Vision In Preschoolers Research Articles

Vision Screening, Vision Disorders, and Impacts of Hyperopia in Young Children: Outcomes of the Vision in Preschoolers (VIP) and Vision in Preschoolers - Hyperopia in Preschoolers (VIP-HIP) Studies.

This review summarizes clinically relevant outcomes from the Vision in Preschoolers (VIP) and VIP-Hyperopia in Preschoolers (VIP-HIP) studies. In VIP, refraction tests (retinoscopy, Retinomax, SureSight) and Lea Symbols Visual Acuity performed best in identifying children with vision disorders. For lay screeners, Lea Symbols single, crowded visual acuity (VA) testing (VIP, 5-foot) was significantly better than linear, crowded testing (10-foot). Children unable to perform the tests (<2%) were more likely to have vision disorders than children who passed and should be referred for vision evaluation. Among racial/ethnic groups, the prevalence of amblyopia and strabismus was similar while that of hyperopia, astigmatism, and anisometropia varied. The presence of strabismus and significant refractive errors were risk factors for unilateral amblyopia, while bilateral astigmatism and bilateral hyperopia were risk factors for bilateral amblyopia. A greater risk of astigmatism was associated with Hispanic, African American, and Asian race, and myopic and hyperopic refractive error. The presence and severity of hyperopia were associated with higher rates of amblyopia, strabismus, and other associated refractive error. In the VIP-HIP study, compared to emmetropes, meaningful deficits in early literacy were observed in uncorrected hyperopic 4- and 5-year-olds [≥+4.0 diopter (D) or ≥+3.0 D to ≤+6.0 D associated with reduced near visual function (near VA 20/40 or worse; stereoacuity worse than 240")]. Hyperopia with reduced near visual function also was associated with attention deficits. Compared to emmetropic children, VA (distance, near), accommodative accuracy, and stereoacuity were significantly reduced in moderate hyperopes, with the greatest risk in those with higher hyperopia. Increasing hyperopia was associated with decreasing visual function.

Detection of Significant Hyperopia in Preschool Children Using Two Automated Vision Screeners.

Moderate to high uncorrected hyperopia in preschool children is associated with amblyopia, strabismus, reduced visual function, and reduced literacy. Detecting significant hyperopia during screening is important to allow children to be followed for development of amblyopia or strabismus and implementation of any needed ophthalmic or educational interventions. This study aimed to compare the sensitivity and specificity of two automated screening devices to identify preschool children with moderate to high hyperopia. Children in the Vision in Preschoolers (VIP) study were screened with the Retinomax Autorefractor (Nikon, Inc., Melville, NY) and Plusoptix Power Refractor II (Plusoptix, Nuremberg, Germany) and examined by masked eye care professionals to detect the targeted conditions of amblyopia, strabismus, or significant refractive error, and reduced visual acuity. Significant hyperopia (American Association for Pediatric Ophthalmology and Strabismus definition of hyperopia as an amblyopia risk factor), based on cycloplegic retinoscopy, was >4.00 D for age 36 to 48 months and >3.50 D for age older than 48 months. Referral criteria from VIP for each device and from a distributor (PediaVision) for the Power Refractor II were applied to screening results. Among 1430 children, 132 children had significant hyperopia in at least one eye. Using the VIP referral criteria, sensitivities for significant hyperopia were 80.3% for the Retinomax and 69.7% for the Power Refractor II (difference, 10.6%; 95% confidence interval, 7.0 to 20.5%; P = .04); specificities relative to any targeted condition were 89.9 and 89.1%, respectively. Using the PediaVision referral criteria for the Power Refractor, sensitivity for significant hyperopia was 84.9%; however, specificity relative to any targeted condition was 78.3%, 11.6% lower than the specificity for the Retinomax. Analyses using the VIP definition of significant hyperopia yielded results similar to when the American Association for Pediatric Ophthalmology and Strabismus definition was used. When implementing vision screening programs for preschool children, the potential for automated devices that use eccentric photorefraction to either miss detecting significant hyperopia or increase false-positive referrals must be taken into consideration.

Associations between visual function and magnitude of refractive error for emmetropic to moderately hyperopic 4‐ and 5‐year‐old children in the Vision in Preschoolers ‐ Hyperopia in Preschoolers Study

To evaluate associations between visual function and the level of uncorrected hyperopia in 4- and 5-year-old children without strabismus or amblyopia. Children with spherical equivalent (SE) cycloplegic refractive error of -0.75 to +6.00 on eligibility testing for the Vision in Preschoolers-Hyperopia in Preschoolers (VIP-HIP) study were included. Children were grouped as emmetropic (<1D SE myopia or hyperopia), low hyperopic (+1 to <+3D SE) or moderate hyperopic (+3 to +6D SE). Children with anisometropia or astigmatism (≥1D), amblyopia or strabismus were excluded. Visual functions assessed were monocular distance visual acuity (VA) and binocular near VA with crowded HOTV charts, accommodative lag using the Monocular Estimation Method and near stereoacuity by 'Preschool Assessment of Stereopsis with a Smile'. Visual functions were compared as continuous measures among refractive error groups. 554 children (mean age 58months) were included in the analysis. Mean SE (SD) {N} for emmetropia, low and moderate hyperopia were +0.52D (0.49) {N=270}, +2.18D (0.57) {N=171} and +3.95D (0.78) {N=113}, respectively. There was a consistent trend of poorer visual function with increasing hyperopia (p<0.001). Although all children had age-normal distance VA, logMAR (Snellen) VA of 0.00 (6/6) or better was achieved (distance, near) among more emmetropic (52%, 26%) and low hyperopic (47%, 15%) children than moderate hyperopes (25%, 9%). Mean (SD) distance logMAR VA declined from emmetropic 0.05 (0.10), to low hyperopic 0.06 (0.10) to moderately hyperopic children 0.12 (0.11) (p<0.001); A mild progressive decrease in near VA also was observed from the emmetropic 0.13 (0.11) to low hyperopic 0.15 (0.10) to moderate hyperopic 0.19 (0.11) groups, (p<0.001). Accommodative responses showed an increased lag with increasing hyperopia (ρ=0.50, p<0.001). Median near stereoacuity for emmetropes, low and moderate hyperopes was 40, 60 and 120 sec arc, respectively. The percentage of these groups with no reduced near visual functions was 83%, 61%, and 34%, respectively. Decreasing visual function was associated with increasing hyperopia in 4- and 5-year-olds without strabismus or amblyopia. As hyperopia with reduced visual function has been associated with early literacy deficits, near visual function should be evaluated in these children.

Comparison of cycloplegic refraction between Grand Seiko autorefractor and Retinomax autorefractor in the Vision in Preschoolers–Hyperopia in Preschoolers (VIP-HIP) Study

To evaluate the agreement of cycloplegic refractive error measures between the Grand Seiko and Retinomax autorefractors in 4- and 5-year-old children. Cycloplegic refractive error of children was measured using the Grand Seiko and Retinomax during a comprehensive eye examination. Accommodative error was measured using the Grand Seiko. The differences in sphere, cylinder, spherical equivalent (SE) and intereye vector dioptric distance (VDD) between autorefractors were assessed using the Bland-Altman plot and 95% limits of agreement (95% LoA). A total of 702 examinations were included. Compared to the Retinomax, the Grand Seiko provided statistically significantly larger values of sphere (mean difference, 0.34 D; 95% LoA, -0.46 to 1.14 D), SE (mean, 0.25 D; 95% LoA, -0.55 to 1.05 D), VDD (mean, 0.19 D; 95% LoA, -0.67 to 1.05 D), and more cylinder (mean, -0.18 D; 95% LoA, -0.91 to 0.55 D). The Grand Seiko measured ≥0.5 D than Retinomax in 43.1% of eyes for sphere and 29.8% of eyes for SE. In multivariate analysis, eyes with SE of >4 D (based on the average of two autorefractors) had larger differences in sphere (mean, 0.66 D vs 0.35 D; P<0.0001) and SE (0.57 D vs 0.26 D; P<0.0001) than eyes with SE of ≤4 D. Under cycloplegia, the Grand Seiko provided higher measures of sphere, more cylinder, and higher SE than the Retinomax. Higher refractive error was associated with larger differences in sphere and SE between the Grand Seiko and Retinomax.

Visual Function of Moderately Hyperopic 4- and 5-Year-Old Children in the Vision in Preschoolers – Hyperopia in Preschoolers Study

To compare visual performance between emmetropic and uncorrected moderately hyperopic preschool-age children without strabismus or amblyopia. Cross-sectional study. setting: Multicenter, institutional. patient or study population: Children aged 4 or 5 years. intervention or observation procedures: Visual functions were classified as normal or reduced for each child based on the 95% confidence interval for emmetropic individuals. Hyperopic (≥3.0 diopters [D] to ≤6.0 D in the most hyperopic meridian; astigmatism ≤1.50 D; anisometropia ≤1.0 D) and emmetropic status were determined by cycloplegic autorefraction. Uncorrected monocular distance and binocular near visual acuity (VA); accommodative response; and near random dot stereoacuity. Mean (± standard deviation) logMAR distance visual acuity (VA) among 248 emmetropic children was better than among 244 hyperopic children for the better (0.05 ± 0.10 vs 0.14 ± 0.11, P < .001) and worse eyes (0.10 ± 0.11 vs 0.19 ± 0.10, P < .001). Mean binocular logMAR near VA was better in emmetropic than in hyperopic children (0.13 ± 0.11 vs 0.21 ± 0.11, P < .001). Mean accommodative response for emmetropic children was lower than for hyperopic subjects for both Monocular Estimation Method (1.03 ± 0.51 D vs 2.03 ± 1.03 D, P < .001) and Grand Seiko (0.46 ± 0.45 D vs 0.99 ± 1.0 D, P < .001). Median near stereoacuity was better in emmetropic than in than hyperopic children (40 sec arc vs 120 sec arc, P < .001). The average number of reduced visual functions was lower in emmetropic than in hyperopic children (0.19 vs 1.0, P < .001). VA, accommodative response, and stereoacuity were significantly reduced in moderate uncorrected hyperopic preschool children compared to emmetropic subjects. Those with higher hyperopia (≥4 D to ≤6 D) were at greatest risk, although more than half of children with lower magnitudes (≥3 D to <4 D) demonstrated 1 or more reductions in function.

Improving vision in underserved Los Angeles County preschoolers

Improving vision in underserved Los Angeles County preschoolers

Risk factors for astigmatism in the Vision in Preschoolers Study.

To determine demographic and refractive risk factors for astigmatism in the Vision in Preschoolers Study. Three- to 5-year-old Head Start preschoolers (N = 4040) from five clinical centers underwent comprehensive eye examinations by study-certified optometrists and ophthalmologists, including monocular visual acuity testing, cover testing, and cycloplegic retinoscopy. Astigmatism was defined as the presence of greater than or equal to +1.5 diopters (D) cylinder in either eye, measured with cycloplegic refraction. The associations of risk factors with astigmatism were evaluated using the odds ratio (OR) and its 95% confidence interval (CI) from logistic regression models. Among 4040 Vision in Preschoolers Study participants overrepresenting children with vision disorders, 687 (17%) had astigmatism, and most (83.8%) had with-the-rule astigmatism. In multivariate analyses, African American (OR, 1.65; 95% CI, 1.22 to 2.24), Hispanic (OR, 2.25; 95% CI, 1.62 to 3.12), and Asian (OR, 1.76; 95% CI, 1.06 to 2.93) children were more likely to have astigmatism than non-Hispanic white children, whereas American Indian children were less likely to have astigmatism than Hispanic, African American, and Asian children (p < 0.0001). Refractive error was associated with astigmatism in a nonlinear manner, with an OR of 4.50 (95% CI, 3.00 to 6.76) for myopia (≤-1.0 D in spherical equivalent) and 1.55 (95% CI, 1.29 to 1.86) for hyperopia (≥+2.0 D) when compared with children without refractive error (>-1.0 D, <+2.0 D). There was a trend of an increasing percentage of astigmatism among older children (linear trend p = 0.06). The analysis for risk factors of with-the-rule astigmatism provided similar results. Among Head Start preschoolers, Hispanic, African American, and Asian race as well as myopic and hyperopic refractive error were associated with an increased risk of astigmatism, consistent with findings from the population-based Multi-ethnic Pediatric Eye Disease Study and the Baltimore Pediatric Eye Disease Study. American Indian children had lower risk of astigmatism.

Stereoacuity of preschool children with and without vision disorders.

To evaluate associations between stereoacuity and presence, type, and severity of vision disorders in Head Start preschool children and determine testability and levels of stereoacuity by age in children without vision disorders. Stereoacuity of children aged 3 to 5 years (n = 2898) participating in the Vision in Preschoolers (VIP) Study was evaluated using the Stereo Smile II test during a comprehensive vision examination. This test uses a two-alternative forced-choice paradigm with four stereoacuity levels (480 to 60 seconds of arc). Children were classified by the presence (n = 871) or absence (n = 2027) of VIP Study-targeted vision disorders (amblyopia, strabismus, significant refractive error, or unexplained reduced visual acuity), including type and severity. Median stereoacuity between groups and among severity levels of vision disorders was compared using Wilcoxon rank sum and Kruskal-Wallis tests. Testability and stereoacuity levels were determined for children without VIP Study-targeted disorders overall and by age. Children with VIP Study-targeted vision disorders had significantly worse median stereoacuity than that of children without vision disorders (120 vs. 60 seconds of arc, p < 0.001). Children with the most severe vision disorders had worse stereoacuity than that of children with milder disorders (median 480 vs. 120 seconds of arc, p < 0.001). Among children without vision disorders, testability was 99.6% overall, increasing with age to 100% for 5-year-olds (p = 0.002). Most of the children without vision disorders (88%) had stereoacuity at the two best disparities (60 or 120 seconds of arc); the percentage increasing with age (82% for 3-, 89% for 4-, and 92% for 5-year-olds; p < 0.001). The presence of any VIP Study-targeted vision disorder was associated with significantly worse stereoacuity in preschool children. Severe vision disorders were more likely associated with poorer stereopsis than milder or no vision disorders. Testability was excellent at all ages. These results support the validity of the Stereo Smile II for assessing random-dot stereoacuity in preschool children.

Risk Factors for Amblyopia in the Vision in Preschoolers Study

To evaluate risk factors for unilateral amblyopia and for bilateral amblyopia in the Vision in Preschoolers (VIP) study. Multicenter, cross-sectional study. Three- to 5-year-old Head Start preschoolers from 5 clinical centers, overrepresenting children with vision disorders. All children underwent comprehensive eye examinations, including threshold visual acuity (VA), cover testing, and cycloplegic retinoscopy, performed by VIP-certified optometrists and ophthalmologists who were experienced in providing care to children. Monocular threshold VA was tested using a single-surround HOTV letter protocol without correction, and retested with full cycloplegic correction when retest criteria were met. Unilateral amblyopia was defined as an interocular difference in best-corrected VA of 2 lines or more. Bilateral amblyopia was defined as best-corrected VA in each eye worse than 20/50 for 3-year-olds and worse than 20/40 for 4- to 5-year-olds. Risk of amblyopia was summarized by the odds ratios and their 95% confidence intervals estimated from logistic regression models. In this enriched sample of Head Start children (n = 3869), 296 children (7.7%) had unilateral amblyopia, and 144 children (3.7%) had bilateral amblyopia. Presence of strabismus (P<0.0001) and greater magnitude of significant refractive errors (myopia, hyperopia, astigmatism, and anisometropia; P<0.00001 for each) were associated independently with an increased risk of unilateral amblyopia. Presence of strabismus, hyperopia of 2.0 diopters (D) or more, astigmatism of 1.0 D or more, or anisometropia of 0.5 D or more were present in 91% of children with unilateral amblyopia. Greater magnitude of astigmatism (P<0.0001) and bilateral hyperopia (P<0.0001) were associated independently with increased risk of bilateral amblyopia. Bilateral hyperopia of 3.0 D or more or astigmatism of 1.0 D or more were present in 76% of children with bilateral amblyopia. Strabismus and significant refractive errors were risk factors for unilateral amblyopia. Bilateral astigmatism and bilateral hyperopia were risk factors for bilateral amblyopia. Despite differences in selection of the study population, these results validated the findings from the Multi-Ethnic Pediatric Eye Disease Study and Baltimore Pediatric Eye Disease Study.

Comparison between the PlusoptiX and IScreen Photoscreeners in Detecting Amblyopic Risk Factors in Children

Purpose: To compare the accuracy of plusoptiX A08 photoscreener (PPS) and iScreen 3000 photoscreener (IPS) in objectively screening for amblyopic risk factors in children age 5 months to 13 years old. Methods: Cross-sectional study of 148 children who received photoscreenings via PPS and IPS and a comprehensive pediatric ophthalmic examination in our office. Patients were considered to have amblyogenic risk factors based on the AAPOS referral criteria guidelines. Results: 45 percent of patients undergoing a pediatric ophthalmology examination were found to have amblyopia or amblyogenic risk factors. In this study, PPS demonstrated an overall sensitivity of 75.4%, specificity of 68.0%, positive predictive value (PPV) of 67.1%, and negative predictive value (NPV) of 76.1%. However, IPS photoscreener had an overall sensitivity of 66.2%, specificity of 87.6%, PPV of 81.8%, and NPV of 75.5%. Discussion: The accuracy of PPS and IPS was compared in different age groups. The sensitivity and specificity were analyzed according to varied amblyogenic risk factors. The statistic results of this study were compared to those of previous studies, including Vision in Preschoolers (VIP) Study and the Iowa PhotoScreening Program. Conclusion: PPS and IPS proved to be useful tools in the objective vision screening in children. PPS was found to have a higher sensitivity, and IPS showed a higher specificity and PPV in detecting amblyopic risk factors. In conclusion, one device may be more beneficial over the other, depending on the patient population and office settings.

Associations of Anisometropia with Unilateral Amblyopia, Interocular Acuity Difference, and Stereoacuity in Preschoolers

To evaluate the relationship of anisometropia with unilateral amblyopia, interocular acuity difference (IAD), and stereoacuity among Head Start preschoolers using both clinical notation and vector notation analyses. Multicenter, cross-sectional study. Three- to 5-year-old participants in the Vision in Preschoolers (VIP) study (n = 4040). Secondary analysis of VIP data from participants who underwent comprehensive eye examinations, including monocular visual acuity testing, stereoacuity testing, and cycloplegic refraction. Visual acuity was retested with full cycloplegic correction when retest criteria were met. Unilateral amblyopia was defined as IAD of 2 lines or more in logarithm of the minimum angle of resolution (logMAR) units. Anisometropia was defined as a 0.25-diopter (D) or more difference in spherical equivalent (SE) or in cylinder power and 2 approaches using power vector notation. The percentage with unilateral amblyopia, mean IAD, and mean stereoacuity were compared between anisometropic and isometropic children. The percentage with unilateral amblyopia, mean IAD, and mean stereoacuity. Compared with isometropic children, anisometropic children had a higher percentage of unilateral amblyopia (8% vs. 2%), larger mean IAD (0.07 vs. 0.05 logMAR), and worse mean stereoacuity (145 vs. 117 arc sec; all P<0.0001). Larger amounts of anisometropia were associated with higher percentages of unilateral amblyopia, larger IAD, and worse stereoacuity (P<0.001 for trend). The percentage of unilateral amblyopia increased significantly with SE anisometropia of more than 0.5 D, cylindrical anisometropia of more than 0.25 D, vertical and horizontal meridian (J0) or oblique meridian (J45) of more than 0.125 D, or vector dioptric distance of more than 0.35 D (all P<0.001). Vector dioptric distance had greater ability to detect unilateral amblyopia than cylinder, SE, J0, or J45 (P<0.001). The presence and amount of anisometropia were associated with the presence of unilateral amblyopia, larger IAD, and worse stereoacuity. The threshold level of anisometropia at which unilateral amblyopia became significant was lower than current guidelines. Vector dioptric distance is more accurate than spherical equivalent anisometropia or cylindrical anisometropia in identifying preschoolers with unilateral amblyopia.

Comparison between the Plusoptix and iScreen photoscreeners in detecting amblyopic risk factors in children

Purpose: To compare the accuracy of plusoptiX A08 photoscreener (PPS) and iScreen 3000 photoscreener (IPS) in objectively screening for amblyopic risk factors in children age 5 months to 13 years old. Methods: Cross-sectional study of 148 children who received photoscreenings via PPS and IPS and a comprehensive pediatric ophthalmic examination in our office. Patients were considered to have amblyogenic risk factors based on the AAPOS referral criteria guidelines. Results: 45 percent of patients undergoing a pediatric ophthalmology examination were found to have amblyopia or amblyogenic risk factors. In this study, PPS demonstrated an overall sensitivity of 75.4%, specificity of 68.0%, positive predictive value (PPV) of 67.1%, and negative predictive value (NPV) of 76.1%. However, IPS photoscreener had an overall sensitivity of 66.2%, specificity of 87.6%, PPV of 81.8%, and NPV of 75.5%. Discussion: The accuracy of PPS and IPS was compared in different age groups. The sensitivity and specificity were analyzed according to varied amblyogenic risk factors. The statistic results of this study were compared to those of previous studies, including Vision in Preschoolers (VIP) Study and the Iowa PhotoScreening Program. Conclusion: PPS and IPS proved to be useful tools in the objective vision screening in children. PPS was found to have a higher sensitivity, and IPS showed a higher specificity and PPV in detecting amblyopic risk factors. In conclusion, one device may be more beneficial over the other, depending on the patient population and office settings.

ROC Analysis of the Accuracy of Noncycloplegic Retinoscopy, Retinomax Autorefractor, and SureSight Vision Screener for Preschool Vision Screening

To evaluate, by receiver operating characteristic (ROC) analysis, the accuracy of three instruments of refractive error in detecting eye conditions among 3- to 5-year-old Head Start preschoolers and to evaluate differences in accuracy between instruments and screeners and by age of the child. Children participating in the Vision In Preschoolers (VIP) Study (n = 4040), had screening tests administered by pediatric eye care providers (phase I) or by both nurse and lay screeners (phase II). Noncycloplegic retinoscopy (NCR), the Retinomax Autorefractor (Nikon, Tokyo, Japan), and the SureSight Vision Screener (SureSight, Alpharetta, GA) were used in phase I, and Retinomax and SureSight were used in phase II. Pediatric eye care providers performed a standardized eye examination to identify amblyopia, strabismus, significant refractive error, and reduced visual acuity. The accuracy of the screening tests was summarized by the area under the ROC curve (AUC) and compared between instruments and screeners and by age group. The three screening tests had a high AUC for all categories of screening personnel. The AUC for detecting any VIP-targeted condition was 0.83 for NCR, 0.83 (phase I) to 0.88 (phase II) for Retinomax, and 0.86 (phase I) to 0.87 (phase II) for SureSight. The AUC was 0.93 to 0.95 for detecting group 1 (most severe) conditions and did not differ between instruments or screeners or by age of the child. NCR, Retinomax, and SureSight had similar and high accuracy in detecting vision disorders in preschoolers across all types of screeners and age of child, consistent with previously reported results at specificity levels of 90% and 94%.

Findings from the Vision in Preschoolers (VIP) Study: Erratum

Findings from the Vision in Preschoolers (VIP) Study: Erratum

Findings from the Vision in Preschoolers (VIP) Study

The Vision in Preschoolers (VIP) Study Group conducted a multicenter, multidisciplinary, two-phase study to evaluate the performance of vision screening tests for identifying pre-school children with amblyopia, strabismus, significant refractive error, or unexplained reduced visual acuity (VA). The results of the VIP Study provide evidence-based guidelines for preschool vision screening. The best screening tests administered by eye care professionals were non-cycloplegic retinoscopy, Retinomax Autorefractor, SureSight Vision Screener, and linear, crowded Lea Symbols VA at 10 feet. The best screening tests administered by trained nurses and/or lay screeners were Retinomax, SureSight, and VIP single, crowded Lea Symbols VA screening test system at 5 feet. Eye care professionals can improve detection of strabismus by combining unilateral cover test with a refraction test and trained lay screeners can improve detection of strabismus by combining Stereo Smile II with SureSight. The best performing tests had high testability whether performed by trained eye care professionals, nurses, or lay screeners (>or=98%). Although very few children were unable to complete these tests, a child who was "unable" was much more likely to have a vision problem than a child who passed; therefore, children who are unable to complete one of these tests should be referred for further evaluation. When screening using the Retinomax, repeated testing to achieve the manufacturer's suggested confidence number is valuable and improves specificity. Federal initiatives to increase the number of pre-school children receiving vision screening or examination will increase the number of pre-school children identified with amblyopia, strabismus, and/or significant refractive error. Although there is general agreement regarding the importance of early detection of amblyopia, controversy exists regarding the importance of early detection of refractive error. Because of the high prevalence of significant refractive errors and lack of evidenced-based guidelines for correction of refractive error in pre-school children, future research is needed to evaluate the value of correcting refractive errors in preschoolers who do not have amblyopia and/or strabismus.

Does Assessing Eye Alignment along with Refractive Error or Visual Acuity Increase Sensitivity for Detection of Strabismus in Preschool Vision Screening?

Preschool vision screenings often include refractive error or visual acuity (VA) testing to detect amblyopia, as well as alignment testing to detect strabismus. The purpose of this study was to determine the effect of combining screening for eye alignment with screening for refractive error or reduced VA on sensitivity for detection of strabismus, with specificity set at 90% and 94%. Over 3 years, 4040 preschool children were screened in the Vision in Preschoolers (VIP) Study, with different screening tests administered each year. Examinations were performed to identify children with strabismus. The best screening tests for detecting children with any targeted condition were noncycloplegic retinoscopy (NCR), Retinomax autorefractor (Right Manufacturing, Virginia Beach, VA), SureSight Vision Screener (Welch-Allyn, Inc., Skaneateles, NY), and Lea Symbols (Precision Vision, LaSalle, IL and Good-Lite Co., Elgin, IL) and HOTV optotypes VA tests. Analyses were conducted with these tests of refractive error or VA paired with the best tests for detecting strabismus (unilateral cover testing, Random Dot "E" [RDE] and Stereo Smile Test II [Stereo Optical, Inc., Chicago, IL]; and MTI PhotoScreener [PhotoScreener, Inc., Palm Beach, FL]). The change in sensitivity that resulted from combining a test of eye alignment with a test of refractive error or VA was determined with specificity set at 90% and 94%. Among the 4040 children, 157 were identified as having strabismus. For screening tests conducted by eye care professionals, the addition of a unilateral cover test to a test of refraction generally resulted in a statistically significant increase (range, 15%-25%) in detection of strabismus. For screening tests administered by trained lay screeners, the addition of Stereo Smile II to SureSight resulted in a statistically significant increase (21%) in sensitivity for detection of strabismus. The most efficient and low-cost ways to achieve a statistically significant increase in sensitivity for detection of strabismus were by combining the unilateral cover test with the autorefractor (Retinomax) administered by eye care professionals and by combining Stereo Smile II with SureSight administered by trained lay screeners. The decision of whether to include a test of alignment should be based on the screening program's goals (e.g., targeted visual conditions) and resources.

Impact of Confidence Number on the Screening Accuracy of the Retinomax Autorefractor

To assess the impact of Retinomax reading confidence number on screening accuracy and to determine whether repeated testing to achieve a higher confidence number improves screening accuracy in preschool children. Lay and nurse screeners trained in the use of the Retinomax Autorefractor screened 1452 children enrolled in the Vision in Preschoolers (VIP) Phase II Study. All children also received a comprehensive eye examination. Using statistical comparison of correlated proportions, we compared sensitivity and specificity for detecting any VIP-targeted condition and conditions grouped by severity and by type (amblyopia, strabismus, significant refractive error, and unexplained decreased visual acuity) among three groups of children who had confidence numbers below, at or above the manufacturer's suggested confidence number of 8. The reading with the highest confidence number for each eye was used in the analysis. Each child's confidence number group was defined based on the lower confidence number of the pair of readings for the two eyes. Among the 771 (53.1%) children who had repeated testing either by lay or nurse screeners because of a low confidence number (<8) for one or both eyes in the initial testing, the same analyses were also conducted to compare results between the initial reading with confidence number<8 and repeated test reading with the highest confidence number in the same child. These analyses were based on the failure criteria associated with 90% specificity for detecting any VIP condition in VIP Phase II. We also examined the association between ocular conditions and confidence number. Hochberg procedure was used to adjust the p value for multiple comparisons. A lower confidence number category was associated with higher sensitivity (0.78, 0.65, and 0.61 for<8, 8, >8, respectively, p=0.04) but much lower specificity (0.64, 0.89, and 0.93, p<0.0001) of detecting any VIP-targeted condition. Through repeated testing, 87% of readings that initially had a confidence number below 8 reached 8 or above, and the increased confidence number that resulted from repeated testing was associated with significantly higher specificity (0.81 vs. 0.86, p=0.002) and a nonsignificant change (by -0.04 to 0.03) in sensitivities. Children with any VIP-targeted condition, significant refractive error, hyperopia, astigmatism, or myopia were more likely to have a low confidence number. A higher confidence number obtained during Retinomax Autorefractor screening is associated with better screening accuracy. Repeated testing to reach the manufacturer's recommended minimum value is worthwhile in preschool vision screening with the Retinomax. Failure to achieve manufacturer's recommended minimum value through repeated testing should be a factor considered in referring children for a comprehensive eye examination.

Field evaluation of the Welch Allyn SureSight ™ Vision Screener: Incorporating the Vision in Preschoolers study recommendations

The prospective Vision in Preschoolers (VIP) study evaluated 11 methods of screening and proposed referral criteria for the Welch Allyn SureSight(trade mark) Vision Screener with 90% and 94% specificity. The SureSight had a higher sensitivity than most other screening techniques when these criteria were applied. We evaluated the usefulness of these criteria in a field study of healthy preschool children. The SureSight software was altered to recommend referral using the VIP referral criteria with 90% specificity. Lions Club volunteers screened preschool children throughout Tennessee. Referred children underwent comprehensive eye examinations with cycloplegic refraction. Examination failure criteria were based upon published standards. Reanalysis using the 94% specificity criteria was then performed. Outcomes included referral rate and positive predictive value. The SureSight was used to screen 4,733 children, and screening was successful in 99.7% of children. The referral rate using the 90% specificity criteria was 12.2%. Most children (73%) were referred for suspected astigmatism. The positive predictive value was 30%. Using the 94% specificity criteria from the VIP study decreased the referral rate to 7.9% and substantially decreased over referral for suspected astigmatism; however, several anisometropes went undetected. Higher specificity was achieved by raising astigmatism referral criteria to 2.2 diopters while leaving the anisometropia criteria unchanged. The SureSight can be used successfully for preschool screening in the field provided that criteria with high specificity are incorporated into the instrument's software program. Higher rates of positive predictive value can be achieved without jeopardizing sensitivity by raising astigmatism referral criteria to 2.2 diopters.

Sensitivity of Screening Tests for Detecting Vision In Preschoolers-targeted Vision Disorders When Specificity Is 94%

To compare the sensitivity of 11 preschool vision screening tests administered by licensed eye care professionals for the detection of the 4 Vision in Preschoolers (VIP)-targeted vision disorders when specificity is 94%. This study consisted of a sample (n = 2588) of 3- to 5-year-old children enrolled in Head Start programs, 57% of whom had failed an initial Head Start vision screening. Screening results from 11 tests were compared with results from a standardized comprehensive eye examination that was used to classify children with respect to the four VIP-targeted vision disorders: amblyopia, strabismus, significant refractive error, and unexplained reduced visual acuity (VA). With overall specificity set to 94%, we calculated the sensitivity for the detection of each targeted vision disorder. With the overall specificity set to 94%, the most accurate tests for detection of amblyopia were noncycloplegic retinoscopy (NCR) (88% sensitivity), the SureSight Vision Screener (80%), and the Retinomax Autorefractor (78%). For detection of strabismus, the most accurate tests were the MTI Photoscreener (65%), the cover-uncover test (60%), the Stereo Smile II stereoacuity test (58%), the SureSight Vision Screener (54%), and the Retinomax Autorefractor (54% in year 1, 53% in year 2). The most accurate tests for detection of significant refractive error were NCR (74%), the Retinomax Autorefractor (66%), the SureSight Vision Screener (63%), and the Lea Symbols VA test (58%). For detection of reduced VA, the most accurate tests were the Lea Symbols Distance VA test (48%), the Retinomax Autorefractor (39%), and NCR (38%). Similar to the previously reported results at 90% specificity, the screening tests vary widely in sensitivity with specificity set at 94%. The rankings of the sensitivities for detection of the 4 VIP-targeted vision disorders are similar to those with specificity set to 90%.

Peripheral vision: The effects of developmental, perceptual, and cognitive factors

The effects of perceptual and cognitive factors on information processing in the visual periphery were studied in 5- and 8-year-old children and in adults. Subjects judged either the similarity (Study 1) or the identity (Study 2) of geometric forms. In both studies, two forms were simultaneously presented for 20 msec at 2, 4, or 6°, with one form on either side of the fovea. Type of form and Axis of presentation were varied. Both studies demonstrated declining performance with increasing distance, poorer performance with open than closed forms, poorest performance along the vertical axis, and no major interaction of these factors with age. Greater “flattening” of the visual field was found in Study 2 than in Study 1 for all age groups. The results indicate that the parafoveal visual field is elliptical and that more difficult tasks accentuate this asymmetry. This effect of task demands on the relative flatness of the effective visual field cannot be interpreted on the basis of anatomical factors. The findings indicated striking developmental similarity in the effect of several variables on parafoveal processing and challenge the idea of greater tunnel vision in preschoolers than in adults. Further, the data suggest that perceptual and cognitive factors influence the size and shape of the effective visual field across the full age range studied.