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Objective: To comprehend the status and changing trend in the burden of refractive errors in China from 1990 to 2019, and to furnish data-driven support for the formulation of rational strategies in refractive error prevention and control. Methods: Using the Global Burden of Disease Database 2019, data on refractive error prevalence and years lived with disability (YLD) in China from 1990 to 2019 were extracted and their standardized rates were calculated. The trend of refractive error prevalence, age, period, and gender was analyzed using joinpoint regression models. Results: From 1990 to 2019, the number of cases, prevalence rate, and YLD rate of refractive errors in China showed an upward trend, which was consistent with global trends. However, the magnitude of the increase in these parameters was higher than the global average. Conversely, the age-standardized prevalence rate and age-standardized YLD rate demonstrated a declining trend, which was also consistent with global trends, but the reduction rate was less pronounced compared to global levels. Notably, all indicators for females, including prevalence and YLD, exceeded those of males. The prevalence and YLD rates of refractive errors in China increased with age. The older individuals had higher rates compared to younger individuals. In 1990, the highest prevalence and YLD rates were found in the ≥70 years group, while the lowest rates were in the <5 years group. The age group with the most substantial increase in the burden of refractive errors was the 15 to 49 years population, which remained consistent during the three decades. The joinpoint regression analysis results revealed a stage-wise fluctuation in the age-standardized prevalence and YLD rates of refractive errors in China from 1990 to 2019. Specifically, the age-standardized prevalence rate increased by 0.765% from 1990 to 2001, decreased by 0.963% from 2001 to 2014, increased by 4.214% from 2014 to 2017, and decreased by 3.029% from 2017 to 2019. In contrast, the age-standardized YLD rate decreased by 0.113% from 1990 to 1995, increased by 2.252% from 1995 to 2000, decreased by 1.102% from 2000 to 2014, increased by 4.326% from 2014 to 2017, and decreased by 5.090% from 2017 to 2019. Conclusions: The standardized prevalence of refractive errors and the standardized YLD rate in China showed a downward trend, which was less than the global average level, but the disease burden was still heavy. Gender and age emerged as significant influencing factors for the prevalence of refractive errors and YLD. It is imperative to enhance efforts in the prevention and treatment of refractive errors among the middle-aged and elderly population. Attention should also be directed towards the increasing burden in the<50 years population.

Myopia has emerged as a public health issue with the increasing prevalence of myopia in children and adolescents in China. In the clinical diagnosis and treatment of myopia, there are clinical stages and classifications, but they are not suitable for the prevention and control of myopia at the public health level. At the public health level, because there is no staging standard for myopia, there is a lack of staging prevention and control guidance for different refractive errors. Therefore, the Public Health Ophthalmology Branch of the Chinese Preventive Medicine Association organized domestic experts in relevant fields to conduct literature searches and discuss based on the research data on myopia at home and abroad, put forward the stages of public health strategies for myopia prevention and control and corresponding group prevention and control measures for each stage to reached this experts consensus. This consensus first proposes a method for assessing myopia risk, in order to predict the occurrence and development of myopia in children and adolescents; From the perspective of public health, myopia prevention and control is further divided into four stages: myopia prodromal stage, myopia development stage, high myopia stage, and pathological myopia stage. According to this consensus, myopia prevention and control technology is targeted and implemented in different stages to provide guidance for myopia prevention and control from the perspective of public health.

Objective: To investigate the influencing factors of refractive status of preschool children in Changdu, Tibet. Methods: From July 2020 to October 2020, a cross-section investigation was performed among preschool children in Changdu, Tibet. The general information was collected, and the uncorrected refractive status was recorded and investigated. The measurement data were expressed by mean±standard deviation, and the t -test and χ 2 test were used for univariate analysis. The questionnaire of factors influencing children's visual acuity was distributed to the parents of the children. The independent variables included height, weight, nutritional status, parents' eyesight, sleeping time and habits that were bad for eyes. Multivariate logistic regression analysis was used to explore the influencing factors of refractive status, including age and gender. Results: A total of 2 793 children were screened, among whom 2 646 (98.64%) children including 1 501 males and 1 145 females were inhabitants in the plateau region. The average age was (4.52±0.97) years. Refractive abnormalities were found in 253 children (9.56%). The detection rate of refractive abnormalities increased with age. There was no significant difference between males and females (χ²=1.79, P >0.05). The total abnormal refraction rate of preschoolers was lower in the plateau region than the non-plateau region (χ² = 13.93, P <0.05). The parental refractive status ( OR =0.06, 95% CI : 0.04-0.08) and nutritional factors ( OR =0.11, 95% CI : 0.04-0.25) had higher correlations with the refractive abnormalities of preschoolers. Conclusions: The rate of refractive abnormalities of preschool children was relatively low in Changdu, Tibet. One of the effective measures to prevent ametropia in the plateau area can be balanced nutrition. (Chin J Ophthalmol, 2021, 57: 772-776) .

Objective: To estimate the prevalence of uncorrected refractive errors among people aged 50 years and above in Funing county, Jiangsu province. Methods: Randomly cluster sampling was used in selecting individuals aged ≥50 years in 82 clusters from Funing County Center for Disease Prevention and Control. Uncorrected refractive error was defined as an improvement of at least 2 lines in best corrected visual acuity compared with presenting visual acuity in the better eye. The mean±standard deviation was used to describe the continuous data, and the rate or composition ratio was used to represent the classified data. Univariate and multivariate logistic regression analyses were used to analyze the prevalence of uncorrected refractive errors in different ages, genders, educational levels, durations of diabetes and levels of glycosylated hemoglobin. Statistical significance was defined as P <0.05. Results: A total of 2 067 persons were enumerated, and 1910 (92.4%) participants were in the statistical analyses. The prevalence of uncorrected refractive error was 25.63%. The prevalence of uncorrected refractive error for myopia only, hyperopia only, astigmatism only, myopia with astigmatism and hyperopia with astigmatism was 72.55% (37/51), 46.77% (58/124), 17.81% (13/73), 63.95% (94/147) and 51.98% (100/194), respectively. The results showed that the older age, level of glycosylated hemoglobin, myopia and lens state were the independent influencing factors of uncorrected refractive error. The odds ratio ( OR ) for people aged 70 to<80 years and ≥80 years was 1.81 and 1.90, respectively, with statistical significance compared to people younger than 60 years. Compared with the level of glycosylated hemoglobin less than 5.6%, the OR with glycosylated hemoglobin from7.1% to 8.0% and more than 10% was 1.84 ( P< 0.05) and 1.82 ( P< 0.05), respectively. The OR of myopia, low myopia, moderate myopia and high myopia was 2.98 ( P< 0.01), 6.94 ( P< 0.01), 42.43 ( P< 0.01) and 77.85 ( P< 0.01), respectively. The OR of opacity of the eye lens was 7.60 ( P <0.01). Conclusions: Uncorrected refractive error is one of the important causes of visual impairment in diabetic patients aged 50 and above in Funing county, Jiangsu province; the important influencing factors were age, glycosylated hemoglobin concentration, myopia and lens status. Relevant health departments should popularize the eye health for diabetic patients and conduct regular optometry and fundus examination. (Chin J Ophthalmol, 2021, 57: 757-765) .

Objective: To investigate the etiological spectrum of moderate to severe visual impairment and blindness in population aged 50 years or more in rural Shandong province, China., Methods: A population based, random cluster sampling was used to screening the adults aged 50 years or more living in rural Shandong Province from April to July 2008. Three counties and one suburb representing the different levels of socioeconomic development within Shandong area were selected as the investigated areas. Geographically defined cluster sampling was used in randomly selecting a cross-section of residents aged ≥ 50 years from each county. Best corrected visual acuity and intra-ocular pressure were evaluated in those with presenting visual acuity ≤ 0.5 and suspected glaucoma respectively. The major causes of visual impairment and blindness were diagnosed in those with presenting visual acuity ≤ 0.3. According to the results of presenting visual acuity and best corrected visual acuity, the etiology constituent ratios of the moderate to severe visual impairment and blindness were analyzed respectively., Results: According to the number of people, the first three principal causes for blindness based on the presenting visual acuity were cataract (59.8%, 168/281), fundus disease (12.1%, 34/281) and corneal opacity (4.3%, 12/281) or ametropia (4.3%, 12/281). The first three principal causes for moderate to severe visual impairment and blindness were cataract (55.2%, 844/1530), uncorrected refractive error (18.2%, 278/1530) and fundus disease (11.9%, 182/1530). Based on the best corrected visual acuity, the first three principal causes for blindness were cataract (64.6%, 153/237), fundus disease (10.5%, 25/237) and corneal opacity (4.7%, 11/237), respectively. The first three principal causes for moderate to severe visual impairment and blindness were cataract (66.4%, 590/889), fundus disease (16.0%, 142/889) and optic nerve atrophy (3.0%, 27/889). According to number of the eyes, proportion of cataract in cases with moderate to severe visual impairment and blindness had positive relation with age, the proportion of ametropia and fundus disease had negative relation with age. The etiology constituent ratio had no difference between male and female. The proportion of cataract in cases with moderate to severe visual impairment and blindness in Huaiyin District of Jinan was slightly lower than those in other areas, however, the proportion ratio of ametropia and fundus disease was slightly higher than those in other areas., Conclusion: Cataract, uncorrected refractive error, and fundus diseases are ranked in the top three causes of moderate to severe visual impairment and blindness in adults aged 50 years or more in rural Shandong Province.

Objective: To evaluate the visual development and prevalence of amblyopia, strabismus among preschool children., Methods: A random sample survey was performed in 4 610 preschool children from both urban and rural, aged 3 to 6 years. Participants underwent eye examination including visual acuity, refractive status, eye position, strabismus and amblyopia., Results: Percentage of visual acuity above 1.0 was 28.4%, 39.3%, 46.2% and 76.5% in children of 3, 4, 5 and 6-year-old group, respectively. The mean visual acuity of each group was 0.63 ± 0.19 in 3-years old, 0.69 ± 0.16 in 4-year-old, 0.71 ± 0.22 in 5-year-old, 0.79 ± 0.29 in 6-year-old. Rural children have better vision acuity compared with those from urban. Hypermetropic was frequent refractive errors. Manifeststrabismus was found in 2.21%, with exotropia being more prevalence than esotropia; detection rate of recessive strabismus was 33.52%, mainly being exophoria; Based on current diagnostic criteria, the prevalence of amblyopia were 2.93% in 6 year-old group, 4.81% in 5-year-old group, 16.21% in 4-year-old group, 33.33% in 3-year-old group., Conclusion: Vision acuity is increasing with age in preschool population. A diagnosis standard of amblyopia suitable for each age group should be established to substitute the current one which has a high visual standard for amblyopia. Refractive error, strabismus and amblyopia are the leading causes of visual impairment among preschool-aged children, which represent the focus of prevention of blindness in preschool children.

Objective: To understand the development of the refractive status in premature infants during their early life., Methods: It was a cross-sectional study. Two hundred fifty-three premature infants without retinopathy of prematurity (ROP) were screened for ROP at 4-6 weeks after born. Refraction with cycloplegic retinoscopy was determined. The refractions of 38 infants were compared with those of mature infants at 40-44 weeks' correct gestational age (CGA)., Results: The spherical equivalent (SE) increased progressively (become more hypermetropic) along with increasing gestational age (GA), birth weight (BW) and CGA at test. BW was the main factor for SE. The incidence of myopia and astigmatism was 14.43% (73 eyes) and 10.28% (52 eyes). The former decreased and the latter did not change along with increasing CGA. The median of astigmatism was 1.00DC, while Percentile 25 (P25) and Percentile 75 (P75) were 0.50DC and 1.13DC, respectively. The degree of astigmatism increased along with increasing CGA and did not change along with GA or BW. The median of axis of astigmatism (AX) was 90 degrees, while P25 and P75 were 90 degrees and 100 degrees, respectively. The AX was not correlated with CGA, GA or BW. Five observations, including SE, incidence of myopia and astigmatism, the degree and axis of astigmatism between premature and mature infants at 40 to 44 weeks' CGA, were compared. It shows that there was no statistical difference between the two groups in all items mentioned above but SE, which indicating that there was more myopic in premature infants., Conclusions: The refraction of premature infants shifts towards hypermetropia along with development, but is still more myopic than mature infants at 40 to 44 weeks' CGA. Further studies on the underlying mechanisms of myopia and the subsequent refractive development are needed.

Objective: To estimate the prevalence of refractive error in school-aged children in urban setting of Southern China., Methods: In this population-based cross-sectional study, children aged 5 to 15 years old were randomly selected by clustering sampling and door-to-door survey, and were examined in 71 schools and 19 community stations from October 2002 to January 2003. The examination included visual acuity measurement, ocular motility evaluation, retinoscopy, autorefraction under cycloplegia and examination of the external eye, anterior segment, media, and fundus., Results: Of 5053 children living in 4814 households enumerated, 4364 (86.4%) were examined. The prevalence of myopia (spherical equivalent, SE < -0.50 D) was 35.1% (95% CI: 33.2%-36.9%) with retinoscopy, this rate increased from 3. 3% in 5-year-old to 73.1% in 15-year-old. Females had a significantly higher risk of myopia (adjusted odds ratio: 1.29, 95% CI: 1.11-1.51). The prevalence of hyperopia (SE > or = + 2.00 D) was 5.8% (95% CI: 5.3%-6.3%) and decreased from 16.7% in 5-year-old to less than 1% in 15-year-old. Astigmatism (cylinder > or = 0.75 D) was presented in 33.6% of children examined with retinoscopy and in 42.7% with autorefraction., Conclusions: The prevalence of myopia is high in Chinese school-age children living in urban Guangzhou, representing an important public health problem. The coverage and quality of refractive correction in the children need to be improved.

The physiological manifestation of myopia is error of refraction. The incidence of myopia in Asian population is increasing much more rapidly compared with several decades ago. Most of the people in the relatively developed Chinese cities are developing or have developed myopia. Recently, researches reported six loci related to myopia. Viewing from the modern civilization and development of China, the sharp increase of the size of the population with myopia and the unbalanced change could not be explained only by gene mutation or any model of Mendelian inheritance. The comparison of the disparity of the economic and educational levels between in urban and rural areas showed that the onset of myopia might be influenced by both environmental and genetic factors. Special attention should be paid to myopia now to prevent severe physical problem in the Chinese urban population.

The visual acuity, refraction and related factors in 471 eyes 60-90 years of age were analyzed with the authors's statistical method for refractive data. The mean logarithmic visual acuity (Lv) of all eyes naked was 4.66 (equivalent to 20/44, or 6/13), and with corrections 5.03 (equivalent to 20/18.7, or 6/5.6). There was significant negative linear correlation between Lv and age (r = -0.9684), Lv = 5.7183-0.0095 x age. The percentages of hyperopia and myopia in the series were 47.8% and 39.7%, the mean refraction being +0.96 DS +0.78 DC and -1.29 DS -0.95 DC respectively. The percentage of mixed astigmatism was 7.86%, averaging +0.71 DC -0.74 DC. The mean refraction of all the patients was -0.05 +/- 2.90 DS -0.04 +/- 1.14 DC.