The tube on the left is connected to an elevated bag of fluid that keeps the eye inflated so it doesn't collapse like a squished grape when you make your other incisions. Those two metal things on either side of the cornea and short hollow tubes that go through the pars plana into the vitreous chamber. We use these two tubes to place instruments through. Usually one hand has a fiberoptic light so you can see what you're doing in there. The other hand has an instrument, like a cutter, or a pick or a laser, or whatever you need at the moment.
It used to be that you would make an incision and just push the instruments in and out of the eye through the cuts. With this new "hollow tube" technique, you just stab the tubes in, do the surgery and then take them out at the end. You don't even need to put any stitches in. It's very cool surgery.
The little lens suspended above the cornea is actually attached to a huge operating microscope. The microscope usually focuses light onto the cornea, but this lens allows you to focus it further back into the vitreous.
Oh, and the big metal thing is a lid speculum. When I operate, people often tell me they're afraid they'll close their eyes. Not to worry. We just pry them open with metal instruments.
One more subtle, but important detail. In the lower right corner of the photo, above the eyebrow, next to the blue drape, there is a purple arrow. That arrow says "operate on this eye." It's bad form to operate on the wrong eye. Especially if you're doing an enucleation. (Look that one up. It gives me the shivers just thinking about it.)
I do have to say that I love my job!