This began as an iPhone photo of a rainbow at the top of our driveway. I used a filter (similar to this one) in Prisma, a cell phone app, then brought the result into Xara.
I cropped the image in a square, applied an FX > Deformation Dent/Bump effect -100 to achieve the spherical effect.
I made a duplicate of the spherical image, reduced it to the size of the iris, and applied a linear transparency.
The highlight at the top of the eyeball is a white shape with a simple Linear transparency applied.
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