I would use ooze's technique for giving the whites of the eyes some sparkle. Don't be too worried about getting the bleach just on the whites of the eyes, even though ferri is a subtractive reducer (acts on all tones at the same rate), a slight bleaching that will render the whites of the eyes white, will have little apparent effect on the pupils of the eyes.
For example, in this photograph
(there was a url link here which no longer exists)
The white water in the left foreground was dull, due to being in the shade. I washed this whole area with Farmer's reducer, using a cotton bud to apply it, and washing off between applications. Six or seven applications of the reducer added a sparkle to the water, but had little noticeable effect, even on the lighter water flowing over the rocks in that area.