1.Numerical computation on the scaffolds models with regular square holes using nonlinear fluid-solid-coupling approaches
Yabin ZHAI ; Yuhong CUI ; Wenjiao LI
Journal of Medical Biomechanics 2010;25(1):4-10
Objective The influencing parameters of solid and fluid computing fields for the scaffolds models with regular square holes were discussed by nonlinear fluid-solid-coupling approaches.The numerical computational resuits of which the models were regarded as both rigid body and non-linear elasticity were compared as well.Method One direct fluid-solid-coupling approach and two indirect fluid-solid-coupling approaches were adopted,and the calculating reliability of three kinds of fluid-solid coupling methods was verified.Rasults The solid-fluidcoupling computational results are obtained in light of 12 kinds of scaffolds models which are constructed by 3 groups of square side length(50,100 and 150 μm)and 4 groups of porosity(61%,65%,77%and 84%).The field parameters of those solid models including stress,strain and displacement and those fluid models including static pressure,velocity,wall shear stress and strain rate are achieved and compared.Conclusion There appear some difference between the results of porous scaffold models as a rigid body and as non-linear elasticity.The different porosity with the same pore radius or the different pore radius with the same porosity would affect the field parameters of solid models and fluid models in varying degrees.
2.Allogeneic corneal small incision intrastromal lenticule inlays for moderate and high hyperopia :one year follow-up
Jing ZHANG ; Changbin ZHAI ; Yan ZHENG ; Qian LIU ; Yue WANG ; Xiumei SONG ; Qiulu ZHANG ; Yabin HU ; Yuehua ZHOU
Chinese Journal of Experimental Ophthalmology 2018;36(5):355-359
Objective This study was to evaluate the long-term clinical efficiency of allogeneic corneal intrastromal lenticule inlay for correction of moderate and high hyperopia.Methods A prospective self-controlled case series study was adopted.Twenty-nine hyperopic patients (53 eyes) were performed with allogeneic corneal intrastromal lenticule inlays.The range of preoperative spherical equivalent was +3.75 to + 10 D,with the mean value of (+6.84±2.95)D.All the cases were followed up for 1 year.Uncorrected and best corrected visual acuity and refraction were compared between before and after operation.Corneal topography and optical coherence topography were used to examine corneal topography.Ocular response analyzer was used to evaluate the shifts of corneal hysteresis.This study followed the Helsinki declaration,and the research process was approved by the Ethic Committee of Beijing Tongren Hospital,and informed consent was signed by each donor and receptor.Results Compared with the before surgery,the uncorrected distance visual acuity (UDVA) and uncorrected near visual acuity (UNVA) were obviously improved and the spherical equivalent (SE) was obviously decresed in 3 months,6 months and 1 year after surgery,with significant differences between them (all at P<0.05),but no significant differences were found between each postoperative time points (all at P>0.05).One year after surgery,14 eyes (26.4%) gained one line of best corrected distance visual acuity (BCDVA),and 12 eyes (22.6%) gained two lines of BCDVA.Only 2 patients (5.66%) lost lines due to opaque lenticules,and no eye lost lines after changing the opaque lenticules.There was no obvious hyperopic fallback phenomenon.Compared with the before surgery,the average corneal curvature value (Avek) was obviously improved,the surface regularity index (SRI),surface asymmetry index (SAI) and central corneal thickness (CCT) were obviously increased in 3 months,6 months and 1 year after surgery,with significant differences between them (all at P<0.05),but no significant differences were found between each postoperative time points (all at P > 0.05).The cornea optical coherence tomography (OCT) examination showed that,after the operation,the corneal stromal implant was in place and clear.One year after surgery,the dividing line of corneal graft was still clearly visible.No significant changes of corneal hysteresis (CH) and corneal resistance factor (CRF) were seen among different time points before and after surgeries (F =1.443,P =0.216;F =1.744,P =0.128).Conclusions Allogeneic corneal small incision intrastromal lenticule inlays can be used to correct moderate and high hyperopic eye with good safety,effectiveness and predictability.It provides a new choice for hyperopic patients.