Study On Choroidal Thickness In Myopia Children Treated By Orthokeratology And Low-intensity Laser Irradiation Therapy

Part 1 Subfoveal Choroidal Thickness in Myopia: an OCT-based Study in Young Chinese PatientsPurpose: The purpose of this study was to investigate choroidal thickness and its distribution across the posterior pole in young myopic Chinese patients using enhanced depth imaging optical coherence tomography(EDI-OCT)and to explore the factors associated with it.Methods: A total of 402 myopic Chinese patients aged 6–16 years who underwent complete ophthalmic examinations,including those for axial length,cycloplegic refraction,and intraocular pressure,were examined with EDI-OCT.Thirteen points,including the central point of the centerline were chosen in 0.5-mm intervals to calculate the choroidal thickness.The choroidal thickness at different locations was compared by repeated measurement ANOVA.Pearson correlation test was used to test the correlation between variables.Multiple regression was used to analyze the correlation between variables and choroidal thickness in macular fovea.Results:Choroidal thickness displayed large variations among different points.The point located 3 mm temporally from the fovea had the thickest choroid,followed by the central fovea sector.Choroidal thickness decreased gradually toward the nasal sector horizontally.We observed a trend for negative correlation between age and Choroidal thickness,but statistical significance was only observed in children < 11 years.Individuals with high myopia had significantly thinner Choroidal thickness than those with low or moderate myopia,although statistical significance was only observed in the temporal sectors.The mean Choroidal thickness of all 13 horizontal lines except T3.0,correlated with the axial length significantly and inversely.The central foveal Choroidal thickness displayed the fastest decrease.Conclusions:Age,axial length and spherical equivalent refraction are the factors that influence choroidal thickness in children and adolescents.We found a significant decrease in choroidal thickness with age in myopic children < 11 years,which then appears to be affected by the pubertal growth spurt.Furthermore,we found a positive correlation between choroidal thickness and spherical equivalent refraction in the myopic population aged ? 11 years with borderline significance.This suggests that the protective effect of the lens thinning against rapid axial elongation disappears with age,whereas axial elongation becomes the dominant determinant of Ch T around the age of 11 years.Part 2 Orthokeratology and Low-Intensity Laser Irradiation for Slowing the Progression of MyopiaPurpose: To study the effects of frame glasses,orthokeratology and LowIntensity Laser Irradiation therapy on juvenile myopia prevention and control.Methods:We recruited a total of 300 children from the Outpatient Clinic of the Nanchang University affiliated eye Hospital from September 2018 to April 2019.Then,we randomly assigned them to the frame glasses(n=100),Orthokeratology(n=100),or Low-Intensity Laser Irradiation(n=100)groups.After 6-months follow-up,refractive degree and ocular axial length of three groups were statistically analyzed.Correlations between changes in parameters at 6 months and baseline factors were analysed using the Pearson correlation analysis.To study the association of axial length changes at 6 months with baseline factors in all groups,we applied stepwise multiple linear regression models.Results:The mean changes in spherical equivalent refraction was-0.50±0.24 D in the frame glasses group and 0.21±0.34 D in the Low-Intensity Laser Irradiation group at 6 month.Changes in spherical equivalent refraction were significantly different in the control group and Low-Intensity Laser Irradiation group at the time of the study.Increases in axial length were significantly smaller in children wearing OK lens(0.06±0.15mm)than in the frame glasses(0.23±0.06mm)group at the 6-month follow-up while decreases in axial length in the Low-Intensity Laser Irradiation group(-0.06±0.15mm)differed significantly from the other two groups.In the orthokeratology group,changes in axial length were negatively correlated with baseline axial length.In the Low-Intensity Laser Irradiation therapy group,changes in axial length were negatively correlated with age and baseline axial length,and positively correlated with the baseline degree of refractive degree.Conclusions:Both orthokeratology and Low-Intensity Laser Irradiation can effectively control the progress of diopter and axial length in juvenile myopia,and their curative effects were better than frame glasses.During the 6-month observation period,our results showed that Low-Intensity Laser Irradiation therapy can help control AL elongation and slow myopia progression better than Orthokeratologywearing.Factors significantly associated with changes in axial length were also found in this study.These factors included age,baseline degree of refractive degree and the baseline axial length.Part 3 Comparison of choroidal thickness difference between myopia children corrected by orthokeratology and Low-Intensity Laser Irradiation therapyPurpose:To investigate choroidal thickness with enhanced depth imaging optical coherence tomography(EDI-OCT)and compare the choroidal thickness difference between myopia children corrected by orthokeratology and Low-Intensity Laser Irradiation therapy.Methods:We recruited a total of 300 children from the Outpatient Clinic of the the Nanchang University affiliated eye Hospital from September 2018 to April 2019.Then,we randomly assigned them to the frame glasses(n=100),Orthokeratology(n=100),or Low-Intensity Laser Irradiation(n=100)groups.After 6-months follow-up,central foveal Choroidal thickness of three groups were statistically analyzed.Correlations between changes in parameters at 6 months and baseline factors were analysed using the Pearson correlation analysis.To study the association of central foveal Choroidal thickness changes at 6 months with baseline factors in all groups,we applied stepwise multiple linear regression models.Results:Increases in central foveal Choroidal thickness at 6 month were significantly smaller in Orthokeratology-wearers(14.98±22.50?m)than in the Low-Intensity Laser Irradiation group(35.30±31.75?m),whereas the central foveal Choroidal thickness in the frame glasses group(-16.84±7.85?m)significantly decreased.The change in central foveal Choroidal thickness correlated with the baseline axial length and age in Orthokeratology group.We observed a trend for negative correlation between the baseline axial length,age and change in axial length in Low-Intensity Laser Irradiation group.Conclusions:Both orthokeratology and Low-Intensity Laser Irradiation can effectively thicken the central foveal Choroidal thickness in juvenile myopia,and their curative effects were better than frame glasses.The factors significantly correlated with the variation of central foveal Choroidal thickness were also found in this study.These factors included age and baseline axial length in patients with myopia.In addition,the influence factors of the variation of central foveal Choroidal thickness were found only in the Orthokeratology group but not in the Low-Intensity Laser Irradiation group.