Thanks to the advancement of lens technology, glasses lenses are no longer a single, one size fits all solution. There are a variety of different lens types that can be used in glasses, giving patients greater flexibility and control over their vision than ever before.
Also known as monovision lenses, these lenses are designed to correct the wearer’s vision at just one distance, and have a single prescription covering the entire surface of the lens. They are most often recommended for people who are either nearsighted (myopia) or farsighted (hyperopia) and who need glasses for a specific activity, such as driving or reading.
Progressive lenses are multifocal lenses that can correct a patient’s vision at different working distances, ranging from far distance to reading distance. However, rather than designating different areas on the lenses for different distances with visible lines separating them, progressive lenses have a gradual change so that the wearer can smoothly transition from one lens power to another.
As you may have guessed from the name, bifocal and trifocal lenses have either two or three lens powers depending on which type you choose. Bifocal lenses support distance vision in the top half of the lens, and near vision in the lower half. Trifocal lenses support distance vision in the top third of the lens, intermediate vision in the middle segment and near vision in the bottom third. Whichever variety you choose, you will see visible lines separating each segment.
Bifocal and trifocal lenses are recommended for patients who are near or farsighted, and those who develop presbyopia, which is the natural hardening of the eye lens, that occurs as we get older. Presbyopia makes it harder for the lens of the eye to adapt to focus at different distances.
Multifocal lenses are the alternative name given to bifocal, trifocal and progressive lenses.