What is the condition known as when one has a lazy eye causing dullness in vision?

Amblyopia is the condition characterized by reduced vision in one eye that is not correctable with glasses or contact lenses. Often referred to as "lazy eye," amblyopia occurs when the brain fails to fully process input from one eye, leading to diminished vision. This phenomenon can result from various factors, such as strabismus (misalignment of the eyes), significant differences in prescription strength between the eyes, or other issues that interfere with normal visual development during childhood. It typically manifests as a state of dullness in vision, where one eye has weaker visual acuity compared to the other.

In contrast, hyperopia (farsightedness), myopia (nearsightedness), and presbyopia (age-related difficulty in focusing on close objects) are refractive errors, but they do not necessarily cause the brain to favor one eye over the other as seen in amblyopia. Therefore, the condition that specifically refers to the dullness in vision associated with a lazy eye is indeed amblyopia.