Vision in Preschoolers (VIP) Study Group. Effect of age using Lea Symbols or HOTV for preschool vision screening

The Freiburg Acuity Test in Preschool Children: Testability, Test-Retest Variability, and Comparison With LEA Symbols

Purpose

To determine the testability, performance, and test-retest variability (TRV) of visual acuity (VA) assessment using the Freiburg Visual Acuity Test (FrACT) compared to the LEA Symbols Test (LEA) in preschool children.

Methods

In 134 preschool children aged 3.0 to 6.8 years, monocular VA of each eye was measured twice with a four-orientation Landolt C version of the FrACT and once with the LEA. FrACT runs were preceded by a binocular run for explanatory purposes. Test order alternated between subjects. Optotypes were presented on a computer monitor (FrACT) or on cards (LEA) at a distance of 3 m.

Results

Overall, 68% completed the FrACT (91/134 children) and 88% completed the LEA (118/134 children). Testability depended on age: FrACT, 19% (<4 years) and 87% (≥4 years); LEA, 70% (<4 years) and 95% (≥4 years). Mean ± SD VA difference between tests was 0.11 ± 0.19 logarithm of the minimum angle of resolution [logMAR], with LEA reporting better acuity. The difference depended on age (0.27 ± 0.23 logMAR [<4 years], 0.09 ± 0.18 logMAR [≥4 years], P < 0.001) and on test sequence (higher age dependence of FrACT VAs for LEA first, P < 0.001). The 95% limits of agreement for the FrACT TRV were ±0.298 logMAR.

Conclusions

The examiner-independent FrACT, using international reference Landolt C optotypes, can be used to assess VA in preschool children aged ≥4 years, with reliability comparable to other pediatric VA tests.

Translational Relevance

Use of the automated FrACT for VA assessment in preschool children may benefit objectivity and validity as it is a computerized test and employs the international reference Landolt C optotype.

Comparison of HOTV optotypes and Lea Symbols: a systematic review and meta-analysis

PURPOSE

To report the findings of our systematic review and meta-analysis comparing the completion time and testing time of visual acuity testing using Lea Symbols or HOTV optotypes.

METHODS

A systematic search of PubMed, SCOPUS, and CINAHL was conducted according to the PRISMA guidelines.

RESULTS

The completion rate for HOTV optotypes and Lea Symbols visual acuity testing was reported for 7,948 patients (average age, 3.59 years; age range, 2-17; 49.96% females). The 3-year-olds' completion rate of HOTV was 74.09% (47.93%-93.29%), compared with a Lea Symbols completion rate of 77.80% (53.93%-94.57%). The 4-year-olds' completion rate was 88.20% (63.48%-99.73%) for HOTV and 90.118% (67.42%-99.90%) for Lea Symbols. In 3-year-olds, the mean testing time was 118.33 ± 6.54 seconds for HOTV and 120.33 ± 6.53 seconds for Lea Symbols (P < 0.0001). The difference in testing times in the 4-year-old age group was also statistically significant (86.98 ± 6.12 seconds for HOTV and 94.32 ± 6.57 seconds for Lea symbols) (P < 0.0001).

CONCLUSIONS

There was a statistically significant difference in the testing times between the HOTV optotypes and Lea Symbols in both the 3- and 4-year-old age groups; however, the difference of 2-7 seconds on average is unlikely to be clinically significant. Testing speed and completion rate improve with age for both tests.

Analysis of age at detection and outcomes of dense unilateral congenital cataract surgery for children on the paediatric cataract register

AIM

Analysis of age at time of detection and surgery of dense unilateral cataract and investigation of best-corrected visual acuity (BCVA) in a nationwide register-based cohort study, based on the routine of maternity ward eye screening.

METHODS

Data were derived from the Paediatric Cataract Register (PECARE). All children (n = 54) diagnosed with dense congenital unilateral cataract between January 2007 and September 2014 who had surgery before 1 year of age, and for whom 5-year follow-up records were available, were included.

RESULTS

The majority, 35/54 (65%), were detected and operated on before age 6 weeks and 30/35 (86%) were referred from maternity wards. Visual acuity (VA) ≥ 0.5 (decimal, 0.3 logMAR) was found in 7/53 (13%) of the cohort at age 5 years; further, 19 children achieved VA ≥ 0.1 (decimal, 1.0 logMAR) (36%) and 19 children VA < 0.05 (decimal, 1.30 logMAR) (36%). Ten-year follow-up records were available for 17/53 (32%) children; 1/17 (6%) achieved VA ≥ 0.5 (decimal, 0.3 logMAR), 4/17 (24%) VA ≥ 0.3-<0.5 (decimal, 0.52-0.30 logMAR), 3/17 (18%) VA ≥ 0.05-0.1 (decimal, 1.30-1.0 logMAR) and 10/17 (59%) VA < 0.05 (decimal, 1.30 logMAR).

CONCLUSION

A total of 90% of the children were detected with cataract within 100 days of birth and 80% were operated on within this period. This study showed better visual acuity in those treated for dense unilateral cataracts than previously reported in an earlier Swedish cohort study.

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

ABSTRACT

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.

Management of amblyopia in pediatric patients: Current insights

Amblyopia is a cause of significant ocular morbidity in pediatric population and may lead to visual impairment in future life. It is caused due to formed visual deprivation or abnormal binocular interactions. Several risk factors in pediatric age group may lead to this disease. Author groups have tried managing different types of amblyopia, like anisometropic amblyopia, strabismic amblyopia and combined mechanism amblyopia, with optical correction, occlusion therapy, penalization, binocular therapy and surgery. We review historical and current management strategies of different types of amblyopia affecting children and outcomes in terms of visual acuity, binocularity and ocular deviation, highlighting evidence from recent studies. Literature searches were performed through Pubmed. Risk factors for amblyopia need to be identified in pediatric population as early in life as possible and managed accordingly, as visual outcomes in amblyopia are best if treated at the earliest. Although, monocular therapies like occlusion or penalization have been shown to be quite beneficial over the years, newer concepts related to binocular vision therapy are still evolving.

Diagnostic accuracy of the Parr vision test, single crowded Lea symbols and Spot vision screener for vision screening of preschool children aged 4-5 years in Aotearoa/New Zealand

PURPOSE

Preschool children in New Zealand undergo vision screening to detect amblyopia at 4-5 years of age. The current test, the Parr vision test, does not meet international visual acuity chart guidelines and has not been validated against other commonly used paediatric vision tests. New Zealand vision screening protocols are also not targeted for detecting other eye conditions such as uncorrected refractive error, which may affect school performance. We compared the Parr vision test with the single crowded Lea symbols and the Spot vision screener for detecting ocular pathology, refractive error and amblyopic risk factors in preschool children.

METHODS

A cross-sectional diagnostic accuracy study recruited children aged 4-5 years via convenience sampling from the University of Auckland Optometry Clinic and through primary schools in Auckland, New Zealand. Participants received vision screening with the three different instruments administered by a lay screener. Comprehensive eye examinations were completed by a paediatric optometrist to determine the presence of vision disorders.

RESULTS

Of 197 children who received a comprehensive eye examination, 14 (7.1%) had amblyopic risk factors and 43 (21.8%) had significant refractive error (15.7% with astigmatism, 9.1% with hyperopia). The sensitivity for detecting any ocular condition did not differ significantly between the tests (50.0% for Parr, 43.5% for Lea, 42.5% for Spot). Specificity was significantly lower for the Parr vision test (80.8%) than for the Lea symbols (93.4%) and Spot vision screener (98.0%). Adding the Spot vision screener to measurements of visual acuity significantly improved sensitivity in detecting any ocular condition with the Parr vision test (67.5% for Parr/Spot vs 50% for Parr alone), but not with the Lea symbols (52.5% for Lea/Spot vs 43.5% for Lea alone).

CONCLUSION

The sensitivity of the Parr vision test for detecting ocular conditions in preschool children does not vary significantly from that achieved by the Lea symbols or the Spot vision screener. However, current New Zealand vision screening protocols could be improved by expanding the target conditions to include significant refractive error and incorporating the use of the Spot vision screener to increase the accuracy with which children with refractive error are identified. Future research should include longitudinal studies to determine the effect of preschool vision screening on later ocular and academic outcomes.

Evidence-Based Clinical Practice Guideline: Comprehensive Pediatric Eye and Vision Examination

Republished with written permission granted from the American Optometric Association, October 2, 2020.

Visual Acuity Assessment and Vision Screening Using a Novel Smartphone Application

OBJECTIVES

To evaluate a smartphone-based application's (Peek Acuity) ability to assess visual acuity and screen for ocular conditions in children, we compared visual acuity assessment between Peek Acuity and the pediatric ophthalmology examination and evaluated Peek Acuity's ability to identify children with referable ocular conditions.

STUDY DESIGN

We prospectively recruited 111 children age 3-17 years, presenting to a pediatric ophthalmology clinic, who could follow instructions. Monocular visual acuity assessments by Peek Acuity and standard clinical methods were performed in randomized order. We compared visual acuity assessments between methods using intraclass correlation coefficient (ICC) and evaluated Peek Acuity's ability to identify children with referable ocular conditions.

RESULTS

ICC comparing visual acuity assessed between methods was 0.88 (95% CI 0.83-0.92) for first and 0.85 (95% CI 0.78-0.89) for second eyes examined. ICC among 3 to 5-year-olds (preschool-age children) was 0.88 (95% CI 0.77-0.94) for first and 0.45 (95% CI 0.13-0.68) for second eyes examined. Peek Acuity had a sensitivity of 83%-86% for decreased vision and 69%-83% for referable ocular disease. Sensitivity was highest among 3 to 5-year-olds with decreased vision, 93%-100%.

CONCLUSIONS

Overall, Peek Acuity visual acuity assessment correlated well with visual acuity assessed by standard clinical methods, though preschool-age children appeared more susceptible to examination fatigue. Peek Acuity performed adequately as a screening tool and had the greatest sensitivity among those with decreased vision and preschool-age children.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03212222.

Diagnostic accuracy and agreement between visual acuity charts for detecting significant refractive errors in preschoolers

BACKGROUND

Preschool vision screenings are considered to be cost-effective methods to identify children with vision disorders. The children of this age group are poor at communicating their symptoms and hence screening is mandated. This study is aimed at estimating the diagnostic accuracy and agreement of Lea, HOTV and E visual acuity charts for detecting significant refractive errors.

METHODS

A cross-sectional study was conducted, in which monocular unaided vision assessment of each study participant was performed with Lea, HOTV and E charts. Stereo acuity was measured with the Randot Preschool Test and a comprehensive eye examination including dilatation was performed. Significant refractive error was defined as hyperopia > 3.25 D, myopia > 2.00 D, astigmatism > 1.50 D, anisometropia if interocular difference > 1.00 D for hyperopia, > 3.00 D for myopia or > 1.50 D for astigmatism. Sensitivity, specificity, positive and negative predictive values were estimated. Bland-Altmann plots were generated to help identify the level of agreement between the vision charts.

RESULTS

A total of 256 eyes were analysed. Lea, HOTV and E had sensitivities of 87.8 per cent, 90.2 per cent and 90.2 per cent, respectively. Specificity and positive predictive values were better for HOTV (77.3 per cent, 65.5 per cent) and Lea (75 per cent, 62.6 per cent), compared to E chart (69.8 per cent, 58.7 per cent). Negative predictive values for Lea, HOTV and E charts were 92.8 per cent, 93.8 per cent and 93.8 per cent, respectively. Bland-Altmann analysis showed good agreement between Lea and HOTV, Lea and E, and HOTV and E visual acuity charts. The acuity difference was least between Lea and HOTV charts (0.1 logMAR). Eighty-five (33.2 per cent) eyes had significant refractive errors. Eighty (94.1 per cent) eyes were astigmatic.

CONCLUSION

The diagnostic accuracy of the visual acuity charts was high for the identification of significant refractive errors in preschool children. There was very good agreement between the visual acuity charts.

Evidence-based preschool-age vision screening: health policy considerations

Background

There are many causes of visual impairment, and even blindness, which are treatable or at least preventable. Two such conditions are strabismus (crossed-eye, squint) and refractive error (visual image not focused on the most sensitive part of the retina). If these are not detected and corrected at an early age, they can lead to an irreversible impairment known as amblyopia (lazy eye). Pediatric vision screening and subsequent treatment for amblyopia and amblyogenic risk factors are thus key to preventing vision loss. Furthermore, vision screening can detect moderate to high hyperopia, which has been found to be associated with poor school readiness.

Evidence-based recommendations call for screening children at 3–5 years of age; they are old enough to cooperate, but still within the window of effective intervention. However, these recommendations have yet to be universally implemented as the standard of care.

Methods

This paper integrates a review of the literature and the international experience of preschool vision screening with the findings from a preliminary feasibility study of expanded screening in Israel to formulate a discussion of the current health policy challenge in Israel and the options for addressing it. The advantages and disadvantages of various venues for vision screening are discussed.

Findings

Screening by optometrists in Mother and Child Health Centers, as implemented in a recent pilot project in the Jerusalem District, would allow the most comprehensive testing. Photo-screening in preschools would reach the most children, but at the cost of missing hyperopia (farsightedness). Either approach would probably constitute improvements over the current situation. The relative strengths of the two approaches depends in part on the ability to purchase automatic screening equipment (and the efficacy of that equipment) vs. the ongoing cost of paying trained personnel.

Conclusions

Further research should be conducted in Israel to determine the prevalence of refractive errors, so that best practices can be established for Israel’s population and social needs. In the interim, the Ministry of Health should promptly implement the inclusion of preschool visions screening for children in the approved “basket of services” covered by the National Health Insurance Laws, using photo-screening, including collection of the clinical data.

Electronic supplementary material

The online version of this article (10.1186/s13584-019-0339-z) contains supplementary material, which is available to authorized users.

Recognition acuity in children measured using The Auckland Optotypes

PURPOSE

Sloan letters displayed by the Electronic Visual Acuity (EVA) system are the gold standard for recognition acuity measurement in research settings. However, letters are not always appropriate for children. The Auckland Optotypes (TAO) are a new, open-access set of 10 pictograms available in regular and vanishing formats. We sought to assess feasibility of using both formats of TAO for measuring visual acuity (VA) in children using a Bayesian adaptive staircase, in a community setting.

METHODS

We tested 121 children (5-12 years old) with both formats of TAO, a handheld flipchart vision screener (Parr vision test), as well as the gold standard EVA. We measured feasibility of the three comparison tests in three ways. First, using limits of agreement (LoA) with EVA, second, calculating area under the receiver operating characteristic curve (AUC), and finally, investigating trial-by-trial responses.

RESULTS

Agreement between tests was within test-retest reliability of EVA measures (LoA_{TAO regular}  = ±0.14, LoA_{TAO vanishing}  = ±0.15, LoA_{P arr}  = ±0.16 logMAR). TAO tests were highly effective at identifying children with vision impairment (AUC_{TAO regular}  = 0.96, AUC_{TAO vanishing}  = 0.95), whereas Parr was less effective (AUC_{P arr}  = 0.82). In 5-6 year old children there was an enhanced advantage of TAO (AUC_{TAO regular}  = 0.97, AUC_{TAO vanishing}  = 0.98) over Parr (AUC_{P arr}  = 0.75). Although each child completed 16 trials, approximately 10 trials were sufficient to achieve excellent LoA, and six trials sufficient for accurate screening.

CONCLUSION

Threshold VA assessment and vision screening are feasible using both vanishing and regular formats of TAO.

Testability Study of the Titmus V3 Test in Pre-school Children

SIGNIFICANCE

Vision screening can identify people who have vision problems requiring a comprehensive examination. When children are screened, the most prevalent serious problem is amblyopia secondary to uncorrected ametropia. Screening also identifies strabismus, which can lead to loss of binocularity. Early diagnosis permits treatment with restoration of balanced vision and binocularity.

PURPOSE

The study evaluated the testability of the Titmus V3 Vision Screener as a method to screen vision and strabismus in pre-school children.

METHODS

Pre-school children between 36 and 66 months of age underwent vision screening in six Michigan counties. The State of Michigan screening consists of the LEA Symbols test for visual acuity and the stereo butterfly for near-strabismus testing. The proposed Titmus V3 screening tests were the LEA Symbols slide for vision and near-strabismus test slide. Primary and secondary objectives of this study were to evaluate the percentage of pre-school children who completed the Titmus V3 screening tests for vision and near strabismus and factors associated with an inability to complete the tests, contrasting the pass/fail results between the state and Titmus V3 results.

RESULTS

Two-hundred sixty-three children were tested. The percentages of children unable to score on the Titmus V3 instrument versus the state's LEA Symbols test were 16.0% and 5.3%, respectively. The percentage of children unable to score on the Titmus V3 near-strabismus test slide was 6.9 versus 3.4% on the State of Michigan stereo butterfly test. Younger age at testing was the most important factor associated with the inability to complete testing.

CONCLUSIONS

Because of testability limitations and higher failure rates relative to the State of Michigan testing methods, the Titmus V3 screening device is not a feasible alternative to the standard methods used by the State of Michigan for vision and near-strabismus screening among the pre-school subjects we tested.

Portable acuity screening for any school: validation of patched HOTV with amblyopic patients and Bangerter normals

Background

We needed to validate and calibrate our portable acuity screening tools so amblyopia could be detected quickly and effectively at school entry.

Methods

Spiral-bound flip cards and download pdf surround HOTV acuity test box with critical lines were combined with a matching card. Amblyopic patients performed critical line, then threshold acuity which was then compared to patched E-ETDRS acuity. 5 normal subjects wore Bangerter foil goggles to simulate blur for comparative validation.

Results

The 31 treated amblyopic eyes showed: logMAR HOTV = 0.97(logMAR E-ETDRS)-0.04 r2 = 0.88. All but two (6%) fell less than 2 lines difference. The five showed logMAR HOTV = 1.09 ((logMAR E-ETDRS) + .15 r2 = 0.63. The critical-line, test box was 98% efficient at screening within one line of 20/40.

Conclusion

These tools reliably detected acuity in treated amblyopic patients and Bangerter blurred normal subjects.

These free and affordable tools provide sensitive screening for amblyopia in children from public, private and home schools. Changing “pass” criteria to 4 out of 5 would improve sensitivity with somewhat slower testing for all students.

Results of a primary care-based quality improvement project to optimize chart-based vision screening for preschool age children

PURPOSE

To design chart-based vision screening for preschool-aged children.

METHODS

Our program consisted of educational sessions for providers as well as hands-on training for practice staff. We evaluated the intervention through pre- and post-intervention review of medical records.

RESULTS

Completion of full vision screening (distance visual acuity in each eye plus stereovision beginning at 3 years of age, as recommended at the time of the project) at well-child visits improved for 5-year-olds (45.0% to 58.2%; risk difference +13.2% [95% CI, 1.7-24.7]) and 4-year-olds (39.3% to 51.4%; risk difference +12.0% [95% CI, 0.7-23.4]) but declined somewhat among 3-year-olds (23.1% to 14.3%; risk difference, -8.8% [95% CI, -17.7 to 0.0]). Risk factors for not being fully screened included being 3 years old (risk ratio of 4.1 compared to 5-year-olds) and being a patient of a small practice (risk ratio of 1.9 compared to large practices).

CONCLUSIONS

This quality improvement project showed that screening for visual acuity and stereovision among preschool-aged children using chart-based techniques is difficult to accomplish and unlikely to be consistently successful, especially among 3-year-olds.

Comparing Visual Acuity Measured by Lea Symbols and Patti Pics

INTRODUCTION

There is little data validating most illiterate eye charts. Lea Symbols®, however, have been well validated in numerous studies. In this study, we compare the assessment of visual acuity employing both the Lea Symbol hanging wall Early Treatment Diabetic Retinopathy Study (ETDRS)-style chart and a similar Patti Pics® ETDRS-style chart in order to determine whether the two charts provide clinically similar data.

METHODS

We tested the vision of the right eyes of fifty-two consecutive patients. Patients were cooperative children or adults between the ages of 3 and 88 years (mean 58 years). We alternated the order of the chart used first. Patients were also categorized by age and by visual acuity.

RESULTS

The visual acuities measured by the two charts were equal for 83% of the measurements (forty-three eyes). In 8% of eyes (four eyes), the visual acuity measured with the Lea Symbols was one line better than that measured by the Patti Pics; in 9% of eyes (five eyes), the acuity from the Patti Pics chart measured one line better than the Lea Symbols. There was no difference in measurements for either adults or children or among patients with different visual acuities.

CONCLUSION

We believe this study will serve to provide useful information when choosing an eye chart to assess visual acuity in a clinic setting. Patti Pics performed similarly to Lea Symbols in adults and children tested in a multi-specialty ophthalmology practice. We suspect that it would also perform similarly in the primary care and school settings.

Test Re-Test Reliability and Validity of Different Visual Acuity and Stereoacuity Charts Used in Preschool Children

BACKGROUND

Preschool vision screenings are cost effective ways to detect children with vision impairments. The use of any vision tests in children must be age appropriate, testable, repeatable and valid.

AIM

To compare the test re-test reliability, sensitivity and specificity of different visual acuity and stereo acuity charts used in preschool children.

MATERIALS AND METHODS

Monocular visual acuity of 90 subjects (180 eyes) of age 36 to 71 months was assessed with HOTV, Lea and E-chart in a preschool located in a semi urban area, Manipal, Karnataka. After the vision assessment, stereo acuity was recorded using Frisby and Titmus stereo charts followed by comprehensive eye examination. Repeated measurements of visual acuity and stereo acuity were done one week after the initial assessment.

RESULTS

Mean age of children was 53± 10 months with equal gender distribution. Intra class correlation (ICC) of Lea, HOTV, E-chart, Frisby and Titmus charts were 0.96, 0.99, 0.92, 1.0 and 1.0 respectively. The area under receiver operating curve (ROC) for Lea and E-chart was 0.892 and 0.776. HOTV was considered as the gold standard as it showed the least difference on repeated measurements. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of E-chart was 99, 15, 45, 94 and 21.8 percent, and Lea was 93, 56, 59 and 92 percent. The sensitivity, specificity, PPV and NPV of Frisby was 75, 27, 9, 92 percent were as of Titmus was 75, 13, 8 and 85 percent respectively.

CONCLUSION

HOTV chart can be used as the gold standard for measuring visual acuity of pre-schoolers in a semi urban area. Lea chart can be used in the absence of HOTV chart. Frisby and Titmus charts are good screening tools, but with poor diagnostic criteria.

Risk of optic pathway glioma in children with neurofibromatosis type 1 and optic nerve tortuosity or nerve sheath thickening

BACKGROUND/AIMS

Optic nerve tortuosity and nerve and sheath thickening are observed on MRI in some patients with neurofibromatosis type 1 (NF-1). This study aimed to determine if tortuosity and thickening are associated with the development of optic pathway glioma (OPG) and subsequent vision loss.

METHODS

Children with NF-1 who underwent brain MRI between 1992 and 2005, and had at least 1 year of subsequent visual acuity (VA) follow-up, were identified retrospectively. The baseline MRI was independently reviewed by three neuroradiologists for consensus assessment. Tortuosity was identified using validated operational criteria. Optic nerve and sheath thicknesses and VA at last follow-up were directly measured.

RESULTS

Of 132 evaluable children, seven (5%) had tortuosity on baseline MRI. 20 subjects (15%) ultimately developed OPG at a median of 1.9 years (range 7 months-8.0 years) following the baseline MRI. Subjects with tortuosity were significantly more likely to develop OPG than those without tortuosity (57% vs 13%, p=0.01). In subjects who developed OPG, the prevalence of tumour-related vision loss was not significantly different between those with and without baseline tortuosity (14% vs 4%, p=0.28). No difference existed between mean baseline optic nerve (2.3 vs 2.2 mm) or sheath (5.2 vs 5.4 mm) thicknesses comparing subjects who did and did not develop OPG.

CONCLUSIONS

Optic nerve tortuosity at baseline is associated with OPG development among patients with NF-1, but does not predispose to aggressive OPG with associated vision loss. Neither nerve nor sheath thickening at baseline is associated with OPG development.

Vision screening for children 36 to <72 months: recommended practices

PURPOSE

This article provides recommendations for screening children aged 36 to younger than 72 months for eye and visual system disorders. The recommendations were developed by the National Expert Panel to the National Center for Children's Vision and Eye Health, sponsored by Prevent Blindness, and funded by the Maternal and Child Health Bureau of the Health Resources and Services Administration, United States Department of Health and Human Services. The recommendations describe both best and acceptable practice standards. Targeted vision disorders for screening are primarily amblyopia, strabismus, significant refractive error, and associated risk factors. The recommended screening tests are intended for use by lay screeners, nurses, and other personnel who screen children in educational, community, public health, or primary health care settings. Characteristics of children who should be examined by an optometrist or ophthalmologist rather than undergo vision screening are also described.

RESULTS

There are two current best practice vision screening methods for children aged 36 to younger than 72 months: (1) monocular visual acuity testing using single HOTV letters or LEA Symbols surrounded by crowding bars at a 5-ft (1.5 m) test distance, with the child responding by either matching or naming, or (2) instrument-based testing using the Retinomax autorefractor or the SureSight Vision Screener with the Vision in Preschoolers Study data software installed (version 2.24 or 2.25 set to minus cylinder form). Using the Plusoptix Photoscreener is acceptable practice, as is adding stereoacuity testing using the PASS (Preschool Assessment of Stereopsis with a Smile) stereotest as a supplemental procedure to visual acuity testing or autorefraction.

CONCLUSIONS

The National Expert Panel recommends that children aged 36 to younger than 72 months be screened annually (best practice) or at least once (accepted minimum standard) using one of the best practice approaches. Technological updates will be maintained at http://nationalcenter.preventblindness.org.

ROC analysis of the accuracy of Noncycloplegic retinoscopy, Retinomax Autorefractor, and SureSight Vision Screener for preschool vision screening

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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%.

A historical review of distance vision screening eye charts: what to toss, what to keep, and what to replace

Vision screening protocol and equipment guidelines differ among schools across the United States. Budget cuts are forcing many school nurses to reevaluate their vision screening programs, as well as items in their vision screening toolboxes. School nurses tasked with inventorying those toolboxes to determine which items to toss, keep, or replace are oftentimes perplexed by the copious choices featured in vendor catalogs and websites. For school nurses who want their vision screening toolboxes to include eye charts, national and international eye chart design guidelines are available to help ensure selected eye charts are standardized. A national consensus policy exists that recommends specific eye charts. And, a large body of vision screening literature is available to help school nurses make informed decisions. Current documents suggest that LEA Symbols are appropriate for young children and Sloan Letters are a better choice than "Snellen" charts for older children.

Development of human visual function

By 1985 newly devised behavioral and electrophysiological techniques had been used to track development of infants' acuity, contrast sensitivity and binocularity, and for clinical evaluation of developing visual function. This review focus on advances in the development and assessment of infant vision in the following 25 years. Infants' visual cortical function has been studied through selectivity for orientation, directional motion and binocular disparity, and the control of subcortical oculomotor mechanisms in fixation shifts and optokinetic nystagmus, leading to a model of increasing cortical dominance over subcortical pathways. Neonatal face processing remains a challenge for this model. Recent research has focused on development of integrative processing (hyperacuity, texture segmentation, and sensitivity to global form and motion coherence) in extra-striate visual areas, including signatures of dorsal and ventral stream processing. Asynchronies in development of these two streams may be related to their differential vulnerability in both acquired and genetic disorders. New methods and approaches to clinical disorders are reviewed, in particular the increasing focus on paediatric neurology as well as ophthalmology. Visual measures in early infancy in high-risk children are allowing measures not only of existing deficits in infancy but prediction of later visual and cognitive outcome. Work with early cataract and later recovery from blinding disorders has thrown new light on the plasticity of the visual system and its limitations. The review concludes with a forward look to future opportunities provided by studies of development post infancy, new imaging and eye tracking methods, and sampling infants' visual ecology.