Which of the following conditions is a common cause of low vision?

Cataracts are indeed a common cause of low vision, as they involve the clouding of the eye's lens, which significantly impairs visual clarity. This condition can develop due to aging, genetics, or other factors, and often leads to blurriness or haziness in vision. People with cataracts may experience difficulty with night vision, sensitivity to glare, and reduced color perception, all of which contribute to low vision.

In contrast, the other options do not primarily lead to low vision. Hypertension can impact vision, but it primarily affects the blood vessels and can cause other eye problems over time rather than being a direct cause of low vision itself. Anemia refers to a deficiency in the number or quality of red blood cells but does not have a direct link to vision impairment. Asthma, a respiratory condition, similarly does not correlate with low vision and primarily affects breathing and lung function. Therefore, cataracts stand out as the leading cause of low vision compared to these other conditions.