Mieko was last seen at 11.30am on Saturday (7 November) when she left the house to go for a walk in Hove Park.
She has not returned or made contact since and concerns grow for her welfare.
Mieko is described as an Asian woman, of a very slim build, with dark hair and was wearing black trousers, beige shoes and a grey sweatshirt.
Anyone who sees her or who has information on her whereabouts is asked to dial 999 immediately.
