Lina Lu

Prevalence and causes of visual impairment and rate of wearing spectacles in schools for children of migrant workers in Shanghai, China

BackgroundTo assess the prevalence of visual impairment and rate of wearing spectacles in schools for children of migrant workers in Shanghai, China.MethodsChildren from grade 1 to 5 in schools for children of migrant workers were randomly chosen for ocular examinations. All children were screened for uncorrected visual acuity and presenting visual acuity. After screening, the children whose uncorrected visual acuity was 20/40 or less received ocular motility evaluation, cycloplegic refraction/non-cycloplegic refraction, and external eye, anterior segment, media, and fundus examinations.ResultsA total of 9673 children were enumerated and 9512 (98.34%) participated in this study. The prevalence of uncorrected, presenting, and best-corrected visual acuity of 20/40 or worse in the better eye were 13.33%, 11.26%, and 0.63%, respectively. The rate of wearing spectacles of the children with visual impairment in one or both eyes was 15.50%. Of these, 26.05% were wearing spectacles with inaccurate prescriptions. Refractive error was a major cause of visual impairment, accounting for 89.48% of all the visual impairment causes. Other causes of visual impairment included amblyopia accounting for 10.12%; congenital cataract, 0.1%; congenital nystagmus, 0.1%; ocular prosthesis, 0.1%; macular degeneration, 0.05%; and opaque cornea, 0.05%.ConclusionsThis is the first study of the prevalence and causes of visual impairment in schools for children of migrant workers in Shanghai, China. The visual impairment rate in schools for children of migrant workers in suburbs of Shanghai in the best eye before vision correction was lower than those of urban children in mainstream schools in Guangzhou in 2012, and higher than students in rural of Beijing in 1998 and in suburb of Chongqing in 2007. The refractive error was the principal cause of the visual impairment of the children of migrant workers. The rate of wearing spectacles was low and the percentage of inaccurate prescriptions, among those who wore spectacles, was high. Uncorrected refractive error was a significant cause of visual impairment in migrant children.

Axial Length/Corneal Radius Ratio: Association with Refractive State and Role on Myopia Detection Combined with Visual Acuity in Chinese Schoolchildren

Purpose To evaluate the association between the AL/CR ratio and refractive state and explore the effectiveness of this ratio in the assessment of myopia, especially when combined with uncorrected visual acuity in schoolchildren among whom myopia is common. Methods Cross sectional study. 4686 children from 6 primary schools, aged from 6 to 12 years were selected using the clustered-stratified random sampling method. Uncorrected visual acuity (UCVA), axial length (AL), corneal radius of curvature (CR), and cycloplegic refraction were tested. Refraction was measured as the spherical equivalent (SE). Results 3922 children were included in the analysis. The mean AL/CR ratio was 2.973±0.002, increased with age, and different in gender. The coefficients of correlations of the SE with the AL/CR ratio, AL, and CR were -0.811, -0.657, and 0.095, respectively. Linear regression showed a 10.72 D shift towards myopia with every 1 unit increase in the AL/CR ratio (P<0.001, r2 = 66.4%). The estimated SE values obtained by substituting the AL/CR ratio and gender back to the regression model that were within a difference of ±0.50 D in ATE/LER (allowable total error and limits for erroneous results) zones compared to the actual measured values was 51%. The area under the ROC curve of the AL/CR ratio, AL, and UCVA for myopia detection were 0.910, 0.822, and 0.889, respectively, and the differences between each pair were statistically significant (P<0.01). At a specificity of 90%, the sensitivities were 72.98%, 50.50%, 71.99%, and 82.96%, respectively, for the AL/CR ratio, AL, UCVA, and the combination of the AL/CR ratio and UCVA. Conclusions The AL/CR ratio was found to explain the total variance in SE better than AL alone. The effectiveness of the AL/CR ratio was statistically significantly better than UCVA for detecting myopia in children, and combining the two produced increased sensitivity without significantly decreasing specificity.

Population Prevalence of Need for Spectacles and Spectacle Ownership Among Urban Migrant Children in Eastern China

IMPORTANCE The number of urban migrants in China is 300 million and is increasing rapidly in response to government policies. Urban migrants have poor access to health care, but little is known about rates of correction of refractive error among migrant children. This is of particular significance in light of recent evidence demonstrating the educational impact of providing children with spectacles. OBJECTIVE To measure prevalence of spectacle need and ownership among Chinese migrant children. DESIGN, SETTING, AND PARTICIPANTS Population-based, cross-sectional study among children who failed vision testing (uncorrected visual acuity ≤6/12 in either eye) between September 15 and 30, 2013, at 94 randomly selected primary schools in predominantly migrant communities in Shanghai, Suzhou, and Wuxi, China. MAIN OUTCOMES AND MEASURES Refractive error by cycloplegic refraction; spectacle ownership, defined as producing glasses at school, having been told to bring them; and needing glasses, defined as uncorrected visual acuity of 6/12 or less correctable to greater than 6/12 in either eye, with myopia of -0.5 diopters (D) or less, hyperopia of +2.0 D or greater, or astigmatism of 0.75 D or greater in both eyes. RESULTS Among 4409 children, 4376 (99.3%) completed vision screening (mean [SD] age, 11.0 [0.81] years; 55.3% boys; 4225 [96.5%] migrant and 151 [3.5%] local). Among 1204 children failing vision testing (total, 27.5%; 1147 migrant children [27.1%] vs 57 local children [37.7%]; P = .003), 850 (70.6%) completed refraction. Spectacle ownership in migrant children needing glasses (147 of 640 children [23.0%]) was less than among local children (12 of 34 children [35.3%]) (odds ratio = 0.55; 95% CI, 0.32-0.95; P = .03). Having uncorrected visual acuity less than 6/18 in both eyes was associated positively with baseline spectacle ownership (odds ratio = 5.73; 95% CI, 3.81-8.62; P < .001), but parental education and family wealth were not. CONCLUSIONS AND RELEVANCE Among urban migrant children, there was a high prevalence of need for spectacles and a very low rate of spectacle ownership. Spectacle distribution programs are needed specifically targeting migrant children.

Four-year analysis of cataract surgery rates in Shanghai, China: a retrospective cross-sectional study

BackgroundThe cataract surgery rate (CSR) is a critical index used to show that cataract blindness is being eliminated. It is considered to be tightly connected to social economic development; however, it is still extremely low in developing countries such as China. Although Shanghai is the most economically developed city in China, its CSR and the obstacles for increasing its CSR have not been previously evaluated.MethodsA retrospective cross-sectional study was conducted. By analyzing the data in the “Shanghai Cataract Operations Database” from 2006 to 2009, the CSR in Shanghai was calculated. The numbers of cataract surgeries between urban and suburban districts as well as among various medical institutions were compared.ResultsThe CSR in Shanghai increased from 1741 in 2006 to 2210 in 2009, reflecting a 26.94% improvement. Phacoemulsification was the most frequent surgical choice for cataract removal, accounting for 94.93% of total cataract surgeries by 2009. In addition, by 2009, the CSR in urban districts had reached 5468, but only 532 in the suburbs. During 2009, cataract surgery records in 68 district hospitals, 23 medical centers, and 6 private hospitals comprised 32.05%, 52.33%, and 15.62%, respectively, of the total. There was a nearly 3.3-fold increase in the number of surgeries performed in private hospitals in the past four years. Furthermore, the average number of cataract surgeries per doctor that took place in private hospitals per year reached 207, which exceeded the average of 145 that took place in medical centers.ConclusionsUntil 2009, the CSR in Shanghai remained below the rates of social development and fell short of targets suggested by the World Health Organization (WHO). Furthermore, increasing the CSR in the suburbs as well as in district hospitals is an important issue that needs to be addressed.

Myopia screening: combining visual acuity and noncycloplegic autorefraction.

Purpose To explore the effectiveness of combining uncorrected visual acuity (UCVA) and noncycloplegic autorefraction (NCAR) for large-scale myopia screening in schoolchildren with a high prevalence of myopia. Methods A total of 1687 children aged between 6 and 12 years, from five primary schools in the Baoshan district of Shanghai participated in the study. We measured UCVA and autorefraction before and after cycloplegia by a Topcon KR-8800. We drew receiver operating characteristic curves to achieve the best cutoff points and their corresponding sensitivities and specificities for the UCVA and NCAR, respectively. We then combined the UCVA and NCAR in serial order to explore the optimal criterion and its effectiveness. A specificity of 90% was set to compare the sensitivities among the three tests. The children were divided into three age groups (aged 6 to 7, 8 to 10, 11 to 12 years) to further examine this new method. Results A total of 1639 children with an average age of 9.35 (SD, 1.6) years were finally included, among which 428 (26.11%) children were diagnosed as being myopic (spherical equivalent refraction (SER) less than or equal to −0.5 diopters [D]). For the UCVA, the cutoff point is 0.2 logarithm of the minimum angle of resolution (20/32), with a sensitivity and specificity of 63.6% and 94.0%, respectively. For NCAR, the cutoff point is SER less than or equal to −0.75 D, with a sensitivity and specificity of 88.6% and 86.1%, respectively. When UCVA is combined with NCAR, the best cutoff point is UCVA less than or equal to 0 logarithm of the minimum angle of resolution (20/20) and SER less than or equal to −0.75 D, with a sensitivity and specificity of 84.4% and 90.5%, respectively. At a specificity of 90%, the sensitivities are 63.55%, 78.50%, and 84.35%, respectively, for UCVA, NCAR, and the combination test. In all age groups, the combination test had the highest sensitivities among the three tests. Conclusions In a population with a high prevalence of myopia, combining the UCVA and NCAR in serial order achieved higher sensitivity than either of the two tests alone, when specificity was set at 90%.

Screening for Significant Refractive Error Using a Combination of Distance Visual Acuity and Near Visual Acuity

Purpose To explore the effectiveness of using a series of tests combining near visual acuity (NVA) and distance visual acuity (DVA) for large-scale screenings for significant refractive error (SRE) in primary school children. Method Each participant underwent DVA, NVA and cycloplegic autorefraction measurements. SREs, including high myopia, high hyperopia and high astigmatism were analyzed. Cycloplegic refraction results were considered to be the gold standard for the comparison of different screening measurements. Receiver-operating characteristic (ROC) curves were constructed to compare the area under the curve (AUC) and the Youden index among DVA, NVA and the series combined tests of DVA and NVA. The efficacies (including sensitivity, specificity, positive predictive value, and negative predictive value) of each test were evaluated. Only the right eye data of each participant were analysed for statistical purpose. Result A total of 4416 children aged 6 to 12 years completed the study, among which 486 students had right eye SRE (SRE prevalence rate = 11.01%). There was no difference in the prevalence of high hyperopia and high astigmatism among different age groups. However, the prevalence of high myopia significantly increased with the age (χ² = 381.81, p<0.01). High hyperopia was the biggest SRE factor associated with amblyopia（p＜0.01，OR = 167.40, 95% CI: 75.14∼372.94). The DVA test was better than the NVA test for detecting high myopia (Z = 2.71, p<0.01), but the NVA test was better for detecting high hyperopia (Z = 2.35, p = 0.02) and high astigmatism (Z = 4.45, p<0.01). The series combined DVA and NVA test had the biggest AUC and the highest Youden Index for detecting high hyperopia, myopia, astigmatism, as well as all of the SREs (all p<0.01). Conclusion The series combined DVA and NVA test was more accurate for detecting SREs than either of the two tests alone. This new method could be applied to large-scale SRE screening of children, aged 6 to 12, in areas that are less developed.

Retinal Nerve Fiber Layer Thickness in Normal Chinese Students Aged 6 to 17 Years

PURPOSE We obtained retinal nerve fiber layer (RNFL) thickness measurements in normal Chinese students aged 6 to 17 years, and investigated the relationship between RNFL thickness and sex, eye laterality, age, axial length, and refractive error. METHODS A total of 4648 eyes in 2324 normal, randomly-selected Chinese students aged 6 to 17 years was examined in this study. The RNFL thickness was measured by optical coherence tomography. The effects of sex, eye laterality (left or right), age, refractive error, and axial length on RNFL thickness were assessed. RESULTS The average age of the subjects was 12.82 ± 3.11 years. The global average RNFL thickness (±SD) was 106.89 ± 12.84 μm. The thickest RNFL measurements were found at the superior (133.22 ± 19.48 μm) and inferior (129.23 ± 20.30 μm) quadrants of the retina, followed by the temporal (93.58 ± 29.15 μm) and nasal (77.10 ± 14.89 μm) quadrants. In the 1529 participants aged 12 to 17, there were no significant differences in RNFL thickness values between the right and left eyes (P > 0.05); significant differences in RNFL were found only in the inferior and temporal quadrants of the retina in different sex groups (P < 0.05). Linear regression analysis revealed that the RNFL thickness values were correlated independently with axial length and refractive error (P < 0.05). CONCLUSIONS For clinical assessment of RNFL thickness, the influence of refractive error and axial length should be taken into account.

Impact of Free Glasses and a Teacher Incentive on Children's Use of Eyeglasses: A Cluster-Randomized Controlled Trial

PURPOSE To study the effect of free glasses combined with teacher incentives on in-school glasses wear among Chinese urban migrant children. DESIGN Cluster-randomized controlled trial. METHODS Children with visual acuity (VA) ≤6/12 in either eye owing to refractive error in 94 randomly chosen primary schools underwent randomization by school to receive free glasses, education on their use, and a teacher incentive (Intervention), or glasses prescriptions only (Control). Intervention group teachers received a tablet computer if ≥80% of children given glasses wore them during unannounced visits 6 weeks and 6 months (main outcome) after intervention. RESULTS Among 4376 children, 728 (16.7%, mean age 10.9 years, 51.0% boys) met enrollment criteria and were randomly allocated, 358 (49.2%, 47 schools) to Intervention and 370 (50.8%, 47 schools) to Control. Among these, 693 children (95.2%) completed the study and underwent analysis. Spectacle wear was significantly higher at 6 months among Intervention children (Observed [main outcome]: 68.3% vs 23.9%, adjusted odds ratio [OR] = 11.5, 95% confidence interval [CI] 5.91-22.5, P < .001; Self-reported: 90.6% vs 32.1%, OR = 43.7, 95% CI = 21.7-88.5, P < .001). Other predictors of observed wear at 6 months included baseline spectacle wear (P < .001), uncorrected VA <6/18 (P = .01), and parental spectacle wear (P = .02). The 6-month observed wear rate was only 41% among similar-aged children provided free glasses in our previous trial without teacher incentives. CONCLUSIONS Free spectacles and teacher incentives maintain classroom wear in the large majority of children needing glasses over a school year. Low wear among Control children demonstrates the need for interventions.

CHOROIDAL THICKNESS IN HEALTHY CHINESE CHILDREN AGED 6 to 12: The Shanghai Children Eye Study.

Purpose: To explore the characteristics of choroidal thickness (ChT) in Chinese children. Methods: A total of 144 healthy children, aged 6 years to 12 years old, were enrolled in the study. The ChT of subfovea and peripheral locations 0.5, 1.5, and 2.5 mm away from the fovea were evaluated by enhanced depth imaging optical coherence tomography. The association between subfoveal ChT and systemic, as well as ocular factors, including age, sex, height, weight, body mass index, axial length, refractive error, intraocular pressure, preterm history, and the refractive status of parents were studied. Results: The mean subfoveal ChT was 302 ± 63 &mgr;m. In the nasal, superior, and inferior areas, the ChT of locations closer to the fovea was thicker than those farther away from the fovea (all P < 0.05); however, ChT was not significantly different among different locations in the temporal area (P = 0.16). The ChT of the nasal quadrant was significantly thinner than that of other areas (P < 0.01). Subfoveal ChT decreased with age, axial length, preterm history, and increased with height. Sex was not statistically associated with subfoveal ChT. Conclusion: In Chinese children, the ChT is thinnest in the nasal quadrant and thicker in central regions than in peripheral areas. The subfoveal ChT independently decreases with age, axial length, preterm history, and increases with height.

Corneal Thickness Profile and Associations in Chinese Children Aged 7 to 15 Years Old.

Corneal thickness (CT) maps of the central (2-mm diameter), para-central (2 to 5-mm diameter), peripheral (5 to 6-mm diameter), and minimum (5-mm diameter) cornea were measured in normal Chinese school children aged 7 to 15 years old using Fourier-domain optical coherence tomography. Multiple regression analyses were performed to explore the effect of associated factors [age, gender, refraction, axial length and corneal curvature radius (CCR)] on CT and the relationship between central corneal thickness (CCT) and intraocular pressure (IOP). A total of 1228 eyes from 614 children were analyzed. The average CCT was 532.96 ± 28.33 μm for right eyes and 532.70 ±28.45 μm for left eyes. With a 10 μm increase in CCT, the IOP was elevated by 0.37 mm Hg, as measured by noncontact tonometry. The CT increased gradually from the center to the periphery. The superior and superior nasal regions had the thickest CTs, while the thinnest points were primarily located in the inferior temporal cornea. The CCT was associated with CCR (p = 0.008) but not with gender (p = 0.075), age (p = 0.286), axial length (p = 0.405), or refraction (p = 0.985). In the para-central region and the peripheral cornea, increased CT was associated with younger age, male gender, and a flatter cornea.