Contributor: Gordon K. Klintworth
Asteroid hyalitis (asteroid hyalopathy, asteroid hyalosis) is a monocular non-inflammatory disorder of the vitreous characterized by an accumulation of minute white spherular particles within an otherwise apparently normal vitreous gel. The condition affects ~1% of the general population and occurs in the elderly. Men are mainly affected. The condition is rarely familial and it has been associated with diabetes mellitus, hypertension, atherosclerosis, gout and hyperopia. The particles, which move within the vitreous, are composed of calcium soaps (calcium stearate) and calcium palmitate). They appear gray in hematoxylin and eosin stained preparations, but lipid and calcium can be detected histochemically in appropriately prepared specimens. The asteroid bodies are moderately  positive with the periodic acid-Schiff reaction and they exhibit a vivid "Maltese cross" pattern of birefringence using polarization microscopy. Asteroid hyalitis does not affect vision and patients are asymptomatic. Examination of the eye reveals countless creamy white stellate opacities within the vitreous that resemble snowballs or Christmas ornaments. Asteroid hyalitis is occasionally confused clinically with synchisis scintillans and amyloidosis.