You gotta get right up in there if you really want to see what’s going on in those eyes.
This is an illustration from a book about birds, oddly enough: The fundus oculi of birds, especially as viewed by the ophthalmoscope; a study in the comparative anatomy and physiology.
Neither of these gentlemen are birds. One of them is using an ophthalmoscope on the other, or really, using one to look into the eyes of the other. As the book advises, “Only a number of months spent in the exploration of the eyes of such domestic animals — including Man — as are most readily accessible and easily observed, followed by ophthalmoscopy of wild species obtained in field work, will make an expert of the student.”
Come a little bit closer….