Vision The Paediatricians perspective Dr Sneha Sadani Dr Gill Robinson

Normal vision Visual history Examining eyes Assessing Vision Abnormalities of eye movement Squint nystagmus

Normal vision development Newborns can see, VA 20/400 ( 20 feet= 6 m) –Fixate on lights, points of contrast Earliest response to formed visual stimulus- regard for mum’s face 2 weeks, sustained interest in large objects 8-10 weeks follows object through 180° Proper co ordination of eye movements + alignement-3 to 6 mo VA continues to improve –20/40 by 3 yrs –20/30 by 4 yrs –20/20 by 5-6 yrs

Newborns look at light source

Early weeks of life fix on human face

8-10 weeks follows object through 180°

3 months hand regard... And together in midline

Proper coordination of eye movements + alignment at 3 to 6 months

Seeing to play

12 months point at distant object

2 to 3 years 3 to 4 years 4 to 5 years

Visual History Do you have any concerns about eyes? Do you think she sees normally? Why/why not? Does she look at your face? Does she watch as you walk away? What sort of things can she see? Bits of fluff on the carpet Airplane high in the sky

Visual History Recognizing faces (not voices) Does she look at toys/pictures? Does she hold objects close to her eyes? Does she feel for objects? Have you seen either eye turning in or out? PMH Are there other disabilities? FH Is there a family history of eye problems?

Examination General –Dysmorphology, albinism –OFC –Look for head tilt and abnormal gaze which can be due to field defects or squint. Eyes – size, shape, symmetry –Lids, sclera, iris, pupil

Examination Ocular Motility (Abnormal eye movements) – at rest – tracking - following torch through horizontal and vertical axis. Alignment (Squint) – Corneal reflections in all positions of gaze – Cover test – more later

Examination Red reflex Ophthalmoscopy Visual fields – by confrontation Functional visual assessment Visual acuity test Colour vision testing

Visual acuity tests Age Birth 6 weeks 6 months 2 yrs 3 yrs 5 yrs + Test Face fixation & following, preferential looking (patterned objects) Optokinetic nystagmus demonstrated on looking at a moving striped target Reaches well for toys Identifies specific pictures of reducing size (Kays or crowded Kays) Letter matching using single letter charts Line of letters on Snellen / logmar chart by naming or matching

Functional visual assessment – older child What objects can a child identify near or in the distance Use books to observe the way the child looks at a picture – Do they hold books up close. What type of pictures can child identify near and in the distance. Note familiar objects and pictures will be recognized more readily than unfamiliar.

Red reflex

Squint / strabismus

Corneal light reflex test

Overt squint Cover the bad eye – nothing happens Cover the good eye – the bad eye moves in to take up fixation

Latent squint – don’t worry these don’t come to the exam

Amblyopia

Preferential looking Infants dislike boring visual stimuli You present a display to a baby, half of which is quite plain and the other have has some pattern to it, the baby will tend to look at the pattern Grating patterns of different widths An observer has to decide, based on their observation of the baby's head and eye movements, where the stimulus is located.

Kay pictures Verbal/matching abilities (2 years +) Single and Crowded format 12 equal step sizes

Crowded Kays Simple and quick – 3 years+ At 3m ask the child to read all the pictures in one vertical row down to smallest size. Can also use matching card Correlates to logamar and snellen screening pass criteria of (3/4.8 or 10/16 Snellen) instructions.

SnellenLogmar

Numerator- distance from chart i.e. 6m/20 feet Denominator – distance at which a person with good vision could read the last line that the patient is able to read logarithm of the minimum angle of resolution One feature seen on snellen LogMAR scale converts the geometric sequence of a traditional chart to a linear scale.

Comparison of Snellen and Logmar MetreLogMAR 6/ / / / / / / / / / / / Poorer than normal Normal Better than normal

Testing colour vision

Common problems 1 in 10 at risk from undiagnosed vision problems 1 in 30 children will be affected by amblyopia 1 in 25 will develop strabismus 1 in 33 will show significant refractive error such as nearsightedness, farsightedness and astigmatism 1 in 100 will exhibit evidence of eye disease – e.g. glaucoma 1 in 20,000 children have retinoblastoma

Strabismus

Causes of squint Paralytic Squint varies with position of gaze III, IV, VI Strabismus syndromes Non paralytic Squint present in all positions of gaze Genetic Refractive error Ocular abnormalities – cataract, neuroblastoma Normal until 3 months of age

III nerve palsy Usually congenital, ominous if acquired Superior, inferior and medial recti and inferior oblique Ptosis Double vision in all positions of gaze Pupil may be dilated and unresponsive

IV nerve palsy –Superior oblique –Vertical separation images –Worse looking down and in –Traumatic or congenital VI nerve Palsy – Lateral rectus – Horizontal diplopia worse on looking to the side of the lesion – Due to birth trauma

Nystagmus Involuntary rhythmic, conjugate oscillatory movements of one or both eyes Complex! Congenital –Pendular –Idiopathic motor Gaze evoked Vestibular – fast jerk in direction of lesion BEWARE ROVING EYE MOVEMENTS OF BLIND CHILD

Congenital Nystagmus Seen shortly after birth Binocular Similar amplitude both eyes Usually horizontal Abolished by sleep Genetic component inc albinism

What is the diagnosis? Name 3 causes What test would you like to do?

Ptosis – congential and acquired Congenital –Absence of levator palpebrae – beware vision –Mostly unilateral –May be familial and acquired causes of ptosis Acquired –3 rd nerve palsy – trauma, tumour, post meningitis –Myasthenia gravis

Tensilon test IV endrophonium chloride (infant 1mg - child 8mg) Photos before and after Dramatic improvement 1 min Lost by 5 mins

Visual Impairment -WHO definitions. These definitions are based on best corrected vision in the better eye. Normal vision6/18 or better (slight VI <6/9) Visual impairment6/18 – 6/30 Low vision<6/30 – 6/60 Severe VI/Blind<3/60 to no light perception (cannot count fingers at 3m) Or fields <10 ° around central fixation

Prevalence (/10,000 children) AgeJust VIVI +All Severe visual impairment and blindness in children in the UK, RahiJS, Cable N, The Lancet, 362,1359, 2003 In Leeds 260 children

Regardless of cause VI affects development

How does VI affect development? Self help

Mummy needs to move closer Mummy needs to move closer !

Communication Early bonding Socialisation Struggle with joint attention Struggle to change between tasks

Vocalisation 2 to 3 words – 19/12 cf 14/12 Name 2 objects – 2 years cf15/12

Behaviour / social interaction Struggle with joint attention Struggle to change between tasks Tendency to repetative play Echolalia Tantrums Resistance to change Sleep Severe VI 17-42% autism

Body awareness Hand awareness

We need mobility for movement and navigation Environment awareness

Concept development

We need vision to learn The text needs to be bigger!

Self help and independance

Examine Eyes General Eyes – size, shape, symmetry –Lids, sclera, iris, pupil Ocular Motility (Abnormal eye movements) – at rest / tracking Alignment (Squint) – Corneal reflections / Cover test Red reflex /Ophthalmoscopy Visual fields – by confrontation

Assess vision Functional visual assessment Visual acuity test Colour vision testing