The sony cybersnap is a good little camera and I don't see why you couldn't use it to take a close up shot of the sclera. I just bought mine so have not bothered to have someone take a picture of my eye with it. I have used lesser cameras and had good results photographing the iris.
I take the digital and place it on a photoshop program on my computer and blow it up on the monitor. I made a copy of an eye chart and copied it to a piece of acetate and hold it up to the picture of the iris on my monitor. I had to work at getting the size of the chart to match the size of the eye.
With just looking at the sclera, you wouldn't have to do all that. Good luck