1.9 High Index Lenses Popular in Europe
1.9 High Index lenses. They’re the crème de la crème of high index lenses, literally the highest index material that can currently be obtained.
Popular European 1.9 High Index Lenses
They’re also made of glass (any high index lens material above a 1.74 is available only in glass), which has some inherent advantages and disadvantages, some described below.
Obtaining a pair of 1.9 high index lenses, however, can be a tricky proposition. Availability of 1.9 lenses can be restricted, and access to them depends on factors such as where you live and what you can afford to spend on eyewear. For these reasons – availability and cost – 1.9’s are relatively scarce in the United States.
1.9 high index glass material is extremely brittle and cannot be hardened. Because of this, and because the proximity of eyeglass lenses to the eyes makes breakage a potentially hazardous issue, the FDA does not endorse the sale of 1.9 glass lenses; not within the boundaries of the organization’s jurisdiction, that is, which encompasses the whole of the United States. According to FDA stipulations, 1.9 high index glass lenses are available only if deemed medically necessary by a qualified optometrist. 1.9 cannot be arbitrarily ordered simply for cosmetic appeal.
However, Canada and overseas countries are not subject to this restriction and freely produce and sell 1.9 high index lenses. This has made 1.9’s a readily-available and somewhat popular option for European wearers of corrective eye-wear, especially those who can enjoy the full benefit of high index lenses by reducing lens thickness on extremely high prescriptions.
In the U.S., plastic (either standard index or high index) is the more common and popular lens material. In Europe, glass is generally preferred. With that preference comes the understanding that high-index glass is extremely breakable, and proper care is afforded to any frames fitted with such lenses. Generally, high-index glass lenses are considered “dress wear” and are not used in situations that expose them to damage. Sports, exercise, and strenuous work conditions; Europeans tend to forego the use of glass lenses in these instances, favoring safety glasses or contacts instead.
Even where they are available, the cost is high. 1.9 high index offers the thinnest possible lens – they’re 80% thinner than standard lenses – and this advantage does not come without paying a premium. 1.9 high index lenses are at the top end of the scale not only in terms of the index but in price, as well.
Should 1.9 high-index lenses be available, here’s a list of “pros and cons” to help you decide if you should choose them for your frames.
1.9 High Index Advantages
- They are 80% thinner than standard index (1.5) lenses
- They represent the highest available index
- They are particularly effective in reducing the lenses thickness of a “minus” prescription
- As glass lenses, they feature a high level of scratch resistance
1.9 High Index Disadvantages
- They are available in glass format only
- They are extremely brittle and cannot be hardened
- They are available for single-vision purposes only – no bifocal options exist.
- They are the most expensive lenses available.
- They have inordinately high reflective properties; an anti-reflective coating is strongly recommended.