GREY'S ANATOMY - "Not Responsible" - Meredith must choose between her fertility treatments and her eyesight when she begins having trouble seeing, Mark makes it clear to Callie and Arizona that he takes his role as father-to-be very seriously, and April discovers there's more to Dr. Stark than first appears, on "Grey's Anatomy," THURSDAY, FEBRUARY 24 (9:00-10:01 p.m., ET) on the ABC Television Network. (ABC/RON TOM) JESSICA CAPSHAW