You could import as strings and then apply ToExpression:
(s = {"1.123*^-8", "2.123*^-8", "3.123*^-8",
"4.123*^-8"} ) // InputForm
(* {"1.123*^-8", "2.123*^-8", "3.123*^-8", "4.123*^-8"} *)
ToExpression[#] & /@ s
(* {1.123*10^-8,2.123*10^-8,3.123*10^-8,4.123*10^-8}*)
