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.
