Bifocal lenses offer a budget-friendly eyewear solution for individuals experiencing presbyopia after the age of 40, requiring correction for both near and distance vision. Despite advancements in progressive lens technology, some people prefer bifocals due to long-term habit, comfortability or budget constraints.
The defining feature of bifocal lenses is their dual-zones, typically with two distinct areas. The upper part corrects distance vision, suitable for activities such as driving or watching television. Meanwhile, the lower part is optimized for near vision tasks such as reading, reducing eye strain from frequent changes of glasses.
Traditional bifocals have a visible dividing line between the distance and near vision segments, clearly marking the lens areas. Consulting with an eye care professional is crucial to determine the prescription that best suits specific needs, whether for work, leisure, or daily tasks, as bifocal lenses provide focused vision in the near segment.
The two major types of bifocal models are:
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Flat-top bifocals (DBF): Also known as D-segment or straight-top bifocals, these lenses have a distinct visible line separating the upper and lower segments. The upper part corrects distance vision, while the lower segment, shaped like a half-moon or "D", corrects near vision. Flat-top bifocals are popular due to their clear division between the two optical powers.
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Round-segment bifocals (KBF): These bifocal lenses have a rounded segment for near vision correction, which blends more smoothly into the distance correction area. Round-segment bifocals provide a more seamless transition between the two powers compared to flat-top bifocals and are preferred by some wearers for aesthetic reasons and improved near vision clarity.
These two types cater to different preferences and visual needs, offering solutions for individuals requiring bifocal correction for both distance and near vision.