Responses not impacted by significant uncorrected RE - Not an accurate measurement of VA - Partially facilitated by motion processing Persistent asymmetry of OKN = strab, ambylopia, unilateral cataract Infants normally develop temporally to nasal first.

Infants Flashcards by Sarah Duong

Purpose of infant exam

early intervention
ensure there are no gross irregularities/abnormalities (pathology: life/vision-threatening, RE outside of norms: amblyogenic factors)
ensure/encourage appropriate visual development for maximum fxn

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Which type of testing should we do first on infants?

Binocular testing - VAs

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Resistance to occlusion is a red flag for

Asymmetry

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Case history

Ocular hx (infant and fam)
Medical hx (infant and fam)
Meds/Allergies

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APGAR

Measured at 1 and 5 min after birth:
1 min - how well baby tolerated birthing process
5 min - how well baby is adapting to the environment

Max score of 2 in each category = overall max score of 10
Score <7 = difficulty adapting; may need immediate medical intervention

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F&F
Resistance to occlusion
ITT
Teller/Face Dot/Lea paddles
OKN
VEP

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Expected VAs

Newborn: 20/400-20/1200 binocularly
6 months: 20/50-20/200 binocularly; 20/80-20/300 monocularly
*same up until 12 months
30 months: 20/20-20/50 bino; 20/20-20/50 mono

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F&F

Measure of GROSS ACUITY only
Monocular
No sound
Only recommended when baby is unable to participate in more accurate testing

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Resistance to occlusion behaviors

Crying, pushing hand away
Problem w/ unoccluded eye

*NOT A TRUE MEASURE OF VA

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ITT/Vertical Prism test

Used w/ pts that have no apparent strabismus

*NOT A TRUE MEASURE OF VA - info on suppression/not a measure of alignment

Fixate on near target
Occlude if possible
10-15 PD BD - upward shift in unoccluded eye
Uncover occluded eye - observe response
- diplopia (ideal response) - eyes will move up and down to try and fixate
- no movement - prefers fixation w/ initially unoccluded eye (hypotropia in unoccluded eye or hypertrophic in occluded eye?)
- single movement to fixate w/ uncovered eye - prefers fixation w/ initially occluded eye

Perform w/ other eye occluded initially and compare symmetry response.
Ex: No movement OS when unoccluded = preferred fixation w/ OD
Occlude OD - single movement to fixate when unoccluded = preferred fixation w/ OD (confirms first test)

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Forced choice preferential looking:
Teller cards - cycles/cm, cycles/deg, Snellen Equivalent
Lea paddles - same
FDT/Richman - variable test distance; approximate Snellen equivalent

Stripes vs gray field of equal size/luminance

Movement of eyes/head toward pattern if detectable

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Lea paddles equation

Cycles/deg = test dist/55cm x cycle/cm
Snellen denom = 20 x 30/(cycles/deg)

Ex: 8 cycles/cm @100cm
100/55 x 8 = 14.55 cycles/deg
Snellen denom = 20 x (30/14.55) = 41.2
8 cycles/cm = 20/41

*Note: 20/20 ~16 cycles/cm ~30 cycles/deg

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OKN

Responses not impacted by significant uncorrected RE

Not an accurate measurement of VA
Partially facilitated by motion processing

Persistent asymmetry of OKN = strab, ambylopia, unilateral cataract

Infants normally develop temporally to nasal first.

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VEP

Capacity for ADULT LEVEL of VEP acuity develops in EARLY INFANCY

VEP = higher level of visual potential

Expected VEP acuity:
- 20/20 6-9mo
Vs
Preferential looking:
- 20/100 @6mo, 20/50 @1yr

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EOMs

Sound CAN be use (contrary to F&F)

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CVF

Central target (bell, light)
Bring SILENT target fr periphery until child notices

NPC

Corneal light reflex w/ light-up toy

TTN or eye drifts out

CT (alignment):

ITT/Vertical prism test - info on suppression, not alignment
Hirshberg
Krimsky
Bruckner

Hirschberg

Eval corneal light reflexes (binocular)
Transillumination at 50cm
Look for symmetrical reflexes (Normal = light reflex slightly nasal d/t angle kappa, +0.5mm = eyes slightly exo)

Hirschberg = bino
Angle kappa = mono
*measure both

1mm displacement ~22PD deviation

Hirschberg recording

Hirschberg: symmetrical, ortho, or +0.5mm OD/OS

Temporal displacement of light reflex = eso
Hirschberg: (-)

Krimsky

Used to neutralize deviation found w/ Hirschberg
Rough estimate of deviation (CT MORE ACCURATE)

Prism in front of non-deviating eye
Adjust prism until reflex of deviating eye matches previous position in non-deviating eye

Ex: light reflex temporal = eso
BO to neutralize
Hering’s law - other eye moves the same amt

Bruckner

DO set to +1.00
50cm to 1m
Observe both eye simultaneously and compare brightness of fundus reflexes

Normal: equal brightness
Different brightness: brighter eye = strab, more anisometropic, pathology (white pupil)

Recording:
Bruckner: OD=OS
OD brighter than OS

Accomodation

Unlikely able to perform

MEM may help

Color testing

Unlikely able to perform

Stereo (develops at 7 months)

``` Smile Stereo Pass test: Forced choice preferential looking Random dot pattern w/ face on one side *VA of at least 20/80 and no constant strab required Polarized glasses ``` ``` Random E: FCPL Control plate w/ 3D image d Test plates: blank vs E Polarized glasses ``` Lang: Recognition (must know shape); gross measurement No polarized glasses

Determining RE

Must be able to rely on OBJECTIVE measurement - Mohindra - Static retinoscopy (ret bars) - Cycloplegic ret

Mohindra

Non-cycloplegic Monocular Dark room Fixates dim ret at 50cm - Dim light viewed mono = poor stimulus for accom Correction factor is subtracted from neutralizing lens - corrects for tonic accom - estimation - looking for agreement w/ cycloplegic values - NOT the same as WD - 0.75 to -1.25 (usually -1.25) Good screening for high RE - If RE is high — CYCLOPLEGIC EXAM If prescribing, CHECK CYCLOPLEGIC RET to determine final Rx - infants have A LOT of accom - poor control - variability in dry ret expected

Static ret

Fixation on dist target | Difficult for infant; more successful w/ toddler

Cycloplegic ret

Cyclopentolate = DOC 0.5% <1 yo 1% >1 yo Complete - pt should fixate ret light (on-axis measurement) Incomplete - fixate on distant target

Cycloplegia infants

Greater accom power Reduced action of cycloplegic action at receptor site Difficulty admin drop Reduced reliability, high deg of astig, high prevalence of anisometropia reported

Why not atropine?

Most potent cycloplegic and mydriatic agent - higher incidence of systemic side effects - blind as a bat, red as a beet, hot as a hare, mad as a hatter Cyclo reveals 0.50 less hyperopia Atropine onset of action: 1-3 hours Cyclo: 45 mins *** You will NOT always prescribe what you find. NORMAL for infants to have small to moderate amts of RE and/or astig.

Refraction

Vergences

Unlikely

Near ret

Consider MEM

Ocular health: ant seg (angles), IOPs, post seg

Ant seg: penlight/Bluminator 20D and transillumination - magnification SLE for older child IOP: Finger touch (usually) Tono-pen Icare Angle eval — Shadow test Bigger shadow = bad Post seg: BIO, DO, PanOptic (MIO) EUA - ophthalmology

Dilation drops

Tropicamide (0.5% or 1%) or Cyclo (0.5%) Phenyl NOT recommended for children under 3 or kids w/ cardiovascular abnormalities (incr side effects)

If recommending glasses for infant, you should

Discuss frame styles: Miraflex Measure PD Set f/u May need to communicate w/ professionals/referring doctor - PT/OT req parental consent/record release