Parapapillary Gamma Zone and Progression of Myopia in School Children: The Beijing Children Eye Study.

Purpose: To assess the development and enlargement of the parapapillary gamma zone in school children. Methods: This school-based prospective longitudinal study included Chinese children attending grade 1 in 2011 and returning for yearly follow-up examinations until 2016. These examinations consisted of a comprehensive ocular examination with biometry and color fundus photographs. The parents underwent a standardized interview. The parapapillary gamma zone was defined as the area with visible sclera at the temporal optic disc margin, and the optic disc itself was measured on fundus photographs. Results: The study included 294 children (mean age in 2016, 11.4 ± 0.5 years [range, 10-13 years]; mean axial length, 24.1 ± 1.1 mm [range, 21.13-27.29 mm]). In multivariate analysis, larger increases in the gamma zone area during the study period were correlated (coefficient of determination for bivariate analysis [r2], r2 = 0.69) with larger increases in the vertical-to-horizontal disc diameter ratios (P < 0.001; standardized regression coefficient beta [beta], 0.53; nonstandardized regression coefficient B [B], 4.05; 95% confidence intervals [CI], 3.37-4.73), larger axial elongation (P < 0.001; beta, 0.32; B, 0.37; 95% CI, 0.26-0.47), a larger vertical disc diameter at baseline (P < 0.001; beta, 0.22; B, 0.98; 95% CI, 0.62-1.33), a larger gamma zone area at baseline (P < 0.001; beta, 0.14; B, 0.41; 95% CI, 0.17-0.64), and more time spent indoors studying (P = 0.015; beta, 0.10; B, 0.09; 95% CI, 0.02-0.17). Conclusions: The development and enlargement of the gamma zone in the temporal parapapillary region were associated with an optic disc rotation around the vertical disc axis as indicated by an increasing vertical-to-horizontal disc diameter ratio. These morphologic findings fit with the notion of a backward pull of the temporal peripapillary sclera through the optic nerve dura mater in axially elongated eyes.

Optic disc-fovea distance and myopia progression in school children: the Beijing Children Eye Study.

PURPOSE: To assess changes in the optic disc-fovea distance (DFD) with progressing myopia in school children. METHODS: The school-based, prospective, longitudinal study included grade-1 children in 2011 who were yearly re-examined until 2016. We measured DFD, optic disc diameters and width of parapapillary gamma zone (parapapillary region without Bruch's membrane (BM)) on fundus photographs. RESULTS: Of 382 grade-1 children examined in 2011, 294 (77.0%) children (mean age in 2011: 6.4 ± 0.5 years) returned to be examined in 2016. In relative terms, the increase in DFD (1.15 ± 0.33 mm) was more due to an increase in gamma zone width (+300% or 0.29 ± 0.30 mm) than an increase in macular BM length (+18% or 0.74 ± 0.21 mm). In multivariate regression analysis, longer increase in DFD was correlated (regression coefficient r2  = 0.79) with longer axial elongation during the study period (p < 0.001; standardized regression coefficient ß: 0.61; non-standardized regression coefficient B: 0.30; 95% confidence interval (CI): 0.26, 0.33), larger increase in gamma zone width (p < 0.001; ß: 0.35; B: 0.40; 95%CI: 0.32, 0.48) and longer axial length in 2011 (p = 0.01; ß:0.07; B:0.03; 95%CI:0.01, 0.06). Larger increase in gamma zone width was associated (r2  = 0.73) with larger increase in DFD (p < 0.001; ß: 0.51; B: 0.46; 95%CI: 0.39, 0.53), larger increase in the vertical-to-horizontal disc diameter ratio (p < 0.001; ß: 0.43; B:1.21; 95%CI: 1.00, 1.42) and longer vertical disc diameter (p < 0.001; ß: 0.15; B:0.24; 95%CI: 0.14, 0.34). CONCLUSION: In adolescent school children, axial elongation-associated increase in DFD was mainly due to an enlargement (+300%) of parapapillary gamma zone, while macular BM length increased to minor degree (+18%). Gamma zone enlargement was correlated with axial elongation-associated vertical optic disc rotation, potentially due to an increased backward pull of the optic nerve on the temporal optic disc border.

High myopia in Greater Beijing School Children in 2016.

PURPOSE: To assess prevalence and associated factors of myopia and high myopia in schoolchildren in Greater Beijing. METHODS: The school-based, cross-sectional Greater Beijing School Children Myopia study was carried out in the year 2016 in 54 schools randomly selected from 15 districts in Beijing. Non-cycloplegic auto-refractometry of the right eyes was performed. RESULTS: The study included 35,745 (99.4%) out of 35,968 eligible pupils with a mean age of 12.6±3.4 years (range 6-18 years). Prevalence of myopia defined as myopic refractive error of ≥-0.50 diopters (D),≥-1D,≥-6D,≥-8D and ≥-10D was 70.9%(95% confidence intervals (CI):70.5,71.4), 60.9% (95%CI:60.4,61.4), 8.6%(95%CI:8.4,8.9), 2.2%(95%CI:2.0,2.4), and 0.3% (95%CI:0.3,0.4), respectively. The frequency of high myopia (≥-6D, ≥-8D, ≥-10D) increased from 1.5% (95%CI:1.0,2.0), 0.4% (95%CI:0.1,0.6) and 0.1% (95%CI:0.00,0.02), respectively in 10-year-olds to 19.4% (95%CI:17.3,21.6), 5.2% (95%CI:4.0,6.4) and 0.9% (95%CI:0.4,1.5), respectively, in 18-year-olds. Mean refractive error in the 18-year-olds was -3.74±2.56D (median:-3.63D;range:-19.6D to + 6.25D). Higher prevalence of high myopia (≥-6D and ≥-8D) was correlated (all P<0.001) with older age (OR:1.18, and 1.15, respectively), female gender (OR: 1.44 and 1.40, respectively), higher body mass index (OR: 1.02 and 1.03, respectively), taller body height (OR: 1.03 and 1.02, respectively), urban region of habitation (OR: 1.26 and 1.33, respectively) and higher school type (OR:1.57 and 2.22, respectively). Prevalence of severe high myopia (≥-10D) was associated only with older age (P<0.001; OR: 1.44; 95%CI: 1.31, 1.59) but not with any education-related parameter such as higher school type (P = 0.48), urban region of habitation (P = 0.07) or female gender (P = 0.37). CONCLUSION: In this most recent survey, prevalence of high myopia (≥-6D:19.4%;≥-8D:5.2%;≥-10D:0.9%) in 18-year-old school children was higher than in previous surveys from mainland China. In contrast to minor high myopia and moderate high myopia (defined as myopic refractive error of <-10D), severe high myopia (myopic refractive error ≥-10D) was not strongly correlated with educational parameters.

Outdoor activity and myopia progression in 4-year follow-up of Chinese primary school children: The Beijing Children Eye Study.

PURPOSE: To investigate factors associated with ocular axial elongation and myopia progression during a 4-year follow-up in primary school children in Beijing. METHODS: This school-based study included 382 grade-1 children at baseline in 2011 (age:6.3±0.4 years) with 305 (79.8%) returning for the follow-up examination in 2015. At baseline and in yearly follow-up examinations, the children underwent a comprehensive eye examination including auto-refractometry, ocular biometry with measurement of axial length, and fundus photography. The parents underwent a standardized interview. RESULTS: During the study period, the mean axial length elongated by 1.15±0.56mm in boys and 1.10±0.63mm in girls. At baseline and at the end of follow-up, axial length was significantly (P<0.001) longer in boys, with no difference (P = 0.50) between genders in axial elongation. In multivariate analysis, greater axial elongation was associated (regression coefficient r2:0.15) with less time spent outdoors (P = 0.004; standardized coefficient beta: -0.22), more time spent indoors with studying (P = 0.02; beta: 0.18) and paternal myopia (P = 0.03; beta: 0.16). Larger increases in the axial length/anterior corneal curvature (AL/CC) ratio were associated (r2:0.09) with less time spent outdoors (PP = 0.003; beta: -0.22) and maternal myopia (PP = 0.02; beta: 0.18). CONCLUSIONS: Myopic axial elongation during a 4-year follow-up was associated with shorter time spent outdoors and longer time spent indoors studying and with parental myopia. Other factors such as level of paternal education, family income, gender and region of habitation were significantly associated with axial elongation and with myopia progression only in univariate analysis.

Retinal oxygen saturation in Chinese adolescents.

PURPOSE: To study the retinal oxygen saturation in normal eyes of Chinese adolescents. METHODS: Performing retinal oximetry with the Oxymap T1 Retinal Oximeter in healthy children and adolescents (aged 5-18 years old), we measured the arterial (SaO2 ) and venular (SvO2 ) oxygen saturation and the arteriovenous difference in oxygen saturation (Sa-vO2 ). RESULTS: The study included 122 individuals with a mean age of 13.0 ± 2.9 years (range: 5-18 years) and a mean refractive error of -3.25 ± 2.49 dioptres (range:-8.88 to +3.13 dioptres). Mean SaO2 , SvO2 and Sa-vO2 was 85.5 ± 7.1%, 48.2 ± 5.5% and 37.3 ± 6.5%, respectively. Mean SaO2 was significantly (p < 0.001) the lowest in the inferotemporal quadrant (79.1 ± 9.0%), followed by the superotemporal quadrant (83.4 ± 9.7%), the inferonasal quadrant (90.4 ± 10.6%) and the superonasal quadrant (93.4 ± 10.8%). In a similar manner, the values of the SvO2 were the lowest (p < 0.001) in the inferotemporal quadrant (42.1 ± 8.3%), followed by the superotemporal quadrant (47.8 ± 7.2%), the inferonasal quadrant (52.3 ± 8.4%) and the superonasal quadrant (55.1 ± 7.6%). Arteriovenous difference in oxygen saturation (Sa-vO2 ) did not differ significantly (all p > 0.05) between the fundus quadrants. In multiple linear regression analysis, SaO2 increased (regression coefficient r2  = 0.28) with older age (standardized regression coefficient ß: 0.23; p = 0.01) and more myopic refractive error (ß: -0.39; p < 0.001). Higher SvO2 was significantly correlated with more myopic refractive error (ß: -0.46; p < 0.001; r2  = 0.20), while Sa-vO2 increased significantly only with older age in the multivariate analysis (ß: 0.26; p = 0.01; r2  = 0.07). CONCLUSIONS: Our study provides normative data for Chinese children and adolescents who showed lower values than adults for SaO2 and SvO2 . SaO2 increased with older age and higher myopic refractive error, SvO2 increased with higher myopic refractive error, and Sa-vO2 increased with older age.

Optic Disc Ovality in Primary School Children in Beijing.

PURPOSE: The purpose of this study was to assess the ovality of the optic disc and its associations with myopia-related factors in primary school children in Beijing. METHODS: This longitudinal school-based study included 382 grade 1 children and 299 grade 4 children who were followed for 2 years. Study participants underwent a comprehensive eye examination including autorefractometry, ocular biometry, and fundus photography. RESULTS: Fundus photographs were available for 562 children (82.5%). The mean optic disc ovality (maximal-to-minimal disc diameter) was 1.17 ± 0.29 (range, 1.00-1.50). Oval discs defined by an ovality of ≥ 1.33 were detected in 37 children (prevalence: 6.6%; 95% confidence interval: 4.5-8.6). In multivariate linear regression analysis, higher optic disc ovality index was significantly associated with older age (P = 0.001), female sex (P = 0.005), larger parapapillary beta zone (P < 0.001), and shorter time spent indoors with studying (P = 0.003) and was marginally significant (P = 0.057), with greater increase in myopic refractive error from 2011 to 2013. From 2011 to 2013, myopic refractive error increased in the oval optic disc group by 1.03 ± 0.99 diopters compared to 0.67 ± 1.31 diopters in the nonoval disc group. CONCLUSIONS: The prevalence of oval optic discs in Beijing school children was markedly higher than in the elderly Beijing Eye Study population (6.6% vs. 0.36%), paralleling the higher prevalence of myopia in school children. The association between oval optic discs and less time spent indoors with studying after adjusting for longitudinal change in myopic refractive error, age, sex and parapapillary beta zone may warrant further exploration of external factors associated with oval optic discs.

Parapapillary beta zone in primary school children in Beijing: associations with outdoor activity.

PURPOSE: To investigate prevalence and size of parapapillary alpha zone and beta zone and associations with myopia-related factors in primary school children in Beijing. METHODS: The school-based study included 382 grade-1 children and 299 grade-4 children. The children underwent a comprehensive eye examination and the parents, an interview. The examination was repeated after 1 year. RESULTS: Beta zone (prevalence: 44.5% ± 2.1%; mean area: 0.17 ± 0.29 mm(2)) was significantly associated with more time spent indoors with studying (P = 0.004; standardized correlation coefficient ß: 0.14; regression coefficient B: 0.05; 95% confidence interval [CI]: 0.02, 0.09) after adjusting for longer axial length (P < 0.001; ß: 0.22; B: 0.07; 95% CI: 0.04, 0.10), more myopic refractive error (P < 0.001; ß: -0.29; B: -0.07; 95% CI: -0.09, -0.04), region of habitation (P = 0.03; ß: 0.11; B: 0.07; 95% CI: 0.01, 0.14), and vertical disc diameter (P = 0.03; ß: 0.10; B: 0.16; 95% CI: 0.02, 0.30). As a corollary, indoors studying time was associated with larger area of beta zone (P = 0.01; ß: 0.11; B: 0.30; 95% CI: 0.07, 0.54) after adjusting for higher axial length/corneal curvature radius ratio (AL/CC; P = 0.006; ß: 0.12; B: 0.94; 95% CI: 0.27, 1.62) and urban region of habitation (P < 0.001; ß: -0.44; B: -0.75; 95% CI: -0.89, -0.61). An increase in AL/CC ratio at 1-year follow-up was associated with more indoors studying time (P = 0.04; ß: 0.10; B: 0.01; 95% CI: 0.00, 0.01) and larger beta zone area (P < 0.001; ß: 0.19; B: 0.04; 95% CI: 0.02, 0.05) after adjusting for axial length (P < 0.001; ß: -0.21; B: -0.01; 95% CI: -0.02, -0.01). CONCLUSIONS: Larger parapapillary beta zone area was associated with more indoors studying time after adjustment for axial length, refractive error, and region of habitation, and reversely, more indoors studying time was associated with larger beta zone in multivariate analysis. The results could indicate that parapapillary beta zone is associated with external factors-dependent development of myopia.

Visual impairment and spectacle use in schoolchildren in rural and urban regions in Beijing.

PURPOSE: To determine prevalence and associations of visual impairment and frequency of spectacle use among grade 1 and grade 4 students in Beijing. METHODS: This school-based, cross-sectional study included 382 grade 1 children (age 6.3 ± 0.5 years) and 299 grade 4 children (age 9.4 ± 0.7 years) who underwent a comprehensive eye examination including visual acuity, noncycloplegic refractometry, and ocular biometry. RESULTS: Presenting visual acuity (mean 0.04 ± 0.17 logMAR) was associated with younger age (p = 0.002), hyperopic refractive error (p<0.001), and male sex (p = 0.03). Presenting visual impairment (presenting visual acuity ≤20/40 in the better eye) was found in 44 children (prevalence 6.64 ± 1.0% [95% confidence interval (CI) 4.74, 8.54]). Mean best-corrected visual acuity (right eyes -0.02 ± 0.04 logMAR) was associated with more hyperopic refractive error (p = 0.03) and rural region of habitation (p<0.001). The prevalence of best-corrected visual impairment (best-corrected visual acuity ≤20/40 in the better eye) was 2/652 (0.30 ± 0.21% [95% CI 0.00, 0.72]). Undercorrection of refractive error was present in 53 children (7.99 ± 1.05%) and was associated with older age (p = 0.003; B 0.53; OR 1.71 [95% CI 1.20, 2.42]), myopic refractive error (p = 0.001; B -0.72; OR 0.49 [95% CI 0.35, 0.68]), and longer axial length (p = 0.002; B 0.74; OR 2.10 [95% CI 1.32, 3.32]). Spectacle use was reported for 54 children (8.14 ± 1.06%). Mean refractive error of the worse eyes of these children was -2.09 ± 2.88 D (range -7.38 to +7.25 D). CONCLUSIONS: Factors associated with presenting visual impairment were older age, myopic refractive error, and higher maternal education level. Despite a prevalence of myopia of 33% in young schoolchildren in Greater Beijing, prevalence of best-corrected visual impairment (0.30% ± 0.21%), presenting visual impairment (6.64% ± 1.0%), and undercorrection of refractive error (7.99% ± 1.05%) were relatively low.

Myopic shift and outdoor activity among primary school children: one-year follow-up study in Beijing.

PURPOSE: To assess whether a change in myopia related oculometric parameters of primary school children in Beijing was associated with indoors and outdoors activity. METHODS: The longitudinal school-based study included school children who were examined in 2011 and who were re-examined in 2012. The children underwent a comprehensive eye examination including ocular biometry by optical low-coherence reflectometry and non-cycloplegic refractometry. Parents and children had a detailed interview including questions on time spent indoors and outdoors. RESULTS: Out of 681 students examined at baseline, 643 (94.4%) returned for follow-up examination. Within the one-year period, mean time spent daily outdoors increased by 0.4±0.9 hours, mean axial length by 0.26±0.49 mm, the ratio of axial length divided by anterior corneal curvature (AL/CC) by 0.03±0.06, and myopic refractive error by -0.06±0.89 diopters. In multivariate analysis, elongation of axial length was significantly associated with less total time spent outdoors (P = 0.02; standardized coefficient beta -0.12) and more time spent indoors with studying (P = 0.007; beta: 0.14) after adjustment for maternal myopia (P = 0.02; beta: 0.12). An increase in AL/CC was significantly associated with less time spent outdoors (P = 0.01; beta:-0.12) after adjustment for paternal myopia (P = 0.003; beta: 0.15) and if region of habitation was excludedors for leisure (P = 0.006; beta:-0.13), with less total time spent outdoors (P = 0.04; beta:-0.10), or with more time spent i. An increase in myopic refractive error, after adjustment for age, was significantly associated with less time spent outdo ndoors with studying (P = 0.005; beta: 0.13). CONCLUSIONS: A change in oculometric parameters indicating an increase in myopia was significantly associated with less time spent outdoors and more time spent indoors in school children in Greater Beijing within a study period of one year. Our study provides additional information on the potentially helpful role of outdoors activity in the prevention of myopia. Public health care measures such as school agendas may potentially take it into account.

Outdoor activity and myopia among primary students in rural and urban regions of Beijing.

OBJECTIVE: To assess associations among outdoor activity, ocular biometric parameters, and myopia among grade 1 and grade 4 primary students in Beijing. DESIGN: School-based, cross-sectional study. PARTICIPANTS: A total of 382 grade 1 and 299 grade 4 children participated in the study. METHODS: The children underwent a comprehensive eye examination, including ocular biometry by optical low-coherence reflectometry and noncycloplegic refractometry. Parents and children participated in a detailed interview, including questions on time spent indoors and outdoors. MAIN OUTCOME MEASURES: Factors associated with myopia. RESULTS: The study included 681 children, with 382 (56.1%) students from grade 1 (mean age, 6.3 ± 0.5 years; range, 5-8 years) and 299 students from grade 4 (mean age, 9.4 ± 0.7 years; range, 8-13 years); 370 students (54.3%) lived in the urban region. The mean daily time spent outdoors was 1.6 ± 0.8 hours (range, 0.5-5.1 hours). In multivariate analysis, axial length was significantly associated with older age (P<0.001; standardized ß coefficient, 0.28), taller body height (P = 0.001; ß, 0.18), maternal myopia (P = 0.03; ß, 0.09), and urban region of habitation (P<0.001; ß, -0.21), or alternatively to the region of habitation, with less time spent outdoors (P = 0.001; ß, -0.16) and more time spent indoors studying (P = 0.02; ß, 0.10). The axial length-to-corneal curvature radius ratio was associated with older age, urban region of habitation, maternal and paternal myopia, and paternal level of education. Presence of myopia (defined as refractive error ≤-1 diopters in the right eye) was associated with older age (P<0.001; odds ratio [OR], 1.45; 95% confidence interval [CI], 1.24-1.69), maternal myopia (P<0.001; OR, 2.99; 95% CI, 1.94-5.35), and urban region of habitation (P<0.001; OR, 0.17; 95% CI, 0.11-0.26), or alternatively to the region of habitation, with less time spent outdoors (P<0.001; OR, 0.32; 95% CI, 0.21-0.48) and more time spent indoors studying (P<0.001; OR, 1.38; 95% CI, 1.09-1.75). CONCLUSIONS: Less outdoor activity, more indoor studying, older age, maternal myopia, and urban region of habitation were associated with longer ocular axial length and myopia in grade 1 and grade 4 primary school children in Greater Beijing. Remaining outdoors more (e.g., during school) may reduce the high prevalence of myopia in the young generation in Beijing.

Enhanced in vitro antitumor efficacy and strong anti-cell-migration activity of a hydroxycamptothecin-encapsulated magnetic nanovehicle.

A 10-hydroxycamptothecin-encapsulated magnetic nanovehicle (HEMN) was fabricated by coencapsulating Fe(3)O(4) nanoparticles and 10-hydroxycamptothecin (HCPT) into a micelle core self-assembled from the amphiphilic copolymer methoxy-poly(ethylene glycol)-poly(d,l-lactide-co-glycolide) through a facile dialysis method. A satisfactory drug-loading content of (9.03 ± 0.67) % and a relatively high encapsulation efficiency of (53.52 ± 6.46) % were achieved. In vitro drug release was performed by membrane dialysis and a pH-dependent release behavior was observed. In comparison with free HCPT dissolved in dimethylsulfoxide, HEMNs showed a greatly improved in vitro antitumor efficacy against three different human cancer cell lines-HeLa, A549, and HepG2-and lower IC(50) values were measured. The mechanism of cell death was investigated, and it was clearly demonstrated that the apoptosis process was triggered. An in vitro wound-healing assay and a transwell assay indicated that HEMNs exerted much stronger activity in inhibiting HeLa cell migration. The cellular uptake of HEMNs in a desired area can be significantly enhanced by an external magnetic field. These results demonstrate HCPT-encapsulated magnetic nanovehicles might have important potential in clinical applications for inhibiting tumor metastasis and for targeted drug delivery.