General Clinical Strategy Flashcards
1
Q
What is the prevalence of strabismus and amblyopia?
A
- 8% of children have significant refractive error
- 2-4% have strabismus – eso more common in Scotland, high Caucasian population, high density of hyperopes
- 3-4% have amblyopia
2
Q
What are common concerns in children?
A
- Blurred vision
o Children often develop suppression – they don’t know what they should be seeing as they are used to it
o Could also be diplopia – determine is it fuzzy or is it two separate images? – they might not be able to tell - Eye related pain/discomfort
o Sore eyes – asthenopic sxs when reading – wouldn’t wake child wit it – tends to get worse as day goes on - Failed vision screening test
o <5years – every child is screened by orthoptist in nursery – vision, cover test & ocular motility (20prism dioptres) – exo, eso, height - Turned eye
- Eyes do not look healthy/normal
o Px may have one big eye – congenital glaucoma - Difficult with school work
o Accommodative problems, decompensating phoria they can control most of the time, convergence weakness – most children will not complain of a problem as they don’t know they’re different to everyone else - None
3
Q
What should be asked in a good history of a child?
A
- Taking a good history is cornerstone of a good binocular routine
- Establish a differential diagnosis
o If baby referred with suspected esotropia – they either have an esotropia or a pseudosquint – it can only be these two – it cannot be accommodative eso as under a year they cannot have developed that – it is not intermittent either - Aid investigation – determining most likely cause
- Since amblyopia & strabismus present at typical ages it is important to elicit details of onset & where possible the course of the condition
o Look for amblyopia first of all – if child squinting & always squinting then they will develop amblyopia – what is happening prohibiting them developing vision normally - Age of onset of symptoms (if any)
o How early did squint happen – develop squint younger then more damage can happen
o The younger you are the more development of vision – develop vision the minute you open your eyes until 8/9 and really tapers off at 5
Longer someone had a problem more serious that can be - Frequency of symptoms
- Time of occurrence of symptoms
- Speed of onset of symptoms
o Squints often happen gradually & start intermittently – something will be making it worse
Accommodative eso if worse when reading
Intermittent distance exo if parent notices it when child looks out window - Constancy of symptoms
o Constancy – started when tired or unwell but now happening all time – losing BV have to have 2 eyes aligned to have a properly developed system - General Health of px at time sxs first noticed
o Has px been unwell? – px may have hydrocephalus – their eso may be due to 6th nerve palsy – do they attend other clinics? – is this a well child who is meeting their milestones or are they unwell? - Any previous ocular investigations &/or tx
o Find out what has happened to this px in past
4
Q
What symptoms may a child have? Which questions would you ask?
A
- Diplopia:
o Horizontal/vertical etc or both
o When does it occur – is it worse when reading, worse when looking in distance?
o Can you make things single?
If yest then they have some binocular control
o Does anything make it better or worse?
Is it worse at end of day?
Is it worse when reading?
Is it worse when watching TV?
o MONOCULAR or BINOCULAR is it one eye or both eyes? – if monocular more likely they are developing cataract – if still double with one eye then that is NOT a BV problem - Awareness:
o Deviation i.e. XOT
Look for info from parent – which eye, is it always one eye, does it swap?
Squint is singular – if child is swapping a squint then this is a good sign as then vision must be roughly equal
If it is always one eye then they are not developing vision in that squinting eye (BAD!) - Pain:
o On motility
o Convergence
Ask about frontal headaches, asthenopia – uncomfortable doing visual tasks - Headaches:
o When, where, nausea, aura
If woken by headaches then less likely to be visual – if HA gets worse throughout day then more likely to be eyes – ask about FGH of migraine etc
Nausea & aura – migraine more likely
Look for papilloedema – if have esotropia & headache then swollen disc – blue light to hop for scan
o Aversion of close work - Blurred Vision:
o Subjective or behavioural
Children make up that they cannot see – can they really not see?
1st test is stereopsis – if they can pick out the ball on Frisby then they must be able to see so need to find other ways to test it
o 1st noticed
o How often/when does it occur
o How it affects px/how severe
o Is it changing/better or worse
o Associated signs or symptoms - Asthenopia:
o Eye strain, sore/red eyes px with dry eye may talk about these sxs
5
Q
Describe age of onset - critical period - restoration of BV?
A
- Critical Period – restoration of binocular vision
o Onset of strabismus at birth
o Poor prognosis for development of binocularity
o Tx must be within first two years
o Critical period is 0-3 years
Most visual development
If find a problem – more serious – if get earlier then can fix it
Once a squint is there its generally there for future & only way to dix is prescribing refractive correction then looking at surgery
Congenital cataract – one eye with no light going through eye to hit visual cortex – NEED to have surgery within first 6 weeks of eye then have contact lens on that eye with patching of good eye – patching for an hour per month of their life – 4month wears for 4 hours - Stimulus deprivation amblyopia – if light can’t get to back of eye due to media opacities for e.g.
Younger you are the faster you vision is developing
Most children without vision in one eye are likely to develop an eso as this is secondary to visual loss
6
Q
Describe age of onset - critical period - restoration of VA?
A
- Critical period – restoration of visual acuity
o Earlier the deprivation the more severe the visual loss
If eyes aren’t aligned then brain will not work with both eyes – only works with the straight eye and cuts off all signal to non-straight eye
Earlier you develop a squint the worse the binocularity & vision
Grandmothers will tell you the child is squinting!
o Susceptibility to the development of amblyopia up to 8-9 years
Certain types of amblyopia can be corrected until 11 or 12
If have squint can’t patch past 7-8 – if anisometropic & don’t have a squint then can patch little longer
o Earlier the treatment the better the prognosis
7
Q
If a child starts squinting over 2 years old, what are they most likely to have?
A
Start squinting over 2 then more likely to be accommodative esotropia – objects start to get more detailed for 2yo
Accommodative eso – hyperopic child (small eyes) – most children born hyperopic
If emmetropisation doesn’t develop normally then may have amblyopia, anisometropia
Most children develop a squint gradually – more alarming if squint happened very quickly
If constant, that is worse than being intermittent – they are developing systems such as suppression & can’t fix this in the brain – if they still have diplopia then they still have use of both eyes & that can be fixed
8
Q
What is suppression and what age does it happen?
A
Suppression is cortical inhibition of image coming from squinting eye (response when child is under 8)
When child develops a squint – they get diplopia but this may only last hours or days before suppression kicks in
Diplopia then confusion (don’t know which eye to look from) then suppression
9
Q
Which questions would you ask in a child who is squinting or suspected to be squinting?
A
Who noticed first?
Why?
Time of day?
Which eye?
Direction?
Position?
Any other defect/symptoms?
look for ptosis, coloboma, head posture(cong 4th)
10
Q
Questions to ask about a child to get idea of VA level?
A
- Is child aware of themselves in a mirror? If so at what distance?
- Is your child aware of a spoonful of food approaching?
- Does your child return a silent smile?
- Does your child reach for a drink?
- Does child follow your movements around room when you given no sound clues?
o NB an acuity of at least 6/60 is required to maintain central steady fixation
11
Q
Describe frequency of symptoms in a child who is suspected to be squinting?
A
- Will help to establish severity of condition
o More frequent – getting worse, losing control of 2 eyes working together - Do symptoms disrupt pxs daily life
o Depends on px – depends on their hobbies – if they do lot of close work then they may be very affected by convergence weakness - Severe & annoying usually suggest recent onset
- Incomitancy? – rule out systemic conditions
o Concomitancy – deviation is same in every direction of gaze
o Incomitancy – deviation changes in different positions of gaze - Decompensating heterophoria important to consider previous tx, general illness, fatigue stress or an increase in workload
o Don’t go from having no latent deviation to having a tropia
o Need adequate fusional reserves to keep eyes working together, not allowing eyes to keep usion – most have tropia as don’t have enough fusion to keep image single - Usually exophoria – most people in adult life
o Children – more likely to be eso as generally hyperopes
12
Q
Describe time of occurrence in a child who is suspected to be squinting?
A
- In young children sxs often occur after close work – pay particular attention to near response
o After close work – related to accommodation – if accommodating too much (as hyperope does) then more likely to squint at near
o If squint only happening in distance or far distance then more likely thinking exophoria - Divergence excess look out for intermittent asthenopia & photophobia for distance fixation (TV, driving)
- Viewing distance may be required at full 6m or more
o If need to get child into corridor and look right down corridor to test far distance – 3m test room not always enough
13
Q
Describe speed of occurrence in a child who is suspected to be squinting?
A
- Diplopia with sudden & recent onset deserves very careful examination
o Sudden onset squint at any age – alarmed
o Gradual onset – more relaxed - Symptoms should always be evaluated with other signs
- Raised ICP can also cause sudden strabismus & is often associated with vision loss – history of headache/nausea, malaise
14
Q
Describe constancy of symptoms in a child who is suspected to be squinting?
A
- Diplopia with sudden & recent onset deserves very careful examination
o Sudden onset squint at any age – alarmed
o Gradual onset – more relaxed - Symptoms should always be evaluated with other signs
- Raised ICP can also cause sudden strabismus & is often associated with vision loss – history of headache/nausea, malaise
15
Q
What questions should you ask about general health in a child?
A
- Some special forms of squint are associated with congenital defects (DRS deafness brevicollous)
- Include maternal during pregnancy
- General development:
o Progress with developmental milestones – compared with norms & older siblings - Birth history:
o Difficult forceps delivery may cause congenital paralytic squint
o Prematurity (low birth weight, perinatal hypoxia) is associated with higher incidence of squint, nystagmus & refractive error (40%)
Retinopathy of Prematurity (RoP) – too much oxygenation in neonatal unit – too many vessels growing that shouldn’t be there – abnormal vessel growth that need lasered or cryo-ed off
Was baby normal weight? Normal gestation period? Cord round neck – less oxygen at birth (may have cerebral palsy)
o Similarly infants with developmental delays & cerebral palsy are likely to experience abnormal visual development as are full-term babies whose mothers smoke, abuse alcohol or drugs
Nystagmus big problem if mother was methodone user
o Is baby a twin? – if one is squinting then likely other is too - Attributed Cause:
o Trauma can cause ocular muscle palsy – febrile illness (really high temp admitted to hosp) can cause muscle weakness & can cause an intermittent deviation becoming constant & parent notices - Family History:
o Hyperopia is hereditary therefore accommodative squint runs in families negative test should review again
o A healthy infant with no strabismic relatives has approx.. 1% chance of developing strabismus
o If one parent or sibling has a strabismus the infants risk is about 15%
Parents with visual problems are very on it to get child screened
o Risk is greater than 20% for infants with two or more strabismic parents or siblings
o Less common retinal disorders, congenital cataract are associated with positive family history
