Free-floating vitreous cyst.

Cysts of the vitreous are an unusual clinical finding, with only about 50 such cases reported in the literature. The sizes of the cyst may vary from 0.15 to 12 mm, and they have been found in the anterior and posterior vitreous. The etiology has been theorized to be both congenital and acquired. Acquired cysts may be due to trauma or other forms of intraocular inflammation. Pigmented cysts are believed to originate from the pars ciliaris and nonpigmented cysts are likely to be derived from the remnants of the hyaloidal artery system. The appearances of the cysts are striking and are often seen as clear spherical bodies in the vitreous with interesting interlacing surface patterns. The cysts are benign and are of little significance, except when they encroach on the visual axis and produce visual disturbances (usually floater symptoms).