Objective To study the therapeutic effect and safety of orthokeratology in the teenagers with high myopia.Methods A retrospective cohort study was carried out.The clinical data of 120 eyes from 60 high myopia patients wearing orthokeratology contact lens for 1 year in Henan Eye Hospital from June 2013 to June 2014 was analyzed,and the data of contemporaneous 118 eyes from 59 matched high myopia patients wearing conventional glasses were used as controls.The initial spherical equivalent (SE) of all the patients was-6.00 to-9.00 D.The maximum correction amplitude of the orthokeratology contact lens was set as 6.00 D based on the Regulation of China Food & Drug Administration.The contact lenses were worn for 1 month firstly and then the conventional glasses were used at daytime and contact lenses were consecutively worn at night for 1 year in the contact lenses group,and only glasses were worn in the conventional glasses group.The uncorrective visual acuity (UCVA),SE,corneal fluorescein staining were examined 1 week,1 month,3 months,6 months and 12 months after wearing lenses.The changes of corneal endothelial cells were examined 6 and 12 months after wearing lenses.Results The UCVA was improved and SE was reduced 1 month and 3,6 and 12 months after wearing lenses in comparison with 1 week after wearing lenses in the contact lenses group (all at P＜0.01);while no significant change was seen in UCVA in the conventional glasses group (all at P＞0.05).Compared with wearing contact lenses,the SE was increased in various time points after wearing glasses in the conventional glasses group (all at P＜0.01).The axial length and SE extended by (0.08±0.12)mm and (0.19±0.21)D in the contact lenses group and those in the conventional glasses group were (0.29±0.14)mm and (0.69±0.27)D,showing significant differences between the two groups (t =10.024,5.691,both at P＜0.01).No significant differences were found in corneal endothelial cell density,percentage of hexagonal cells and coefficient of variation of corneal endothelial cells in various time points after wearing contact lenses (corneal endothelial cell density:Fgroup =0.090,P =0.769;Ftime =0.133,P =0.563.percentage of hexagonal cells:Fgroup =0.071,P=0.836;Ftime =1.091,P =0.203.coefficient of variation:Fgroup =0.107,P =0.734;Ftime =1.948,P =0.156).The incidence of corneal fluorescein staining was 31.67％ in the contact lens group,which was much higher than 3.51％ in the conventional glasses group (x2 =97.910,P =0.001).Conclusions Compared with wearing only conventional glasses,orthokeratology can improve UCVA and control axial length extension in juvenile with high myopia,but orthokeratology is more likely to damage the corneal superficial layer.

Objective:To analyze the trends in refractive error and ocular biological parameters in elementary school students over 5 years, and to investigate the patterns of change before and after myopia onset.Methods:A cohort study was adopted.A total of 1 986 first-grade students from the Anyang Childhood Eye Study were enrolled in this cohort study and their right eye data were taken for analysis, including 1 126 boys and 860 girls.Every year, cycloplegic autorefraction was performed with 1% cyclopentolate eyedrops to obtain the spherical equivalent (SE).The axial length (AL), anterior chamber depth, lens thickness, mean corneal curvature (Km) and other parameters were obtained by ocular biometry.The lens refractive power (LP) was calculated using the Bennett formula.The subjects were assigned to persistent myopia group, non-myopia group and new onset myopia group.According to the age of myopia onset, the new onset myopia group was subdivided into the 8-, 9-, 10-, 11- and 12-year-old myopia groups to compare the differences in refractive error and ocular bioparameters among groups at different time points of follow-up.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Beijing Tongren Hospital, Capital Medical University (No.TRECKY2018-030).Written informed consent form was obtained from the guardians of each subject.Results:All children had a gradual SE drift toward myopia and a gradual increase in the AL with age, and there were significant differences in SE and AL between adjacent follow-up ages within the three groups (all at P<0.05).The earlier the onset of myopia, the higher the myopia SE and the longer the AL of the eye at the same follow-up age, the differences in SE between adjacent groups were statistically significant (all at P<0.05), and the differences in AL between adjacent groups at the follow-up age of 8 to 12 years were statistically significant (all at P<0.05).In the nonmyopia group, SE drifted toward emmetropia at a slow and steady rate of (-0.23±0.27)D/year, and AL also increased slowly and steadily at (0.18±0.13)mm/year.In the new onset myopia group, the changes in SE in the third, second, and first years before myopia onset were (-0.32±0.25), (-0.45±0.33), and (-0.98±0.44)D, and the increases in AL were (0.25±0.12), (0.32±0.15), and (0.48±0.19)mm, respectively.Both SE and AL change rates began to accelerate before myopia onset and slowed down after myopia onset, with statistically significant differences in the overall comparison of SE and AL change rates at different time intervals before and after myopia onset (all at P<0.001).The AL at myopia onset in boys was (24.11±0.70)mm, which was longer than (23.60±0.66)mm in girls ( t=159.71, P<0.01).LP decreased with age in all groups, with a faster rate before the age of 9 years and a slower rate after the age of 9 years.The mean decrease rate in LP was (-0.48±0.19), (-0.44±0.20), (-0.49±0.16), (-0.51±0.18), and (-0.48±0.19)D/year in the persistent myopia group and 8~11-year-old myopia group, respectively, which were significantly faster than -0.42±0.17 D/year in 12-year-old myopia group and (0.37±0.15)D/year in nonmyopia group (all at P<0.05).There was no statistically significant difference in Km among groups at different follow-up ages (all at P>0.05). Conclusions:The AL begins to grow at an accelerated rate 3 years before myopia onset, and the increase rate of the AL slows down after the onset of myopia, but it is still significantly faster than that of non-myopic children.In this process, the decrease in LP plays a compensatory role; there is no significant change in corneal curvature.The AL of males at the onset of myopia is longer than that of females at the same age.AL is an important indicator for the prevention and control of myopia.It is important to consider gender differences and to pay more attention to the growth rate when assessing AL.

In recent years, the high prevalence of myopia has become a global public health concern.Understanding the mechanism will help to achieve precise prevention and treatment of myopia.Animal models are important tools for studying the pathogenesis and prevention strategies.Mice are commonly used in myopia research, because they are easy to breed, feed and genetically manipulate.However, their small eye size makes it difficult to accurately measure the changes in biological parameters such as refraction and axial length.In addition, the refractive developmental pattern of mice is opposite to that of humans.This article reviews the structural features of the mouse cornea, lens, vitreous body, retina and sclera, the pattern of refractive development, and the latest progress about the establishment and evaluation of murine myopia models to provide some hints and references for further research.

Objective To establish simple screening models for nonalcoholic fatty liver disease (NAFLD) in the adult Blang population. Methods Based on the survey data of metabolic diseases in the Blang people aged 18 years or above in 2017, 2993 respondents were stratified by sex and age (at an interval of 5 years) and then randomly divided into modeling group with 1497 respondents and validation group with 1496 respondents. Related information was collected, including demographic data, smoking, drinking, family history of diseases and personal medical history, body height, body weight, waist circumference, and blood pressure, and related markers were measured, including fasting plasma glucose, 2-hour postprandial plasma glucose or blood glucose at 2 hours after glucose loading, triglyceride, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase. The chi-square test was used for comparison of categorical data between two groups. Logistic regression analysis was used to establish the screening model. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, and negative predictive value were used to evaluate the screening performance of established models versus existing models in the study population, and the DeLong method was used for comparison of AUC. Results Three screening models for NAFLD were established based on physical and biochemical measurements, i.e., simple noninvasive model 1 (age, body mass index, and waist circumference), noninvasive model 2 with the addition of blood pressure, and model 3 with the combination of hematological parameters (diabetes and ALT/AST). In the modeling group, the three models had an AUC of 0.881 (95% confidence interval [ CI ]: 0.864-0.897), 0.892 (95% CI : 0.875-0.907), and 0.894 (95% CI : 0.877-0.909), respectively, and there was a significant difference between model 1 and models 2/3 ( P =0.004 0 and P < 0.001); in the validation group, the three models had an AUC of 0.891 (95% CI : 0.874-0.906), 0.892 (95% CI : 0.875-0.907), and 0.893 (95% CI : 0.876-0.908), respectively, and there was no significant difference between the three groups ( P > 0.05). Based on the overall consideration of screening performance, invasiveness, and cost, the simple noninvasive model 1 was considered the optimal screening model for NAFLD in this population. Model 1 had the highest Youden index at the cut-off value of 5 points, and when the score of ≥5 points was selected as the criteria for NAFLD, the model had a sensitivity of 86.5%, a specificity of 79.7%, a positive predictive value of 50.3%, and a negative predictive value of 96.1% in the modeling group and a sensitivity of 85.6%, a specificity of 80.6%, a positive predictive value of 51.7%, and a negative predictive value of 95.8% in the validation group. Conclusion The NAFLD screening models established for the adult Blang population based on age and obesity indicators have relatively higher sensitivity, specificity, and negative predictive value, and this tool is of important practical significance for the intervention of NAFLD and its closely related metabolic diseases in this population.