Optometric examination of children part 1 Flashcards
what age does majority of accommodative strabismus start to be noticed and what does this mean for us as a primary care advisor
- accommodative strabismus starts to be noticed around age of 18-30 months
- as a primary care advisor, we should be equipped to test children
list 4 things you should do before you begin a sight test on a child
- Smile!
- Say hello to the child and parent/carer/guardian
- Introduce yourself
- Observe appearance and visual behaviour:
Note obvious manifest deviation
Broad epicanthal folds
at what age can a child: Understand several short words Imitate sounds Speak 20 words or more Use short sentences Know name and gender Understand abstract words Sit alone Crawl Walk Touch object with forefinger Begin to knows colours
Understand several short words - 1 year Imitate sounds - 1 year Speak 20 words or more - 18 months Use short sentences - 2 years Know name and gender - 3 years Understand abstract words - 5 years Sit alone - 6 months Crawl - 8 months Walk - 12 months Touch object with forefinger - 10 months Begin to knows colours - 3 years
describe 3 things about how communication with a child 0-6 months usually is
- Non-verbal
Facial expressions - Tone of voice
Baby talk
Singing! - Child is held by parent/ guardian
describe 4 things about how communication with a child 6-18 months usually is
- Mainly non-verbal
- Talk to child
- Beware of stranger anxiety
- Child is held by parent/guardian
describe 6 things about how communication with a child 18-36 months is
- More verbally independent
- Some reliance on non-verbal
- Understand more words than they can speak
- Stranger anxiety
- Still prefers parents lap
- Do not like to sit still!
describe 3 things about how communication with a child 3-6 years is
- Learning to explore and be
- Can be very talkative
Understand most simple and some complex words - May prefer to sit alone
describe 5 things about how communication with a child 6-12 years is
- Address child
use more complex sentences but simple terms - Try to engage child
talk about favourite character, toys etc - Avoid babyish terms
- Involve child in discussions
Which eye shall I put the drops in first? - Fear failure, inferiority
describe 2 things about how communications with a child 12+ years is
- Talk to the child directly
Treat them like a mini-adult
Involve them in decisions - May be aware of body image
Wearing spectacles
Cosmesis of deviations
what 3 main things does the optometric examination of children consist of
- History and symptoms
- Investigation
- Management
what 5 things are investigated in an optometric examination of children
- Visions/visual acuity
- Binocular vision assessment
- Refractive error
- Ocular health
- Colour vision
list 5 main things you will ask during history and symptoms and 4 things you will ask to identify risk factors
- Reason for visit
Routine
Specific problem - Observations of parents, family members, teachers
- Does visual behaviour seem normal?
- Allergies
- General health
To identify risk factors:
- Birth history
- Developmental history
- Family ocular history of refractive error
- Family ocular history of strabismus
if a parent reports that they can see a turn in their child’s eye, list all the follow up questions you will ask and what each answer can entail
Does one or both of the eyes appear to turn in/out/up/down?
Which eye affected?
Same eye, amblyopia likely
Alternating, amblyopia unlikely
Duration of deviation
Early onset, most likely non-accommodative, surgery probably required
Late onset, most likely accommodative, surgery probably not required
Frequency of deviation
Intermittent, some BSV present
Constant, no BSV present
when does sensory and motor fusion develop and what can this mean in your investigation
Sensory and motor fusion develop between the ages of 3 to 6 months therefore an intermittent manifest deviation is not uncommon before this age
Reassure the patient
what 4 questions will you ask about birth history
- FTDN (full term delivery normal)
- Low birth weight (2.5kg, 5lb 8oz)
- premature birth
- problems in utero or on delivery
what 2 questions will you ask about developmental history
- Normal developmental milestones achieved
- Sitting up, walking, talking
what will you ask about family ocular history of refractive error and why
- Spectacles at an early age
Genetic link for refractive error
Link between refractive error and development of strabismus
why is it important to ask about family ocular history of strabismus
- 30% children with strabismic parent will develop manifest deviation
- 73% of monozygotic twins will develop manifest deviation if other twin does
- Amblyopia (lazy eye)
why is it important to ask about allergies
- important for when putting in eye drops
- allergies to Elastoplast, as need to know if can do patting to treat amblyopia
list 2 ocular problems a child with cerebral palsy and downs’s syndrome may have and 2 ways to treat/manage this
Less likely to emmetroparise
Reduced accommodation
Don’t undercorrect hyperopic prescriptions
Consider bifocal correction
what ocular outcome can a child who has had a recent debilitating illness have
Decompensating latent deviation
what 4 things can a unexplained poor progress in school be due to
- Uncorrected refractive error
- Binocular vision problems
- Specific learning difficulties
- Other non-ocular non intellectual factors
what may you not use when testing visual acuity on children under 5 years old
a mirror
what type of visual acuity should you always try to do on a child and what clues can this give to you
- Try and do monocular acuity where possible
- Use palm of hand or special glasses to occlude
- Observe response to occlusion
Equal reaction?
If young child is objecting to occlusion always of one eye, it may mean that un-occluded eye is not seeing very good
list the four basic types of acuity measurement and what should you always try to go for and why
- Detection (minimum visible)
- Resolution (minimum resolvable)
- Recognition (minimum recognisable)
- Hyperacuity (minimum discriminable)
Go for the most complicated test for age of child to do to get most accurate results/refined visual acuity
which 2 tests can you do to measure vision/visual acuity on a 0-12 month old child and give disadvantages to each
Detection tests - Refer to smallest test object that can be detected
- Hundreds and thousands test
6/26 at 1/3m > 6 months
Used by health visitors
Caution – may fail test because of motor problem reducing fine hand movements - Steady, maintained fixation to light with one eye occluded
Less affected by visual impairment
May grossly overestimate vision
which test can you do to measure vision/visual acuity on a 0-12 month old child, give an example of what is used for this and list the steps of how the test is carried out
Resolution test - Measure smallest angular separation between adjacent targets that can be resolved
- Preferential looking (PL)
Infant looks towards a pattern rather than a blank stimulus
Square wave gratings (alternating black and white lines of equal thickness and length)
High spatial frequency = finer gratings
Stimulus is isoluminant to the grey background
Using: Keeler Acuity Cards
PL cards
Use at 38cm
Examiner is unaware of stimulus position
Judgements regarding position of stimulus based on eye movements
Look through peep hole
Two presentations of same stimulus correctly identified means child can resolve pattern
what is the expected vision/visual acuity found to be on children between 0-12 months with a resolution test using keeler acuity cards at: Birth 1 month 3 months 6 months 9 months 12 months
Birth 6/300 1 month 6/200 to 6/90 3 months 6/90 to 6/60 6 months 6/36 to 6/30 9 months 6/24 12 months 6/18
name another that is also based on spatial frequency, but is used to test vision/visual acuity on children aged 12-30 months and list the steps of how to use it, name a disadvantage to this test
Resolution test
Cardiff cards:
Optotype formed by alternate white and black bands
Used at either 50cm or 1m
Shorter working distance for younger children
Practitioner should not know position of optotype
Judge where child is looking
Want 2 correct identifications to ensure that child is seeing optotype
No crowding = overestimates the visual acuity
what is the expected vision/visual acuity found to be on children between 12-30 months with a resolution test using cardiff cards at: 12 months 18 months 24 months 36 months
12 months 6/18
18 months 6/12
24 months 6/12 to 6/9
36 months 6/9 to 6/6
which test can you do to measure vision/visual acuity on a 24-36 month old child, give an example of what is used for this and list the steps of how the test is carried out. what is a disadvantage to this test
Recognition test
Kay Picture Test: Single pictures Crowded at 3 or 6 meters matched or named
Tends to over estimate visual acuity in moderate to marked amblyopia
which test can you do to measure vision/visual acuity on a 3-4 year old child, give an example of what is used for this and list the steps of how the test is carried out
Recognition tests
Keeler LogMAR Crowded test:
Flip-chart measures acuity from 6/38 (0.80) to 6/3 (-0.30)
Used at 3 metres
Letters in regular logarithmic
progression
Screening and uncrowded sets also available
Comparable to LogMAR
Snellen acuity is written on back of card
If child doesn’t know letters, they can still do the test as they just have to match the cards up
what is the expected monocular vision/visual acuity found to be on children between 3-4 years old with a recognition test using Keeler LogMAR Crowded test at: 3 years 4 years 5 years 6 years 7 years
3 years +0.450 to -0.025 4 years +0.250 to -0.100 5 years +0.175 to -0.150 6 years +0.175 to -0.200 7 years +0.175 to -0.225
from which age is near visions tests carried out on a child and name 3 tests used to do this
- From 30 months (or when child’s at school ~5/6 yrs old)
- Kay (33cm)
- Lea symbols (40cm)
- Sonksen-Silver Sheridan Gardiner
list 6 types of tests you will carry out on a child in order to assess their binocular vision/functions
- Stereopsis
- Hirschberg test
- Cover test
- Motor fusion
- Motility
- Near point of convergence
what does the presence of stereopsis demonstrate and what does poor or none not necessarily demonstrate and after which age is stereopsis generally demonstrable
- Presence demonstrates good visual acuity and binocularity
- Poor or none does not necessarily mean poor vision or poor binocular function
Requires further careful assessment to establish cause - Demonstrable after 6 months of age
what 2 categories of stereopsis tests are there
- local
- global
for a local stereopsis test describe: the stimulus type what it requires what the test needs to be an example of this type of test
- Simple contoured disparity stimulus
- Requires less visual perception
- Tests need to be sensitive
- e.g. Titmus - requires spx
for a global stereopsis test describe: the stimulus type the absence of what it requires what its affected more by 2 examples of this type of test
- Random dot stereogram (RDS)
- Absence of monocularly visible contours
- Requires more visual perception
- Gross tests effective
- Affected more by strabismus
- TNO, Lang
name 2 stereo tests that do not require the child to wear glasses
Lang I and II
Frisby
how far are the Lang I and II stereo tests held
what 2 types of stimulus does it have
what should they not be used to measure
- Held at 40 cm
- Random dot stereogram and cylindrical gratings
- Should not be used to measure stereo thresholds
what 3 stereo results can a Lang I test measure up to and which types of children fail this test and how much % of them
- 1200”, 600”and 550”
- 0 – 36% strabismic children fail this test
what 3 stereo results can a Lang II test measure up to
what qualities does it have
which type of children is it better at detected over which and why
what are children most likely to miss on this test
- 600”, 400” and 200”
- Low sensitivity, high specificity, regardless of age
- Better at detecting strabismic than anisometropic amblyopia monocular clues
- Children are more likely to miss elephant
how does the frisby test present its objects
what are the 3 different plate thicknesses
how far is it held
what range of stereopsis does it measure
which type of children is it better to test on
how can you get monocular clues
what is the sensitivity like
- Presents objects viewed with “real” depth
- No spx required
- 6mm, 3mm and 1mm
- Held at near (~40cm)
- Measures stereopsis from 600’ to 15’
- Better for non-verbal children
- Monocular clues through parallax movements
- Low sensitivity – 17%
which type of test is the TNO what does it require at what age is it used from how many plates does it consist of what do the plates stand for and what level of stereopsis does it measure what is the TNO better at detecting what is its sensitivity and specificity
- RDS
- Requires wearing of red-green glasses
- Used after 30 months
- 7 plates
Plates I to 3 screening 2000”
Plates 4 Suppression
Plates 5 to 7 qualitative 480” to 15” - Better at detecting strabismic amblyopia
- Sensitivity = 47%
- Sensitivity 37%, specificity = 86% children age 3-6 years
which type of binocular vision test will you do on a little baby who doesn’t co-operate very well and explain how its done
Hirschberg Test - Corneal reflections - Pen torch at 33cm - Compare symmetry of corneal reflections 1mm = 20 △
what can a Hirschberg Test be refined by and how is it done
Refine with Krimsky test
as Hirschberg but prism placed before fixing eye to align corneal reflections
describe how you will perform a cover test/PCT on a chid to assess their binocular vision
- Use a small target requiring precise accommodation and fixation
Target on budgie stick
Toy in younger child
Anything that attracts attention - engage child in conversation about the target to maintain concentration - Occluder
Introduce the concept first
Frosted
Thumb
May be limited number of times you can perform this
- May only be possible at near in a young child
- At 6m and 1/3m viewing distance and at
- In distance exo deviations > 6m
- Effect of accommodation on deviation
using spot light as a target e.g. eso deviations - Perform with and without spx
compare effect of refractive correction on deviation
what test is used on children to test their motor fusion
what is it good for determining
what is it not ideal for
at what age is motor fusion not present in
- 20 ^ base-OUT test
- Assesses motor fusion and gross BSV
- Shows at least 20^ convergent prism fusion range at near
- Good for determining presence of BSV in uncooperative children
- Not ideal for amblyopia assessment
- Not present below age 4-6 months
- If not possible with 20^, use a smaller prism
list the steps of how a binocular visual assessment is carried out
- Child fixes on target e.g. toy and a 20^ base-OUT prism placed in front of one eye
- Eye behind prism converges (i.e. in direction of prism apex)
- Eye not behind the prism diverges (Hering’s law)
then converges to refixate - If no refixation, weak fusion likely. Suggests poor vision in one eye
at what age will a child develop smooth pursuit
how will you carry out a test on motility on a child
- Smooth pursuit age 3-5 months
- Arc around head ~50cm
Use illuminated toy
observe reflexes - Use cover test if anomalies suspected
Younger child can be rotated about practitioner - Childs head may need to be restrained gently
at what age does near point of convergence develop in a child
what results are expected
what difference does the results make with a non accommodative target
- Develops age 6 months
- Variety of targets advocated
- Break 6cm recovery 12cm with accommodative target
- Greater for a non- accommodative target
