Lea Symbols Research Articles

Comparative analysis of Lea Symbols chart and ETDRS chart in Chinese preschool children's vision examination

Objective To investigate the effect of Toll-like receptor 9 (TLR9) on high glucose-induced retinal ganglion cells-5 (RGC-5) apoptosis and the inhibitory effects of small interfering RNA-TLR9 (si-TLR9) on apoptosis. Methods RGC-5 cells were divided into normal control group, high glucose group, high glucose+ negative control group and high glucose+ si-TLR9 group which cells were respectively dealt with normal culture medium, high glucose medium, transfection of non-specific siRNA under high glucose and transfection of siRNA-TLR9 under high glucose.The expression of TLR9 mRNA was detected by real time PCR; the survival rate of the cells was evaluated by MTT assay; the apoptotic rate of the cells was detected by flow cytometry; the caspase-3 activity in the cells was detected by related kit, and the expressions of TLR9, B cell lymphoma (bcl-2), bcl-2 associated X protein (bax), p38 mitogen-activated protein kinases (p38MAPK) and phosphorylated (p)-p38MAPK proteins were detected by Western blot. Results The expressions of TLR9 mRNA and protein in the high glucose+ si-TLR9 group were significantly decreased in comparison with the high glucose+ negative control group (both at P<0.05). The cell survival rate of the high glucose group and high glucose+ negative control group was (78.36±5.13)% and (75.12±4.25)%, respectively, which was significantly lower than (95.48±7.25)% in the normal control group, and that in the high glucose+ si-TLR9 group was (86.58±5.32)%, which was significantly reduced in comparison with the high glucose+ negative control group (all at P<0.05). The apoptotic rate of the cells in the high glucose group and high glucose+ negative control group was (13.23±1.22)% and (12.52±1.38)%, respectively, which was significantly higher than (2.26±0.15)% of the normal control group, and apoptotic rate in the high glucose+ si-TLR9 group was (7.15±0.24)%, which was significantly lower than that in high glucose+ negative control group (all at P<0.05). The expression of bax in the cells of the high glucose+ si-TLR9 group was significantly decreased, and the expression of bcl-2 in the cells of the high glucose+ si-TLR9 group was significantly increased in comparison with the high glucose+ negative control group (both at P<0.05). Caspase-3 activity in the cells was significantly decreased in the high glucose+ si-TLR9 group compared with the high glucose+ negative control group (P<0.05). The relative expression of p-p38MAPK in the cells was significantly decreased in the high glucose+ si-TLR9 group compared with the high glucose+ negative control group (P<0.05). Conclusions Down-regulation of TLR9 expression in the RGC-5 cells can inhibit the apoptosis induced by high glucose probablely by suppressing p38MAPK signaling pathway. Key words: Toll-like receptor 9; Small interfering RNA; Retinal ganglion cells; High glucose; Apoptosis; Cell culture

Parents' performance using the AAPOS Vision Screening App to test visual acuity in Malaysian preschoolers

To evaluate parents' performance in using the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) Vision Screening App (application) as a vision screening tool among preschool children and to evaluate the reliability of this app. A total of 195 5- and 6-year-old preschoolers were recruited from children attending Hospital Selayang, Selangor, Malaysia, to test the app. Uncooperative children and those with visual acuity of >logMAR 0.6 were excluded. Results from parents and the screening doctor using the app (Lea symbols) to test visual acuity were compared to each other and to gold standard vision testing by an optometrist using the Lea symbols chart. Children 5years of age represented 46.7% of the study population. The mean age of parents was 37.27±7.68years. Bland-Altman scatterplot agreement between assessors mainly was within the 95% confidence interval for bilateral eyes screening. Parents obtained a sensitivity of 86.6% (right vision) and 79.5% (left vision) and specificity of 78.9% (right vision) and 71.8% (left vision). Parents took a mean of 191.2±70.82seconds for bilateral screening. The intraclass correlation coefficient between optometrist and parents in bilateral eyes screening was good (P<0.001). Cronbach's α for all three assessors was >0.7, indicating high internal reliability of the app. Most parents (178/195 [91.3%]) strongly agreed on the app's acceptability and ease of use. The AAPOS Vision Screening App used by parents is a promising tool for visual acuityscreening among Malaysian preschool children and a reliable app for vision screening.

Visual acuity and contrast sensitivity outcomes based on photoreceptor layer after retinal reattachment surgery

Aims: To evaluate correlation between photoreceptor layer thickness with visual acuity and contrast sensitivity in primary retinal reattachment after vitrectomy. Methods: Twenty seven eyes of 27 patients (mean age 45.6±12.7 years) with successfully retinal reattached were analyzed. Snellen chart visual acuity (VA) to evaluate best-corrected visual acuity (BCVA) converted to the logarithm of the minimum angle of resolution scale (logMAR) and contrast sensitivity in photopic and mesopic illumination using Lea Symbol Flip Chart, funduscopy examination and High Definition Optical Coherence Tomography (HD-OCT) were used to measure retinal condition and photoreceptor layer thickness. Results: Nineteen (70.4%) cases of total 27 cases were reported with macularon RRD. The thickness of the photoreceptor layer was 43.8±10.8 µm which was significantly correlated with BCVA (logMAR 0.3-2.4, mean 1.0) with p is less 0.005 and also with contrast sensitivity in mesopic with p 0.033 (p ≤ 0.05). Contrast sensitivity in photopic was better than in mesopic. Foveal anatomic abnormalities were detected in six eyes (22.2%), that was disruption of inner segment (IS)/outer segment (OS) junction and also disruption of external limiting membrane (ELM). Duration of detachment also significantly correlated with BCVA with mean 36±29 days. The macular status before surgery determines the quality of vision, whereas the macular-on rhegmatogen retinal detachment gives visual acuity, contrast sensitivity, that is better in both photopic and mesopic, than macular-off. Conclusion: Photoreceptor layer thickness significantly correlated with visual acuity and contrast sensitivity in mesopic illumination, whereas thicker the photoreceptor, better the visual acuity and mesopic contrast sensitivity.

Comparing Three Different Contrast Sensitivity Tests in Adults and in Children with and without Amblyopia.

Tests of contrast sensitivity (CS) are not routinely performed in the clinic, although CS is reduced in many conditions, such as amblyopia or glaucoma. This may be due to perceived time constraints or unaffordability of equipment. Monocular CS functions obtained with the FACT, CSV 1000E, and Lea Symbols were compared in 19 healthy subjects aged 24 - 78 years and 24 subjects aged 5 - 16 years, 9 of whom had amblyopia. CS functions could be obtained with all three tests. The tests were equally comfortable for young and adult patients, and took less than 5 minutes to perform (one eye). All measured CSs at 3, 6, 12, and 18 cycles per degree (cpd), but the FACT included 1.5 cpd. LINEAR MIXED EFFECT MODELS: were performed. While there was no significant difference at low spatial frequencies, the Lea CS test showed a ceiling effect in that range, while the FACT showed a floor effect at high spatial frequencies. CS in amblyopic children did not differ between the contralateral and the amblyopic eye. Overall, amblyopic eyes had lower CS values than the control eyes and CS did not correlate significantly to visual acuity at distance. All three CS tests could be usefully applied in the clinic in adults as well as children over the age of 4 years. Only the CSV 1000E exhibited neither a ceiling nor a floor effect. This was also the fastest test. In children with amblyopia, CS testing offers additional information on visual function. In contrast to previous reports, we did not find that the CSV and FACT are interchangeable.

Long-term Follow-up After Cryocoagulation in Preterm Newborns from Northern Greece with Retinopathy of Prematurity: Three Year Results

This is a retrospective study of the efficacy of treatment of neonates (NN) with exocryocoagulation retinopathy of prematurity (ROP) with respect to morphology of the retina and visual function. Out of a total of 3103 neonates, 304 (9.8%) had a ROP. 66 of these were treated. All neonates were observed for 3 years after this treatment. When the patients suffered retinal ablation or dragging of the macula, the treatment was rated as unsuccessful. Best corrected grid visual acuity and best corrected visual acuity were assessed with Lea symbols and Kay pictures. The 66 treated neonates (132 eyes) had a gestation age of less than 28 weeks and weight at birth of < 1280 g. 28neonates exhibited ROP and the rest in zone 2. Among these 66 neonates, 64 (128 eyes) exhibited improved vision. 37 neonates (74 eyes) also exhibited morphological improvement. Only one neonate developed retinal detachment. Early treatment with cryopexia of neonates with ROP can improve vision and stabilise the retina.

Prevalence of Refractive Errors Among the Children of Special Education Complex, Peshawar

OBJECTIVES:The objective of our study was to determine the prevalence of refractive errors among children of special education complex.&#x0D; METHODOLOGY:A cross-sectional study was conducted to determine refractive error among the children of special education complex Hayatabad, Peshawar. A total of 272 children were examined from age 5-19 years. Refractive errors were determined by doing retinoscopy, subjective and objective refraction, ophthalmoscope and, hand held auto refractors. Snellen’s charts, lea symbol chart and kay pictures were used for assessing the visual acuity in children who could cooperate.&#x0D; RESULTS:Among 272 children, 225 children were males (82.7%). 34(12.5%) were mentally retard, 182(66.9%) were hearing impaired and 56(20.6%) were physically handicapped. Children suffering from refractive errors were 47(17.3%). 11(4.0%) reported that they were using glasses. Squint was present in 5(1.8%). On examination status of right eye 5(1.8%) were with visual acuity 6/60 or less. For children who were unable to comprehend with Snellen visual acuity chart, they were be assessed by using other charts like Lea symbol chart or Kay pictures. 19(7.0%) were assessed by Lea symbol chart, 9(3.3%) by Kay pictures and maximum number of children easily understand Snellen visual acuity chart that was 244(89.7%).&#x0D; CONCLUSION:This study concluded that refractive errors were common in special children.

Comparison of visual acuity measurement with Landolt rings versus numbers

Landolt rings are commonly used for the measurement of visual acuity, especially for legal purposes. For multiple reasons, in clinical practice these optotypes are not in use and not practical. Therefore, the difference between visual acuity tested with Landolt rings as opposed tonumbers was evaluated. Visual acuity measurements of 2335 eyes from 1394 patients (aged 5-98years, median 51years) were retrospectively analyzed at the Low Vision Department of the University of Heidelberg. The patients had abroad range of ophthalmological disorders. In all patients the measurement of visual acuity was performed with numbers as well as Landolt rings according to DIN58220. Visual acuity was determined in LogMAR and compared between the two optotypes. Correlation between both optotypes was high with r2 = 0.927 but there was apronounced mean difference in visual acuity of 0.13 ± 0.14 LogMAR. Using numbers, visual acuity was 0.13 LogMAR higher, somewhat more than one line. These differences were mostly independent of visual acuity and increased slightly with age; however, the variations were greater for lower visual acuity. Whereas in clinical practice visual acuity is typically determined using numbers and early treatment diabetic retinopathy study (ETDRS) charts are the gold standard for a scientific assessment of visual acuity, only the use of Landolt rings enables an examination without the influence of form recognition. The use of Landolt rings is therefore valid for legal reasons in Europe according to EN ISO 8596 and in Germany according to DIN 58220. Comparing Landolt rings with the SnellenE chart or LEA symbols, these results confirm previous reports that visual acuity measured with Landolt rings results in lower visual acuity. On average visual acuity is approximately one line worse than when tested with numbers, afact that has to be taken into account when comparing different examination results. This may be explained by incorrect correlation of the used numbers exceeding the allowed difference in eligibility of 0.05 LogMAR. Hence, it is important for legal assessment to measure visual acuity correctly with Landolt rings.

Is LEA symbol better compared to Snellen chart for visual acuity assessment in preschool children?

Aim: To compare visual acuity using the LEA symbol chart with Snellen E test chart in preschool children of age 3-5 years. Patients and methods: Inclusion criteria: 50 emmetropic children aged 3 to 5 years. Exclusion criteria: Strabismus, amblyopia, ametropia, and any organic eye disease. A pseudo randomized protocol was used to test visual acuity (VA) in each subject monocularly on both eyes using Snellen E chart and LEA symbol chart. Visual acuity for both charts was scored as smallest optotype size which the child correctly identified 3 of maximum 4 optotypes. The strength of agreement on VA between two charts was tested using Interclass correlation coefficient (ICC). A Mann-Whitney U test was applied to compare both the groups. Results: Boys: Girls = 26:24 with a mean age and standard deviation of 4.12 + 0.79 years. ICC between Snellen's and LEA symbol chart was 0.256 and 0.213 for right and left eye respectively. Analysis of the two samples using Mann-Whitney test showed a significant difference between the two charts (p value <0.000). Conclusion: LEA symbol test showed only a fair agreement with Snellen E charts for visual acuity measurements. Visual acuity measurement with LEA symbol chart showed significantly higher scores as compared to Snellen's chart.

Prevalence and Causes of Visual Impairment Among Nigerian Children Aged 3 to 5 Years

Objectives: This article determines the prevalence and causes of visual impairment (VI) in children aged 3 to 5 years in Ilorin East Local Government Area of Kwara State, Nigeria. Methods: The study was a descriptive, cross-sectional, school-based study of 464 children enrolled by multistage sampling. The sample size was calculated based on the prevalence of ocular morbidity of 19.9% found in a previous Ilorin study by Ayanniyi et al. (Causes and prevalence of ocular morbidity among primary school children in Ilorin, Nigeria. Niger J Clin Pract 2010;13:248-53) using the Fisher’s formula. Visual acuity (VA) of selected children was assessed using the Lea symbols chart. Children meeting the referral criteria of VA worse than 20/30 (6/9.5), two lines difference in VA between the eyes, visible anterior and posterior segment anomalies, and untestable children with the Lea symbols thereafter had a comprehensive eye examination. Results: Seventy (15.1%) of the children screened were 3 years’ old, 176 (37.9%) were 4 years, whereas 218 (47%) were 5 years’ old. Nine hundred twenty-eight eyes of 464 children were screened; 707 (76.2%) eyes in 332 (71.6%) children had VA 6/9.5 or better, whereas 184 (19.8%) eyes in 112 children (24.1%) had VA worse than 6/9.5 and 37 (4%) eyes in 20 children (4.3%) were untestable. An identifiable cause of VI was found in 36 eyes of 23 children, giving a prevalence of 5%. The causes of VI were myopia (2.5%), astigmatism (1.8%), hypermetropia (0.2%), anisometropic amblyopia (0.2%), and strabismus (0.2%). Conclusion: The prevalence of vision impairing conditions in this age group underscores the importance of preschool vision screening to ensure early detection and treatment to prevent the permanent damage of amblyopia.

Relationship Between Consanguineous Marriages and Incidence and Severity of Refractive Errors: A Cross-sectional Study

Congenital and genetic ocular disorders are linked to parental consanguinity. The aims was to investigate the effects of consanguineous marriages on the refractive errors of preschool-aged and adolescent patients. Two sample groups were recruited: the preschooler group (3–6 years; 335 participants) and the adolescent group (12–20 years; 998 participants). The required sample size was calculated using a sample size estimation software. Visual acuity was measured using the 15-line Lea symbols chart in the pre-school aged group and non-illuminated ETDRS VA chart in the adolescent group. Spherical equivalent refractive errors were noted with near-retinoscopy technique in young children and with the ARK-30 autorefractor in the adolescent group. In order to explore the impact of consanguineous marriages, the data were analyzed separately based on the age group using SPSS version 21 software. In the preschooler group, myopia was found in 4.2%, hyperopia in 8.1%, and astigmatism in 20%. Three children had high myopic scores (-10.00 D, -13.50 D and -17.50 D). In the adolescent group, 45.6% participants were myopic, 3.8% were hyperopic, and 22.3% were astigmatic. Despite the higher frequency of RE in those 15 years and older in the cousins group and the consanguineous parents of the three preschool-aged children with high myopia, there were no statistically significant (<i>p</i>>0.05) evidence that consanguineous marriages impact the refractive errors of their children. In conclusion, despite previous studies showing a link between ocular genetic or congenital disorders and consanguinity, no such link could be established with regard to refractive errors.

The cost-effectiveness of alternative vision screening models among preschool children in rural China.

To explore the accuracy and cost-effectiveness of three vision screening models among preschool children in rural China. Vision screening was carried out among children aged 4-5years in 65 preschools in two counties in Northwest China, using Crowded Single Lea Symbols to test visual acuity. Children were assigned randomly by school to one of three screening models: screening by teachers (15 schools, 1835 children), local optometrists (30 schools, 1718 children) or volunteers (20 schools, 2183 children). Children identifying ≥2 symbols incorrectly in either eye failed screening. Accuracy of screening was compared with screenings executed by experienced optometrists among 141 children selected randomly from the three screening models. Direct and indirect costs for each model were assessed. Costs to detect a true case failed screening were estimated. The sensitivity for three models ranged from 76.9% to 87.5%, specificity from 84.9% to 86.7% and standardized positive predictive value from 83.7% to 85.7%. None differed significantly between models. The costs per case detected were $37.53, $59.14 and $52.19 for the teachers, local optometrists and volunteers. In producing the cost estimates for teacher screening and local optometrist screening models, we used a salary payment that was identical for both models (with the salary being equal to that of the optometrist). The teacher screening model was the most cost-effective. Accuracy of screening by teachers, local optometrists and volunteers was the same in this setting, but the use of teachers was most cost-effective, reducing the cost per case detected by almost 40%.

High rate of failed visual-acuity measurements with the Amsterdam PictureChartin screening at the age of 36months.

PurposeIn the Netherlands, youth health care physicians and nurses screen all children for general health disorders at Child Health Care Centers. As part of this, the eyes are screened seven times, with the first visual acuity (VA) measurement at 36 months with the Amsterdam Picture Chart (APK). The suitability of the APK has been questioned.MethodsChildren born between July 2011 and June 2012 born in the provinces Drenthe, Gelderland and Flevoland and invited for screening at 36 months were eligible. Parents were sent the APK picture optotypes to practise with their children in advance. Data were collected from electronic screening records. The Dutch vision screening guideline prescribes that children with VA <5/6, or one line interocular difference (not logMAR, however) should be retested or referred.ResultsOf 10 809 eligible children, 1546 did not attend and 602 attended but had no VA measurement at age 36 months, 247 of these were under orthoptic treatment. Of the 8448 children examined, VA was sufficient in 5663 (67.0%) and insufficient in 1312 (15.5%). In 1400 (16.6%), the measurement of VA itself failed. In 73 (0.9%), data were missing. Of the 216 children with 2 failed VA measurements, 150 (69%) were not referred, and measurement of VA was deferred to the next general screening examination at 45 months.ConclusionAlthough most parents had practised the APK picture optotypes at home with their children, the rate of failed APK measurements plus the measurements with insufficient VA was 32.1% at 36 months. Similar rates have previously been reported for Lea Symbols and HOTV, permitting the conclusion that measurement of VA at the age of 36 months cannot be recommended as a screening test in the general population.

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

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

Review on visual acuity charts for preschool children

The preschool age is an important stage for the development of children's vision.Visual problems can affect visual development of children, so it is necessary for preschool children to have vision examination.As an important method of preschool vision screening, visual acuity charts can be used for early screening of eye diseases in children.The benefits of screening before school entry have been demonstrated in practice.There are many kinds of visual acuity charts that can be used to test the vision acuity of preschool children aged 3 to 6 years.This review introduced the design of visual acuity charts and lists several types of charts for screening of preschool children.Simultaneously, we have analyzed a number of papers that compared preschool vision screening methods.The vision examination on children aged 3 to 6 years was necessary to discover various visual impairments.Choosing an appropriate visual acuity chart is the focus of low vision rehabilitation research. Key words: Preschool children; Visual acuity chart; Lea Symbols chart

Comparison of the efficacy of Lea Symbol chart and Sheridan Gardiner chart for preschool vision screening

Purpose:To compare the efficacy of Lea symbols (LS) chart and Sheridan Gardiner (SG) chart for vision screening among preschool children, in a semi-urban district of South India.Methods:Vision screening was conducted among 260 preschool children aged 3–5 years in cluster sampled kindergartens using LS chart and SG chart. Pass/fail scores and time taken for visual acuity (VA) estimation were compared. VA scores and time taken were compared using unpaired t-test. Sensitivity, specificity, and positive and negative predictive values were compared between the charts.Results:There was a significant difference between LS and SG charts in the VA score in both the eyes (P = 0.04). LS showed 76.09% pass score and 23.90% fail score, whereas SG showed 87.65% pass score and 12.35% fail score with a cutoff value of > 0.3 log MAR. Time for screening using LS was higher, when compared to SG, both for the right eyes (P < 0.001) and the left eyes (P < 0.001). The sensitivity of the LS was 94.74% (95% confidence interval [CI]: 70.13%–81.06%) and that of SG was 52.63% (95% CI: 45.29%–59.8%). The specificity of LS was 66.67% (95% CI: 90.26%–97.30%) and SG was 83.33% (95% CI: 70.12%–91.30%).Conclusion:LS chart showed better sensitivity and negative predictive value when compared to SG chart. However, SG chart showed better specificity and positive predictive value, and screening was less time-consuming. Considering the high sensitivity and negative predictive value, LS is the preferred tool, when compared to SG chart in preschool vision screening in our population.

Effect of simulated refractive error on adult visual acuity for paediatric tests.

Although vanishing optotype preferential-looking tasks are commonly used to measure visual acuity (VA), the relative sensitivity of these tests to refractive error is not well understood. To address this issue, we determined the effect of spherical and astigmatic simulated refractive errors on adult VA measures obtained using vanishing optotypes, picture optotypes and Sloan letters. VA was determined uniocularly for adults under conditions of spherical (0.0-3.0 DS; n=23) and astigmatic (0.0-3.0 DC at 90° and 180°; n=20) defocus using the Cardiff Acuity Test (vanishing optotypes), crowded linear Lea Symbols (picture-optotype recognition task) and the Early Treatment of Diabetic Retinopathy Study (ETDRS) letter chart. The Cardiff Acuity Test over-estimated VA compared with the Lea Symbols and ETDRS charts in both focused and defocused conditions. The mean difference between the Cardiff Acuity Test and the ETDRS chart was 0.31 logMAR (95% limits of agreement (LOA) 0.10-0.52 logMAR) in focused conditions and 0.64 logMAR (95% LOA 0.25-1.05 logMAR) with 3D of spherical defocus. Defocus degraded VA on all charts, however there was a significant chart-by-defocus interaction whereby the Cardiff Acuity Test was more resistant to the effects of both spherical (P<0.0001) and cylindrical (P<0.001) optical defocus than the recognition acuity tasks at all defocus levels. Although the Cardiff Acuity Test provides an easy method for VA measurement in infants and toddlers, there is a considerable overestimation of VA compared with recognition acuity tasks particularly in the presence of defocus. A simple correction factor (of for example three lines overestimate) cannot be applied to Cardiff acuity measures as there is increasing over-estimation of VA with increasing defocus. Infants with significant refractive error may fall within normal visual acuity ranges for the Cardiff Acuity Test.

Validity of Different Screening Tests for Detecting Visual Impairment in 3 to 6 Year Old Children

Background: Preschool vision screenings (PVS) are recommended for early detection and treatment of childhood visual disorders. At present, the vision screening protocols in childhood varies from country to country and even within countries Objective: To determine the sensitivity and specificity of different screening tests used for visual impairment detection in the 3 to 6 year old children Method : Ethical Committee approval and parental consent obtained. Each child was assessed with Lea symbol and E charts for vision, stereo acuity measurement with Randot preschool stereo test, photo refraction by Plus optix A09, cover tests, cycloplegic refraction and retinal evaluation. Visual impairment (VI) was defined as presenting visual acuity in better eye <6/12. Receiver Operating Characteristics Curve (ROC) was used for statistical analysis. Results: A total of 200 eyes (100 participants) were analysed. 52% were males and 48% females.49.5% had visual impairment. The sensitivity and specificity of Lea symbol chart, Randot preschool and Plus optix A09 (spherical and cylindrical values) for detecting visual impairment were 91.8%, 56.2%, 51.8% ,81.8% and specificity were 91.9%,83.3%,50% , 68% respectively . Conclusion: Lea symbol chart had high sensitivity to pick up visual impairment in 3 to 6 year old children.

Investigating the Visual Status Of Preschool Children in Riyadh, Saudi Arabia.

PURPOSE:The purpose of the study was to explore the vision status of preschool children aged 3–6 years in Al Riyadh and to identify children at risk of amblyopia.MATERIALS AND METHODS:This was a cross-sectional population-based study. Visual acuity (VA) was measured using 15-line Lea symbols, refractive error was assessed using the Mohindra near retinoscopy technique, and peak contrast sensitivity (CS) was measured with the aid of the numerical CS test. We recruited 335 children, with their parents' written consent, from 14 kindergartens.RESULTS:A total of 335 children were recruited; 42 children (13%) exhibited reduced VA (Median [interquartile ranges (IQRs)], 0.00 [0.01]); most were emmetropic (87.7%). Myopia (4.2%), hyperopia (8.1%), and astigmatism (20%) were also observed. Most children had normal CSs. About 14% of children were at risk of amblyopia. It has been observed that 26% of families have some kind of refractive error.CONCLUSIONS:It is important to perform vision screening of preschoolers. Early detection of abnormalities in refractive errors could help to minimize the effect of visual impairment.

The heterophoria of 3-5 year old children as a function of viewing distance and target type.

Heterophoria is the misalignment of the eyes in monocular viewing and represents the accuracy of vergence driven by all classical cues except disparity. It is challenging to assess restless children using clinical cover tests, and phoria in early childhood is poorly understood. Here we used eye tracking to assess phoria as a function of viewing distance and target in adults and young children, with comparison to clinical cover tests. Purkinje image tracking (MCS PowerRefractor) was used to record eye alignment in adults (19-28 years, N = 24) and typically developing children (3-5 years, N = 24). Objective unilateral and alternating cover tests were performed using an infrared filter while participants viewed a pseudo-randomised sequence of Lea symbols (0.18 logMAR; Snellen: 20/30 or 6/9) and animated cartoon movies at distances of 40 cm, 1 m, and 6 m. For the unilateral cover test, a 10 s binocular period preceded and followed 30 s of occlusion of the right eye. For the alternating cover test, a 10 s binocular period preceded and followed alternate covering of right and left eyes for 3-s each. Phoria was derived from the difference in weighted average binocular and monocular alignment. A masked prism-neutralised clinical cover test was performed for each of the conditions for comparison. Closer viewing distance resulted in greater exophoria for both children and adults (p < 0.001). Phorias were similar for adults and children for each viewing distance and target, with mean differences of less than 2 prism dioptres (pd). Overall, the average PowerRefractor phorias (pooled across protocols) for adults were 1.3, 2.3 and 3.8 pd exophoria and for children were 0.1 pd esophoria, 0.94 and 3.8 pd exophoria for the 6 m, 1 m and 40 cm distances respectively. The corresponding clinical cover test values were 0.7, 1.9, and 4.1 pd exophoria for adults and 0, 1.5 and 3.3 pd exophoria for the children. Refractive states were also similar (≤0.5 D difference) for viewing the Lea symbols or movie for any protocol tested. Phoria estimation can be challenging for a pre-school child. These data suggest that by 3-5 years of age objective eye-tracking measures in a typically developing group are adult-like at the range of distances tested, and that use of an animated movie produces similar average results to a small optotype (0.18 logMAR; Snellen 20/30 or 6/9).

Assessment of near visual acuity in 0-13 year olds with normal and low vision: a systematic review.

BackgroundThe inclusion for rehabilitation of visually impaired children is partly based on the measurement of near vision, but guidelines for near visual acuity assessment are currently lacking. The twofold purpose of this systematic review was to: (i) provide an overview of the impact of the chart design on near visual acuity measured, and (ii) determine the method of choice for near vision assessments in children of different developmental ages.MethodsA literature search was conducted by using the following electronic databases: PubMed, Cochrane Library, and EMBASE. The last search was run on March 26th 2016. Additional studies were identified by contacting experts and searching for relevant articles in reference lists of included studies. Search terms were: vision test(s), vision assessment(s), visual acuity, chart(s) and near.ResultsFor children aged 0–3 years the golden standard is still the preferential looking procedure. Norms are available for this procedure for 6–36 month old children. For 4–7 year olds, we recommend using the LEA symbols, because these symbols have been properly validated and can be used in preliterate children. Responses can be verbal or by matching the target symbol. In children aged 8–13 years, the recommended method is the ETDRS letter chart, because letter acuity is more predictive for functional vision and reading than symbol acuity. In 8–13 year olds, letter acuity is 0.1–0.2 logMAR poorer than symbol acuity.ConclusionsChart design, viewing distance, and threshold choice have a serious impact on near visual acuity measurements. Near visual acuity measured with symbols is lower than near visual acuity measured with gratings, and near visual acuity measured with letters is lower than near visual acuity measured with symbols. Viewing distance, chart used, and letter spacing should be adapted to the child’s development and reported in order to allow comparisons between measurements.