Ok what the person did there was simple clip1 and clip2 ,crossfade as transition and zooming out the clip2 from a zoomed potition at the first frame then at the normal position a few frames later.??.wut u probably wanna do is actually a classic.?.u should try this Clip -1 = clip from witch u want to transition
Clip -2= the clip containing the eye

Put clip 1 in the timeline.?.then on a video track above place clip 2.?.move clip 2 on the timeline towards the end of clip 1 but still on a video-track above..put it so it overlays a few frames with clip 1..now where the few frames of overlaying ends cut clip 2..then go to pan/crop.?.at first keyframe of the little cut resulted(the one above the duration of clip 1) zoom in and position the square so its inside the black/central part of the eye then go to the last keyframe of that short cut and just restore the pan/croping to his regular position covering the borders of clip 2..now.?.copy this short subclip u did the zooming one video-track above .perfectly above and on this 2nd one..that also has the zooming out u edited before set opacity to 0 at first frame and to 100% at the last keyframe.??.now go back one video track bellow.?.at the short sequence u cut and do a negative mask on the black part of the eye.? (still dunno how its called)?.frame by frame incase it mooves a little and its ot static..its negative in Sony Vegas or substractin AE and probably premiere i think..depending on what u use..the result should be something like the one at the beggining of
http://www.youtube.com/watch?v=76HqGeqUAhY.?.sorry for using one of my edits as example.?.well thats the basics of the effect in case this is what you were looking for..hope i did make it understandable..not verry good at explaining usually