and lifestyle only
  • only 8% refered based on cataract affecting va and willingness for surgery only
  • only 72% referred based on cataract affecting visual acuity
  • so theres more benefit with the direct referral scheme as your sure your referring every px who has the 3 criteria
23
Q

assuming that a cataract px is willing to have surgery, what is the most important criterion to follow

A

Visual symptoms, as a result of the cataract, are impacting on the individual’s lifestyle
i.e. need to determine how much the patient is handicapped by the opacity

24
Q

what is a major factor in assessing the degree of handicap in a patient with a cataract
and what is a contradiction to this

A
  • Major factor in assessing the degree of handicap is the VA in the better eye
    so when referring, always look at VA of the better eye, as if their BVA is 6/6 and dont suffer from glare, then px may not yet want to be referred
  • However, different patients will experience more/less of a handicap as a result of a similar reduction in VA
25
Q

list 3 good questions that will help find out how much the patient’s desired lifestyle is affected by the cataract

A
  • Do you have any problems with glare or in bright sunlight?
  • Do you have any problems driving at night or on sunny days?
  • Ask about the effect of vision on the patient’s job, sporting interests or hobbies
    e. g. a truck driver compared to retired who don’t drive much
26
Q

other than visual acuity, glare and lifestyle factors affecting a patient with cataract, list 4 other factors that will influence whether you want to refer a px with cataract

A
  • Contrast sensitivity (may be reduced even is va is fine)
  • The likely improvement in visual performance (post surgery)
  • The patients age, general health
  • Presence of monocular diplopia
27
Q

how will you know the likelihood of improvement in visual performance before doing/referring for cataract surgery

A
  • By carrying out tests that are available to assess the integrity of the retinal and neural system behind cataract
    E.g. Ultrasonography, VEP and ERG
  • Hyperacuity tests hold great potential, and are more likely to be used by optometrists as they are insensitive to blur, if the px has large hyperacuity values, it suggests theres something wrong behind the eye and its not just the cataract causing the problem
    e. g. motion detection
28
Q

what will you say to a px who has a cataract

and what must you stress to the patient

A

“you have some cataract but most people over 60 (or everyone over the age of 80, etc) has some cataract. It is nothing for you to worry about at the moment. If it gets worse we can easily do something about it.”

Stress importance of regular eye examinations

29
Q

what is deaf the general term for
what is the prevalence for people over 70 and people over 50 yrs old
what is it mostly due to

A
  • General term for people with all degrees of hearing loss (c10m in UK)
  • 70% of people over 70 and 40% over 50 have some form of hearing loss
  • Most due to “presbyacusis”
30
Q

what type of hearing loss do people who are hard of hearing have
when do they tend to become hard of hearing

A
  • Mild to severe hearing loss

- Usually people who have lost hearing gradually (most likely age related)

31
Q

when do people who have become defended, become deaf

A

People who were born hearing and became severely or profoundly deaf after learning to speak

32
Q

what are the 4 classifications of deafness

A
  • mild deafness
  • moderate deafness
  • severe deafness
  • profound deafness
33
Q

when can mild deafness deaf people encounter hearing problems
what is the quietest sounds they can hear

A
  • It can cause some difficulty following speech, mainly in noisy situations. (but can function in most situations)
  • 25 to 39 decibels
34
Q

when can moderate deafness deaf people encounter hearing problems
what is the quietest sound that can hear

A
  • May havedifficulty following speech without a hearing aid.
  • 40 to 69 decibels
35
Q

what do people who are severely deaf rely on
what are the quietest sounds that they can hear
what may be there first or preferred language

A
  • Rely a lot on lip-reading, even with a hearing aid
  • 70 to 94 decibels
  • BSL (British Sign Language) may be their first or preferred language
36
Q

what is the quietest sound a px with profound deafness hear

what may be their preferred or first language and what may some patients prefer

A
  • Average 95 decibels or more

- BSL may be their first or preferred language but some prefer to lip-read

37
Q

what are the 2 types of profoundly deaf patients

A
  • People who are deafened (deaf with speech):
    Born with hearing and became profoundly deaf after learning to speak
    c150,000 aged 16 years and over in the UK
  • People who are deaf without speech
38
Q

how many people in the UK are born both visually and hearing impaired

A

more than 350,000

39
Q

what 6 things can you do to help when you examine a patient who is hard of hearing

A
  • Speak clearly
    Form your words properly and speak at a regular volume
    Don’t shout, for shouting distorts your voice and may make you sound angry
  • Move closer
  • Direct voice to “good” side
  • Ask px to switch on hearing aid
  • Write things down if necessary
  • Consider leaving out complicated tests e.g. fixation disparity
40
Q

what 6 things can you do to help when you examine a patient who is deafened - deaf with speech

A
  • Articulate well if they can lip read
  • Communicate through someone whose lips they can read
  • Communicate through someone who can sign
  • Learn to sign (BSL)
  • Write things down if necessary
  • Consider leaving out complicated tests
41
Q

what 5 things can you do to help when you examine a patient who is deaf without speech

A
  • Communication is often surprisingly easy as they have learned to cope with their communication problems
  • Communicate through someone who can sign
  • Learn to sign
  • Write instructions down if required
  • Consider leaving out complicated tests
42
Q

what 5 things can you do to help when you examine a patient with whom you do not share a common language with

A
  • Ideally use an interpreter
  • Keep instructions simple
  • Do not be too ambitious
    Tests such as fixation disparity and crossed cyls are unlikely to go smoothly and may be best ignored
  • Tumbling Es and/or Landolt Cs may be useful if Roman alphabet is unfamiliar to the patient
    or can use a chart with numbers
  • A library of foreign language newspapers is a useful asset
43
Q

what 3 things can you do to help when you examine a patient who has a learning disability
how many people in the UK suffer from a learning disability

A
  • Establish the extent of the disability as soon as possible
  • Gear routine around extent of patient’s disability
  • Have a third party in the consulting room
  • About 1.5 million people in the UK

Clinical and professional practice (16 decks)

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