[Asteroid hyalosis within an epiretinal membrane]

In May 2007 an 80-year-old man with a known proliferative diabetic retinopathy presented in our outpatient department with a decrease in visual acuity of his right eye. There was a thick asteroid hyalosis preventing fundus examination. Sonographically, there were vitreoretinal tractions requiring a vitrectomy. During surgery an epipapillary membrane was removed.

Microscopically round amorphous bodies were conspicuous which were slightly basophilic in the H&E stain. The amorphous bodies were strongly positive in the periodic acid-Schiff staining. They were embedded in a fibrovascular stroma and partly surrounded by inflammatory cells with numerous giant cells of foreign body reaction.

Asteroid hyalosis is a common degenerative disorder in the vitreous body. The aetiology and the pathogenesis of the asteroid bodies are not yet fully understood. An association of asteroid hyalosis with systemic diseases like diabetes mellitus, arterial hypertension, hyperlidpidaemia and atherosclerotic vasculopathy is postulated. Normally, therapy for an asymptomatic asteroid hyalosis is not necessary. The tractive proliferative diabetic retinopathy in our patient did require surgery. The incorporation of hyaloid bodies into an epiretinal membrane with the induction of a foreign body reaction is unusual.