Option Explicit
Dim CollOBn As New Collection
Private Sub UserForm_Initialize()
Dim Ctrl As MSForms.Control
For Each Ctrl In Me.Controls
If TypeName(Ctrl) = "OptionButton" Then CollOBn.Add Ctrl, Ctrl.Caption
Next Ctrl
CollOBn("toto") = True ' (j'ai mis "toto" comme Caption à l'un d'eux)
End Sub