简介：板层角膜移植术常用于治疗角膜病变,可分为前板层角膜移植术、中间板层移植术和后板层角膜移植术.其中后板层角膜移植术是近年来发展较快的手术方式.板层角膜移植的供体也有多种类型,各有其特点,人工角膜和异种角膜的应用仍需要进一步的研究.

简介：AIM:Toevaluatetheaccuracyofsphericalequivalent(SE)estimatesofadouble-passsystemandtocompareitwithretinoscopy,subjectiverefractionandatablemountedautorefractor.METHODS:Non-cycloplegicrefractionwasperformedon125eyesof65healthyadults(age23.5±3.0years)fromOctober2010toJanuary2011usingretinoscopy,subjectiverefraction,autorefraction(AutokeratorefractometerTOPCONKR-8100,Japan)andadoublepasssystem(OpticalQualityAnalysisSystem,OQAS,VisiometricsS.L.,Spain).Nineconsecutivemeasurementswiththedouble-passsystemwereperformedonasubgroupof22eyestoassessrepeatability.ToevaluatethetruenessoftheOQASinstrument,theSElaboratorybiasbetweenthedoublepasssystemandtheothertechniqueswascalculated.RESULTS:TheSEmeancoefficientofrepeatabilityobtainedwas0.22D.SignificantcorrelationscouldbeestablishedbetweentheOQASandtheSEobtainedwithretinoscopy(r=0.956,P<0.001),subjectiverefraction(r=0.955,P<0.001)andautorefraction(r=0.957,P<0.001).ThedifferencesinSEbetweenthedouble-passsystemandtheothertechniquesweresignificant(P<0.001),butlackedclinicalrelevanceexceptforretinoscopy;Retinoscopygavemorehyperopicvaluesthanthedouble-passsystem-0.51±0.50Daswellasthesubjectiverefraction-0.23±0.50D;Moremyopicvalueswereachievedbymeansofautorefraction0.24±0.49D.CONCLUSION:Thedouble-passsystemprovidesaccurateandreliableestimatesoftheSEthatcanbeusedforclinicalstudies.Thistechniquecandeterminethecorrectfocuspositiontoassesstheocularopticalquality.However,ithasarelativelysmallmeasuringrangeincomparisonwithautorefractors(-8.00to+5.00D),andrequirespriorinformationontherefractivestateofthepatient.

简介：Thekeratoprosthesis(KPro;artificialcornea)isaspecialrefractivedevicetoreplacehumancorneabyusingheterogeneousformingmaterialsfortheimplantationintothedamagedeyesinordertoobtainacertainvision.Themainproblemsofartificialcorneaarethebiocompatibilityandstabilityofthetissueparticularlyinpenetratingkeratoplasty.Thecurrentstudiesoftissue-engineeredscaffoldmaterialsthroughcomprisingcompositesofnaturalandsyntheticbiopolymerstogetherhavedevelopedanewwaytoartificialcornea.Althoughawideagreementthatthelong-termstabilityofthesedeviceswouldbegreatlyimprovedbythepresenceofcorneacells,modificationofkeratoprosthesistosupportcorneacellsremainselusive.Mostofthestudiesoncornealsubstratematerialsandsurfacemodificationofcompositeshavetriedtoimprovethegrowthandbiocompatibilityofcorneacellswhichcannotonlyreducethestimulusofheterogeneousmaterials,butalsomoreimportantlycontinuousandstablecorneacellscanpreventthedestructionofcollagenase.Thenecrosisofstromaandspontaneousextrusionofthedevice,allowformaintenanceofaprecornealtearlayer,andplaytheroleofensuringagoodopticalsurfaceandresistingbacterialinfection.Asaresult,improvementincornealcellshasbeenthemainaimofseveralrecentinvestigations;someefforthasfocusedonbiomaterialforitswellbiologicalpropertiessuchaspromotingthegrowthofcorneacells.Thepurposeofthisreviewistosummarythegrowthstatusofthecornealcellsaftertheimplantationofseveralartificialcorneas.