简介:AIM:Toevaluatetheinterchangeabilityofkeratometricandasphericitymeasurementsprovidedbythreemeasurementsystemsbasedondifferentopticalprinciples.METHODS:Atotalof40eyesof40patientswithameanageof34.1ywereincluded.Inallcases,acornealcurvatureanalysiswasperformedwithIOL-Master(IOLM),iDesign2(ID2),andSiriussystems(SIR).Differencesbetweeninstrumentsforflattest(K1)andsteepest(K2)keratometricreadings,aswellasformagnitudeandaxisofcornealastigmatismwereanalyzed.Likewise,differencesinasphericity(Q)betweenSIRandID2werealsoevaluated.RESULTS:MeandifferencesbetweendevicesforK1were0.20±0.21(P<0.001),-0.12±0.36(P=0.046)and-0.32±0.36D(P<0.001)forthecomparisonsIOLM-SIR,IOLM-ID2andSIR-ID2,respectively.Therangesofagreementforthesecomparisonsbetweeninstrumentswere0.41,0.70,and0.70D.ForK2,meandifferenceswere0.31±0.33(P<0.001),-0.08±0.43(P=0.265)and-0.39±0.38D(P<0.001),withrangesofagreementof0.65,0.84,and0.74D.Concerningmagnitudeofastigmatism,rangesofagreementwereinthelimitofclinicalrelevance(0.49D,P=0.011;0.55D,P=0.386;0.43D,P=0.05).Incontrast,rangesofagreementwereclinicallyrelevantforastigmaticaxis(26.68o,33.83oand18.37o,P≥0.121)andforQbetweenSIRandID2(0.16,P<0.001).CONCLUSION:Thekeratometriccornealpower,astigmaticaxisandasphericitymeasurementsprovidebythethreesystemsevaluatedcannotbeconsideredasinterchangeable,whereasmeasurementsofcornealastigmatismobtainedwithSIRandID2canbeconsideredasinterchangeableforclinicalpurposes.
简介:Wedemonstratelow-losshydrogenatedamorphoussilicon(a-Si:H)waveguidesbyhot-wirechemicalvapordeposition(HWCVD).Theeffectofhydrogenationina-SiatdifferentdepositiontemperatureshasbeeninvestigatedandanalyzedbyRamanspectroscopy.Weobtainedanopticalqualitya-Si:Hwaveguidedepositedat230°CthathasastrongRamanpeakshiftat480cm-1,peakwidth(fullwidthathalf-maximum)of68.9cm-1,andbondangledeviationof8.98°.Opticaltransmissionmeasurementshowsalowpropagationlossof0.8dB/cmatthe1550nmwavelength,whichisthefirst,toourknowledge,reportforaHWCVDa-Si:Hwaveguide.