The Evolution Of Refractive Status In ShanDong Infants During The First Year Of Life And Its Affected Factors

Part 1 Refractive screening for infants during the first year of life and its characteristicsObjective:To study the prevalence and evolutionary characters of the refractive error in former preterm and full-term infants during the first year of life in Shandong area,the refractive status with a large sample size have been investigated.This study provides reference data for early refractive screening,and lays a foundation for the prediction of refraction,the screening of high risk children with ametropia and the individualized prevention and control.Methods:In this cross-sectional study,1718 infants under one year old who met the experimental conditions underwent detailed ophthalmologic examination.Ophthalmologic examinations included orthoptic examination,slit lamp checking and fundus imaging.For association analysis with refractive status,the following data was collected and included in multivariable analysis:sex,gestational age(GA),birth weight(BW),age and weight at examination,delivery mode(DM).Their past history,personal history,and family history were reviewed.Patients with diseases which might affect refractive status were excluded from the cohort.Then the cycloplegic retinoscopy with the use of 0.5%cyclopentolate was performed.Refractive error was recorded in the form of spherical equivalent(SE),SE=sphere+cylinder/2.With parental informed consent,some samples were randomly selected from the total samples,then biological measurements were made using A-ultrasound,including anterior chamber depth(ACD),crystal thickness(CT),vitreous depth(VD),and eye axis length(AL).Second,we divided refractive status into several groups according to its SE,age,astigmatism,and astigmatic axis.SPSS 11.0 was used to facilitate data management and statistical analysis.Data are reported as the mean ± standard deviation.Variance analysis was used to compare the mean of the two groups.Two-sided P<0.05 was considered statistically significant.The research was performed in accordance with the Declar-ation of Helsinki,and was approved by the Ethic Committee of Qilu children’ hospital of Shangdong university.Informed consent was obtained from all parents or legal guardians prior to examination.Results:1.A total of 1718 children(3536 eyes)aged 34 weeks old to 11 months participated in the study.The cohort included 1064 boys(2128 eyes)and 654 girls(1308 eyes);The GA ranged between 34 weeks and 42 weeks,and the mean GA was 34.58±3,96 weeks;The BW ranged between 0.60 kg and 6.20 kg,and the mean BWwas 2.37±0.91 kg;The weight at examination ranged between 1.00 kg and 14.00 kg,and the mean weight at examination was 4.74±2.29 kg;There were 714 infants(41.6%)undergoing transvaginal delivery,and 1004 infants(58.4%)undergoingcesarean delivery at the birth.The value of SE ranged-2.50D～+9.50D,the mean SE of refraction was +1.87 ± 1.53 diopters(D)in the right eye and +1.86± 1.54 D in the left eye.Most of the infants were hyperopic(85.7%).Myopia was observed in only 5.4%.Astigmatism was found in 44.4%of the infants.The mean value of astigmatism was-1.05±0.59DC,93.5%of astigmatism was with-the-rule and 5.9%of astigmatism was against-the-rule,irregular astigmatism was 0.7%.135 cases were selected toaccept A-scan biometer to measure the AL,ACD,LT,and VD.The mean ACD was 2.24±0.36mm,the mean LT was 4.110±0.26mm,the mean VD was 11.70±1.07mm,and the mean ALwas 18.045± 1.38mm.The change of LT coincided with the SE.2.1108 preterm infants(66.4%)were involed to the test,the mean SE was +1.77±1.51D,the value of SE ranged-3.75D～+8.00D.1873 eyes were hyperopic(85.4%).Myopia was observed in 6.6%.Astigmatism was found in 37.6%of the infants,93.0%of astigmatism was with-the-rule and 6.3%of astigmatism was against-the-rule,irregular astigmatism was 0.7%.3.610 full-term infants(35.64%)were involed to the test,the mean SE was +2.03± 1.56D,the value of SE ranged-3.38D～+9.50D.1072 eyes were hyperopic(87.9%).Myopia was observed in 3.4%.Astigmatism was found in 56.8%of the infants,94.0%of astigmatism was with-the-rule and 5.6%of astigmatism was against-the-rule,irregular astigmatism was 0.5%.4.According to single factor analysis of variance,SE of premature infants is lower than that of full-term infants.ACD,VA and AL were shorter than that of the full-term infants.However,there was no significant difference between LT.Conclusion:1.Refractive diopter in infancy was mainly low hyperopia,and the average SE was +1.86±1.53D.2.The average SE of full-term infants was+2.03± 1.56D,and that of premature infants was +1.77±1.5 1D.3.The percentage of hyperopia,myopia and astigmatism in infancy was 85.7%,5.4%and 44.4%,separately.4.The prevalence of myopia of premature infants was higher than that of full-term infants.5.The spherical crystal of premature infant was one of the reasons for the low hyperopia and higher myopia rate in premature infants.Part 2 Risk factors analysis of infant refractive error in Shandong during the first year of lifeObjective:To find the risk factors affecting refractive error and provide clues for the clinical control of the development of the refractive error,the evolution of the refractive status had been studied,which provided data for the risk factor.Methods:The data files formed in the first part were analyzed by partial correlation analysis and multiple linear regression analysis.SE was taken as the dependent variable,Sex,DM,BW,BA,age and weight was taken as independent variable.The relationship between refractive power and various factors was obtained by partial correlation analysis,controlling the level of other variables,analyzing the DM,BW,GA,age and weight at examination,and drewing relevant charts.Further multiple linear regression analysis was performed to get the association of SE with each of the variables.We got the regression equaton by using the stepwise introduction-elimination method,introducing each variable,buliding models,calculating correlation parameters and testing the linear regression analysis which included test of homogeneity of variance,test of significance of regression coefficient,test of partial regression coefficient and constant term,test of error term independence of regression model,test of residual normality of regression model.SPSS 11.0 was used to facilitate data management and statistical analysis.The comparison between the two sample mean using single factor analysis of variance,inspection level a set to 0.05,as the number of the test statistics of the actual probability(P value)is equal to or less than 0.05 think the difference was statistically significant.Results:1.Infant group(including premature infants and full-term infants),the GA,BW,weight,age and DM were all correlated with SE.The Pearson correlation coefficients were 0.112,0.105,0.080,0.127 and 0.047,and the P values were 0.000,0.000,0.000,0.000,0.003,respectively.The difference was statistically significant.Correlation coefficients between SE and ACD,CT,VD,AL were-0.0.098,0.278,-0.157 and-0.0.077,respectively,and P values were 0.138,0.000,0.058 and 0.243,respectively.The difference between SE and CT was statistically significant.2.Preterm infant group,correlation coefficients between SE and GA,BW,weight,age and DM were 0.125,0.114,0.156,0.226 and 0.070,respectively,and P values were 0.000,0.000,0.000,0.000,0.000 and 0.000,respectively,with statistically significant differences.Full-term infant group,the correlation coefficients between SE and body weight and age were-0.15 and-0.214,respectively,and P values were 0.000 and 0.000,respectively.The difference was statistically significant.3.There was a positive correlation between SE and GA of premature infants after 32 weeks.4.The infant’s refractive index increased and then decreased with age,SE within 1 month was positively correlated with age,and was relatively stable at 1-6 months.The age with the peak of SE was in the first three months after birth,and SE was negatively correlated with age after 6 months.The trend of SE in premature infants and full-term infants was the same with age.5.For premature infants within 2.00kg of BW,SE in infancy was positively correlated with birth weight.6.For infants under 4.00kg in weight,SE was positively correlated with weight,while for infants above 8.00kg in weight,SE was negatively correlated with weight.7.The average SE for infants delivered via vulva was +1.78 ± 1.54D,and for caesarean babies was+1.92 ± 1.86D,The difference between the two was statistically significant by analysis of single factor variance analysis.8.After controlling the age,the correlation coefficients of SE and ACD,CT,VD,AL were-0.098,0.278,-0.157,-0.077,and P values were 0.138,0.000,0.058 and 0.243,respectively.The differences between SE and CT were statistically significant.The change trend of SE with age was consistent with that of crystal thickness.9.Regression equation between SE and affected factors:Infant group:y= 1.056+0.044x1+0.089x2+0.155x3;Premature infants group:y=0.552+0.076x1+0.225x2+0.133x3;Full-term infant group:y=3.99-0.343 x2(y refers to SE.x1,x2 and x3 represent the age,age and mode of delivery,respectively);Infant group:y= 1.092+0.180x1+0.156x3;Premature infants group:y=0.430+0.206x1+0.263x2 +0.204x3;Full-term infant group:y=3.082-0.271x2(y refers to SE,x1,x2,x3 refers to birth weight,body weight and delivery mode,respectively).Conclusion:1.The changes in the refraction diopter of premature infants are related to the GA,BW,age,weight and DM,while are only related to age and weight at examination for full-term infants.2.Refraction diopter changes with age,the risk factors for the occurrence and development of myopia include low birth weight,obesity,premature birth and dystocia.3.The change of crystal thickness is one of the factors influencing the refractive diopter.4.According to the regression equation,the refractive diopter can be predicted after knowing the baby’s birth weight,gestational age,age at the time of examination,weight and mode of delivery.