Hindi pa kasi fully developed ang vision ng babies na ganyan kalaki, pero yung constant staring up at parang di responsive sa objects ay worth checking with your pedia, especially kung combined pa with other things like feeding or movement na parang off sa iyo. A few of my mum friends had similar observations and nag-relay lang sa doctor during check-up, kaya don't worry na, pero best to mention it sa next visit mo or mag-call na if worried ka talaga, better safe than sorry with these things. Basta reassure mo lang siya habang nag-talk ka or nag-play, at see what doc says!