Running an efficient school programme:
refractive error component
Child Eye Health course: IAPB General Assembly
Clare Gilbert, ICEH, LSHTM
School eye health programmes:
questions that need to be addressed
 Is a school eye health programme indicated?
• prevalence of uncorrected refractive errors
• prevalence of endemic diseases e.g. VADD; trachoma
• resources available
 Age at which vision should be tested?
 Which schools should be included?
 How often should vision be tested?
 Who will measure the vision?
 What chart should be used?
 What should the cut-off visual acuity be?
 Should each eye be tested separately?
School eye health programmes –
questions that need to be asked for uRE
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Who should refract, where and how?
Should prescribing guidelines be used?
How will children needing glasses get them?
What about children found with other eye conditions?
What factors influence spectacle wearing rates and how
can wearing rates be improved?
Are ready-made / self-adjusting spectacles suitable?
How will it be monitored and evaluated?
How can quality be assured?
Will the programme be cost effective?
School eye health programmes –
questions that need to be asked for uRE
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Who should refract, where and how?
Should prescribing guidelines be used?
How will children needing glasses get them?
What about children found with other eye conditions?
What factors influence spectacle wearing rates and how
can wearing rates be improved?
Are ready-made / self-adjusting spectacles suitable?
How will it be monitored and evaluated?
How can quality be assured?
Will the programme be cost effective?
 Will it make any difference to childrens’ lives?
School eye health programmes:
questions that need to be addressed
 Is a school eye health programme indicated?
• prevalence of uncorrected refractive errors
• prevalence of endemic diseases e.g. VADD; trachoma
• resources available
 Age at which vision should be tested?
 Which schools should be included?
 How often should vision be tested?
 Who will measure the vision?
 What chart should be used?
 What should the cut-off visual acuity be?
 Should each eye be tested separately?
Prevalence and types of uncorrected
RE in children
 A neglected area until recently
 VISION 2020 Refractive Error Working Group
– recommended standardised surveys
– results from 8 standard surveys now available
 More data available other studies
 Still to be determined:
– Global importance of RE as a cause of blindness
and visual impairment in children
Prevalence of visual impairment (acuity
<6/12 in one or both eyes)(REWG)
20
Uncorrected
Presenting
Best corrected
15
10
5
0
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n
In
di
a
ru
ra
In
l
di
a
ur
ba
N
n
ep
al
ru
ra
M
l
al
ay
si
a
(U
)
C
hi
le
(U
S
)
Af
ri c
a
(U
)
Prevalence (%)
25
Prevalence of visual impairment (acuity
<6/12 in one or both eyes)
Uncorrected
Presenting
Best corrected
20
15
10
Met need
Unmet need
5
0
C
hi
na
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C
hi
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na
ur
ba
n
In
di
a
ru
ra
In
l
di
a
ur
ba
N
n
ep
al
ru
ra
M
l
al
ay
si
a
(U
)
C
hi
le
(U
S
)
Af
ri c
a
(U
)
Prevalence (%)
25
Refractive errors as a cause of visual
impairment
Refractive error
100%
Amblyopia
Other
80%
60%
40%
20%
0%
China
rural
China
urban
India rural
India
urban
Nepal
Malaysia
Chile
South
Africa
Tanzania
S
Data from other studies
 Asian school children 7-9 years [Saw]
• Myopia
• Malays in Singapore
• Chinese Singapore
≥0.5D
22%; in Malaysia
40%; in Malaysian
 Malaysian primary school children [Hashim]
• Criteria
• All children
<6/12 uncorrected
8%
 Chinese children in rural junior schools [He]
• Criteria
• All children
≥6/12 uncorrected
17%
9%
31%
Data from other studies
 Different ethnic groups in the UK aged 10-11 years [Rudnicke]
•
•
•
•
Myopia & VA ≤6/9
South Asian
Black African Caribbean
European
25%
10%
3%
 Tanzania, rural primary school attendees aged 7-19 year
[Wedner]
• <6/12 in both eyes
0.6%
• <6/12 in one eye
0.4%
India: urban population
(retinoscopy findings)
Age (yrs)
Myopia ≥ -0.5D
Myopia (D)
% (95% CI)
Hyperopia (D)
% (95% CI)
China: urban population
(retinoscopy findings)
Age (yrs)
Myopia ≥ -0.5D
Myopia (D)
% (95% CI)
Hyperopia (D)
% (95% CI)
South Africa: semi-urban pop
(retinoscopy findings)
Age (yrs)
Myopia (D)
% (95% CI)
Hyperopia (D)
% (95% CI)
1% had the potential to benefit from spectacles
Summary of evidence
Regional differences in prevalence:
 Asia > Europe/Latin America > Africa
 low prevalence in Africa may not justify the RE
component of school eye health programme
Type of refractive error and age:
 myopia increases with age
 hypermetropia decreases with age
Urban / rural differences:
 myopia more common in urban areas
Which schools and how often?
 In Asia focus on:
• middle/secondary schools
• urban then rural schools (unmet need high even in urban areas)
 South Asia:
• include primary school children
 Africa:
• pilot studies and decide if a good use of resources
 Frequency of visits:
• No evidence
• ? every 2-3 years if prevalence <5% and but 1-2 years if
prevalence >5%
School eye health programmes:
questions that need to be addressed
 Is a school eye health programme indicated?
• prevalence of uncorrected refractive errors
• prevalence of endemic diseases e.g. VADD; trachoma
• resources available
 Age at which vision should be tested?
 Which schools should be included?
 How often should vision be tested?
 Who will measure the vision?
 What chart should be used?
 What should the cut-off visual acuity be?
 Should each eye be tested separately?
Measuring visual acuity
Teachers measuring visual acuity in school
children in Brazil
Measuring visual acuity
 Teachers are used in many programmes
 Can reliably test in the short term
• in China: 85% sensitivity and specificity [Sharma]
 How do they perform long term?
 What criteria make good VA testers?
 How can their motivation be maintained?
 Also trainee optometrists and nurses; army cadets
Sharma A. Strategies to improve the accuracy of vision measurement by teachers
in rural Chinese secondary school children. Arch Oph 2008 1434-40
School eye health programmes:
questions that need to be addressed
 Is a school eye health programme indicated?
• prevalence of uncorrected refractive errors
• prevalence of endemic diseases e.g. VADD; trachoma
• resources available
 Age at which vision should be tested?
 Which schools should be included?
 How often should vision be tested?
 Who will measure the vision?
 What chart should be used?
 What should the cut-off visual acuity be?
 Should each eye be tested separately?
Vision testing
 Cut off options:
 Chart options:
 Eyes:
6/9 or 6/12
Full chart vs relevant row
Separately vs together
 Cut off options:
• 6/9: many false positives which can overload the system
• 6/12: more likely to find significant myopia/astigmatism
• Both can miss hypermetropia
 Chart options:
• one row is quicker.
• more care with quality control
Uniocular vs binocular VA screening
in Tanzania
Methods:
 Secondary school pupils (n=2,379; 12-23 yrs) tested with full
Snellen: each eye separately and both eyes together
 Refracted if <6/9 in one eye or <6/9 testing binocularly
 RE needing correction (in better seeing eye) defined as:
– myopia
-1.0D or more
– hypermetropia
+3.0D or more
– Astigmatism
cyl 1.5D or more
Results:
 <6/12 both eyes had highest PVP (71.4%) & PNV (99.7%)
Shilio B. MSc dissertation, ICEH. 2000
VA tested, age and rates of refraction and
prescribing
Prescribed glasses
Country
India 1993-7
[Limburg]
S Africa
[Congdon]
Mexico
[Holgiun]
China
[Li]
Mozambique
[Roba]
Tanzania
[Wedner]
VA tested N tested
R and/or
L
<6/9
5.39m
Age
group
Refracted
Of those
refracted
Overall
6-15
205,000 (4%)
24%
0.8%
≤6/12
8,500
6-19
2,120 (25%)
38%
9.5%
≤6/12
10,096
6-18
5,772 (57%)
ND
ND
≤6/12
1,892
11-15
960 (50%)
70%
28%
<6/9
10,320
5-15
3%
67%
1%
<6/12
6,900
11+
ND
ND
1.8%
Influence of age at VA testing in India (<6/9)
Schools
Prescribed glasses
Of
Overall
refracted
24.4%
0.8%
Age group
N tested
Refracted
All
6-15
5.39m
205,000 (3.8%)
Middle
11-15
3.23m
148,200 (4.6%)
26.5%
1.2%
Primary
6-10
2.16m
56,900 (2.6%)
19.0%
0.5%
Only 1 in 200 primary school children tested
at <6/9 were prescribed glasses compared
with 1 in 83 middle school children
School eye health programmes –
questions that need to be asked for uRE









Who should refract, where and how?
Should prescribing guidelines be used?
How will children needing glasses get them?
What about children found with other eye conditions?
What factors influence spectacle wearing rates and how
can wearing rates be improved?
Are ready-made / self-adjusting spectacles suitable?
How will it be monitored and evaluated?
How can quality be assured?
Will the programme be cost effective?
 Will it make any difference to childrens’ lives?
Refraction, prescribing and
dispensing
Refraction:
 Lots of options: ideal = high quality refraction done at the same
time as VA testing, preferably at the school, to improve uptake
Prescribing and dispensing:
 Lots of options: ideal = only children who will really benefit are
dispensed high quality spectacles, using prescribing guidelines
to prevent over prescribing
 Should not treat the myopia, but functional impairment arising
from it.
Type of RE and protocols for
prescribing
Country Type of prescription (RE)
Protocols for
prescribing
India
No data
S Africa
60% none (<+/-0.5D); 35% myopia; 5% hyperopia Yes ? Followed
Mexico
85% myopia; 10% no RE; 5% hyperopia
No data
China
No data
Yes
Tanzania 86% myopia
? Up to local optom
No data
School eye health programmes –
questions that need to be asked for uRE









Who should refract, where and how?
Should prescribing guidelines be used?
How will children needing glasses get them?
What about children found with other eye conditions?
What factors influence spectacle wearing rates and how
can wearing rates be improved?
Are ready-made / self-adjusting spectacles suitable?
How will it be monitored and evaluated?
How can quality be assured?
Will the programme be cost effective?
 Will it make any difference to childrens’ lives?
Spectacle wearing/carrying rates
Country
Wearing/carrying rates
India
93% (? >100% some areas)
Independent variables associated with
wearing spectacles
No data
S Africa
31%
Females
Mexico
47% (13% wearing)
Higher myopic; rural; younger children
China
35% purchased specs
24% wearing specs
Higher myopia; worse presenting VA;
willingness to pay
Tanzania 47% if given free specs
(trial)
26% if given prescription
Higher myopia; worse presenting VA
China
(trial)
Intervention group of students: lower
wearing rates
Types of spectacles prescribed/given
 Mexico: very low spectacle wearing rates when
children all given the same round framed spectacles.
 Increased when more variety provided
Role of self- adjusting spectacles or
ready-made spectacles
Other types of spectacles
Self correction:
 Accuracy of refraction using “Adspecs” in China: VA corrected
with Adspecs lower than with standard methods, but were within
1 line in 98% of students [Zhang and Congdon]
Ready made spectacles:
 Up to 70% of adults have potential to benefit (pop based
surveys); in a clinical trial of adults ready made spectacles
compared favourably with custom made. O studies in children
[Keay and Friedman]
Barriers to spectacle wearing
Mexico (1 reason given)
Tanzania (FGDs)
China (q’aire)
Forgot them
Appearance /teasing
No felt need
Appearance /teasing
Parents fear VA will decline
Make eyes “weak”
Broken / lost
Mistrust of opticians
Parents not involved
Use occasionally
Prefer diet and traditional
remedies
Cost
No improvement in VA
Not a health priority
Conspiracy theories
Cost
School eye health programmes –
questions that need to be asked for uRE









Who should refract, where and how?
Should prescribing guidelines be used?
How will children needing glasses get them?
What about children found with other eye conditions?
What factors influence spectacle wearing rates and how
can wearing rates be improved?
Are ready-made / self-adjusting spectacles suitable?
How will it be monitored and evaluated?
How can quality be assured?
Will the programme be cost effective?
 Will it make any difference to childrens’ lives?
Monitoring and evaluation
Some real M&E data.....
Are programmes cost effective?
Methods:
 Mathematical simulation of annual screening for 10 years using
six different screening strategies
 Outcome: international $ / DALY averted
Results:
 Most cost effective strategy:
screening 11–15 year olds
 Cost per DALY averted:
$ 67 in Asia to

$ 458 in Europe
 Incremental cost for 5–15 yr olds:
$ 111 in Asia to
$ 672 in Europe
Conclusions:
 Screening of school children for refractive error is economically
attractive in all regions in the world.
Baltussen et al. Cost-effectiveness of screening and correcting refractive errors
in school children in Africa, Asia, America and Europe. Health Policy 2008
Suggestions for RE based on
available evidence 1
Is a programme indicated?
1. Yes: urban schools in all areas but Africa, where pilot studies needed
2. Possibly: rural schools in Asia and Latin America - need pilot studies
3. Probably not: rural schools in Africa unless there is a high
prevalence of trachoma etc
Prevalence criteria for uncorrected RE: ? ≥2%. Depends on
available resources; competing demands; prevalence of other eye
conditions
Suggestions for RE based on
available evidence 2
Age group:
 children aged 10/11 years to 15 years. Not younger
VA testing:
 teachers OK in short term
 <6/12 with available correction with both eyes open,
but needs more evidence that important pathology is
not missed in worse eye
Prescribing:
 clear protocols need to be used and enforced to
increase compliance and reduce over prescribing:
Suggestions for RE based on
available evidence 3
Prescribing:
 According to guidelines to prevent over prescribing of
children with minimal RE
Dispensing:
 fashionable, acceptable frames
 at the school, if possible
Charging:
 depends on local situation
 must be affordable
Health education:
 essential: to dispel myths and increase compliance
 parents must be included
What I would not advocate for RE
 Including children 6-10 years, except in China:
- prevalence is low
- measuring vision is difficult <6 years
- prescribing my interfere with emmetropization in
young children
- too late to treat/prevent amblyopia
Using trained eyecare staff to measure vision
Using better level of vision as the cutoff, or
unilateral testing
- many false positives
- over prescribing of spectacles
- increases cost
More evidence is badly needed
Impact of programmes
• do spectacles for low myopia improve function and quality of life?
• does spectacle wearing improve school attendance/performance?
• is there any harm from bullying/teasing for wearing glasses?
Optimal screening VA
Increasing compliance
• what are optimal protocols for prescribing spectacles?
• what is the most effective health education strategy?
Factors which promote sustainability:
• % of need that could be met by ready-made spectacles
• willingness to pay
School health initiatives
 UNICEF’s Child Friendly School Initiative
 WHO Global School Health Initiative : Health
Promoting Schools
 United Nations Girls Education Initiative (UNGEI)
 UNESCO
 Partnership for Child Development
 World Bank
 Millennium Development Goals
Integration
Work with Ministries of health / education so that
• eye health is part of broader school and child health
• schools are safe and healthy places
• children learn about eye health
Should not be a stand alone, vertical program
that only deals with refractive error