Myopia is the global public health issue among adults. Myopic retinopathy has become the first leading cause for irreversible blindness in China. The risk factors of myopia are always the hotspot for epidemiology researches. The baseline refractive error， parents with myopia and time spending outdoors are relatively explicit factors for myopia. In China， though the quality and quantity of myopia epidemiology research are improving in recent years， design and study management should be emphasized and meet the international standard.

Objective To explore the relative contribution of refractive status and stereopsis in a school population and to determine the associations between refractive status and stereoacuity， age， and axial length. Methods Subject data were sampled from the materials of a population-based cluster sampling of children in 8 primary schools in Shanghai in this cross-sectional investigation. According to the standards established for this study， a table was created based on a questionnaire and the examination of vision， stereopsis and axial length of the subjects. SPSS 20 software was used to analyze the data for the different ages （6， 7， 8， 9 and 10 years of age） and refractive status （emmtropia， mild myopia， severe myopia， mild hyperopia and severe hyperopia）. A χ² test was used to compare groups. An ANOVA was used to compare the normal distribution measurement data among groups. For non-normal distributions data， nonparametric tests were used throughout. Results ①The trend for the incidence of myopia increased and for the incidence of hyperopia decreased with an increase in age. There was a positive correlation between the prevalence of myopia and increased age （r=0.427， P<0.01）， and a negative correlation between the prevalence of hyperopia and increased age （r=0.269， P<0.01）. There was a significant difference in stereopsis with normal uncorrected vision （Kruskal Wallis， χ²＝88.867， P<0.01）. There was a statistically significant difference in stereopsis between ages 6 and 7 （Kolmogorov-Smirnov， Z=2.584， P<0.01）， but no difference between ages 7 and 8， 8 and 9， and 9 and 10 （P>0.05）. The difference in the detection rate of anomalous stereopsis was statistically significant for different refractive states （χ²＝57.294， P<0.01）. Stereoacuity also differed significantly among different refractive groups （Kruskal Wallis， χ²＝67.428， P<0.01）. The differences were statistically significant between severe hyperopia （Z=2.584， P<0.01）， severe myopia （Z=2.138， P<0.01）， and mild hyperopia （Z=1.819， P<0.01） and normal groups respectively. The mean value of axial length gradually increased with an increase in age and the differences were significant among age groups （F=115.248， P<0.01）. The differences were significant when all age groups were compared to each other （P<0.01）. Conclusion ①The results suggest that the prevalence of myopia increases with age， but the prevalence of hyperopia decreases with age in school-aged children. The eye in school-aged children goes from farsightedness to myopia. ②Stereopsis reaches maturity at 7 to 8 years of age. ③Mild and severe hypermetropia obviously influenced the development and establishment of stereopsis. ④The mean axial length of the eye gradually increased with age.

Objective To examine the prevalence of refractive errors among preschool children and schoolchildren in Guanxian county， Shandong province. Methods Using a random cluster sampling in a cross-sectional school-based study design， children ranging in age from 4 to 18 years were selected from kindergartens， primary schools， and junior and senior high schools in Guanxian county. All children underwent a complete ocular examination including measurement of uncorrected （UCVA） and best corrected visual acuity （BCVA）， auto-refractometry under cycloplegia and ophthalmic examination. The prevalence rates of refractive error and its association with age and gender were analyzed by a bivariate regression model. Results Of 3 112 eligible children， cycloplegic refraction was completed on 3 111 and the visual acuity of 3 094 was successfully tested. The overall prevalence of myopia was 31.3%（95%CI： 29.7%-33.0%）. Myopia was associated with older children [OR： 1.45（95%CI： 1.41-1.50）； P<0.01]， female gender [OR： 1.45（95%CI： 1.41-1.50）； P<0.01] and children in urban areas [OR： 2.54（95%CI： 2.11-3.07）； P<0.01]. The prevalence of high myopia， astigmatism and anisometropia was 1.4%（95%CI： 1.0%-1.8%）， 32.4%（95%CI： 30.8%-34.0%） and 6.2%（95%CI： 5.4%-7.1%）， respectively. All prevalences were associated with older children （P<0.01） but not gender （P＞0.05）. The prevalence of astigmatism and anisometropia was also associated with children in urban areas （P<0.01）. The overall prevalence of hyperopia was 8.2%（95%CI： 7.2%-9.2%）， and the trend decreased with age [OR： 0.72（95%CI： 0.68-0.76）； P<0.01]. UCVA was 20/40 or worse in the better eye in 675（21.8%） children， and 20/200 or worse in the better eye in 85（2.7%） children. UCVA≤20/40 in one or both eyes was found in 880（28.4%） children， with undercorrected refractive error as the cause in 837（95.1%） children. Conclusion Visual impairment in students 4-18 years of age in Guanxian county was mainly attributed to refractive errors， especially myopia. The prevalence of refractive errors increased with age.

Objective To investigate the visual acuity and refractive state of preschool children in the Cheng Guan district of Lanzhou， to identify the children outside the normal range of vision and refraction for early-stage detection and treatment. Methods It was a cross-sectional study. 2 841 children ranging in age from 3 to 6 years who were enrolled in 10 kindergartens in the Cheng Guan district of Lanzhou were selected through cluster random sampling. And 2 754 cases （5 508 eyes） in fact tested. The children were examined with a standard logarithmic visual acuity chart and the Suresight Vision Screener handheld autorefractor. The measurement data were analyzed by t test or ANOVA， classificated data were analyzed by χ² test or linear trend test. Results The incidence of abnormal visual screening was 13.9% at the preschool level. There was a difference in visual disorder detection rates among different age groups （χ²=31.80， P<0.05）， and the prevalence of abnormal vision declined with age （χ²lineartrend=31.59， P＜0.05）. Refractive error accounted for 13.13% of the total number and， as age increased， the incidence of compound hyperopic astigmatism and simple hyperopia gradually declined （χ²lineartrend=16.01， P＜0.05； χ²lineartrend=9.11， P＜0.05）. Conclusion The incidence of abnormal vision identified from screening preschool children who ranged in age from 3 to 6 years declined with age in the Cheng Guan district of Lanzhou city. These findings indicate that visual acuity improves as children age. Ametropia is the most common condition in preschoolers. Hyperopia constitutes the majority of refractive errors identified in the visual screening of preschool children， which is consistent with visual acuity and refractive development in children.

Objective To provide a basis for prevention and treatment by investigating eye health status among primary school students in the city of Qingzhou. Methods A cross-sectional survey was used to divide the students into three-tiers based on geographical location： urban， hilly plains and mountain areas. A stratified cluster was established with a proportional sampling by school unit： 7 169 individuals from 12 primary schools were used in the sample. Results The prevalence of myopia in the sample population of primary school students in the city of Qingzhou was 20.23%. The prevalences in urban， hilly plains and mountain areas were 25.75%， 17.02% and 17.92%， respectively. A multiple rate chi-square test showed the differences in the prevalence among the three districts were statistically significant （χ2=68.9586， P<0.01）. The prevalence in urban areas was higher than that in hilly plains and mountain areas （χ2=68.3740， P<0.01）. The prevalences of myopia from grade one to grade six were 3.64%， 6.43%， 11.64%， 19.57%， 30.09%， and 40.29%. The prevalence was different for different grades， the higher the grade， the higher the prevalence （χ2= 804.4739， P<0.01）. In this survey， the prevalence of myopia was 17.90% for boys and 22.77% for girls. There was a higher prevalence among girls than boys （χ2=26.2603， P<0.01）. Conclusion The results of the investigation show a high prevalence of myopia among primary school students in the city of Qingzhou. Prevalence was highest in urban areas； factoring in age， prevalence was higher in the higher grades； from a gender perspective， prevalence was higher for girls than for boys. These results provide a baseline for in-depth primary eye disease prevention and control.

Objective To evaluate the therapeutic effect of the bandage contact lens （BCL） using ultra-high resolution optical coherence tomography （UHR-OCT） after pterygium surgery. Methods Prospective case-control study. Sixty eyes of 60 patients undergoing pterygium excision and conjunctival autografting were randomly allocated into 2 groups： 30 eyes were covered with silicone hydrogel BCLs at the conclusion of surgery and 30 eyes served as a control. UHR-OCT scans of the cornea were performed sequentially on day 1， day 2， day 3， and then every other day until the end of re-epithelialization after surgery. Complete corneal epithelial healing was verified with fluorescein staining after removal of the BCLs. Post-surgical pain was evaluated using the visual analogue scale （VAS）. An independent t test and a Mann-Whitney U test were used. Results All BCLs were successfully fit without any contact lens-related complications. UHR-OCT images clearly revealed the architectural features of the postoperative cornea with BCL in situ and showed the epithelial healing process. UHR-OCT imaging highly agreed with the fluorescein staining in detecting corneal epithelial defects （95%）. Based on the assessment by UHR-OCT， the average time line for re-epithelialization in the BCL group was 3.7±1.2 days while in the control group it was 4.8±1.5 days （t=16.78， P<0.01）. VAS scores reported lower pain levels in the BCL group compared to the control group at each time point （Z=-4.75， -3.84， -2.96， -2.52， -1.98， all P<0.05）. Conclusion Silicone hydrogel BCL is recommended as an adjuvant therapy after pterygium surgery for its efficacy in improving re-epithelialization and postoperative comfort. UHR-OCT is an excellent tool in monitoring corneal epithelial healing under BCLs and determining the appropriate time for lens removal.

The anatomy of the eye′s orbit is the major factor in complications after surgery， especially visual loss. Monitoring the pupil during orbital surgery provides quantitative information about the pupil and the pupillary light reflex． This approach may be valuable in judging a condition， an informative finding for the diagnosis and prognosis of diseases．