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The high prevalence of AAPOS amblyopia risk factors
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Volume 15 Number 1 / February 2011
Discussion: The Infant Aphakia Treatment Study revealed that 88% of all unilateral cataract cases were associated with a posterior capsular plaque. All children with a nuclear opacity in the IATS (45/45) had an associated posterior capsular plaque. Observations such as this have led to the hypothesis that most unilateral cataracts are the result of a mild form of persistent fetal vasculature (PFV), even if no obvious hyaloid remnant is visible. If true, children with bilateral congenital cataracts should be less likely to have posterior capsular plaques. Conclusions: The lower incidence of posterior capsular plaque in bilateral congenital cataract lends presumptive evidence to the hypothesis that unilateral lens opacities may represent a variant of persistent fetal vasculature.
Results: Conventional vision assessment could not be performed on 4 children due to lack of cooperation. In all 4 cases however, the children demonstrated interest in the OKN-video and an OKN-visionscore could be obtained. A favorable association was found between the scores of the OKN-tool and the distance-equivalent scores of the conventional tests for the 42 remaining children (Spearman rank correlation, 0.3602, p-value, 0.0044). Discussion: These preliminary results suggest that our OKN-video tool is a reliable test that is particularly useful in cases resistant to conventional testing. Conclusions: An alternative and new computer based OKN-video tool is a promising, cost-effective and user-friendly option for assessing infant's and toddler's visual acuity.
Papers
007 The high prevalence of AAPOS amblyopia risk factors. Robert W. Arnold Purpose: In 2003, the Vision Screen Committee of AAPOS published the consensus of anatomic and refractive risk factor levels for amblyopia in preschoolers to provide critical comparability between researchers, manufacturers and policymakers. We do not yet have direct evidence for the prevalence of these risk factors. Methods: All available large-scale, non-enhanced, population studies with confirmatory exams were analyzed by manuscript review and correspondence. Independent and priority risk factor prevalence was either directly extracted, or derived through curvilinear interpolation between non-AAPOS threshold levels. The inter-dependence of some risk factors was estimated. Results: From 12,107 complete eye exams on preschoolers, the estimated prevalence of media opacity was 0.1%, constant strabismus 1%, anisometropia .1.5D 1.2%, Hyperopia . 3.5D 5.5%, Astigmatism .1.5D (or .1.0D oblique) 8%, myopia .3D 1%, ptosis 1%, Acuity less than 20/40 5%. Accounting for coincident risk factors in certain patients, about 17 4% of normal preschoolers have AAPOS amblyopia risk factors. VIPS prevalences were moderately higher. Discussion: The estimated prevalence of substantial amblyopia (2 or more lines difference or \ 20/40) is only about 2% whereas 8 times that many have one or more AAPOS risk factors. Perhaps many such children adequately compensate for their risk factors. Conclusions: This higher-than-expected prevalence has important implications for interpreting vision screen research; a perfect sensitivity is not necessarily desired.
005 Development of fusional vergence in patients with a history of strabismic amblyopia who are treated with Bangerter foils. Michael S. Abrams, Candace L. Duncan, Ryan McMurtney Purpose: To document the development of motor fusion when patients with a history of strabismic amblyopia are treated parttime with Bangerter foils. Methods: This was a prospective interventional outcome study of consecutive patients with a history of strabismic amblyopia, horizontal strabismus (only) # 20Δ, visual acuity of 20/60 or better in the non-fixating eye, and no surgery or motor fusion (as indicated by the absence of prism vergence) for one year prior to study entry. Subjects wore a 0.1 density Bangerter foil 3-4 hours per day. Data on visual acuity, alignment and motor fusion status were collected for a minimum of 2 years. Patients were then followed for a minimum of 18 months to assess the stability of their motor fusion status after the Bangerter foil was discontinued. Results: Of the 46 patients (mean age, 5.3 1.7 years) who completed follow-up, 28 (61%) developed motor fusion. Motor fusion was retained in all 17 patients followed after the foil was discontinued for a mean of 13.3 months. Discussion: Many believe a child's motor fusion status is established during an early formative period of visual development. The development of motor fusion in many of our patients during the course of part-time Bangerter foil treatment suggests that improvements in motor fusion status can occur later than previously believed. Conclusions: To our knowledge this is the first observation of the development of motor fusion in a substantial proportion of patients with a history of strabismic amblyopia who did not previously have evidence of motor fusion. 006 A novel video tool for the assessment of infants visual acuity. Irene Anteby, Claudia Yahalom, Hadas Mechoulam, Karen Hendler, Evelyne Cohen, Ilana Karshai, Joshua Kruger Introduction: Preferential visual acuity cards allow for the quantification of an infant's visual acuity. Their use in clinics is limited however, due to the equipment costs, skills and time required to administer the test. Visual acuity can be assessed by testing for optokinetic nystagmus (OKN). We have developed a computer-screen OKN-movie for infants that determines visual acuity by presenting variously sized OKN stimuli. Methods: In this pilot study, 46 children, ranging between 4 months and 12 years, were assessed both with our tool and a conventional near-vision test (Teller, Lea symbols, or Jaeger). Both normal and diseased eyes were assessed. The study was approved by the local Helsinki ethics review board.
008 Central corneal thickness in children. Yasmin Bradfield, Michael Repka, Brett Kaminski Purpose: To report the central corneal thickness (CCT) in healthy white, African American, and Hispanic children from birth to 17 years of age. Methods: Children from birth to 17 years of age with normal corneas had CCT measured in the clinic or under general anesthesia using a single model of pachymeter. Results: 2079 children were studied (807 White, 494 Hispanic, 474 African-American, 177 Asian, and 127 of mixed, other or unknown race). African-American children had thinner corneas on average than those of both white (p \ .001) and Hispanic children (p \ .001) by approximately 20 mm. The range of normal CCT between the 5th and 95th reference percentiles at any age is about 120 mm. Thicker median CCT was observed with each successive year of age from 1 to 11 years, with differences from the prior year steadily decreasing and reaching a plateau at 573 mm in white and Hispanic children and 551 mm in African American children. For every 100 mm of thicker CCT
Journal of AAPOS
Volume 15 Number 1 / February 2011
Discussion: The Infant Aphakia Treatment Study revealed that 88% of all unilateral cataract cases were associated with a posterior capsular plaque. All children with a nuclear opacity in the IATS (45/45) had an associated posterior capsular plaque. Observations such as this have led to the hypothesis that most unilateral cataracts are the result of a mild form of persistent fetal vasculature (PFV), even if no obvious hyaloid remnant is visible. If true, children with bilateral congenital cataracts should be less likely to have posterior capsular plaques. Conclusions: The lower incidence of posterior capsular plaque in bilateral congenital cataract lends presumptive evidence to the hypothesis that unilateral lens opacities may represent a variant of persistent fetal vasculature.
Results: Conventional vision assessment could not be performed on 4 children due to lack of cooperation. In all 4 cases however, the children demonstrated interest in the OKN-video and an OKN-visionscore could be obtained. A favorable association was found between the scores of the OKN-tool and the distance-equivalent scores of the conventional tests for the 42 remaining children (Spearman rank correlation, 0.3602, p-value, 0.0044). Discussion: These preliminary results suggest that our OKN-video tool is a reliable test that is particularly useful in cases resistant to conventional testing. Conclusions: An alternative and new computer based OKN-video tool is a promising, cost-effective and user-friendly option for assessing infant's and toddler's visual acuity.
Papers
007 The high prevalence of AAPOS amblyopia risk factors. Robert W. Arnold Purpose: In 2003, the Vision Screen Committee of AAPOS published the consensus of anatomic and refractive risk factor levels for amblyopia in preschoolers to provide critical comparability between researchers, manufacturers and policymakers. We do not yet have direct evidence for the prevalence of these risk factors. Methods: All available large-scale, non-enhanced, population studies with confirmatory exams were analyzed by manuscript review and correspondence. Independent and priority risk factor prevalence was either directly extracted, or derived through curvilinear interpolation between non-AAPOS threshold levels. The inter-dependence of some risk factors was estimated. Results: From 12,107 complete eye exams on preschoolers, the estimated prevalence of media opacity was 0.1%, constant strabismus 1%, anisometropia .1.5D 1.2%, Hyperopia . 3.5D 5.5%, Astigmatism .1.5D (or .1.0D oblique) 8%, myopia .3D 1%, ptosis 1%, Acuity less than 20/40 5%. Accounting for coincident risk factors in certain patients, about 17 4% of normal preschoolers have AAPOS amblyopia risk factors. VIPS prevalences were moderately higher. Discussion: The estimated prevalence of substantial amblyopia (2 or more lines difference or \ 20/40) is only about 2% whereas 8 times that many have one or more AAPOS risk factors. Perhaps many such children adequately compensate for their risk factors. Conclusions: This higher-than-expected prevalence has important implications for interpreting vision screen research; a perfect sensitivity is not necessarily desired.
005 Development of fusional vergence in patients with a history of strabismic amblyopia who are treated with Bangerter foils. Michael S. Abrams, Candace L. Duncan, Ryan McMurtney Purpose: To document the development of motor fusion when patients with a history of strabismic amblyopia are treated parttime with Bangerter foils. Methods: This was a prospective interventional outcome study of consecutive patients with a history of strabismic amblyopia, horizontal strabismus (only) # 20Δ, visual acuity of 20/60 or better in the non-fixating eye, and no surgery or motor fusion (as indicated by the absence of prism vergence) for one year prior to study entry. Subjects wore a 0.1 density Bangerter foil 3-4 hours per day. Data on visual acuity, alignment and motor fusion status were collected for a minimum of 2 years. Patients were then followed for a minimum of 18 months to assess the stability of their motor fusion status after the Bangerter foil was discontinued. Results: Of the 46 patients (mean age, 5.3 1.7 years) who completed follow-up, 28 (61%) developed motor fusion. Motor fusion was retained in all 17 patients followed after the foil was discontinued for a mean of 13.3 months. Discussion: Many believe a child's motor fusion status is established during an early formative period of visual development. The development of motor fusion in many of our patients during the course of part-time Bangerter foil treatment suggests that improvements in motor fusion status can occur later than previously believed. Conclusions: To our knowledge this is the first observation of the development of motor fusion in a substantial proportion of patients with a history of strabismic amblyopia who did not previously have evidence of motor fusion. 006 A novel video tool for the assessment of infants visual acuity. Irene Anteby, Claudia Yahalom, Hadas Mechoulam, Karen Hendler, Evelyne Cohen, Ilana Karshai, Joshua Kruger Introduction: Preferential visual acuity cards allow for the quantification of an infant's visual acuity. Their use in clinics is limited however, due to the equipment costs, skills and time required to administer the test. Visual acuity can be assessed by testing for optokinetic nystagmus (OKN). We have developed a computer-screen OKN-movie for infants that determines visual acuity by presenting variously sized OKN stimuli. Methods: In this pilot study, 46 children, ranging between 4 months and 12 years, were assessed both with our tool and a conventional near-vision test (Teller, Lea symbols, or Jaeger). Both normal and diseased eyes were assessed. The study was approved by the local Helsinki ethics review board.
008 Central corneal thickness in children. Yasmin Bradfield, Michael Repka, Brett Kaminski Purpose: To report the central corneal thickness (CCT) in healthy white, African American, and Hispanic children from birth to 17 years of age. Methods: Children from birth to 17 years of age with normal corneas had CCT measured in the clinic or under general anesthesia using a single model of pachymeter. Results: 2079 children were studied (807 White, 494 Hispanic, 474 African-American, 177 Asian, and 127 of mixed, other or unknown race). African-American children had thinner corneas on average than those of both white (p \ .001) and Hispanic children (p \ .001) by approximately 20 mm. The range of normal CCT between the 5th and 95th reference percentiles at any age is about 120 mm. Thicker median CCT was observed with each successive year of age from 1 to 11 years, with differences from the prior year steadily decreasing and reaching a plateau at 573 mm in white and Hispanic children and 551 mm in African American children. For every 100 mm of thicker CCT
Journal of AAPOS