Asteroid hyalosis. Biomicroscopy, ultrastructure, and composition
H. W. Topilow, K. R. Kenyon, M. Takahashi, H. M. Freeman, F. I. Tolentino and L. A. Hanninen
The vitreous in 16 patients (average age, 65 years) with asteroid hyalosis
was studied and photographed using a preset lens (El Bayadi-Kajiura) and
slitlamp. Asteroid hyalosis was bilateral in one patient (6%) and
unilateral in 15 patients (94%). The gel was biomicroscopically normal in
13 patients (81%) and showed moderate liquefaction in three patients (19%).
In ten (63%) of the 16 patients, there was no posterior vitreous
detachment, in four patients (25%), there was partial vitreous detachment,
and in two patients (12%), there was complete vitreous detachment. The
preponderance of complete vitreous detachment was lower than expected for
patients in this age group, probably because of a reduced preponderance of
vitreous liquefaction in patients with asteroid hyalosis. A vitreous
aspirate from one of these patients was studied using phase-contrast
microscopy and scanning and transmission electron microscopy. Asteroid
bodies were enmeshed within normal vitreous collagen fibrils and some were
attended by macrophages or multinucleated epithelioid cells. Transmission
electron microscopy disclosed irregular calcific material and complex
lipids within the asteroid bodies. X-ray spectroscopy demonstrated calcium
and phosphorus.
