Vitreous degeneration

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Asteroid hyalosis in a dog due to age-related vitreous degeneration[1]

Vitreous degeneration (vitreous syneresis) is a common ophthalmic disorder or dogs characterized by changes in the liquidity of the vitreous humor of the eye.

This may occur as a primary condition associated with progressive retinal atrophy or secondary to uveitis, hypermature cataracts[2] or lens luxation.

The significance of this disease is the consequent development of retinal degeneration and retinal detachment.

Although a presumptive diagnosis may be determined based on visual inspection of the eye, showing retinal degeneration with various degrees of hyper-reflectivity of the tapetal fundus and/or attenuation of retinal vessels.

A definitive diagnosis usually requires ultrasonographic imaging to confirm the presence of vitreal syneresis (separation of thicker and thinner layers of vitreous) and asteroid hyalosis (small white opacities in the vitreous humor)[3].

There is no specific treatment for this condition as it usually has an underlying disease process involved in its etiology.


  2. van der Woerdt A et al (1993) Ultrasonographic abnormalities in the eyes of dogs with cataracts: 147 cases (1986-1992). J Am Vet Med Assoc 203(6):838-841
  3. Labruyère JJ et al (2008) Ultrasonographic evaluation of vitreous degeneration in normal dogs. Vet Radiol Ultrasound 49(2):165-171