The present invention relates to a cosmetic or dermatological composition comprising, in a physiologically acceptable support: a) at least one oily phase and b) at least one merocyanine compound of formula (1) defined hereinbelow and c) at least one organic UVB-screening agent chosen from: v) a liquid lipophilic organic UVB-screening agent vi) a hydrophilic organic UVB-screening agent vii) a triazine UVB-screening agent and viii) mixtures thereof and d) at least one organic UVA-screening agent other than the said merocyanine compound when the said UVB-screening agent is liquid and lipophilic, the said composition contains less than 2% by weight of cyclohexasiloxane relative to the total weight of the composition. Another subject of the present invention consists of a non-therapeutic cosmetic process for caring for and/or making up a keratin material, comprising the application, to the surface of the said keratin material, of at least one composition according to the invention as defined above. The invention also relates to a non-therapeutic cosmetic process for limiting the darkening of the skin and/or improving the colour and/or uniformity of the complexion, comprising the application, to the surface of the keratin material, of at least one composition as defined previously. The invention also relates to a non-therapeutic cosmetic process for preventing and/or treating the signs of ageing of a keratin material, comprising the application, to the surface of the keratin material, of at least one composition as defined previously.
