Led out of Singapore for the sub-region, the pitch is thought to have also included Mindshare and incumbent Carat.
Carat Singapore announced the win only in September 2011, upon the appointment of client services director Masie Ong.
Aegis recently restructured its Singapore operation for a more regional focus, with the appointment of Audrey Kuah and the departure of Anupriya Acharya and Gan Boon Guan.
Covering four markets, Singapore, Malaysia, the Philippines and Hong Kong, the media account is believed to be worth in the region of US$3 million.
Transitions Optical is best known for its fast-reacting photochromic lenses with extensive advertising across a range of media including TV, online and outdoor.
PHD Singapore is headed up by Sony Wong, who joined the agency in July 2011, following Howard Smith's departure to Isobar Asia Pacific. Wong was unavailable for comment on the win.