Central anterior chamber depth correlated with white-to-white distance in normal, long, and short eyes.

PURPOSE: To explore the associations between central anterior chamber depth (CACD) and other anterior segment biometric parameters and to determine the possible determinants of CACD in short, normal, and long eyes. METHODS: The biometric data of pre-operation patients aged 50-80 years with coexisting cataract and primary angle-closure disease or senile cataract were reviewed. Axial length (AL), CACD, lens thickness (LT), central corneal thickness (CCT), and white-to-white distance (WTW) were measured by Lenstar optical biometry (Lenstar 900). The data of 100 normal eyes (AL = 22 to 26 mm), 100 short eyes (AL ≤ 22 mm), and 100 long eyes (AL ≥ 26 mm) were consecutively collected for subsequent analyses. RESULTS: The mean age of the subjects was 66.60 ± 7.85 years, with 25.7% of the sample being men. Both CACD and WTW were found to be smallest in short eyes and were smaller in normal eyes than in long eyes (F = 126.524, P < 0.001; F = 28.458, P < 0.001). The mean LT was significantly thicker in short eyes than in normal and long eyes (4.66 mm versus 4.49 mm versus 4.40 mm; F = 18.099, P < 0.001). No significant differences were observed in CCT between the three AL groups (F = 2.135, P = 0.120). Stepwise regression analysis highlighted AL, LT, and WTW as three independent factors associated with CACD in the normal AL group. In the short AL group and long AL group, LT and WTW were independent factors associated with CACD. CONCLUSIONS: CACD increases as AL elongates and reaches a peak when AL exceeds 26 mm. Furthermore, CACD showed inverse correlation with LT and positive correlation with WTW. A relatively small WTW results in an anteriorly positioned lens, and thus, a decrease in CACD.

ASSOCIATION OF OCULAR PERFUSION PRESSURE AND CEREBROSPINAL FLUID PRESSURE WITH CHANGES IN DIABETIC RETINOPATHY.

PURPOSE: To investigate the association between mean ocular perfusion pressure (MOPP), estimated cerebrospinal fluid pressure (CSFP), and changes in diabetic retinopathy (DR) in a Northeastern Chinese population with Type 2 diabetes. METHODS: A total of 1,322 subjects from the Fushun Diabetic Retinopathy Cohort Study were enrolled. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and intraocular pressure (IOP) were recorded. MOPP was calculated by the following formula: MOPP = 2/3 [DBP + 1/3 (SBP - DBP)] - IOP, and CSFP was estimated according to the following formula: CSFP = 0.44 × body mass index + 0.16 × DBP - 0.18 × age - 1.91. New development, progression, and regression of DR were graded based on fundus photographs at baseline and during follow-up examinations with a mean interval of 21.2 months using the modified Early Treatment Diabetic Retinopathy Study criteria. RESULTS: Increasing MOPP was associated with the incidence of DR in the multivariate model (per 1-mmHg increase: relative risk, 1.06; 95% confidence interval, 1.02-1.10; P = 0.007) and showed a borderline negative association with DR regression (per 1-mmHg increase: relative risk, 0.98; 95% confidence interval, 0.97-1.00; P = 0.053). However, MOPP was not associated with progression of DR. Cerebrospinal fluid pressure was not associated with new development, progression, or regression of DR. CONCLUSION: The MOPP, but not the CSFP, was found to influence the development, but not the progression of DR in this Northeastern Chinese cohort.

Intraocular Pressure and Myopia Progression, Axial Length Elongation in Rural Chinese Children.

SIGNIFICANCE: This study reported the relationship between intraocular pressure (IOP) and myopia progression, which helps to understand more comprehensively whether IOP can be an important reference factor to intervene in the progression of myopia. PURPOSE: This study aimed to investigate the association between IOP and myopia progression as well as axial length elongation in rural Chinese children. METHODS: A total of 598 (598 of 878 [68.1%]) children (6 to 17 years) from the baseline Handan Offspring Myopia Study who completed a 3.5-year follow-up vision examination were included. Ocular examinations at both visits included cycloplegic autorefraction, IOP, and axial length measurements. RESULTS: Children with myopia had the highest baseline IOP of the three refractive groups (14.13 ± 1.31, 13.78 ± 1.71, and 13.59 ± 1.64 mmHg in myopes, emmetropes, and hyperopes, respectively, P = .002). However, IOPs showed no significant difference between eyes with or without newly developed myopia (13.63 ± 1.68 vs. 13.89 ± 1.68, P = .16), with or without faster myopia progression (13.75 ± 1.61 vs. 13.86 ± 1.63, P = .46), or with axial length elongation (13.80 ± 1.61 vs. 13.76 ± 1.64, P = .80). The multivariate regression analysis demonstrated that neither baseline refractive error ( ß = -0.082, P = .13) nor baseline axial length ( ß = -0.156, P = .08) was associated with baseline IOP. CONCLUSIONS: Myopic eyes have slightly higher IOP compared with emmetropic and hyperopic eyes, although it was not clinically significant. However, IOP was not found to be associated with either myopia progression or axial length elongation in this cohort sample of rural Chinese children.

A Novel and Reversible Experimental Primate Ocular Hypertension Model: Blocking Schlemm's Canal.

INTRODUCTION: The purpose of this study was to establish a novel and reversible experimental ocular hypertension primate model by blocking Schlemm's canal. METHODS: A model was induced in adult cynomolgus monkeys (n=4) by blocking Schlemm's canal with an inserted microcatheter (200 µm diameter); it was removed 6 weeks later from one monkey to reverse the elevated intraocular hypertension. All animals were monitored for 11 months; weekly measurements of intraocular pressure and biweekly examinations with spectral domain optical coherence tomography and disc photography were performed. Histopathology of the eye and retinal ganglion cell counts were completed at the end of the study. RESULTS: The intraocular pressure of the blocked eyes was significantly higher than that of the contralateral eyes at 1 month after the blockage (P <0.001); the mean intraocular pressure was similar to the contralateral eye from 1 week to 11 months after the microcatheter was removed in monkey A (P=0.170). The mean intraocular pressure of the blocked eyes of the remaining monkeys was significantly higher than that of the contralateral eyes throughout the follow-up period (P <0.001). The fundus imaging showed decreases in the retinal nerve fibre layer thickness, and localised defects were observed in two blocked eyes. A histological examination demonstrated that the number of retinal ganglion cells in blocked eyes of monkeys A, B, and C was significantly decreased compared with the control. CONCLUSION: Schlemm's canal blockage alone in the monkey model produces sustained elevation of intraocular pressure, which present a novel animal model for studying the pathogenesis of glaucoma.

Prevalence of and Risk Factors for Diabetic Retinopathy and Diabetic Macular Edema in Patients with Early- and Late-Onset Diabetes Mellitus.

PURPOSE: The aim of this study was to compare the prevalence of diabetic retinopathy (DR) and diabetic macular edema (DME), as well as their risk factors in patients with early-onset diabetes (EOD, ≤40 years) and late-onset diabetes (LOD, >40 years). METHODS: Patients were recruited from a community-based study, Fushun Diabetic Retinopathy Cohort Study (FS-DIRECT), conducted between July 2012 and May 2013 in China. The presence and severity of DR and DME were determined by a modified Early Treatment Diabetic Retinopathy Study (ETDRS) retinopathy scale of six-field fundus photographs. RESULTS: A total of 1,932 patients (796 male, 41.2%) with gradable fundus photography were included. The prevalence of any DR and DME was 67.0% (95% confidence interval [CI]: 60.3-73.7%) and 39.3% (95% CI: 32.1-46.5%) in the EOD patients, respectively, which were both significantly higher than that in the LOD patients (DR: 41.9%, 39.6-44.2%, p < 0.001; DME: 14.4%, 12.7-16.1%, p < 0.001). Insulin use was associated with both the presence of DR and DME in both EOD and LOD patients. Besides insulin use, a high level of income (odds ratio [OR], 95% CI: 0.05, 0.01-0.51) was negatively associated with DR, and higher high-density lipoprotein (OR, 95% CI: 4.14, 1.44-11.91) was associated with DME among EOD patients. CONCLUSION: In this sample of patients with type 2 diabetes, both prevalence of DR and DME were apparently higher in patients who developed diabetes ≤40 years of age than those who developed it later.

Interocular Asymmetry of Visual Field Loss, Intraocular Pressure, and Corneal Parameters in Primary Open-Angle Glaucoma.

OBJECTIVES: This study aimed to assess the association between the corneal biomechanical parameters and visual field (VF) loss in patients with asymmetric primary open-angle glaucoma (POAG). METHODS: A total of 89 POAG patients (50 males, 56.2%) with asymmetric VF loss, aged 65.2 ± 13.3 years, were enrolled in this study. Asymmetric VF loss was defined as an interocular difference of the global index mean deviation (MD) >2 dB. Intraocular pressure (IOP), central corneal thickness (CCT), and corneal biomechanical parameters such as maximum amplitude at the apex of highest concavity (def ampl HC) were measured. The worse eye was defined as the eye with a smaller MD. RESULTS: The worse eyes had lower MD (-11.9 ± 6.7 dB vs. -5.3 ± 5.0 dB; p < 0.001) and higher IOP (14.6 ± 3.3 vs.13.9 ± 2.6 mm Hg, p = 0.04) than the better eyes. There was no significant difference between the 2 groups for CCT. The interocular difference of MD (IDMD) was negatively correlated with the interocular difference of IOP (r = -0.22, p = 0.04), while positively correlated with the interocular difference of def ampl HC (r = 0.27, p = 0.01). In patients with moderate asymmetric VF loss (IDMD ≥6 dB), def ampl HC of the worse eyes group (1.07 ± 0.12 mm) was significantly lower than the better eyes group (1.10 ± 0.11 mm, p = 0.02). CONCLUSION: Asymmetric POAG was associated with asymmetry in IOP and corneal biomechanical parameters but not in CCT. Lower deflection amplitude and higher IOP were found in eyes with more severe VF damage in POAG patients.

Genetic signatures of high-altitude adaptation in Tibetans.

Indigenous Tibetan people have lived on the Tibetan Plateau for millennia. There is a long-standing question about the genetic basis of high-altitude adaptation in Tibetans. We conduct a genome-wide study of 7.3 million genotyped and imputed SNPs of 3,008 Tibetans and 7,287 non-Tibetan individuals of Eastern Asian ancestry. Using this large dataset, we detect signals of high-altitude adaptation at nine genomic loci, of which seven are unique. The alleles under natural selection at two of these loci [methylenetetrahydrofolate reductase (MTHFR) and EPAS1] are strongly associated with blood-related phenotypes, such as hemoglobin, homocysteine, and folate in Tibetans. The folate-increasing allele of rs1801133 at the MTHFR locus has an increased frequency in Tibetans more than expected under a drift model, which is probably a consequence of adaptation to high UV radiation. These findings provide important insights into understanding the genomic consequences of high-altitude adaptation in Tibetans.

Accuracy of isolated-check visual evoked potential technique for diagnosing primary open-angle glaucoma.

PURPOSE: The aim of this study was to determine the diagnostic accuracy, sensitivity and specificity of isolated-check visual evoked potentials (icVEP) in primary open-angle glaucoma (POAG). METHODS: Ninety POAG patients and sixty-six healthy controls were recruited consecutively. All subjects underwent icVEP and visual field testing. Swept icVEP response functions were obtained by increasing contrast in six stimulus steps, recording the electroencephalogram synchronized to the stimulus display's frame rate and calculating the corresponding signal-to-noise ratio (SNR) of the response at the fundamental frequency to evaluate visual function. Depth of modulation of the check luminance was increased as follows: 2, 4, 8, 14, 22 and 32%, about an equal level of standing contrast, so that the pattern appeared and disappeared at a frequency of 10.0 Hz. SNR above 0.85 was deemed to be significant at the 0.1 level and SNR above 1 significant at the 0.05 level. RESULTS: The results show that SNR is contrast dependent. It significantly rose as contrast increased. The areas under receiver-operating-characteristic curves (AUCs) indicating classification accuracy for all POAG cases in comparison with normal subjects were 0.790 (sensitivity 91.1%, specificity 69.7%) with the cutoff SNR of 0.85, and 0.706 (sensitivity 95.6%, specificity 51.5%) with the cutoff SNR of 1. The AUC of early glaucoma cases (EG) in comparison with normal subjects was 0.801 (sensitivity 93.3%, specificity 69.7%) with the cutoff SNR of 0.85, and 0.717 (sensitivity 97.8%, specificity 51.5%) with the cutoff SNR of 1. CONCLUSION: icVEP has good diagnostic accuracy (high sensitivity and moderate specificity) in distinguishing early POAG patients from healthy subjects. It might be a promising device to use in conjunction with complementary functional and structural measures for early POAG detection.

Near work, outdoor activity, and myopia in children in rural China: the Handan offspring myopia study.

BACKGROUND: The near work and outdoor activity are the most important environmental risk factors for myopia. However, data from Chinese rural children are relatively rare and remain controversial. Therefore, the purpose of this study was to evaluate the relationship of both near work and outdoor activities with refractive error in rural children in China. METHODS: In this cross-sectional study, 572 (65.1%) of 878 children (6-18 years of age) were included from the Handan Offspring Myopia Study (HOMS). Information from the parents on these children, as well as the parent's non-cycloplegic refraction, were obtained from the database of the Handan Eye Study conducted in the years 2006-2007. A comprehensive vision examination, including cycloplegic refraction, and a related questionnaire, were assessed on all children. RESULTS: The overall time spent on near work and outdoor activity in the children was 4.8 ± 1.6 and 2.9 ± 1.4 h per day, respectively. Myopic children spent more time on near work (5.0 ± 1.7 h vs.4.7 ± 1.6 h, p = 0.049), while no significant difference was found in outdoor activity hours (2.8 ± 1.3 h vs. 3.0 ± 1.4 h, p = 0.38), as compared to non-myopic children. In the multiple logistic analysis, in general, no association between near work and myopia was found after adjusting for the children's age, gender, parental refractive error, parental educational level, and daily outdoor activity hours [odds ratio (OR), 95% confidence interval (CI): 1.10, 0.94-1.27]. However, a weak protective effect of the outdoor activity on myopia was found (OR, 95% CI: 0.82, 0.70-0.96), after adjusting for similar confounders. CONCLUSIONS: In general, no association between near work and myopia was found, except for the high near work subgroup with moderate outdoor activity levels. A weak protective effect of outdoor activity on myopia in Chinese rural children was observed.

The difference between cycloplegic and non-cycloplegic autorefraction and its association with progression of refractive error in Beijing urban children.

PURPOSE: To investigate the difference between cycloplegic and non-cycloplegic autorefraction and its association with the progression of refractive error in Beijing urban children. METHODS: A total of 386 children aged 6-17 years were enrolled in the baseline investigation of the Beijing Myopia Progression Study in 2010. They were invited for follow-up vision examinations in the years 2011, 2012, and 2013, including cycloplegic (cyclopentolate 1%, three times) autorefraction. We investigated the difference between the cycloplegic spherical equivalent (SE) and the non-cycloplegic SE (DSE) provided by autorefraction and its association with refractive error progression. The progression of refractive error was defined as the difference between the cycloplegic SE at follow-up and at baseline. RESULTS: Two hundred and nineteen children (57%) with completed refractive data (mean ± standard deviation: -1.36 ± 2.44 D at baseline) were ultimately enrolled. The DSE reduced from 0.51 ± 0.72 D at baseline to 0.19 ± 0.43 D in the third year of follow-up (p = 0.01). The baseline DSE was positively associated with the children's baseline cycloplegic refraction (ß = 0.193 dioptre dioptre-1 , p < 0.001). After further divided by refractive status, the DSE was consistently higher in the hyperopic group than in either the emmetropic or myopic groups at each follow-up (all p < 0.001). In the multivariate regression analysis, the myopic children with larger baseline DSE (ß = -0.404 dioptre dioptre-1 , p = 0.01) exhibited more myopic refractive change. However, baseline DSE was not found to be a significant risk factor (relative risk, 95% confidence interval: 1.06, 0.79-1.41) for those with newly developed myopia. CONCLUSION: In this sample, the children's DSE was found to be increased as the hyperopic refraction increased. Furthermore, greater the DSE was associated with the progression of refractive error among the myopic children, but not with the onset of myopia.

The influence of near work on myopic refractive change in urban students in Beijing: a three-year follow-up report.

PURPOSE: To investigate the influence of daily activities on myopic refractive change and myopic onset in Chinese urban students. METHODS: The Beijing Myopia Progression Study was a 3-year cohort study. Cycloplegic refraction and a daily activity questionnaire were assessed at baseline and at follow-up examinations. Refractive change was defined as the difference in cycloplegic spherical equivalent (SE) between the final follow-up and baseline. 386 students were initially enrolled in the baseline study. RESULTS: At the final follow-up, 222 students (57.5 %) with completed refractive error and daily activity data were analyzed. These students spent 0.32 ± 2.33 h/day more on near work (p = 0.04), and 0.21 ± 1.31 h/day less on outdoor leisure (p = 0.02), than they did at baseline. In the multivariate analysis, the younger among the secondary students (ß = 0.06, p < 0.001), and those with more near work hours at baseline (ß = -0.028, p = 0.033), exhibited more myopic refractive change. However, myopic refractive change was not found to be significantly associated with near work hours in the primary students, or with time spent outdoors, in either school level. After stratifying the activity hours into quartile groups, students with a greater near work load at baseline (trend P = 0.03) exhibited a greater myopic refractive change and had a higher risk to develop myopia (hazard ratio, 95 % confidence interval: 5.19, 1.49-18.13), after adjusting for the confounders. However, no significant association was found related to outdoor activity. CONCLUSIONS: In this cohort, children with a greater near work load at baseline exhibited more myopic refractive change and were also more likely to develop myopia. The protective effect of outdoor activity on myopic refractive change was not observed.

Eye exercises of acupoints: their impact on myopia and visual symptoms in Chinese rural children.

BACKGROUND: Chinese traditional "eye exercises of acupoints" have been advocated as a compulsory measure to reduce visual symptoms, as well as to retard the development of refractive error, among Chinese students for decades. The exercises are comprised of a 5-min, bilateral eye acupoint self-massage. This study evaluated the possible effect of these eye exercises among Chinese rural students. METHODS: Eight hundred thirty-six students (437 males, 52.3 %), aged 10.6 ± 2.5 (range 6-17) years from the Handan Offspring Myopia Study (HOMS) who completed the eye exercises and vision questionnaire, the convergence insufficiency symptom survey (CISS) questionnaire, and had a cycloplegic refraction were included in this study. RESULTS: 121 (14.5 %) students (64 males, 52.9 %) performed the eye exercises of acupoints in school. The multiple odds ratio (OR) and 95 % confidence interval (CI) for those having a "serious attitude" towards performing the eye exercises (0.12, 0.03-0.49) demonstrated a protective effect for myopia, after adjusting for the children's age, gender, average parental refractive error, and the time spent on near work and outdoor activity. The more frequently, and the more seriously, the students performed the eye exercises each week, the less likely was their chance of being myopic (OR, 95 % CI: 0.17, 0.03-0.99), after adjusting for the same confounders. However, neither the "seriousness of attitude" of performing the eye exercises (multiple ß coefficients: -1.58, p = 0.23), nor other related aspects of these eye exercises, were found to be associated with the CISS score in this sample. CONCLUSIONS: The traditional eye exercises of acupoints appeared to have a modest protective effect on myopia among these Chinese rural students aged 6-17 years. However, no association between the eye exercises and near vision symptoms was found.

Ocular Trauma in a Rural Population of North China: The Handan Eye Study.

OBJECTIVE: To determine the prevalence of ocular trauma and the proportion of blindness and visual impairment due to trauma in a rural population in northern China. METHODS: The Handan Eye Study is a population-based cross-sectional study that surveyed 6830 Chinese people aged 30+ years from 13 randomly selected villages in Yongnian County, city of Handan, Hebei Province, in July, 2006. All participants underwent a standardized interview and extensive examinations. A structured questionnaire was used to collect information on ocular trauma. RESULTS: Of the 5837 participants who filled out the questionnaire, 124 subjects [2.1%; 95% confidence interval (CI), 1.8%-2.5%] reported a history of ocular trauma in either eye, including 19 (0.3%) persons reporting trauma in both eyes. Men were more likely to have an eye injury than women [odds ratio (OR), 3.3; 2.2-4.9]. In multiple logistic regression models, ocular trauma was significantly more frequent among normotensive participants when compared with hypertensive participants (hypertensive vs. normotensive: OR, 0.6; 0.4-0.9) and among participants who had a history of falls (OR, 2.4; 1.2-4.8). The proportion of unilateral visual impairment and unilateral blindness due to trauma were 10.5% (13 subjects) and 21.0% (26 subjects), respectively. CONCLUSION: Our study reports the prevalence of severe ocular trauma among adults in rural China, revealing a high proportion of blindness and visual impairment due to trauma. These findings suggest the need for educational strategies to increase eye health awareness in this rural population with focus on providing at least appropriate first aid care to reduce blindness due to trauma.

Associations between cardiovascular risk factors and early age-related macular degeneration in a rural Chinese adult population.

BACKGROUND: There have been a limited number of population-based studies investigating the associations between cardiovascular disease risk factors and early age-related macular degeneration (AMD). METHODS: A total of 7,557 eligible people aged 30 or older were recruited from 2006 to 2007. Cardiovascular risk factors and serum lipids including total cholesterol, total triglycerides, low density lipoprotein cholesterol, high density lipoprotein cholesterol, and fasting plasma glucose, and urines were assessed. Digital photographs of the optic disk and macula fields (Early Treatment of Diabetic Retinopathy Study) were taken and graded after the modified Wisconsin Age-related Maculopathy Grading System. Logistic regression models were constructed to assess odds ratios and 95% confidence intervals. Cases of late AMD were excluded. RESULTS: Of 6,577 subjects included in the analysis, there were 200 (3.04%) cases with early AMD. Multivariate analysis showed that higher age, untreated hypertension, coronary heart disease, and smoking were associated with an increased risk of early AMD. After adjusting for other variables in the final model, no variable was significantly associated with hyperpigmentation while smoking was significantly associated with an increased risk of hypopigmentation; higher age and any cardiovascular disease were associated with an increased risk of large drusen, and higher age, smoking, untreated hypertension, and coronary heart disease were associated with an increased risk of soft drusen. CONCLUSION: Our findings support the associations between smoking, coronary heart disease, and early AMD.

Ocular monochromatic aberrations in a rural Chinese adult population.

PURPOSE: To investigate the distribution of monochromatic aberrations in a rural Chinese adult population and the possible effect of aberrations on the development of refractive error. METHODS: A total of 404 Chinese adults who grew up in rural Yongnian County, Handan City, Northern China, were included. Monochromatic aberrations of left eyes were measured using iTrace Dynamic Laser Refraction at 5.0-mm pupil size without cycloplegia. RESULTS: Mean age of all participants was 49.9 ± 10.5 years (range, 31 to 86 years). Mean spherical equivalent was 0.22 ± 1.14 diopters (D) (range, -7.06 to +3.62 D). With age, the refraction demonstrated a significant hyperopic shift (r = 0.25, p < 0.01). Oblique trefoil (C3), vertical coma (C3), horizontal coma (C3), and spherical aberration (SA) (C4) significantly differed from zero (-0.065 ± 0.133 µm, -0.043 ± 0.161 µm, +0.070 ± 0.115 µm, and +0.058 ± 0.082 µm, respectively). Total root mean square values of higher-order aberrations (HOAs) were 0.296 ± 0.147 µm, with predominant ones of coma (0.180 ± 0.115 µm), trefoil (0.151 ± 0.116 µm), and SA (0.081 ± 0.060 µm). Root mean square values of total HOAs, coma, trefoil, SA, and third- to seventh-order aberrations significantly increased with age (p < 0.01). Total HOAs, SA, coma, and trefoil were not significantly different between hyperopic, emmetropic, and myopic eyes after adjusting for age (p = 0.26, 0.15, 0.24, and 0.28, respectively). Zernike coefficient of SA showed a significant difference between hyperopic (0.076 ± 0.086), emmetropic (0.056 ± 0.079), and myopic (0.028 ± 0.088) eyes (p = 0.00). CONCLUSIONS: Ocular refraction in rural Chinese adults showed significantly hyperopic shift with age. Magnitudes of HOAs in rural Chinese adults were similar to that of other populations and significantly increased with age but showed no differences in myopic, emmetropic, and hyperopic adults. The existence of HOAs is not, in itself, sufficient to account for the myopia epidemic in China.

Near work, outdoor activity, and their association with refractive error.

PURPOSE: To assess the relationship between near work, outdoor activity, and refractive error in schoolchildren in Beijing. METHODS: The Beijing Myopia Progression Study is a hospital-based myopia study, in which 386 students from primary (aged 6 to 12 years) and secondary (aged 13 to 17 years) schools in the inner city of Beijing were enrolled. Cycloplegic refraction and a detailed questionnaire probing near, intermediate, and distance visual activities were completed. RESULTS: Three hundred seventy (95.9%) of 386 students with complete cycloplegic autorefraction and myopia questionnaire data were enrolled in this study. Children with more near work time did not exhibit a significantly more myopic refraction in both the primary and secondary school levels after adjusting for the children's gender, outdoor activity time, and average parental refractive error. A significant association between outdoor activity time (in hours per day) and the children's spherical equivalent (in diopters) was found in the primary school students (ß = 0.27, p = 0.03) but not in the secondary school students (ß = 0.04, p = 0.70) after adjusting for similar confounders. The time spent on outdoor sports and outdoor leisure in the primary school students was also significantly associated with the children's spherical equivalent (ß = 0.46, p = 0.04 and ß = 0.31, p = 0.02, respectively). Primary school students with more time outdoors exhibited relatively less myopic refraction than their peers (ptrend = 0.0003), but this relation was not demonstrated in the secondary school children (ptrend = 0.53) after adjusting for similar confounders. CONCLUSIONS: Higher levels of outdoor activity were associated with less myopic refraction in primary school students in the inner city of Beijing. Near work activity was not found to be associated with refraction at either school level.

Circulating Small Extracellular Vesicles Involved in Systemic Regulation Respond to RGC Degeneration in Glaucoma.

Glaucoma is a leading cause of irreversible blindness worldwide and is characterized by progressive retinal ganglion cell (RGC) degeneration and vision loss. Since irreversible neurodegeneration occurs before diagnosable, early diagnosis and effective neuroprotection are critical for glaucoma management. Small extracellular vesicles (sEVs) are demonstrated to be potential novel biomarkers and therapeutics for a variety of diseases. In this study, it is found that intravitreal injection of circulating plasma-derived sEVs (PDEV) from glaucoma patients ameliorated retinal degeneration in chronic ocular hypertension (COH) mice. Moreover, it is found that PDEV-miR-29s are significantly upregulated in glaucoma patients and are associated with visual field defects in progressed glaucoma. Subsequently, in vivo and in vitro experiments are conducted to investigate the possible function of miR-29s in RGC pathophysiology. It is showed that the overexpression of miR-29b-3p effectively prevents RGC degeneration in COH mice and promotes the neuronal differentiation of human induced pluripotent stem cells (hiPSCs). Interestingly, engineered sEVs with sufficient miR-29b-3p delivery exhibit more effective RGC protection and neuronal differentiation efficiency. Thus, elevated PDEV-miR-29s may imply systemic regulation to prevent RGC degeneration in glaucoma patients. This study provides new insights into PDEV-based glaucoma diagnosis and therapeutic strategies for neurodegenerative diseases.

Malignant glaucoma treated by low-dose laser cycloplasty: a 1-year multicenter prospective non-comparative study.

AIM: To report a one-year clinical outcomes of low-dose laser cycloplasty (LCP) among malignant glaucoma patients. METHODS: In this prospective, multicenter, non-comparative clinical study, participants with malignant glaucoma were recruited and underwent LCP at eight ophthalmic centers in China. Patients were followed up at 1wk, 1, 3, 6, and 12mo. Intraocular pressure (IOP), number of glaucoma medications, anterior chamber depth (ACD), and complications were recorded. Anatomical success was defined as the reformation of the anterior chamber based on slit-lamp biomicroscopy. Recurrence was defined by the presence of a shallow or flat anterior chamber after initial recovery from treatment. RESULTS: A total of 34 eyes received LCP. Mean IOP and medications decreased from 36.1±11.5 mm Hg with 3.3±1.5 glaucoma medications pre-treatment to 20.9±9.8 mm Hg (P<0.001) with 2.9±1.6 medications (P=0.046) at 1d, and 17.4±6.7 mm Hg (P<0.001) with 1.3±1.7 medications (P<0.001) at 12mo. The ACD increased from 1.1±0.8 mm at baseline to 1.7±1.0 mm and to 2.0±0.5 mm at 1d and 12mo, respectively. A total of 32 (94.1%) eyes achieved initial anatomical success. During follow-up, 2 (5.9%) eyes failed and 8 (23.5%) eyes relapsed, yielding a 12-month anatomical success rate of 64.3%. Complications including anterior synechia (8.82%), choroidal/ciliary detachment (5.88%) and hypopyon (2.94%) were observed within 1wk. CONCLUSION: LCP is simple, safe, and effective in reforming the anterior chamber in malignant glaucoma.

Prevalence of blindness and outcomes of cataract surgery in Hainan Province in South China.

OBJECTIVE: To define the prevalence of blindness and visual impairment (VI) in people in rural Hainan using the rapid assessment of avoidable blindness (RAAB) and to report the outcomes of cataract surgery among the residents. DESIGN: Population-based, cross-sectional survey. PARTICIPANTS: A total of 6482 rural residents of the Hainan province. METHODS: A total of 136 clusters, each of which consisted of 50 people aged ≥50 years, were selected through probability-proportionate-to-size sampling. Door-to-door visits were performed by 2 outreach teams. Visual acuity (VA) was measured on site, and those with VA <6/18 in either eye were examined by an ophthalmologist. Causes of blindness and VI were determined. The causes of poor visual outcome after cataract surgery were evaluated. Information regarding barriers to receiving surgery was collected by trained interviewers. MAIN OUTCOME MEASURES: Prevalence and causes of blindness (VA <3/60), severe VI (SVI) (VA <6/60 but ≥3/60), and VI (VA <6/18 but ≥6/60) based on presenting VA (PVA) were assessed. Outcomes of cataract surgery performed in public and private hospitals and charitable organizations were compared. RESULTS: A total of 6482 subjects were examined (response rate, 95.3%). The sample prevalence of blindness was 4.4% (95% confidence interval [CI], 2.0-6.8). The prevalence of SVI and VI was 1.9% (95% CI, 0-4.3) and 9.9% (95% CI, 7.6-12.2), respectively. Age and sex were associated with increased prevalence of blindness, SVI, and VI. Overall, cataract accounted for approximately 60% of blindness and SVI. Of the 524 eyes that had received cataract surgery, 87.2% had intraocular lenses implanted, 21% had a poor visual outcome (PVA <6 /60), and 20% had a borderline visual outcome (PVA <6/18 but ≥6/60). Eyes that received surgery in charitable organizations had a higher rate of intraocular lens implantation and good visual outcome (VA ≥6/18) compared with eyes that were operated on elsewhere. CONCLUSIONS: The prevalence of blindness, SVI, and VI was high among rural residents in Hainan. Cataract remained the leading cause of avoidable blindness. Outcomes of cataract surgery performed in public hospitals were suboptimal. Quality-control initiatives should be introduced to improve cataract surgery outcomes.