Which systemic disease is known to affect ocular health?

Diabetes mellitus is particularly known for its impact on ocular health due to the way it affects blood glucose levels and subsequently the vascular system. Persistently high blood sugar can lead to diabetic retinopathy, a condition where damage occurs to the retina's blood vessels. This can result in vision problems and, in severe cases, blindness. In addition to diabetic retinopathy, diabetes can also lead to cataracts and glaucoma, further complicating ocular health.

On the other hand, other diseases listed, such as hypertension, can indeed impact vision by causing issues like hypertensive retinopathy, but diabetes has a more direct and well-established connection to a range of specific ocular conditions. Asthma primarily affects the respiratory system, while kidney disease may lead to ocular complications, but neither of these directly poses as widespread a threat to eye health as diabetes does.