Infants Flashcards
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
Which type of testing should we do first on infants?
Binocular testing - VAs
Resistance to occlusion is a red flag for
Asymmetry
Case history
Ocular hx (infant and fam) Medical hx (infant and fam) Meds/Allergies
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
VA
F&F Resistance to occlusion ITT Teller/Face Dot/Lea paddles OKN VEP
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
F&F
Measure of GROSS ACUITY only
Monocular
No sound
Only recommended when baby is unable to participate in more accurate testing
Resistance to occlusion behaviors
Crying, pushing hand away
Problem w/ unoccluded eye
*NOT A TRUE MEASURE OF VA
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)
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
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
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.
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
EOMs
Sound CAN be use (contrary to F&F)
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
No
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
