Which lens type provides three distinct viewing zones across the lens?

Which lens type provides three distinct viewing zones across the lens?

• A. Bifocals
• B. Monovision
• C. Trifocals
• D. Progressives

Answer: (C)

Three distinct viewing zones across a single lens are provided by trifocals. This design divides the lens into three sections: the top for distance vision, a middle section for intermediate work like computer use, and the bottom for near tasks such as reading. Each zone has a defined boundary, often visible as lines, so you can switch quickly between viewing distances. Bifocals have two zones—distance and near—with a single dividing line, while progressives blend powers gradually so there isn’t a sharp separation into three distinct areas. Monovision uses different corrections in each eye rather than three zones on one lens.

Three distinct viewing zones across a single lens are provided by trifocals. This design divides the lens into three sections: the top for distance vision, a middle section for intermediate work like computer use, and the bottom for near tasks such as reading. Each zone has a defined boundary, often visible as lines, so you can switch quickly between viewing distances. Bifocals have two zones—distance and near—with a single dividing line, while progressives blend powers gradually so there isn’t a sharp separation into three distinct areas. Monovision uses different corrections in each eye rather than three zones on one lens.