Imagine that you are looking through binoculars, set the sharpness and observe the surroundings, the view around is magnificent. And then take and rub the glasses of the binoculars with sand, the visibility will immediately deteriorate. It is the same with cataracts, only there the lens of the eye (natural lens) is not rubbed with sand, it becomes cloudy for other reasons. A person does not distinguish objects around well, he has poor coordination, etc. Semi-blind.
Cataract - a decrease in the transparency of the lens (lenses inside the eye), in the vast majority of cases associated with age. The lens begins to thicken at the age of 30-35, because of this, it becomes more difficult for the eye to adjust up close and at 45-50 years old you have to put on glasses for near, and for myopic ones take off glasses when reading. At the age of 65-70, the density of the lens reaches such a degree that it begins to retain light. This condition is called cataract. Due to the fact that less light enters the eye, a person's vision deteriorates, and often mood. It has been proven that depression is more common in patients with cataracts (https://pubmed.ncbi.nlm.nih.gov/21076306/). The resulting difference in vision between the eyes can lead to disorientation and, as a result, to falls and accidents. With a pronounced decrease in vision, the ability to self-care may be lost.