Monovision for presbyopia
It is the only condition that affects 100% of the human population, and it is pretty devastating when it hits. It is called presbyopia, which translates to 'aging vision'. And we have all seen it in action.
The problem starts subtly, when people begin to notice that they cannot hold objects or books close to their face and see clearly. They begin to back things up away from themselves to see them clearly.
Next, they joke that their arms aren't long enough, and that when they hold things farther away, they can't read because the print is too small. So they are forced to buy over-the-counter readers, or get bifocals.
Another solution to the problem is monovision correction. This can be done with contact lenses, lasik surgery, or with lens implant surgery. The non-dominant eye is intentionally corrected for near vision, and the dominant eye is corrected for distance. In about 90% of patients, the brain adapts to this strange situation, and blends the images so that all activities can be done without glasses.