Abnormal Opacities of the Vitreous Body
These usually unilateral opacities of the
vitreous body (75% of all cases) are not all that infrequent. They are thought
to be linked to diabetes mellitus and hypercholesterolemia. The disorder is
characterized by white calcific deposits that are associated with the collagen
fibers of the vitreous body and therefore are not very mobile. Most patients
are not bothered by these opaci-ties. However, the examiner’s view of the
fundus can be significantly obscured by “snow flurries” of white opacities.
Interestingly, these opacities do not interfere with fluorescein angiography.
Vitrectomy to remove the opacities is rarely necessary and is performed only
when the opacities adversely affect the patient, i.e., when visual acuity is
rare opacities of the vitreous body usually occur unilaterally fol-lowing
recurrent intraocular inflammation or bleeding. In contrast to asteroid
hyalosis, these opacities are free floating cholesterol crystals in the
vitreous chamber that respond to gravity. Fractile crystals are typical.
Surgery is only indicated in rare cases in which the opacities impair visual
inherited autosomal dominant disorder begins at about the age of 20, progresses
for decades, and finally leads to diminished visual acuity. Amy-loidosis causes
characteristic amyloid deposits around the collagen fibers of the vitreous body
except for the hyaloid canal, which remains unaffected. The amyloid exhibits
histologically typical staining. The disorder can be treated by vitrectomy.