AIM:Tofindasimplemathematicalcorrelationbetweenthelensbasecurve(BC)andkeratometryfindings(krf).METHODS:Thisretrospectivestudyincluded400keratoconiceyes(350patients)previouslyfitwithrigidcontactlensesatanacademiceyecenteroverafiveyearperiod.Thepatientswereclassifiedintofivegroupsbasedonthekeratometryfindings(krf<7,krf:7-8,krf>8,krf-krs(differencebetweentwokeratometry;flatandsteep)=0.3-0.6,krf-krs>0.6mmasgroups1to5,respectively.MultivariatelinearregressionandMunro’scorrelationcoefficientwereemployedtodefertheformulas.RESULTS:Alinearcorrelationcouldbefoundinallgroupsexceptforpatientsingroup3.Forgroup1,BC=0.211×krf+5.904.Forgroup2,BC=0.456×krf+4.160.Forgroup4,BC=0.321×krf+5.219.Forgroup5,BC=0.337×krf+5.090.CONCLUSION:ThedevelopmentofnewformulasforRGPfittingenablesophthalmologiststoworkwithconfidenceandpreventsunnecessaryandfrequentlenstrials.Thecustomarylensfittingmethodsareneededtobereplacedbynewformulas,whichhelptosavetimeandcosts.
