As Parsons succinctly put it, "The exact mechanism of detachment is not completely understood; indeed detachment of the retina is still one of the difficult problems of pathology." In other words, as it is not known how a detachment is produced, its relation to trauma must remain vague. Yet one cannot but be struck by how generally the thesis of a traumatic origin is accepted. For some time I have noted, in examining patients with retinal detachment, how rare a traumatic origin really is, and this has led me to review 400 successive cases in which I have had the opportunity to make examination. These 400 cases may be classified as follows:1 Cases of bilateral detachment numbered 58, or 14 per cent. The degree of myopia was over 10 D. in 25 per cent, from 5 to 10 D. in 42 per cent and up to 5 D. in