22. Robertson, D. M. Vitreous floaters and flashing lights. Vitreous collapse and sequelae. Minn Med 55, 314-7 (1972).
Of 100 patients with a prepapillary annular opacity in age-related posterior vitreous detachment with collapse, 44 had floater symptoms corresponding to their opacity. Ninety-two of the patients had a prepapillary annular opacity in only one eye. Two-thirds of the opacities could be observed within plus or minus one diopter of four diopters into the posterior chamber, and all of the opacities could be observed within a two to seven diopter range. Approximately one-third of all the prepapillary annular opacities were complete rings.