Kanski is pretty decent, but like redhawk said, it's not a book you can get through during a month rotation. I would use it as a reference and then use the "big books" to read about important stuff. I read the sections on retinal detachment, diabetic retionpathy, and macular degeneration in the 3 volume set entitled "Retina". These were really great and informative readings.
I don't think there is any 1 book, but I would completely read the book Redhawk suggested, and use the bigger reference books to reinforce the big stuff. You want to be sharp as possible to get your killer letters of recommendation.