TECHNIQUES AND ADVANCES IN VISION SCREENING Neither I nor my - - PDF document

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TECHNIQUES AND ADVANCES IN VISION SCREENING Neither I nor my - - PDF document

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DISCLOSURES TECHNIQUES AND ADVANCES IN VISION SCREENING Neither I nor my immediate family members have a personal financial relationship with a manufacturer of Maanasa Indaram, MD pharmaceutical products or services that will be discussed

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SLIDE 1

TECHNIQUES AND ADVANCES IN VISION SCREENING

Maanasa Indaram, MD Assistant Professor Pediatric Ophthalmology and Adult Strabismus University of California San Francisco

18th Annual Developmental Disabilities: An Update for Health Professionals March 14-145 2019

DISCLOSURES

  • Neither I nor my immediate family members have a

personal financial relationship with a manufacturer of pharmaceutical products or services that will be discussed in this presentation.

WHY PERFORM VISION SCREENING?

  • 1/4 American school children have vision problems
  • Young children do not realize it and will not be

able to tell you

  • Primary care providers are the first line of defense

to detect vision loss in children

  • Timely referral to optometry/ ophthalmology

VISION PROBLEMS IN CHILDREN

  • Amblyopia
  • Refractive
  • Strabismic
  • Form deprivation
  • Non-amblyopic refractive error
  • Non-amblyopic strabismus
  • Structural eye abnormalities
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SLIDE 2

AMBLYOPIA (AKA: “LAZY EYE”)

  • Definition: “Reduction of best-corrected distance visual

acuity that cannot be attributed to any structural abnormality of the eye or visual pathway.”

  • Neurodevelopmental disorder
  • Brain doesn’t receive normal stimulation from one or both eyes
  • 2-3% of children in the U.S. (4.5 million)
  • 2.6x increase at age 8 years if no screening done at age 2

SCREEN FOR AMBLYOPIA EARLY

  • Risk factors present in early

childhood (<6 years)

  • Usually does not occur if risk

factors develop later because visual system has already developed

  • Reversible only in sensitive

period: 90% at age 3  nearly untreatable at age 10

Sloper J., J AAPOS 2016

WHY TREAT/ PREVENT AMBLYOPIA?

  • Leading cause of monocular vision loss in children
  • 75% of pediatric eye visits
  • Limits educational and career options
  • Cost of unilateral vision loss by age 10
  • > $67,000 over the lifetime
  • 10% decrease in quality of life

CURRENT RECOMMENDATIONS

  • Vision screening for all children at least once

between 3-5 years of age to detect the presence

  • f amblyopia or amblyopia risk factors
  • The US Preventive Service Task Force
  • US Public Health Service
  • American Academy of Ophthalmology, American Academy of

Pediatrics, American Association for Pediatric Ophthalmology and Strabismus

  • Prevent Blindness America
  • National Association for School Nurses
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SLIDE 3

WHAT ACTUALLY HAPPENS

  • Requirements for preventive eye care vary broadly
  • 40 states require any vision screening for school-aged children
  • Only 16 states require vision screening for preschool-aged children
  • In 2011, only 40% of children <= 5 years received vision screening
  • Up from 21% in 1983
  • No clear standards in screening protocol: type, frequency, referral,

follow-up WHAT DOES SCREENING LOOK FOR? AMBLYOPIA VS. AMBLYOPIA RISK FACTORS

  • Amblyopia: determined by measurement of visual acuity
  • Amblyopia Risk Factors (ARF):
  • Refractive error: anisometropia, isometropia
  • Strabismus: misalignment of visual axis  competitive/ inhibitory

interaction

  • Form deprivation (e.g. cataract): blockage of visual axis  image

degradation

  • Mixed mechanism

AAPOS 2003 GUIDELINES FOR AMBLYOPIA RISK FACTORS

  • Amblyopia risk factors determined by consensus,

not necessarily epidemiologic evidence

  • Only 1/8 children with ARFs developed amblyopia
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SLIDE 4

AAPOS 2013 GUIDELINES FOR AMBLYOPIA RISK FACTORS

Jonas et al., U.S. Preventative Task Force 2017

  • 1. Separate criteria for different age

groups

  • 2. Lower referral rate by raising

threshold referral values

  • 3. Use traditional
  • ptotype screening for children

who can read letters

  • 4. Detection of a constant

strabismus at all ages

NORMAL REFRACTION BY AGE

Mayer et al., JAMA Ophthalmology 2001 Zadnik et al., CLEERE Study 2003

CONVENTIONAL SCREENING TESTS VISUAL ACUITY NORMS BY AGE Normal adult visual acuity (20/20) is typically achieved between the ages of 5-6 years

Mayer et al., IOVS 1995

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SLIDE 5

OPTOTYPE VISUAL ACUITY TESTING

  • Quantitative test; best

method to test how well a child sees

  • Detects refractive error and

amblyopia (difference between eyes)

  • Cutoffs for screening: 20/40

(age 3-4), 20/32 (age 5)

OPTOTYPE VISUAL ACUITY TESTING

  • Prevent Blindness North California
  • PPV of ARFs: 60% (most experienced

screener)

  • Referral rate: 4%
  • Vision in Preschoolers (VIP) Study
  • PPV of ARFs: 27% (lay screener)
  • Referral rate: 13%

BRUCKNER RED REFLEX

PPV: 89% (experienced examiner) BARRIERS TO CONVENTIONAL SCREENING TESTS

  • Works better in older, cooperative children
  • Difficult in younger children, developmental delay,

behavioral issues

  • Need highly trained staff for best predictive value
  • Monocular test  time consuming (4 minutes)
  • Poor reimbursement for physicians
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SLIDE 6

AUTOMATED VISION SCREENING DEVICES

Autorefractors: Photorefractors: Foveal birefrigence:

HANDHELD AUTO-REFRACTORS

  • Determine refractive status of each eye
  • Monocular test  no information about strabismus
  • Detects amblyopia risk factors, not actual amblyopia
  • Takes <1 minute to get result
  • Requires fixation from subject and well trained screener
  • Validated in several large studies (VIP, MEPEDS,

BPEDS) HANDHELD AUTO-REFRACTORS Retinomax

  • Sensitivity: 62%
  • Specificity: 90%
  • PPV: 32% vs. 50%*
  • *Lay screener

(VIP) vs. nurse (PBNC)

Suresight

  • Sensitivity: 61%
  • Specificity: 90%

Images courtesy of Dr. Alejandra De Alba

PHOTOREFRACTORS

  • Designed to be operated by lay screeners with

little training

  • Binocular test; done at distance from the subject
  • Detects ARF (refractive error, misalignment), not

actual amblyopia

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SLIDE 7

HOW PHOTOREFRACTORS WORK

  • Examines reflection of light off retina using a

photograph

  • Type/ degree of refractive error affects size/

placement light crescent SPOT VISION SCREENER

  • Infrared scanner
  • Determines refractive state +

strabismus

  • Instant interpretation with

“Pass” or “Fail” result based

  • n pre-set criteria (AAPOS)
  • T

esting distance: 1 meter

  • 7814 children aged 6 months - 6 years
  • Tested by novice operators in daycares and preschools

in Southern CA between 2011-2012

  • PPV for any amblyogenic risk factor: 65.7%
  • Referral rate: 30.6%
  • False positive rate: 34%

PLUSOPTIX

  • Infrared scanner
  • Determines refractive state + strabismus
  • Can modify referral criteria settings
  • Instant interpretation with “Pass” or

“Refer” (few seconds)

  • Testing distance: 1 meter
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SLIDE 8
  • 1443 children aged 18 months - 5 years
  • Screened by lay operators at >100 daycare centers

in Canada between 2015-2016

  • PPV for any amblyogenic risk factor: 81.8%
  • Referral rate: 6.1%
  • False positive rate: 15.4%

GOCHECK KIDS

  • App on Smartphone (uses

camera with flash)

  • Determines refractive state

and checks visual acuity

  • Instant interpretation of

results to target referral

  • Reduces false positives with

remote MD review

  • 206 children aged 6 months – 6

years screened by at Storm Eye Center (MUSC)

  • Using 2013 AAPOS guidelines
  • PPV for any ARF: 57%*
  • *UCSF data: PPV ~50% (worse if <12

mo.)

  • 108 children aged 9 months – 12

years in a pediatric eye practice in Alaska

  • Using 2003 AAPOS guidelines
  • PPV for any ARF: 92%

“The revised AAPOS guidelines for defining risk factors in preschool vision screening studies …divert attention from the goal

  • f screening, which is not to

detect risk factors but to detect amblyopia and strabismus.”

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SLIDE 9

BLINQ BY REBION

  • New technology that uses

Neural Performance Scanning

  • Can detect strabismus (<1o)

AND amblyopia directly (not just ARFs)

  • 82% amblyopia in < 3 y/o

secondary to strabismus (not any other ARFs)

NEURAL PERFORMANCE SCANNING

  • 300 children aged 2 - 6 years screened with the Pediatric Vision

Screener (PVS) at two pediatric eye clinics between 2010-2013

  • Sensitivity: 97%
  • Specificity: 87%
  • PPV for true amblyopia or strabismus: 92.9%
  • False positive rate: 12.6%

COMPARISON OF VISION SCREENERS

VA T esting Retinomax SPOT PlusOptix GoCheck Kids Blinq PPV

27% (60%) 32% (50%) 65.7% 81.8% 57% 92.9%

False Positive Rate

  • 34%

15.4%

  • 12.6%

PRO’S

Can directly detect amblyopia Quick Accurate with experience Quick Test from distance Quick Can change referral criteria Quick Familiar interface Detects true amblyopia

CON’S

Needs experience Time Cooperation Needs experience Proximity/ contact Requires fixation Inconclusives Noises/ clown face Inconclusives Accuracy? New tech

Additional Cost

$0 ~$3000 ~$7000 ~$7000 $60/month ??

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SLIDE 10

CONCLUSIONS

  • Early vision screening is needed to prevent amblyopia
  • Automated vision screening can improve efficiency and

accuracy of testing, especially in uncooperative children

  • However, automated techniques have limitations (low PPV)

and cannot detect amblyopia directly

  • Not a surrogate for subjective acuity in cooperative, older children
  • New technology promises direct detection of amblyopia and

strabismus