Asteroid bodies--an ultrastructural study.

An ultrastructural study of asteroid bodies in a vitreous aspirate from a patient suffering visual loss as a result of asteroid hyalosis is presented. Under appropriate conditions of fixation and high resolution transmission electron microscopy, a lamellar arrangement with a periodicity of 4.6 nm was observed. This lamellar arrangement is typical of liquid crystalline phases of lipids in water. X-ray micro-analysis confirmed the presence of calcium and phosphorus in the asteroid bodies. We propose that the asteroid bodies are not true crystals but rather liquid crystals of phospholipids in the vitreous humor.