Asteroid Hyalosis
Calcium-lipid complexes suspended throughout collagen fibrils of vitreous
It is characterized by yellow-white brilliant reflecting particles surrounded by tightly adherent fibrils inside the vitreous cavity
These particles are known as asteroid bodies (ABs) due to their resemblance to stars (asteroids) in the night sky
The exact etiology is unknown
PATHOPHYSIOLOGY
Voerhoeff postulated that angiosclerosis of intraocular vessels, along with local deposition of lipids and fats, leads to AH formation
Rodman described type 1 AH in normal vitreous and type 2 AH in vitreous with associated inflammation
Streeten suggested that ABs are produced from exogenous sources since the contents are not present in sufficient quantity in the normal vitreous
Bergren et al. suggested that the release of phospholipid and calcium from degenerated retinal cells could produce AH
Gass observed that AH initially develops near retinal blood vessels
Zauberman and Livni demonstrated the formation of asteroid bodies in the vitreous of albino rats in conjunction with hypercholesterolemia and closure of vertex veins
The unilateral occurrence of asteroid hyalosis can be postulated by the contribution from various factors, eg., local inflammation, retinal pigment epithelial degeneration, local changes in pH, vitreous collagen degeneration, and increased retinal vascular permeability altering the calcium and lipid levels of the vitreous
Systemic diseases like diabetes mellitus (DM), systemic hypertension, and hyperlipidemia have been associated with asteroid hyalosis
EVALUATION:
Ophthalmoscopy - small round refractile opacities associated with vitreous strands and suspended in the vitreous cavity. They move along with the movement of the vitreous body and get back to their previous position after the movement stops and do not settle with gravity
B scan - presence of moderate to high amplitude point spikes in the vitreous cavity separated by a clear zone from the retinal surface
Small white rounded structures - stains with alcian blue and stains for neutral fats, phospholipids, calcium - Metachromatic and birefringent
TREATMENT:
Usually asymptomatic - Observation
Image from Rajan Eye Care Hospital
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