Asteroid hyalosis

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, and chinchillas. [cite journal |author=Wang M, Kador P, Wyman M |title=Structure of asteroid bodies in the vitreous of galactose-fed dogs |journal=Mol Vis |volume=12 |issue= |pages=283–9 |year=2006 |pmid=16617295] 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 [cite journal | author = Akram A, Niazi M, Ishaq M, Azad N | title = Frequency of diabetics in asteroid hyalosis patients. | journal = J Ayub Med Coll Abbottabad | volume = 15 | issue = 3 | pages = 10–1 | year = | pmid = 14727330] , hypertension, hypercholesterolemia [cite journal | author = Bergren R, Brown G, Duker J | title = Prevalence and association of asteroid hyalosis with systemic diseases. | journal = Am J Ophthalmol | volume = 111 | issue = 3 | pages = 289–93 | year = 1991 | pmid = 2000898] , and tumors of the ciliary body.cite book|author=Gelatt, Kirk N. (ed.)|title=Veterinary Ophthalmology|edition=3rd ed.|publisher=Lippincott, Williams & Wilkins|year=1999|id=ISBN 0-683-30076-8] In dogs, asteroid hyalosis is considered to be an age related change. [cite web | last = Bjerk | first = Ellen | title = Ocular Disease of the Aging Dog | work = Proceedings of the 29th World Congress of the World Small Animal Veterinary Association | date = 2004 | url = http://www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2004&PID=8721&O=Generic | accessdate = 2007-03-23 ] The asteroid bodies are made up of hydroxylapatite, which in turn consists of calcium and phosphates or phospholipids [cite journal | author = Komatsu H, Kamura Y, Ishi K, Kashima Y | title = Fine structure and morphogenesis of asteroid hyalosis. | journal = Med Electron Microsc | volume = 36 | issue = 2 | pages = 112–9 | year = 2003 | pmid = 12825125 | doi = 10.1007/s00795-002-0211-y] . 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 [cite journal | author = Wong S, Sampath R | title = Erroneous automated refraction in a case of asteroid hyalosis. | journal = J Cataract Refract Surg | volume = 28 | issue = 9 | pages = 1707–8 | year = 2002 | pmid = 12231337 | doi = 10.1016/S0886-3350(01)01224-X] . While treatment of asteroid hyalosis is usually unnecessary, vitrectomy may occasionally be indicated, for both diagnostic and therapeutic purposes [cite journal | author = Olea Vallejo J, Muñoz Corrales E, Mateos Poch J, Mulet Perera P, Suñer Capo M | title = [Vitrectomy for asteroid hyalosis] | journal = Arch Soc Esp Oftalmol | volume = 77 | issue = 4 | pages = 201–4 | year = 2002 | pmid = 11973661] [cite journal | author = Feist R, Morris R, Witherspoon C, Blair N, Ticho B, White M | title = Vitrectomy in asteroid hyalosis. | journal = Retina | volume = 10 | issue = 3 | pages = 173–7 | year = 1990 | pmid = 2236940] .

References

ee also

*Synchysis scintillans