简介：AIM:Todeterminethenormativevaluesofwhite-towhitecornealdiameterwithOrbscanIITopographySystemandtocomparerightandlefteyesdatainthenormalyoungpopulation.METHODS:Atotalof1001healthyparticipantsaged18-45yparticipatedinthisobservationalcross-sectionalstudy.Thestudypopulationconsistedof616femaleand385malesubjects.ThecornealdiameterwasmeasuredwiththeOrbscanII.Thedifferencesbetweengenders,betweenrightandlefteyesandage-relatedchangeswereevaluated.StatisticalanalyseswereperformedusingStudent’st-test.RESULTS:Theaveragewhite-to-whitedistanceinourstudypopulationwasrecordedas11.65±0.36mm(median:11.60mm,mode:11.70mm,minimum:10.50mmandmaximum:13.60mm).Thewhite-to-whitedistancewas11.60±0.35mminmalesand11.71±0.36mminfemaleswhichwasstatisticallydifferentbetweengenders(P<0.01).However,white-to-whitedistancewasnotstatisticallydifferentbetweenrightandlefteyes.Inaddition,thisparameterdecreasedwithincreasingage.Considering95%confidenceinterval,cornealdiameterlessthan10.93mmandgreaterthan12.34mmwouldbeconsideredasmicrocorneaandmegalocornea,respectivelybasedonthisstudypopulation,usingtheOrbscanIItopography.CONCLUSION:DetaileddescriptionandanalysisofcornealdiameterwithOrbscandemonstratethattheobtainedaveragevalueofhorizontalwhite-to-whiteishigherinmalethanfemaleanddecreasesslightlywithincreasingage.Ourdataalsosuggeststhecutoffvaluesfordefinitionofmicrocorneaandmegalocornea,whichcanbeemployedwiththispopulation.