Pediatric eye and vision

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Pediatric Eye And VisionExamination

شکرالله شفائی کارشناس ارشد اپتومتری

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Pediatric population can be divided into three subcategories: (Press LJ, Moore BD.1993)

■ Infants and toddlers (birth to 2 years, 11 months)

■ Preschool children (3 years to 5 years, 11 months)

■ School-age children (6 to 18 years).

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Patient AgeAsymptomatic/ At-risk

Patient Age risk-freeAt-risk

Birth to 24 months

At 6 months of ageAt 6 months of age or as recommended

2 to 5 yrs.At 3 years of ageAt 3 years of age

or as recommended

6 to 18 yrs.Before first grade

and every 2 years

thereafter

Annually or as

recommended

Recommended Eye Examination Frequency for the Pediatric Patient (OPTOMETRIC CLINICAL PRACTICE GUIDELINE ; Mitchell M. Scheiman, 2002)

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A. Examination of Infants and Toddlers

1 .General Considerations - time of examination; morning visit

- types of examination; objective - fast but exact; age appropriate

2 .Early Detection and Prevention3 .Examination Sequence

a. Patient History

■Nature of the presenting problem, including chief complaint ■Visual and ocular history

■General health history, including prenatal, perinatal, and postnatal history and review of systems

■Family eye and medical histories ■Developmental history of the child.

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b. Visual Acuity

Assessment of visual acuity for infants and toddlers may include these procedures:

•Gross estimate of visual function at near •Fixation maintenance & preference tests

-10 prism diopter (PD) lens

•OKN •Preferential looking visual acuity test

•VEP

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pincer grasp to pick up cake decoration ( or raisin).

Candy beads at 40 cm = 20/285 ( Frenkel & Evans, 1980)

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lights on lights turned down.

Note marked retraction of the upper lids. indicating some visual function.

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Fixation maintenance test

■To test central & steady fixation

■Shine a light at uncovered eye

■Estimate the position of the light reflexes (or angle Kappa); displaced +0.5 mm nasally

■Any deviation = eccentric fixation

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Fixation preference test

■can be judged when obvious strabismus is present ■cover and uncover the fixing eye to force fixation to the

nonpreferred eye ■ observe the fixation pattern

- good vision in case of alternate fixation

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Teller cards

-pack of 16 cards

-from 38.0 to 0.32 cycles/cm

-test dist. 38 cm for infants , 55 cm for toddlers

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Spatial frequency paddles

-calibrated for a specific distance( 1 m)

-4 paddles and 6 different sp. fr. -hold the gray over one of sp. fr .

-separate the paddles and notice the fixation

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Preferential looking tests of visionKeeler/Teller cards for infants

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Normal levels of visionPreferential looking tests (Mayer et al, 1995)

1 month 24/400 – 20/1600

4 month 20/100 – 20/400

12 month 20/80 – 20/300

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Vertical optokinetic nystagmus testing using an OKNdrum. If a vertical nystagmus can be elicited, vision is 20/400 or better.

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vestibular-ocular reflex, which stimulates the semicircular canals, causing the eyes to deviate in the direction of rotation.

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The early decreased visual acuity in the infant is due to:

1 -foveal cone immaturities; small and stumpy - at 4 years, the length of an adult cone

- at 3.5 – 4 years, adult level of cone density

2 -cortical immaturities

3 -incomplete myelination of the optic pathways

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Cardiff acuity cards for toddlers; vanishing optotype

■in children from 1 to 3 years of age■ 11 sets of cards are available ; 20/400 to 20/20

■ test dis. 0.5 m and 1.0 m

■ present one set of cards and notice the fixation

■ better done binocularly first( Adoh and Woodhouse,1994)

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Cardiff acuity test (Monocular; Adoh & Woodhouse 1994)

12-18 months(20/50-20/120) +0.4 to +0.8 L.MAR

18 -24 months( 20/25- 20/100)+0.1 to +0.7 L.MAR

24-30 months( 20/25-20/60) +0.1 to +0.5 L.MAR

30-36 months(20/20-20/40)+0.0 to +0.3 LMAR

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c. Refraction

Traditional subjective procedures , ineffective with infants or toddlers because of short attention span and poor fixation. (Ciner EB, 1990)

The two most commonly used procedures are:

■Cycloplegic retinoscopy

■ Near retinoscopy

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Take several precautions: (Gray L. 1979)

• Select the cycloplegic agent carefully (e.g., an increased response to drugs in fair-skinned children with blue eyes and more frequent or stronger dosages in darkly pigmented children ).

• Avoid overdosage (e.g., children with Down syndrome, cerebral palsy, trisomy 13 and 18, and other central nervous system disorders in whom there may be an increased reaction to cycloplegic agents, 1% tropicamide may be used).

• Be aware of biologic variations in children (e.g., low weight infants may require a modified dosage).

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Cyclopentolate hydrochloride , the cycloplegic agent of choice

One drop , twice, 5 minutes apart, in each eye , - 0.5% for children from birth to 1 year

- 1% for older children. (Amos JF, 2001)

Spray administration of the drug , a viable alternative. (Amos JF,

2001) )1 (The child has less of an avoidance response

)2 (A single application can achieve both cycloplegia and pupillary dilation )3 (a mixture of 0.5% cyclopentolate, 0.5% tropicamide, and 2.5% phenylephrine is used.

Retinoscopy may be performed 20-30 minutes after instillation. (Bartlett JD, 1993 )

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Near retinoscopy

May have some clinical value in the following situations:

• When frequent followup is necessary

• When the child is extremely anxious about instillation of cycloplegic agents

• When the child has had or is at risk for an adverse reaction to cyclopentolate or tropicamide.

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■ Near retinoscopy , an alternative to cycloplegic refraction in children and infants (Mohindra 1977) .

■A dim retinoscope light is used as a fixation target and seen in complete darkness and perform retinoscopy using a lens rack or individual trial case lenses .

■Working at 50 cm, -1.25 DS rather than the standard -2.00 DS is added to the final retinoscopy result .(Mohindra 1977).

■The test is comparable to cycloplegic retinoscopy (e.g. Saunders & Westall1992).

■Add - 0.75 DS for infants (2 years) ; -1.00 DS for children (over 2 years) rather than the original 1.25 DS. (Saunders & Westall (1992)

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REFLEX SCANING To get a quick idea of the prescription in both eyes,

)Lynne Speedwell, 2007(

-hold a pair of +2.00DS trial lenses in front of the child’s eyes in a

darkened room.

-With the child fixing on the retinoscope light at 50 cm,

quickly move the retinoscope horizontally and then vertically

across both eyes.

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Refractive Error

Green line – cycloplegic refraction on infants (0-6mths)

Blue line – non-cycloplegic refraction on infants (0-6mths)

Red line – Refraction in older children

-6 -4 -2 0 2 4 6 8

0

10

20

30

40

50

60

70

80

Fre

qu

en

cy

(%

)

Spherical Equivalent (Dioptres) Adapted from Gwiazda et al 1993

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d. Binocular Vision and Ocular Motility

•Observation

•Hirschberg test

•Krimsky test

•Brückner test

•Cover test

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1 -General observation

■size of head

■ IPD

■ nose bridge

■ lid asymmetries

■ pupil or orbit position

■ epicanthal folds

lid asymmetries

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2 -Hirschberg test

■ fixate your penlight at 50 cm

■ +0.5 mm ( nasal displacement of reflex)

■ note any asymmetric displacement

■ 1mm = 22 pd( Eskridge et al, 1988)

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)A (The light reflection in the deviated right eye is temporal to the pupillary

center .

)B (Using a prism, the Krimsky test measures the amplitude of the esotropia by centering the light reflection in the right pupil.

3 -Krimsky test

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4 -Brückner test

■ fixate an ophthalmoscope light at one meter

■ illuminate both eyes at the same time

■observe the relative whiteness & brightness of each pupillary reflex

■strabismus in case of whiter & brighter reflex

■it can help in the diagnosis of small angle strabismus (Miller et al. 1995)

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5 -Cover test

-Targets; brightly colored with sound & fine detail -Use your thumb to avoid

distraction -For distance, moving targets

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Binocular vision testing

■ intermittent esotropia should stop by the age of two months ■ exotropia by six months (Sondhi et al, 1988).

There are three types of prism test that are useful on young

children:

1 -The 20Δ base out prism test

2 -A 20Δ base in lens

3 -A 10Δ base down

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1 -The 20Δ base OUT prism test

■Assesses motor fusion and gross binocular function , not ideal for amblyopia assessment.

■The child fixes a toy and a 20Δ base OUT lens is placed in front of one eye.

■Both eyes should move in the direction of the prism apex and then the eye not being covered by the prism should be seen to

refixate to the centre .

■If no refixation movement is seen with one eye, it is likely that there is only weak fusion, suggesting one eye has poorer vision.

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The 20 Δ base out test. A- fixation toy is used as a target and corrective eye B - movements are observed in response to a 20 diopters base out prism challenge.

A B

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2 .A 20Δ base IN lens

■will assess fixation preference and will therefore demonstrate amblyopia.

■The prism is held in front of first one eye then the other, whilst the child fixes a light .

■The eye underneath the prism should move outwards (in the direction of the prism apex).

■If the eye under the prism is amblyopic, it will not move when the prism is placed in front of it .

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A B

A 20Δ base IN lens test

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3 .10Δ base DOWN

-In front of each eye in turn

-The upward vertical movement is easy for the observer to see.

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e. Ocular Health Assessment and Systemic Health Screening

An evaluation of ocular health may include:

•Evaluation of the ocular anterior segment and adnexa

•Evaluation of the ocular posterior segment

•Assessment of pupillary responses

•Visual field screening (confrontation).

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Testing visual fields in a young child. Begin by attractingthe child’s attention

straight ahead (top) .

Then move an object in from the side. A head movement to the side of the target (bottom) indicatesintact peripheral field.

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B. Examination of Preschool Children

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b. Visual Acuity •Lea Symbols chart

•Broken Wheel acuity cards

•HOTV test.

•Allen chart

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The LH or Lea Cards

■make use of a logMAR scoring system and produce accurate results

■available in linear and single optotype formats and use shapes instead of letters

■at a dist. of 10 ft to 20 ft

Lea optotypes

A Lea symbol presented in a 'crowded box'

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Broken Wheel acuity cards

-best for testing 3 year olds( McDonald and Chaudry, 1989)

-a set of 7 matched pairs of cards -20/20 to 20/100, held at 10 ft.

-should point to the car with broken wheels -if the child gets 4 of 4, go to the smaller sets

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Kay picture cards

Having vision checked using the crowded 3 meter LogMAR

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HOTV test

-for children , 21/2 to 5 yrs. of age. -no verbal response

-just point to the appropriate letter -at a dist. of 3 m.

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The Allen Preschool Vision Test

ALLEN CARDS -7 optotypes for 2.5 to 5 yrs. of age

-20/30 , 20/40 ,20/50,20/70 ,20/100 ,20/200 -ask the child to call off the name of the pictures he see

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Expected levels of vision

Age Vision

Neonate 6/300

1 month 6/200 – 6/90

3 months 6/60 – 6/36

6 months 6/60 – 6/36

9 months 6/36 – 6/24

1 year 6/24 – 6/12

2 years 6/12 – 6/9

3 years 6/9 – 6/6

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c. Refraction

•Static retinoscopy

•Cycloplegic retinoscopy.

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Cyclopentolate (1%) is the cycloplegic agent of choice. Two drops should be instilled, one at a time, 5 minutes apart, in each eye.

(Bartlett JD , 2001)

The use of a spray bottle to administer the drug is also effective for this age group.

Retinoscopy may be performed with a lens rack or loose lenses 20-30 minutes after instillation.(Bartlett JD, 1993)

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d. Binocular Vision, Accommodation and Ocular Motility

•Cover test •Positive and negative fusional vergences (prism

bar/step vergence testing) •Near point of convergence (NPC)

•Stereopsis (Lang stereotest , Frisby tests) •Monocular estimation method (MEM) retinoscopy

•Versions.

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•Evaluation of the ocular posterior segment

•Color vision testing

•Assessment of pupillary responses


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C. Examination of School-Age Children

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b. Visual Acuity

LogMAR chart

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c. Refraction

•Static (distance) retinoscopy

•Cycloplegic retinoscopy

•Subjective refraction.

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d. Binocular Vision, Accommodation ,and Ocular Motility

•Cover test •Near point of convergence (NPC)

•Positive and negative fusional vergences, AC/A •Accommodative amplitude and facility,NRA,NPA •Monocular estimation method (MEM) retinoscopy

•Stereopsis (random dot stereopsis test) •Versions

- assessment of stability of fixation - saccadic function ,

- pursuit function

BV equipment

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Cover-uncover test

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Alternate cover test

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The near point of convergence (NPC) is performed with a 6/9 target on a fixation stick

NPC assessment

Fusional reserves assessment

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The negative/positive relative accommodation)NVA/PRA (is done in the phoropter with a 6/9 target

at 40cm

64Measuring the fusional reserves with a prism bar

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The monocular/binocular accommodative flippers (MAF/BAF) is performed with ±2D flippers and a 6/9 target on a fixation stick held at 40cm

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•Evaluation of the ocular posterior segment •Measurement of intraocular pressure

•Color vision testing •Assessment of pupillary responses


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Peripheral visual field assessment by confrontation

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Finger mimicking visual fields. The child is asked to show the same number of fingers as the examiner. These should be displayed quickly to avoid fixation artifact.

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Thank you

Health & Medicine

Pediatric eye and vision