Slab-off lenses, also known as bicentric grind lenses, are specialized lenses designed to correct vertical imbalance in vision, typically caused by significant differences in prescription strength between the two eyes (anisometropia). This imbalance can lead to double vision or discomfort when looking down, such as when reading. Slab-off lenses feature a special grinding technique that adds prism correction to the lens, compensating for the imbalance and ensuring that both eyes work together more effectively. This results in more comfortable and stable vision for the wearer, particularly during activities that involve frequent shifts in focus.