 Now we're going to show you a few examples of transillumination. These are things that you can do on the infrared pupilometer. Here's an in vitro globe specimen that has melanoma and we're transilluminating an infrared light and what we're showing is the actual demarcation of the tumor tissue in the globe. The pathologists are going to use this to help them decide where to make their cuts. Although we don't have a picture of this, it was very hard to see the full extent of the tumor by just gross inspection of this globe. So in this particular example, the pathologists are using this technique to help them decide grossly where to examine the tissue. It seems as though the more we use the infrared pupilometer, the more clinical uses that we find for it. Now here's an in vivo example of a tumor. Now there's obviously something going on in the superior iris and globe of this patient but it's kind of tough to find out the extent of what this mass is. Now with transillumination, we're going to try and identify the full extent of this mass and look at that. It shows up very clearly from the normal surrounding structures. This is presumably an iris melanoma with an extension posteriorly. Look at how large it is. You never saw that extent of it when you're looking at it grossly in room light. This is a very nice technique to define the size, extent and perhaps even the invasiveness of a globe tumor. I think you can see by transillumination on the inferior aspect of the globe that this tumor is sort of hanging down into the globe itself. You can get a shadow effect. Look at that for example. You almost get the feel that this tumor is hanging down from the inside of the globe. That's a pretty ugly looking tumor. And I don't think by gross examination you got the full feel for how large this tumor actually was.