Which ocular finding is NOT associated with Down's syndrome?

Asteroid hyalosis is an ocular finding that is not commonly associated with Down's syndrome. This condition involves the presence of small, white, opacities in the vitreous humor of the eye, typically made up of calcium-lipid complexes. Unlike other ocular manifestations associated with Down's syndrome, such as prominent epicanthal folds (which can contribute to a characteristic appearance), congenital glaucoma, and keratoconus, asteroid hyalosis does not have a recognized link to the chromosomal abnormalities that cause Down's syndrome.

Congenital glaucoma occurs due to abnormal development of the eye's drainage system and is seen at a higher prevalence in patients with Down's syndrome. Similarly, keratoconus, characterized by a conical shape of the cornea due to progressive thinning, has been more frequently reported in individuals with this condition. Prominent epicanthal folds are a hallmark feature in the facial phenotype of those with Down's syndrome, often observed during the examination of patients.

In summary, while several ocular abnormalities can be associated with Down's syndrome, asteroid hyalosis stands out as a condition that is not linked to the syndrome, making it the correct answer in this context.