Zeiss Glass High Index 1.9
Zeiss is an international leader in the fields of optics and opti-electronics.
High Index 1.9 Zeiss Glass
In business for over 160 years, Zeiss produces and develops solutions for businesses as varied as eyeglass and camera lenses, semiconductors, automotive and mechanical engineering, medical, and biomedical industries. Superior optics, craftsmanship, and quality are synonymous with the Zeiss name.
Zeiss produces a high index 1.9 Lantel (glass) that works well for people in need of strong prescriptions, be they of the high myopia or high hyperopia variety. While popular overseas and in Canada, Zeiss 1.9 Lantel is not currently approved for sale in the United States. The ban is not due to quality concerns with the Zeiss product or manufacturing process, but rather for safety issues, which are generally more closely enforced in the U.S. than in other countries.
The Zeiss 1.9 high index glass lenses are not approved due to the following safety issues:
- Inability to be Hardened
Due to the thinness of high index glass and the inherent properties of glass, 1.9 high index glass lenses of any construction are innately brittle. Zeiss 1.9 Lantel, however, is especially thin at the center, leading to a structural fragility that makes it very prone to breakage. In other words, Zeiss glass is actually too thin at the center (reportedly 1mm) to pass muster for practical usage in the U.S., where a 2mm minimum is the general application.
Zeiss 1.9 glass – again, because of its thinness – cannot be hardened, or tempered, for additional strength. This increases the chances of breakage and, being in close proximity to the eye, potential eye injury if glasses are struck by any object while being worn. This has contributed to the FDA decision to discontinue sale in the United States.
It should be noted that Zeiss 1.9 Lantel is not technically illegal in the USA; it is the sale of the material, not the use of it, that is restricted. Several glass manufacturers produce 1.9 glass that is compatible with U.S. standards and is thereby available within the States. Authentic Zeiss Lantel features a “Z” laser mark to identify it.
Also, proponents of the material in other countries are often supportive of the increased high index effects of Zeiss 1.9 Lantel for anyone with an excessively strong prescription, and generally seem to feel that the U.S. safety concerns are overblown. Although usage is common outside the U.S., actual judgment as to the validity of breakage concerns will vary with the individual.