| Chapter 1 A study on the changes of refractive parameters in adolescent myopia after discontinuation of orthokeratologyObjective:To observe changes of refraction error and corneal topography parameters in adolescent myopia after discontinuation of toric and spherical orthokeratology,and analyses the related factors of refraction error growth.Methods:A total of 64 myopic patients(126 eyes)who wore orthokeratology lens and stopped wearing the lens for one month were collected in our department for nearly three years.The patients were divided into two group(toric lens for group T1 and spherical lens for group S1)in the light of the type of lens design.The parameters of refraction,axial length,corneal curvature,corneal astigmatism and corneal topography were measured and compared before orthokeratology and 1 month after discontinuation.And the observed data were statistically analyzed by SPSS 19.0.Results:Compared to pre-orthokeratology,spherical and cylindrical refractive error of two groups were increased significantly after cessation of orthokeratology wear(P<0.05).The amount of annual increase in spherical and spherical equivalent power of group T1 was lower than that of group S1(P<0.05),otherwise the amount of annual increase in cylindrical power of group T1 was higher than that of group S1(P<0.05).Axial length was increased slowly at 6 months after wearing the lens with the growth of 0.04(-0.22～+0.31)mm in group T1 and 0.05(-0.09～+0.50)mm in group S1.But it was increased rapidly at 12 months and 1 month after discontinuation.Axial length increased by 0.19(-0.05～+0.76)mm in group T1 and 0.32(+0.01～+1.03)mm in group S1 at 12 months visit.Axial length increased by 0.33(-0.02～+0.85)mm in group T1 and 0.50(0.10～1.21)mm in group S1 at 1 month after discontinuation(P<0.001).Compared with the values at baseline,corneal curvature became decreased for two groups 1 months after discontinuation(P<0.001).Compared with the state at baseline,SAI,SRI and IAI of the corneal topography were decreased,but DSI,CSI,SF and E6 were slightly increased in group T1 after discontinuation for 1 month(P<0.05).There was no statistical difference in CYL of group T1 after discontinuation for 1 month(P>0.05).On the contrary,SAI and SRI of the corneal topography had statistically significant increase,but DSI,CSI,SF and E6 had little significant decrease in group S1 after discontinuation for 1 month(P<0.05).But there were no significant changes in CYL and IAI of group S1 after discontinuation for 1 month(P>0.05).The amount of annual increase in spherical diopter of group T1 was positively correlated with age at baseline(r=0.496,P<0.01).The amount of annual increase in cylindrical power of group T1 was negatively correlated with initially cylindrical power(r=-0.317,P<0.05)and central corneal thickness(r=-0.297,P<0.05),and it was positively correlated with K_f(r=0.266,P<0.05)and K_s(r=0.265,P<0.05)at baseline.But the amount of annual increase in spherical diopter of group S1 was negatively correlated with age at baseline(r=-0.355,P<0.05).The amount of annual increase in cylindrical power of group S1 was negatively correlated with axial length(r=-0.293,P<0.05)at baseline.Conclusion:After wearing toric designed orthokeratology lens for adolescent myopia,the amount of annual increase in spherical diopter and axial length are lower than that of spherical orthokeratology lens.Toric orthokeratology lens has better effect of inhibiting axial length growth and controlling the progress of myopia with low-to-moderate astigmatism.Toric orthokeratology lens wearing in adolescent myopia,the surface of central cornea can have a regular change,and the surface symmetry of the cornea and the stability of the lens are better.While spherical orthokeratology lens can increase the irregularity of the corneal surface.After 1 month cessation of short-term toric and spherical orthokeratology wear in adolescent myopia,refractive error exceeds to the original completely and corneal curvature became flatter than that of pre-treatment.The recovery of refractive power is inconsistent with that of cornea.Chapter 2 A study on changes of fundus microcirculation and vision quality in adolescent myopia control by orthokeratologyObjective:To observe the alterations of the fundus microcirculation in adolescent myopia after wearing toric and spherical orthokeratology lens by using optical coherence tomography angiography(OCTA),and to explore the effect of orthokeratology lens on retinal and choroid blood flow,and to further analyze the mechanism of orthokeratology lens on the control of myopia.At the same time,the impact of orthokeratology on the vision quality of adolescents with myopia was evaluated by the pediatric refractive error profile(PREP)questionnaire.To investigate the correlation between visual quality and fundus micro vessel density in adolescent myopia patients after wearing orthokeratology.Methods:A total of 48 patients were enrolled and divided into two group(toric lens for group T2 and spherical lens for group S2)according to the type of lens design.OCTA was used to measure the superficial and deep retinal vessel density at the macular region,the radial peripapillary capillary(RPC)density,foveal avascular zone(FAZ)area,choriocapillaris(Ch C)perfusion area,subfoveal choroidal thickness(SFCh T),retinal thickness,peripapillary retinal nerve fiber layer(p RNFL)thickness before and after wearing orthokeratology for three months.The PREP questionnaire was used to evaluate the vision quality of adolescents with myopia after wearing orthokeratology for 1 day and 3 months.And the observed data were statistically analyzed by SPSS 19.0.Results:Compared to pre-orthokeratology treatment,the superficial vessel density in the fovea and para-fovea of group T2 were significantly increased,and the deep vessel density in the whole area and fovea were significantly increased at three months(P<0.05).The superficial vessel density only in the para-fovea of group S2 at three months was significantly higher than that pre-orthokeratology treatment,and the deep vessel density in the whole area and para-fovea at three months were significantly higher than that pre-orthokeratology treatment(P<0.05).The RPC density of both two groups increased after 3 months of orthokeratology treatment in whole image and inside disc area(P<0.05).Three months after toric orthokeratology treatment,FAZ area of group T2significantly decreased by 0.05(-0.41～+0.08)mm~2and Ch C perfusion area increased by 0.06±0.12 mm~2.FAZ area of group S2 significantly decreased by0.01(-0.19～+0.01)mm~2and Ch C perfusion area increased by 0.06(-0.07～+0.50)mm~2.There were no significant differences in the change of FAZ and Ch C perfusion area between two groups(P>0.05).Retinal thickness of two groups increased after 3 months of orthokeratology treatment in whole image and para-fovea area(P<0.05).And SFCh T increased by14.0±6.3μm in group T2 and by 14.7±9.0μm in group S2.There were no significant differences in p RNFL thickness between before and after wearing orthokeratology for three months(P>0.05).The p RNFL thickness of group S2 decreased after 3months of orthokeratology treatment(P<0.05).Before wearing orthokeratology,the axial length of group T2 was positively correlated with the superficial vessel density in the whole image and fovea area(r=0.429,P=0.036;r=0.422,P=0.040),and the superficial vessel density of group T2 was positively correlated with the retinal thickness in the whole image and fovea area(r=0.476,P=0.019;r=0.519,P=0.009).But,the deep vessel density of group S2 was negatively correlated with the retinal thickness in the whole image and fovea area(r=-0.433,P=0.035;r=-0.454,P=0.026).According to the results of PREP questionnaire after wearing orthokeratology lens for 1 day,handling scores in group S2 was significantly higher than that of group T2(P<0.05),and no significant differences were found in other items between two groups(P>0.05).After wearing lens for 3 months activities score of groups S2was significantly higher than that of group T2(P<0.05),and no significant differences were found in other items between two groups(P>0.05).Compared with 1 day after wearing orthokeratology lens,there were not significant differences in activities,academic performance and peer perceptions of group T2 after 3 months of wearing orthokeratology(P>0.05).But overall vision,near vision,far vision,symptoms,appearance,satisfaction,and handling scores as well as overall scores in group T2 were increased(P<0.05).No significant differences in near vision,far vision,satisfaction,academic performance,handling,and peer perceptions were found in group S2 between two visits(P>0.05).But overall vision,symptoms,appearance,activities,and overall scores in group S2were significantly better than those of wearing lens for 1 day(P<0.05).After wearing orthokeratology lens for 3 months,overall vision score of group T2 was positively correlated with the superficial vessel density in the fovea area(r=0.595,P=0.002),and far vision score of group T2 was negatively correlated with the deep vessel density in the fovea area(r=-0.444,P=0.030).But,in S2 group,there was no significant correlation between overall vision,far vision score and retinal vessel density in the fovea(P>0.05).Conclusion:Increased retinal microvessel density,reduced area of FAZ and enlarged Ch C perfusion area of adolescent myopia were observed after wearing orthokeratology lens for three months.The amount of FAZ and Ch C perfusion area changes had no significant difference between toric and spherical orthokeratology.Increased RPC density,macular retinal thickness and SFCh T of adolescent myopia were also observed after wearing orthokeratology lens for three months.With axial length elongation,the superficial vessel density of adolescent myopia increased.With an increase of superficial vessel density,the thickness of fovea also was increased.And the more superficial microvascular are distributed,the thicker the retina is.After wearing orthokeratology lens for 3 months,the visual related quality of adolescent myopia patients improved significantly.The retinal microvessel density in the fovea can be used as an indicator to evaluate the vision quality of adolescent myopia patients after wearing orthokeratology. |
PDF Full Text Request