Which condition is characterized by an asymmetric cup-to-disc ratio on fundoscopy?

The condition characterized by an asymmetric cup-to-disc ratio on fundoscopy is glaucoma. In glaucoma, particularly open-angle glaucoma, increased intraocular pressure leads to damage of the optic nerve, resulting in changes in the optic disc appearance. The cup, which is the central indentation of the optic disc, can become larger in relation to the disc itself, leading to an increased cup-to-disc ratio.

When there is asymmetry in this ratio between the two eyes, it often indicates that one eye might be at a higher risk for glaucomatous damage. This finding is crucial for identifying patients at risk and providing timely interventions to prevent vision loss.

In contrast, conditions such as diabetic retinopathy primarily present with retinal changes rather than abnormalities in the cup-to-disc ratio. Normal tension glaucoma might show similar findings but typically does not produce a significantly asymmetric cup-to-disc ratio unless there is existing optic nerve damage. Cataract formation influences the lens of the eye and would not affect the optic disc observations on fundoscopy. Therefore, the presence of an asymmetric cup-to-disc ratio is a key indicator of glaucoma.