My introduction to floaters came on a sunny September afternoon in the orchard. I was high on a ladder picking Jonagold apples when I felt a pop in my left eye, followed by blurriness. I thought that maybe a branch had slapped across my glasses, dirtying the lens, and I went inside to clean it. But the blurriness - a sort of floating haze - persisted overnight. After hearing the symptoms, my ophthalmologist, Dr. William Kirber, diagnosed a posterior vitreous detachment, one of several causes of floaters, sensations that many people describe as specks, bugs or cobwebs floating in their...