Synchysis scintillans Vs Asteroid Hyalosis
By Dr.Ahmed Omara
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Synchysis scintillans is a degenerative condition of the eye seen uncommonly in dogs, resulting in liquefied vitreous humor and the accumulation of cholesterol crystals within the vitreous. It is also known as cholesterolosis bulbi. The vitreous liquifies in a process known as syneresis. Synchysis scintillans appears as small white floaters that freely move in the posterior part of the eye, giving a snow globe effect. It is most commonly seen in eyes that have suffered from a degenerative disease and are end-stage.
In humans as well, the condition is seen rarely. Associated with the advanced stages of diabetic retinopathy, but the exact pathogenesis is unknown.
Asteroid hyalosis is a degenerative condition of the eye involving small white opacities in the vitreous humor. It is known to occur in humans, dogs, cats and chinchillas.Clinically, these opacities are quite refractile, giving the appearance of stars (or asteroids) shining in the night sky—except that ocular asteroids are often quite mobile. Ocular asteroids must be distinguished from the more common typical vitreous floaters, which are usually fibrillar or cellular condensates. The cause of asteroid hyalosis is unknown, but it has been associated with diabetes mellitus, hypertension, hypercholesterolemia, and, in certain animals, tumors of the ciliary body. In dogs, asteroid hyalosis is considered to be an age related change. asteroid bodies are made up of hydroxylapatite, which in turn consists ofcalcium and phosphates or phospholipids. While asteroid hyalosis does not usually severely affect vision, the floating opacities can be quite annoying, and may interfere significantly with visualization and testing of the retina. While treatment of asteroid hyalosis is usually unnecessary, vitrectomy may occasionally be indicated, for both diagnostic and therapeutic purposes.