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ZEISS Bifocal CT 25 / CT 28

Optical Knowledge

Here you get background information on eyeglass lenses: Basics of ophthalmic optics, surface geometry and progressive lenses, lens materials, lens production and coatings.

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Contacts

Are you interested in a ZEISS Partnership or do you have questions you would like to ask?

Optical Knowledge

Here you get background information on eyeglass lenses: Basics of ophthalmic optics, surface geometry and progressive lenses, lens materials, lens production and coatings.

more

ZEISS Flattop Lenses

The Classic Bifocal Product for Presbyopes

The introduction of the first bifocal lenses by ZEISS, as long ago as 1952, represented a real revolution at the time. In the past few years, however, the popularity of bifocals has considerably decreased due to the constant improvement in the quality of progressive lenses.

While a large number of segment shapes existed in the past, the type with a curved top is now the most common in most countries and is indicated in the product name by a "C" (curved). Fewer reflections result on the curved surface than on the straight edge of an S segment (S = straight). Today’s Bifocal lenses from ZEISS therefore provide wearers with improved cosmetic benefits and enhanced functionality.

Segments

Segment Widths

Bifocal lenses are available with two different segment widths: 25 mm and 28 mm. The number after the "CT" in the product name indicates the segment width in millimeters. The segment width of 25 mm is adapted to standard conditions of use, providing a sufficiently large visual field for reading purposes. The diameter 28 mm provides correspondingly wider fields of view.

Segment Material

For the segments of glass bifocals from ZEISS, materials with different refractive indices are selected according to the addition in order to ensure that, even with higher additions, all bifocal lenses are as thin and flat as possible.

Benefits

Benefits for the wearer

  • Two different segment sizes to meet individual requirements
  • Reduced reflections due to curved segment top
  • Segment fusing or molding on front surface and inner toric surface design ensure excellent optical quality and cosmetically attractive lenses
  • Wide selection available: various materials, photochromic bifocal lenses and sunglass lenses

Product Range

Bifocal ZEISS Flattop lenses are available in a range of materials.

 

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