When I was being initially diagnosed as a diabetic 20+ years ago, I had a fluorescein retinograph performed. Strong dilation with a significant numbing agent, fluorescein dye injected into an I/V in the back of my hand, and in just a few seconds, a camera with a very strong ring flash was taking pictures of my eye (think of the chair in _A Clockwork Orange.) The flash was so strong, I felt pressure, not just heat. Intellectually speaking, a neat procedure, but yes, a little nerve-wracking.
Larry, I hope your eyes are in good shape.