Ageneralexpressionofthescintillationindexisproposedforopticalwavepropagatinginturbulentat-mosphereunderarbitraryfluctuationconditions.Theexpressiondependsonextremebehaviorsofthescintillationindicesunderbothweakandstrongfluctuations.ThemaximumscintillationindexintheonsetregionandthecorrespondingRytovindexcanbeevaluatedfromthegeneralexpression.Planeandsphericalwavesinthecasesofzeroandnon-zeroturbulenceinnerscalearegivenasexamplesforillustra-tionofthegeneralbehaviorsofscintillationindices.
