Community-Screening-Programs-Identifying-Undetected-Refractive-Error

COMMUNITY SCREENING PROGRAMS:
IDENTIFYING UNCORRECTED REFRACTIVE ERROR
Dr. Sarah Wassnig, B.Optom, MPH
New England College of Optometry, Boston, USA
LECTURE OBJECTIVES
1. To understand the importance of optometry in the global
effort of reducing visual impairment
2. To understand the impacts of high refractive error on
communities
3. To understand the ethical issues of screening communities
4. To have the ability to begin incorporating refractive error
into your community screening protocol
a. Tests to incorporate
b. Testing procedures
c. Which personal to train
d. Equipment required
WHY ARE WE TESTING FOR
REFRACTIVE ERROR?
WHAT DO YOU THINK THE BIGGEST CAUSE OF VISUAL
IMPAIRMENT IS GLOBALLY?
1. Age Related Macular Degeneration
2. Corneal Opacity
3. Glaucoma
4. Trachoma
5. Cataract
6. Diabetic Retinopathy
7. Uncorrected Refractive Error
GLOBAL CAUSES OF VISUAL IMPAIRMENT
Results released on World Sight Day October 2017 indicating that refractive error has
become even larger a burden since WHOs 2010 assessment of global visual impairment.
Bourne, R., Resnikoff, S., & Ackland, P. (2017). Vision Atlas. IAPB. http://atlas.iapb.org/global-burden-vision-impairment/
GLOBAL CAUSES OF VISUAL IMPAIRMENT
Estimated global prevalence of Myopia – 2000 to 2050
20.2%
1,243m
2.7%
163m
77.1%
24.3%
1,673m
2000
Low to Moderate Myopia
● 20.2%
1,243m
● 2.7% 163m
● 77.1%
4.0%
277m
71.7%
2010
High Myopia
● 24.3%
5.2%
399m
66.1%
2020
Non-Myopes
1,673m
● 4.0% 277m
● 71.7%
● Low to Moderate Myopia
28.7%
2,221m
2,221m
● 5.2% 399m
● 66.1%
● High Myopia
Data correct as at 12th Oct 2017
60.1%
2030
Numbers = people affected
● 28.7%
33.8%
6.1%
2,844m 517m
● 33.8%
7.7%
696m
54.8%
40.0%
3,820m
2040
2,844m
● 6.1% 517m
● 60.1%
● Non-Myopes
37.5%
3,393m
● 37.5%
9.8%
938m
50.2%
2050
3,393m
● 7.7% 696m
● 54.8%
● 40.0%
3,820m
● 9.8% 938m
● 50.2%
Numbers = people affected
© IAPB Vision Atlas
Sankaridung, P., & Naidoo, K. (2017). The impact of Myopia throughout the developing world. IAPB.
Accessed on Nov 21 from http://atlas.iapb.org/vision-trends/myopia/
(Flaxman, et al. Lancet, 2017)
WHAT IS THE IMPACT OF REFRACTIVE ERROR
1. Financial burden
2. Progression to sight threatening conditions
3. Limited educational potential
With glasses this Bangladeshi potter was able to
increase her production from two pieces a day to
ten.
http://visionspring.org/why-eyeglasses/; https://www.theworldweekly.com/reader/view/magazine/2016-06-02/restoring-the-worlds-vision/8117
WHICH POPULATIONS SHOULD
WE TARGET IN SCREENING?
Presbyopes
Women
Children
PRESBYOPES
Bourne, R., Resnikoff, S., & Ackland, P. (2017). Vision Atlas. IAPB. http://atlas.iapb.org/global-burden-vision-impairment/
WOMEN
Bourne, R., Resnikoff, S., & Ackland, P. (2017). Vision Atlas. IAPB. http://atlas.iapb.org/global-burden-vision-impairment/
CHILDREN
Getting Syria's children back to school in Lebanon, DFID - UK Department for International Development; Creative Commons: commons.wikimedia.org
WHY DO WE NEED SCREENING IN COMMUNITIES
•
Remote communites
– Limited access
– Limited transport options to city hospitals
•
Difficult to self identify as a child
•
Lack of health education in communities regarding vision
conditions
ORGANIZING A REFRACTIVE
VISION SCREENING
WHAT ARE THE STEPS?
WHAT IS A COMMUNITY SCREENING
Girl at vision screening, Ermalfaro; Creative Commons: commons.wikimedia.org
WHO CAN WE RECRUIT?
•
Who can we leverage to help us reach those who are unable to
reach eye care services or unaware of eye care services?
COMMUNITY LEADERS
ALLIED EYE CARE PROFESSIONALS
Number of Ophthalmologists per million population
for the 191 countries for which data is available
Lowest
High Income
incidence of
uncorrected
Central
Europe,
refractive
Eastern
Europe
error
& Central Asia
South Asia
Latin America
& Caribbean
Higher
South-East
incidenceAsia,
of
East Asia
uncorrected
&
Oceania
refractive
error
North
Africa
& Middle East
Sub-Saharan
Africa
Global
Global
0
Data correct as at 12th Oct 2017
50
100
150
© IAPB Vision Atlas
http://atlas.iapb.org/global-action-plan/gap-implementation/gap-implementation-eye-health-workforce/
Number of Optometrists per million population
for the 128 countries for which data is available
Lowest
High Income
incidence of
uncorrected
Central Europe,
refractive
error
Eastern Europe
& Central Asia
South Asia
Latin America
& Caribbean
Higher
incidence
of
South-East
Asia,
uncorrected
East Asia
refractive
& Oceania
error
North Africa
& Middle East
Sub-Saharan
Africa
Global
Global
0
Data correct as at 12th Oct 2017
100
200
300
© IAPB Vision Atlas
http://atlas.iapb.org/global-action-plan/gap-implementation/gap-implementation-eye-health-workforce/
Number of Allied Ophthalmic Personnel per million
population for the 95 countries for which data is available
High Lower
Income
incidence of
uncorrected
Central Europe,
refractive
error
Eastern Europe
& Central Asia
South Asia
Latin America
& Caribbean
Higher
South-East
Asia,
incidence
of
East Asia
uncorrected
& Oceania
refractive
error
North Africa
& Middle East
Sub-Saharan
Africa
Global
Global
0
Data correct as at 12th Oct 2017
100
200
300
400
© IAPB Vision Atlas
http://atlas.iapb.org/global-action-plan/gap-implementation/gap-implementation-eye-health-workforce/
NURSES VS LAY PEOPLE
•
Vision In Preschoolers Study (VIP Study) Phase II (2009)
– Study compared trained nurses and trained lay people’s ability to
administer screening tools successfully in children
•
BOTH groups were able to correctly identify up to 68 percent of
children with at least one vision disorder
•
Increase our supporting personnel by increasing the of training
of lay people: community leaders, teachers, government officials
WHAT ARE THE MOST SUCCESSFUL TOOLS FOR
SCREENING REFRACTIVE ERROR?
•
Vision In Preschoolers Study (VIP Study) Phase I (2004)
1. The most successful tools for assessing refractive error
– Two hand-held auto-refractors (Retinomax and SureSight)
– Retinoscopy
2. The most successful tool for assessing visual acuity
– chart displaying lea symbols 10 feet away and patient names each
symbol as the screener points to it (children)
WHAT CAN BE INCLUDED IN A SCREENING?
•
Visual Acuity
•
Retinoscopy/Auto-refraction
•
OTHER TESTS:
– Cover Test (distance and near)
– Extraocular Muscle (EOM) testing
– Bruckner
– Near Point of Convergence
– Stereopsis
– Color Vision
– Confrontation fields
– Pupil testing
EQUIPMENT NEEDED
1. Visual acuity chart
–
tumbling E, ETDRS letters or LEA
–
preferably logMAR
–
tape measure to 10ft/5meters
2. Near visual acuity chart
3. Occluder
4. Diagnostic kit
–
Retinoscope
•
Retinoscopy racks
–
Direct ophthalmoscope
–
Transilluminator (or pen torch)
5. Auto refractor
WHERE DO WE START?
HISTORY QUESTIONS
•
Ask about:
IS YOUR PATIENT A CHILD?
– previous eye tests
Ask:
– glasses or contact lenses
•
Parental concerns?
– concerns about vision
•
Do you like reading?
– family ocular history
•
Favorite subject?
– general health
•
Can you see the board at school?
– occupation/daily tasks
REFRACTIVE ERROR
- AUTO REFRACTORS
•
Advantages
– Quick
– Requires minimal cooperation from the patient
– Portable
– Great for pre-verbal children and pre-literate children
•
Disadvantages
– Limited ability to detect strabismus
– Difficult to accurately assess higher hyperopia
– Cost of instrument
– Require electricity or batteries
– May be less reliable in children = active accommodation and less stable fixation
Sensitivity and specificity will depend on the referral criteria. Whilst adjusting referral
criteria to be tighter may increase the number of patients correctly identified it will also
increase the number of unnecessary referrals (lower specificity).
AUTO REFRACTORS AVAILABLE
•
•
Welch Allyn SureSight 140 Vision Screener
Welch Allyn VS100S-B Spot Vision Screener
•
PlusOptix Vision Screening Device
•
Retinomax
•
Mobile cell phone screening devices…watch this space!
– Virtual reality headset utilised for auto-refraction with an app
(NETRA/BLINK)
– The eye scan app (TESA)
WHAT IS THE EXPECTED REFRACTIVE ERROR FOR A
1.5 YEAR OLD TODDLER?
1. -1.00D
2. -2.00D
3. <+2.00D
4. <+1.00D
REFERRAL BASED ON REFRACTIVE ERROR?
4
9
MONTHS MONTHS
Hyperopia
<3.50D
REFRACTIVE
ERROR
Anisometropia
VISION
<1.00
Convergence
good,
Fixates on
faces
12
MONTHS
1.5 YEARS
BY 4
YEARS
4-6 YEARS
Hyperopia
<2.50D
Hyperopia
<2.25D
Hyperopia
<2.00D
Hyperopia
<1.50D
Hyperopia
<1.50D
Anisometropia
<1.00
Attentive to
near and far
Anisometropia
<1.00
Tracks ball,
looks at picture
in book
Anisometropia
<1.00
Letter matching
by 2years
Anisometropia
<1.00
3/6 to 3/4.8
(3.5 years)
Anisometropia
<1.00
6/9.5 – 6/6
3/7.5 - 3/6
(3years)
6/12 (4 years)
WHAT CONDITIONS DO WE IDENTIFY IN CHILDREN
IN REFRACTIVE ERROR SCREENING?
•
Is this child at risk of amblyopia?
– Is refraction within normal?
– Is the vision and refractive error equal?
•
Is the media clear?
•
Are there abnormal eye movements or an eye misalignment
(strabismus)?
WHAT ARE THE MOST SUCCESSFUL TOOLS FOR
SCREENING REFRACTIVE ERROR?
•
Vision In Preschoolers Study (VIP Study) Phase I
1. The most successful tools for assessing refractive error
– Two hand-held auto-refractors (Retinomax and SureSight)
– Retinoscopy
2. The most successful tool for assessing visual acuity
– chart displaying lea symbols 10 feet away and patient names each
symbol as the screener points to it (children)
VISUAL ACUITY CHARTS
•
•
Single line crowded HOTV or Lea symbols for children
– Can match or name symbols
Tumbling E or ETDRS chart for adults
•
LogMAR scaled
– Calibrated for 5ft (1.5meters) or 10ft (3meters)
•
Crowding or crowding bars
– “Crowding” refers to symbols being surround
– Amblyopic patients can recognize smaller objects when presented
singularly as there is no competition for visual attention. This is not
realistic measure as visual acuity as our world is full of visual stimuli.
VISUAL ACUITY PROCEDURE
1. Examiner asks the patient to cover one eye
2. Examiner points to the “optotype” without covering the optotype
3. Start at the top of the chart and ask the patient to identify the first
symbol. If easily identified, move to line below.
4. If patient is squinting, leaning forward, incorrect or hesitant, test
entire line above.
5. Continue moving down the chart until the patient reads 3 or more
optotypes incorrectly in one line – this is your end point.
6. Maintain a positive attitude!
VISUAL ACUITY CLINICAL PEARLS
•
Confirm they can name each symbol (children), understand how
to point in the direction of the E, or are literate with Roman
alphabet.
– Allow the child to give the symbol any name they like
•
Observe the patient not the chart!
– leaning forward, squinting, peaking around occluder or through fingers.
– Opaque glasses allow one examiner to screen a young child
Good-Lite.com
•
Test one eye and then the other
– May start binocularly and with larger letters to practice the test if testing
children.
•
Test with the patient’s glasses first if they are wearing them
WHAT IS ACCEPTABLE VISUAL ACUITY FOR A
4 YEAR OLD?
1. 20/40 (6/12) at 5 ft (1.5m)
2. 20/20 (6/6) at 5 ft (1.5m)
3. 20/60 (6/12) at 10 ft (1.5m)
4. 20/60 (6/12) at 5 ft (1.5m)
REFERRAL BASED ON VISUAL ACUITY
•
36-47 months (3-4 years) old:
– Less than 20/50, 5ft away, either eye
– Two line difference between eyes
•
>4 – 6 years old:
– Less than 20/40, 5ft away, either eye
– Two line difference between eyes
•
Older than 6 years:
– Less than 20/30-2, 10ft away, either eye
– Two line difference between eyes
•
Adults (>10 years):
– Should achieve 20/25 at distance and near with both eyes
American Academy of Pediatrics
VISUAL ACUITY CONDITIONS
•
Mark where your chart distance is (10ft or 5ft) on the floor.
•
Have a clean chart with white background and distinct black
letters for good contrast
•
Hold/place at eye level
•
Test in good lighting with minimal shadows around the chart
NEAR VISUAL ACUITY IN ADULTS OVER 40
•
Ask the patient to hold the chart at their reading distance
•
You can assume most adults over 50 will have difficulties at near
with the expectation of low mopes
•
What prescription would you expect at each age if distance vision
is corrected?
– Age 45 = +0.75D add
– Age 50 = +1.00D add
– Age 55 = +1.50D add
– Age 60 = +2.00D add
– Age 65 = +2.50D add
OTHER TESTS TO IDENTIFY IF
LOW VISUAL ACUITY = REFRACTIVE ERROR
1.
Pin hole
2.
Bruckner
3.
Retinoscopy
PINHOLE OCCLUDER
BRUCKNER
•
Type of reflex?
– Refractive error?
•
Asymmetric?
– OD vs OS
– Opaque – strabismus? Media opacity?
optometrystudents.com
BRUCKNER
What type of refractive error is this?
1. Myopia
2. Emmetropia
3. Hyperopia
4. Other concern
http://www.ojoonline.org/article.asp?issn=0974-620X;year=2010;volume=3;issue=3;spage=131;epage=135;aulast=Amitava;
https://www.google.com/search?biw=1204&bih=706&tbm=isch&q=bruckner+test&sa=X&ved=0ahUKEwjf6ojzpe7WAhWsxYMKHddCB1sQhyYIJQ#imgrc=
BRUCKNER
What type of refractive error is this?
1. Myopia
2. Emmetropia
3. Hyperopia
4. Other concern
http://www.ojoonline.org/article.asp?issn=0974-620X;year=2010;volume=3;issue=3;spage=131;epage=135;aulast=Amitava;
https://www.google.com/search?biw=1204&bih=706&tbm=isch&q=bruckner+test&sa=X&ved=0ahUKEwjf6ojzpe7WAhWsxYMKHddCB1sQhyYIJQ#imgrc=
BRUCKNER
What type of refractive error is this?
1. Myopia
2. Emmetropia
3. Hyperopia
4. Other concern
http://www.ijo.in/viewimage.asp?img=IndianJOphthalmol_2013_61_10_608_121092_f2.jpg
BRUCKNER
What type of refractive error is this?
1. Myopia
2. Emmetropia
3. Hyperopia
4. Other concern
http://www.ijo.in/viewimage.asp?img=IndianJOphthalmol_2013_61_10_608_121092_f2.jpg
http://www.aafp.org/afp/2013/0815/p241.html
Childhood Eye Examination
BRUCKNER
What now?
1. Myopia
Figure 6.
Figure 5.
Asymmetry in the red reflexes. Red reflex should be equal in both eyes when the red reflexes are viewed
simultaneously. An abnormality is exposed if one reflex appears more prominent than the other, or if one reflex is
of a different color or intensity, as in this patient.
Red reflex examination. (A) Normal, symmetric red reflex. (B) Norma
abnormal, diminished red reflex in the patient's left eye, which is mos
between the eyes, but can also be caused by a more serious patholo
3. Hyperopia
reflex in the patient's right eye and no reflex in the patient's left eye, w
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4. Other concern
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SCREENING FLOW AFTER VISUAL ACUITY
- NOT AN ABSOLUTE LIST, BUT A GOOD PLACE TO START IN CHILDREN
1.
Hirschberg
2.
Cover test
3.
Near Point of Convergence
4.
Excursions
5.
Observations including pupils
HIRSCHBERG
•
•
•
•
Compares the corneal reflex
position
Identifies the non-focusing
eye
Deviation and magnitude
identified
Fixating eye will be along the
principle visual axis
– Is the patient using the
fovea to fixate??
Procedure:
• 50cm – 100cm
• Transilluminator/pen torch
• Done binocularly
• Monocularly assists in cover
test
HIRSCHBERG
www.sciencedirect.com
HIRSCHBERG
What type of deviation is this?
1. Exotropia
2. Exophoria
3. Esotropia
http://www.dijetaizdravlje.com/zdravlje/razrokost/
4. Esophoria
https://entokey.com/diagnostic-evaluation-of-strabismus-and-torticollis/
HIRSCHBERG
What type of deviation is this?
1. Exotropia
2. Exophoria
3. Esotropia
http://webeye.ophth.uiowa.edu/eyeforum/cases/124-infantile-esotropia.htm
4. Esophoria
https://entokey.com/diagnostic-evaluation-of-strabismus-and-torticollis/
COVER TEST
PHORIA:
• Alternating cover test
• Identify type and deviation of deviation
• Procedure – cover eye for at least 2-3 seconds
• Normal?
– Distance 1 esophoria - 3exophoria
– Near orthophoria to 6 exophoria
TROPIA
• Unilateral cover test
• Always a REFER
Cover test – Should I use my thumb, mum’s hand, my hand,
occluder?
UNILATERAL COVER TEST
EXOPHORIA
Childhood Eye Examination
EXOTROPIA
•
•
•
•
www.aafp.org
Cover-uncover one eye at a time
Determines tropia or phoria
Observe movement of opposite eye
Determines tropia laterality and frequency
http
ALTERNATING COVER TEST
ESOPHORIA
•
•
•
•
•
•
Eye not occluded will go into it’s
phoria position
Cover one eye for 2-3 seconds
then the other
Determines phoria direction &
magnitude
Disrupting fusional vergence
The eyes move to the same degree
under cover
Good lighting!
www.aafp.org
NEAR POINT OF CONVERGENCE “NPC”
•
With accommodative target
•
Assess break point based on observation NOT a child’s responses as they
cannot reliably understand “double”
•
Observe facial expression, ease or difficulty of convergence, break/recovery
point? Is child actually engaged and looking at target?
•
Normal:
– Accomodative target 5cm/7cm
– Light target 7cm/10cm
OBSERVATIONS
•
Nystagmus
•
Ptosis, lid anomolaies
•
Head posture
•
Tearing, discharge
•
Corneal clouding, large cornea (glaucoma in child, with watery eye and photophobia)
•
Red eye
•
Lumps
•
Refractive glasses
•
Developmental milestones/behaviour?
•
Squinting to see
PUPILS
WHAT ARE WE LOOKING FOR?
1.
2.
3.
4.
Color – same in both eyes? Freckles?
Size – even between the eyes in both dark and dim lighting?
Position – central?
Response – constrict with direct light, constrict with fellow pupil?
EYE MOVEMENTS
EXCURSIONS:
• Head straight
• Examiner ~ 50cm from patient at same
level
• Follow light with eyes keeping head still
• Move light/target in double H and X
pattern
• Record if
– smooth
– accurate
– extensive
http://www.tedmontgomery.com/the_eye/eom.html; https://www.slideshare.net/Rajkohila/extra-ocular-muscles-ppt
PROS AND CONS OF VISION SCREENING
•
Benefits of screenings
– Early identification those requiring extensive vision care
– Improve learning of children
– Identify those with refractive error earlier rather than later
•
Limitations of screenings
– Cost to parent and government
• time, transport, space, equipment, personal
– Language, culture
– False negatives
– False positives
LECTURE OBJECTIVES REVISITED
1. To understand the importance of optometry in the global
effort of reducing visual impairment
2. To understand the impacts of high refractive error of
communities
3. To understand the ethical issues faced with screening
4. To have the ability to begin incorporating refractive error
into your community screening protocol
a. Tests to incorporate
b. Testing procedures
c. How to train personal
d. Equipment required
THANK YOU
QUESTIONS?