Disclosed is a method for treating an ophthalmic lens comprising two main sides, wherein at least one side comprises an organic or mineral external layer coated with a MgF.sub.2 temporary protective layer, comprising one of the following treating steps: a liquid phase chemical treatment of the temporary protective layer, leading to the formation of MgO and/or Mg(OH).sub.2 in and/or on the temporary protective layer; or a deposit of at least one non-fluorinated metallic oxide and/or of at least one non fluorinated metallic hydroxide on the temporary protective layer through transfer thereof from an electrostatic film or through vacuum evaporation thereof directly on the temporary protective layer.