- Email: [email protected]
Accuracy of referrals from an orthoptic vision screening program for 3- to 4-year-old preschool children
Accuracy of referrals from an orthoptic vision screening program for 3- to 4-year-old preschool children Victor H. Hu, MB, BCh,a Amanda Starling, DBO,a Shelagh N. Baynham, DBO,a Hilary Wager, DBO,b and G. Adrien Shun-Shin, MB, BSa,b PURPOSE
To determine the accuracy of orthoptist referrals from a preschool-based vision screening program for children 3-4 years of age and to report the outcomes of referred children.
METHODS
This was a retrospective review of records of participants in the preschool vision screening program in the Walsall, United Kingdom, area for the 2006-2007 school year. Screening examinations were performed by orthoptists and included assessment of visual acuity, ocular alignment, ocular motility, and stereoacuity. For the 2006-2007 school year, 2,830 of 3,623 children (78%) were screened, Of these, 413 were referred to the Hospital Eye Service. Comparison of the screening results and the Hospital Eye Service examination revealed that recorded visual acuities were similar in 81% of subjects and ocular alignment in 94%. Visual acuity was 6/9 or better at the hospital examination in 87% of referred children, with 46% requiring spectacle use only; 17% of referrals were diagnosed with amblyopia. Although the Walsall vision screening program diverged from UK national guidelines by testing at an earlier age, there was no evidence that earlier screening led to a large number of incorrect referrals, and early screening may allow for better outcomes. Sensitivity of screening was not tested, and orthoptist screening in the United Kingdom is likely to be more accurate in this age group than nonspecialist or lay screening that is performed in many other areas. ( J AAPOS 2012;16:49-52)
RESULTS
CONCLUSIONS
V
ision screening in children can detect unsuspected amblyopia or amblyogenic risk factors, allowing for early treatment. In three historical comparison studies,1-3 authors have associated the introduction of preschool vision screening with a lowering of the prevalence of amyblyopia. Hall and Elliman4 recommend that vision screening should be performed by orthoptists between the ages of 4 and 5 years. This recommendation is supported by several UK organizations.5 However, one randomized controlled trial showed that screening led to better visual acuity outcomes if performed before the age of 37 months (compared with a single screening at 37 months).6,7 The vision screening program in Walsall, United Kingdom, is performed exclusively by orthoptists on children 3-4 years of age. In view of the discrepancy Author affiliations: aWolverhampton Eye Infirmary, Wolverhampton, United Kingdom; and bManor Hospital, Walsall, United Kingdom Institution at which the study was conducted: Manor Hospital, Walsall, United Kingdom. Submitted October 3, 2010. Revision accepted June 8, 2011. Published online January 12, 2012. Correspondence: Victor H. Hu, MB, BCh, Birmingham and Midland Eye Centre, Dudley Road, Birmingham, West Midlands, B18 7QH (email: [email protected]). Copyright Ó 2012 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 doi:10.1016/j.jaapos.2011.06.013
Journal of AAPOS
with national guidelines, we conducted a comprehensive review of the Walsall orthoptic vision screening program to determine whether visual acuity and ocular alignment could be accurately assessed in a screening setting at this young age, using a Hospital Eye Service examination as the gold standard for comparison.
Subjects and Methods This was a retrospective review of records from the 2006-2007 school year. Amblyopia was defined was as difference in 2 or more Snellen lines in best-corrected visual acuity with no other identifiable cause of reduced vision. Significant refractive error was defined as one of the following: hyperopia, defined as . 13.0 D; myopia, defined as . 3.0 D; astigmatism, defined as $2.0 D; spherical anisometropia, defined as a difference $1 D; anisometropic astigmatism, defined as a difference of $1.5 D.8 Statistical analysis was performed with STATA 10.0 (StataCorp LP, College Station, TX). Detailed orthoptic examinations included visual acuity testing via the use of Sheridan-Gardiner letters, corneal light reflex assessment testing, cover testing for near and distance, ocular motility testing with a small target, assessment of convergence, a 15D base-out prism reflex test, and Lang stereoacuity testing. Children who missed screening during that school year were screened the following year at 4-5 years of age. The outcomes of the screening visit were as follows: (1) pass; (2) rescreen at
49
50
Hu et al
Volume 16 Number 1 / February 2012
Table 1. Background details of children referred from screening Parameter Sex Male Female Source of referral Nursery Preschool Visual acuity at screening Normal Reduced Not cooperative Main reason for referral Reduced visiona Esophoriab Exophoriab Esotropiab Exotropriab Other Not cooperative a
Table 4. Outcomes of children referred from screening
Number (N 5 413)
%
216 196
52.3 47.7
294 119
71.2 28.8
48 362 3
11.6 87.7 0.7
277 46 46 21 4 15 4
67.1 11.1 11.1 5.1 1.0 3.6 1.0
Without strabismus. With or without reduced vision.
b
Table 2. Outcome of follow-up of referred children Outcome of review
Number (N 5 413)
%
Notes reviewed Notes not found Did not attend appointment Appointment cancelled
291 58 57 7
70.5 14.0 13.8 1.7
Table 3. Comparison of screening and HES findings Findings Visual acuity on HES visit 6/6 or better Worse than 6/6 Uncooperative Visual acuity at HES compared with screening Within 1 Snellen line Better (more than 1 Snellen line difference) Worse (more than 1 Snellen line difference) Uncooperativea Ocular alignment on HES visit No significant squint Esophoria Esotropia Exophoria Exotropia Uncooperative Ocular alignment at HES compared with screening Similar Different Uncooperative
Number (N 5 291)
%
58 232 1
20.0 80.0 0.3
236 32 18 5
81.1 11.0 6.2 1.7
221 21 20 24 4 1
76.0 7.2 6.9 8.2 1.4 0.3
274 16 1
94.2 5.5 0.3
Outcome Refraction Normal Hyperopia Spherical anisometropia Hyperopic Myopic Anisometropic astigmatism Hyperopic Compound Myopic Astigmatism Hyperopic Compound Myopic Total Prescribed spectacles Yes No Total Amblyopia Yes No Total Prescribed occlusion Yes No Total Final visual acuities 6/6 or better Between 6/6 and 6/9 Worse than 6/9 Total Vision improved to normal with spectacles only with no manifest squint or other pathology Yes No Total
na
%
129 43
45.9 15.3
38 2
13.5 0.7
3 13 2
1.1 4.6 0.7
13 37 1 281
4.6 13.2 0.4 100
221 59 280
78.9 21.1 100
41 205 246
16.7 83.3 100
34 211 245
13.9 86.1 100
128 76 30 234
54.7 32.5 12.8 100
117 137 254
46.1 53.9 100
a
HES, Hospital Eye Service. a 4 children at screening and 1 child at the HES were uncooperative. a later date; or (3) refer. Referrals were made to the Walsall Hospital Eye Service, an optician, or a general practitioner or family doctor.
N variable since some children were lost to follow-up after initial visit to Hospital Eye Service from nonattendance, appointment cancelation, or transfer to another unit.
Results In the 2006-2007 school year, of the 3,623 children ages 3-4 in the Walsall area, 3,316 (92%) attended nursery school (data provided by personal communication from Walsall Primary Care Trust). Of these, 2,830 children were screened by orthoptists: 2,124 (58.6%) at nursery school and 706 (19.5%) the following year at school. Of the 2,830 children, 413 (17%) were referred to the Walsall Hospital Eye Service. The baseline details of these children are shown in Table 1. The main reason for referral was poor vision without strabismus, followed by latent strabismus with or without reduced vision. Other reasons for referral included manifest strabismus and a wide range of conditions, such as cataract, ptosis, nystagmus, corneal scarring, Duane retraction syndrome, unexplained vision loss, and latent strabismus. Four children were referred because they were uncooperative during the examination. Reduced vision ranged from 6/9 to 2/60, and 21 children were found to have vision of 6/60 or worse in one eye.
Journal of AAPOS
Volume 16 Number 1 / February 2012
Hu et al
51
Table 5. Comparison of the vision screening in Walsall with other programs
Coverage rate Outcomes of referrals Refractive errorc Amblyopia Strabismus without amblyopiad False positivese Otherf Total Age of screening
Walsall n (%)
Cambridge13 n (%)
Sweden4 n (%)
Cornwall12 n (%)
2830 (78)
8566a (79)
3126b (99)
441 (74)
– – – 83 (30) – 280 (100) 4 and 5.5 years
– – – 18 (5) – 335 (100) 3-4 years
117 (44) 41 (16) 9 (3) 35 (13) 62 (24) 264 (100) 3-4 years
100 (33) 91 (30) 40 (13) 61 (20) 7 (4) 299 (100) 3.5 years
a
Screening from 2 consecutive years. Samples from 2 different years. c Vision improved to normal with spectacles only; no manifest strabismus or other pathology found. d Strabismus, implies a manifest lesion. e Unaided vision found to be normal at the Hospital Eye Service with no manifest squint or other pathology seen. f Includes detection of a range of pathology, including cataract, ptosis, nystagmus, corneal scarring, primary persistent hyperplastic vitreous, Duane’s retraction syndrome, optic nerve hypoplasia, and megalocornea. b
Records of 291 (70%) of the referred children were reviewed (Table 2) and compared with the results of the Hospital Eye Service examinations (Table 3). Visual acuity was within 1 Snellen line equivalent in 236 (81%) of the children. Table 4 lists the outcomes of children referred from the screening program. Spectacles were prescribed for 221 of referred children (79%); vision improved to normal with spectacle use only in 117 (46%). Amblyopia was diagnosed in 41 (17%) of referred children. Of these, 25 had significant refractive error without a manifest strabismus or other abnormality, 7 had esotropia associated with hyperopia, 3 had esotropia without significant refractive error, 1 had exotropia without significant refractive error, and 5 had no detected amblyogenic risk factors. Overall, 53% of children diagnosed with amblyopia achieved a final visual acuity of 6/9 or better in both eyes. Comparison with other screening programs is shown in Table 5.
Discussion Nearly 80% of children received screening in the Walsall vision screening program, which is comparable with the screening rate of other programs in the United Kingdom and Sweden (range, 74%-99%).9-11 The assessment, although described here as a screening, is considerably more detailed than is performed in the United States, where nurses or lay persons performed simplified tests of visual acuity and stereopsis. Visual acuity and ocular alignment results were similar between screening and hospital settings. The falsepositive rate of 13% is comparable with that of other programs (range, 5%-30%).6,9-11 Unfortunately, we were unable to assess the false-negative rate in this study. However, we believe that this rate would have been low because children received a detailed examination by orthoptists and needed to demonstrate good visual acuity to pass the screening examination. Although current UK guidelines recommend screening children when they are between the ages of 4 and 5 years,
Journal of AAPOS
we believe that screening them when they are 3-4 years of age will allow for earlier detection and treatment of amblyopia, which may result in a better long-term outcome. There is some evidence for this from the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC) study group,7 who found slightly less amblyopia and a slightly better outcome in children who received preschool vision screening at 37 months compared with those screened at school entry.6,7 The same study group also found that screening at 37 months compared with school entry led to slightly better visual acuity at age 7.5 years (0.14 vs 0.20 logMAR).12 In favor of delaying screening to school age, the authors of a randomized controlled trial examining treatment of amblyopia showed that delaying treatment until the age of school entry did not limit their potential for improvement and nearly halved the proportion of children needing patching at all.13 In various studies from the Pediatric Eye Disease Investigator Groups,14-17 investigators have shown benefit in amblyopia treatment in children up to the age of 12 years. Our study shows that screening of 3- to 4-yearold patients by orthoptists in a community-based program can complement institutional care and yield an acceptable false-positive rate.
References 1. Kvarnstrom G, Jakobsson P, Lennerstrand G. Screening for visual and ocular disorders in children, evaluation of the system in Sweden. Acta Paediatr 1998;87:1173-9. 2. Eibschitz-Tsimhoni M, Friedman T, Naor J, Eibschitz N, Friedman Z. Early screening for amblyogenic risk factors lowers the prevalence and severity of amblyopia. J AAPOS 2000;4: 194-9. 3. Edwards RS, Abbott AG, Whitelaw AJ. The outcome of preschool visual screening. Br Orthopt J 1993;50:2-6. 4. Hall D, Elliman D. Health for All Children. Oxford: Oxford University Press; 2003. 5. National Screening Committtee. Child health sub-group report on vision screening, May 2005. Available at: www.screening.nhs.uk/ policydb_download.php?doc524. Accessed November 8, 2011.
52
Hu et al
Volume 16 Number 1 / February 2012
6. Williams C, Harrad RA, Harvey I, Sparrow JM. Screening for amblyopia in preschool children: Results of a population-based, randomised controlled trial. ALSPAC Study Team. Avon Longitudinal Study of Pregnancy and Childhood. Ophthalmic Epidemiol 2001;8:279-95. 7. Williams C, Northstone K, Harrad RA, Sparrow JM, Harvey I. Amblyopia treatment outcomes after screening before or at age 3 years: Follow-up from randomised trial. BMJ 2002;324:1549. 8. Holmes JM, Clarke MP. Amblyopia. Lancet 2006;367:1343-51. 9. Ingram RM, Holland WW, Walker C, Wilson JM, Arnold PE, Dally S. Screening for visual defects in preschoolchildren. Br J Ophthalmol 1986;70:16-21. 10. Wormald RP. Preschool vision screening in Cornwall: Performance indicators of community orthoptists. Arch Dis Child 1991;66:917-20. 11. Newman DK, Hitchcock A, McCarthy H, Keast-Butler J, Moore AT. Preschool vision screening: Outcome of children referred to the hospital eye service. Br J Ophthalmol 1996;80:1077-82. 12. Williams C, Northstone K, Harrad RA, Sparrow JM, Harvey I. Amblyopia treatment outcomes after preschool screening v school
13.
14.
15. 16.
17.
entry screening: Observational data from a prospective cohort study. Br J Ophthalmol 2003;87:988-93. Clarke MP, Wright CM, Hrisos S, Anderson JD, Henderson J, Richardson SR. Randomised controlled trial of treatment of unilateral visual impairment detected at preschool vision screening. BMJ 2003; 327:1251. Repka MX, Beck RW, Holmes JM, et al. A randomized trial of patching regimens for treatment of moderate amblyopia in children. Arch Ophthalmol 2003;121:603-11. A randomized trial of atropine vs patching for treatment of moderate amblyopia in children. Arch Ophthalmol 2002;120:268-78. Repka MX, Kraker RT, Beck RW, et al. A randomized trial of atropine vs patching for treatment of moderate amblyopia: Follow-up at age 10 years. Arch Ophthalmol 2008;126: 1039-44. Scheiman MM, Hertle RW, Kraker RT, et al. Patching vs atropine to treat amblyopia in children aged 7 to 12 years: A randomized trial. Arch Ophthalmol 2008;126:1634-42.
An Eye on the Arts—The Arts on the Eye
“‘Doctor,’ he said, ‘please sir.’ ‘You have a questions?’ Bolotin asked, turning to face the student. ‘Yes sir, I do! Are you, I mean, are you really.’ he stopped, red-faced. Boloton smiled patiently. It was the usual question. ‘You want to know if I am really blind.’ ‘Y-y-yes sir,’ the student stammered. ‘Well, I have no eyesight.’ Bolotin replied. ‘I was born blind, but my other senses serve as my eyes, so I feel no handicap.’ ‘But, sir,’ the student persisted, ‘how could you become a doctor?’ Bolotin laughed, ‘It’s a long story. Let’s just say it wasn’t easy!’” —Rosalind Perlman, from The Blind Doctor: The Jacob Bolotin Story (Santa Barbara, California, Blue Point Books, 2007)
Journal of AAPOS
To determine the accuracy of orthoptist referrals from a preschool-based vision screening program for children 3-4 years of age and to report the outcomes of referred children.
METHODS
This was a retrospective review of records of participants in the preschool vision screening program in the Walsall, United Kingdom, area for the 2006-2007 school year. Screening examinations were performed by orthoptists and included assessment of visual acuity, ocular alignment, ocular motility, and stereoacuity. For the 2006-2007 school year, 2,830 of 3,623 children (78%) were screened, Of these, 413 were referred to the Hospital Eye Service. Comparison of the screening results and the Hospital Eye Service examination revealed that recorded visual acuities were similar in 81% of subjects and ocular alignment in 94%. Visual acuity was 6/9 or better at the hospital examination in 87% of referred children, with 46% requiring spectacle use only; 17% of referrals were diagnosed with amblyopia. Although the Walsall vision screening program diverged from UK national guidelines by testing at an earlier age, there was no evidence that earlier screening led to a large number of incorrect referrals, and early screening may allow for better outcomes. Sensitivity of screening was not tested, and orthoptist screening in the United Kingdom is likely to be more accurate in this age group than nonspecialist or lay screening that is performed in many other areas. ( J AAPOS 2012;16:49-52)
RESULTS
CONCLUSIONS
V
ision screening in children can detect unsuspected amblyopia or amblyogenic risk factors, allowing for early treatment. In three historical comparison studies,1-3 authors have associated the introduction of preschool vision screening with a lowering of the prevalence of amyblyopia. Hall and Elliman4 recommend that vision screening should be performed by orthoptists between the ages of 4 and 5 years. This recommendation is supported by several UK organizations.5 However, one randomized controlled trial showed that screening led to better visual acuity outcomes if performed before the age of 37 months (compared with a single screening at 37 months).6,7 The vision screening program in Walsall, United Kingdom, is performed exclusively by orthoptists on children 3-4 years of age. In view of the discrepancy Author affiliations: aWolverhampton Eye Infirmary, Wolverhampton, United Kingdom; and bManor Hospital, Walsall, United Kingdom Institution at which the study was conducted: Manor Hospital, Walsall, United Kingdom. Submitted October 3, 2010. Revision accepted June 8, 2011. Published online January 12, 2012. Correspondence: Victor H. Hu, MB, BCh, Birmingham and Midland Eye Centre, Dudley Road, Birmingham, West Midlands, B18 7QH (email: [email protected]). Copyright Ó 2012 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 doi:10.1016/j.jaapos.2011.06.013
Journal of AAPOS
with national guidelines, we conducted a comprehensive review of the Walsall orthoptic vision screening program to determine whether visual acuity and ocular alignment could be accurately assessed in a screening setting at this young age, using a Hospital Eye Service examination as the gold standard for comparison.
Subjects and Methods This was a retrospective review of records from the 2006-2007 school year. Amblyopia was defined was as difference in 2 or more Snellen lines in best-corrected visual acuity with no other identifiable cause of reduced vision. Significant refractive error was defined as one of the following: hyperopia, defined as . 13.0 D; myopia, defined as . 3.0 D; astigmatism, defined as $2.0 D; spherical anisometropia, defined as a difference $1 D; anisometropic astigmatism, defined as a difference of $1.5 D.8 Statistical analysis was performed with STATA 10.0 (StataCorp LP, College Station, TX). Detailed orthoptic examinations included visual acuity testing via the use of Sheridan-Gardiner letters, corneal light reflex assessment testing, cover testing for near and distance, ocular motility testing with a small target, assessment of convergence, a 15D base-out prism reflex test, and Lang stereoacuity testing. Children who missed screening during that school year were screened the following year at 4-5 years of age. The outcomes of the screening visit were as follows: (1) pass; (2) rescreen at
49
50
Hu et al
Volume 16 Number 1 / February 2012
Table 1. Background details of children referred from screening Parameter Sex Male Female Source of referral Nursery Preschool Visual acuity at screening Normal Reduced Not cooperative Main reason for referral Reduced visiona Esophoriab Exophoriab Esotropiab Exotropriab Other Not cooperative a
Table 4. Outcomes of children referred from screening
Number (N 5 413)
%
216 196
52.3 47.7
294 119
71.2 28.8
48 362 3
11.6 87.7 0.7
277 46 46 21 4 15 4
67.1 11.1 11.1 5.1 1.0 3.6 1.0
Without strabismus. With or without reduced vision.
b
Table 2. Outcome of follow-up of referred children Outcome of review
Number (N 5 413)
%
Notes reviewed Notes not found Did not attend appointment Appointment cancelled
291 58 57 7
70.5 14.0 13.8 1.7
Table 3. Comparison of screening and HES findings Findings Visual acuity on HES visit 6/6 or better Worse than 6/6 Uncooperative Visual acuity at HES compared with screening Within 1 Snellen line Better (more than 1 Snellen line difference) Worse (more than 1 Snellen line difference) Uncooperativea Ocular alignment on HES visit No significant squint Esophoria Esotropia Exophoria Exotropia Uncooperative Ocular alignment at HES compared with screening Similar Different Uncooperative
Number (N 5 291)
%
58 232 1
20.0 80.0 0.3
236 32 18 5
81.1 11.0 6.2 1.7
221 21 20 24 4 1
76.0 7.2 6.9 8.2 1.4 0.3
274 16 1
94.2 5.5 0.3
Outcome Refraction Normal Hyperopia Spherical anisometropia Hyperopic Myopic Anisometropic astigmatism Hyperopic Compound Myopic Astigmatism Hyperopic Compound Myopic Total Prescribed spectacles Yes No Total Amblyopia Yes No Total Prescribed occlusion Yes No Total Final visual acuities 6/6 or better Between 6/6 and 6/9 Worse than 6/9 Total Vision improved to normal with spectacles only with no manifest squint or other pathology Yes No Total
na
%
129 43
45.9 15.3
38 2
13.5 0.7
3 13 2
1.1 4.6 0.7
13 37 1 281
4.6 13.2 0.4 100
221 59 280
78.9 21.1 100
41 205 246
16.7 83.3 100
34 211 245
13.9 86.1 100
128 76 30 234
54.7 32.5 12.8 100
117 137 254
46.1 53.9 100
a
HES, Hospital Eye Service. a 4 children at screening and 1 child at the HES were uncooperative. a later date; or (3) refer. Referrals were made to the Walsall Hospital Eye Service, an optician, or a general practitioner or family doctor.
N variable since some children were lost to follow-up after initial visit to Hospital Eye Service from nonattendance, appointment cancelation, or transfer to another unit.
Results In the 2006-2007 school year, of the 3,623 children ages 3-4 in the Walsall area, 3,316 (92%) attended nursery school (data provided by personal communication from Walsall Primary Care Trust). Of these, 2,830 children were screened by orthoptists: 2,124 (58.6%) at nursery school and 706 (19.5%) the following year at school. Of the 2,830 children, 413 (17%) were referred to the Walsall Hospital Eye Service. The baseline details of these children are shown in Table 1. The main reason for referral was poor vision without strabismus, followed by latent strabismus with or without reduced vision. Other reasons for referral included manifest strabismus and a wide range of conditions, such as cataract, ptosis, nystagmus, corneal scarring, Duane retraction syndrome, unexplained vision loss, and latent strabismus. Four children were referred because they were uncooperative during the examination. Reduced vision ranged from 6/9 to 2/60, and 21 children were found to have vision of 6/60 or worse in one eye.
Journal of AAPOS
Volume 16 Number 1 / February 2012
Hu et al
51
Table 5. Comparison of the vision screening in Walsall with other programs
Coverage rate Outcomes of referrals Refractive errorc Amblyopia Strabismus without amblyopiad False positivese Otherf Total Age of screening
Walsall n (%)
Cambridge13 n (%)
Sweden4 n (%)
Cornwall12 n (%)
2830 (78)
8566a (79)
3126b (99)
441 (74)
– – – 83 (30) – 280 (100) 4 and 5.5 years
– – – 18 (5) – 335 (100) 3-4 years
117 (44) 41 (16) 9 (3) 35 (13) 62 (24) 264 (100) 3-4 years
100 (33) 91 (30) 40 (13) 61 (20) 7 (4) 299 (100) 3.5 years
a
Screening from 2 consecutive years. Samples from 2 different years. c Vision improved to normal with spectacles only; no manifest strabismus or other pathology found. d Strabismus, implies a manifest lesion. e Unaided vision found to be normal at the Hospital Eye Service with no manifest squint or other pathology seen. f Includes detection of a range of pathology, including cataract, ptosis, nystagmus, corneal scarring, primary persistent hyperplastic vitreous, Duane’s retraction syndrome, optic nerve hypoplasia, and megalocornea. b
Records of 291 (70%) of the referred children were reviewed (Table 2) and compared with the results of the Hospital Eye Service examinations (Table 3). Visual acuity was within 1 Snellen line equivalent in 236 (81%) of the children. Table 4 lists the outcomes of children referred from the screening program. Spectacles were prescribed for 221 of referred children (79%); vision improved to normal with spectacle use only in 117 (46%). Amblyopia was diagnosed in 41 (17%) of referred children. Of these, 25 had significant refractive error without a manifest strabismus or other abnormality, 7 had esotropia associated with hyperopia, 3 had esotropia without significant refractive error, 1 had exotropia without significant refractive error, and 5 had no detected amblyogenic risk factors. Overall, 53% of children diagnosed with amblyopia achieved a final visual acuity of 6/9 or better in both eyes. Comparison with other screening programs is shown in Table 5.
Discussion Nearly 80% of children received screening in the Walsall vision screening program, which is comparable with the screening rate of other programs in the United Kingdom and Sweden (range, 74%-99%).9-11 The assessment, although described here as a screening, is considerably more detailed than is performed in the United States, where nurses or lay persons performed simplified tests of visual acuity and stereopsis. Visual acuity and ocular alignment results were similar between screening and hospital settings. The falsepositive rate of 13% is comparable with that of other programs (range, 5%-30%).6,9-11 Unfortunately, we were unable to assess the false-negative rate in this study. However, we believe that this rate would have been low because children received a detailed examination by orthoptists and needed to demonstrate good visual acuity to pass the screening examination. Although current UK guidelines recommend screening children when they are between the ages of 4 and 5 years,
Journal of AAPOS
we believe that screening them when they are 3-4 years of age will allow for earlier detection and treatment of amblyopia, which may result in a better long-term outcome. There is some evidence for this from the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC) study group,7 who found slightly less amblyopia and a slightly better outcome in children who received preschool vision screening at 37 months compared with those screened at school entry.6,7 The same study group also found that screening at 37 months compared with school entry led to slightly better visual acuity at age 7.5 years (0.14 vs 0.20 logMAR).12 In favor of delaying screening to school age, the authors of a randomized controlled trial examining treatment of amblyopia showed that delaying treatment until the age of school entry did not limit their potential for improvement and nearly halved the proportion of children needing patching at all.13 In various studies from the Pediatric Eye Disease Investigator Groups,14-17 investigators have shown benefit in amblyopia treatment in children up to the age of 12 years. Our study shows that screening of 3- to 4-yearold patients by orthoptists in a community-based program can complement institutional care and yield an acceptable false-positive rate.
References 1. Kvarnstrom G, Jakobsson P, Lennerstrand G. Screening for visual and ocular disorders in children, evaluation of the system in Sweden. Acta Paediatr 1998;87:1173-9. 2. Eibschitz-Tsimhoni M, Friedman T, Naor J, Eibschitz N, Friedman Z. Early screening for amblyogenic risk factors lowers the prevalence and severity of amblyopia. J AAPOS 2000;4: 194-9. 3. Edwards RS, Abbott AG, Whitelaw AJ. The outcome of preschool visual screening. Br Orthopt J 1993;50:2-6. 4. Hall D, Elliman D. Health for All Children. Oxford: Oxford University Press; 2003. 5. National Screening Committtee. Child health sub-group report on vision screening, May 2005. Available at: www.screening.nhs.uk/ policydb_download.php?doc524. Accessed November 8, 2011.
52
Hu et al
Volume 16 Number 1 / February 2012
6. Williams C, Harrad RA, Harvey I, Sparrow JM. Screening for amblyopia in preschool children: Results of a population-based, randomised controlled trial. ALSPAC Study Team. Avon Longitudinal Study of Pregnancy and Childhood. Ophthalmic Epidemiol 2001;8:279-95. 7. Williams C, Northstone K, Harrad RA, Sparrow JM, Harvey I. Amblyopia treatment outcomes after screening before or at age 3 years: Follow-up from randomised trial. BMJ 2002;324:1549. 8. Holmes JM, Clarke MP. Amblyopia. Lancet 2006;367:1343-51. 9. Ingram RM, Holland WW, Walker C, Wilson JM, Arnold PE, Dally S. Screening for visual defects in preschoolchildren. Br J Ophthalmol 1986;70:16-21. 10. Wormald RP. Preschool vision screening in Cornwall: Performance indicators of community orthoptists. Arch Dis Child 1991;66:917-20. 11. Newman DK, Hitchcock A, McCarthy H, Keast-Butler J, Moore AT. Preschool vision screening: Outcome of children referred to the hospital eye service. Br J Ophthalmol 1996;80:1077-82. 12. Williams C, Northstone K, Harrad RA, Sparrow JM, Harvey I. Amblyopia treatment outcomes after preschool screening v school
13.
14.
15. 16.
17.
entry screening: Observational data from a prospective cohort study. Br J Ophthalmol 2003;87:988-93. Clarke MP, Wright CM, Hrisos S, Anderson JD, Henderson J, Richardson SR. Randomised controlled trial of treatment of unilateral visual impairment detected at preschool vision screening. BMJ 2003; 327:1251. Repka MX, Beck RW, Holmes JM, et al. A randomized trial of patching regimens for treatment of moderate amblyopia in children. Arch Ophthalmol 2003;121:603-11. A randomized trial of atropine vs patching for treatment of moderate amblyopia in children. Arch Ophthalmol 2002;120:268-78. Repka MX, Kraker RT, Beck RW, et al. A randomized trial of atropine vs patching for treatment of moderate amblyopia: Follow-up at age 10 years. Arch Ophthalmol 2008;126: 1039-44. Scheiman MM, Hertle RW, Kraker RT, et al. Patching vs atropine to treat amblyopia in children aged 7 to 12 years: A randomized trial. Arch Ophthalmol 2008;126:1634-42.
An Eye on the Arts—The Arts on the Eye
“‘Doctor,’ he said, ‘please sir.’ ‘You have a questions?’ Bolotin asked, turning to face the student. ‘Yes sir, I do! Are you, I mean, are you really.’ he stopped, red-faced. Boloton smiled patiently. It was the usual question. ‘You want to know if I am really blind.’ ‘Y-y-yes sir,’ the student stammered. ‘Well, I have no eyesight.’ Bolotin replied. ‘I was born blind, but my other senses serve as my eyes, so I feel no handicap.’ ‘But, sir,’ the student persisted, ‘how could you become a doctor?’ Bolotin laughed, ‘It’s a long story. Let’s just say it wasn’t easy!’” —Rosalind Perlman, from The Blind Doctor: The Jacob Bolotin Story (Santa Barbara, California, Blue Point Books, 2007)
Journal of AAPOS