Ultraviolet (UV) radiation is always present, all day, every day, in winter as
well as summer. The importance of providing protection from the harmful effects of UV radiation has been long-recognised within optometric practice, whether it be in contact, intraocular or spectacle lenses.
It is estimated that nearly 70% of the UK population wear prescription spectacle lenses to help them see; representing a significant opportunity to meet the everyday UV protection challenges for the eyes and surrounding skin.
To provide protection from UV radiation all year round, Zeiss has introduced full UV protection up to 400nm in all clear plastic lenses, with the launch of UVProtect Technology.
The impact of UV exposure
Chronic UV exposure can cause accelerated ageing of the skin around the eyes, and it is implicated in the development of ocular conditions commonly seen in clinical practice, eg cataracts, pterygium and eyelid cancers. While shorter wavelength UV radiation has higher energy levels, longer wavelength UV radiation penetrates tissue more deeply.
Spectacle lens standards for UV protection
A recent survey found that 99% of spectacle wearers think it is important to protect the eyes from UV and 99% of consumers agree that sunglass-level UV protection in clear lenses would be beneficial. Yet, some of the most popular clear spectacle lens materials do not completely block the most intense source of UV radiation: the solar spectrum between 380 and 400nm (figure 1), accounting for 40% of the total amount of solar UV irradiance.
The World Health Organization (WHO) and the International Commission of Non-Ionizing Radiation Protection (ICNIRP) define UV radiation hazard as extending up to 400nm. Current industry standards, such as ISO 8980-3, require clear lenses to provide UV protection up to 380m, not 400nm, which creates a UV protection gap. This means that up until the launch of Zeiss UVProtect lenses, most clear lenses fell short of fully protecting individuals’ eyes from UV radiation up to 400nm, potentially posing a risk to eye health.
Zeiss has raised its standards of eye care by introducing full UV protection up to 400nm in all clear plastic lenses, with Zeiss UVProtect Technology.
Technical features
Two innovative Zeiss solutions resolve the ocular UV protection challenges spectacle lens wearers face; direct UV radiation incident through the front of the lens, accounting for approximately 90% of incident UV , and indirect UV radiation reflecting off the back surface of the lens (figure 2).
Figure 2: Schematic demonstrating ocular exposure to UV with a back surface UV coating only and a Zeiss UVProtect lens
1. Zeiss UVProtect Technology: absorbing direct UV radiation
Zeiss scientists have discovered innovative ways to modify the lens polymer to offer full UV protection up to 400nm in 1.5, 1.6, 1.67 and 1.74 refractive index lens materials, without noticeably changing visible light transmission.
2. Zeiss DuraVision UV Coating: reducing reflected indirect UV radiation
The new clear lens polymers are complemented by an enhanced back surface anti-reflective coating, with two additional layers to significantly reduce indirect UV radiation reflected into the eye from the back surface of the lens.
Table 1: Product availability
In isolation, back surface anti-reflective coatings do not provide any protection from the UV radiation incident through the front surface of the lens. Therefore, as you would expect, significantly more UV radiation reaches the eye when wearing lenses incorporating only an enhanced back surface anti-reflective coating when compared to wearing lenses also incorporating a UV absorber within the lens substrate.3
Zeiss UVProtect and DuraVision UV Coating Technologies are incorporated as standard in all Zeiss clear plastic lenses, meaning practitioners can now offer their patients UV protection up to 400nm, even in clear lenses.
Benefits to patients
- Full UV protection, up to 400nm, exceeding the current British standards and matching the level of protection provided by premium sunglasses.
- Provides all day protection for patients’ eyes and surrounding skin from the harmful effects of UV exposure.
- UV protection in a clear, plastic lens, without a significant hue that compromises the cosmetic appearance and visual performance of the lens.
- Available across the Zeiss lens portfolio as standard.
A 2018 Zeiss wearer trial of 106 participants found that 95% of wearers were satisfied with the clarity and aesthetics of Zeiss UVProtect lenses.1
Dispensing notes
Zeiss UVProtect Technology is available as standard across the entire Zeiss lens portfolio. Zeiss UVProtect back surface anti-reflective coating is available with DuraVision Platinum UV, DuraVision DriveSafe UV, DuraVision BlueProtect UV, DuraVision Silver UV, DuraVision Sun UV, DuraVision Mirror UV and LotuTec UV coatings.
Table 2: Lens portfolio availability range*
Zeiss UVProtect lenses are recommended for general everyday use and a second pair of sunglasses (also providing UV protection up to 400nm) should be recommended for wear on sunny days to reduce glare and provide visual comfort and clarity.
Zeiss sun lens tints portfolio provides full UV protection as standard, as well as offering relief from glare on sunny days. The Zeiss sun lens tints portfolio consists of 34 solid, 14 gradients, four double gradients, three Skylet and three polarised colours, as well as Zeiss PhotoFusion photochromic lenses.
For further information contact call Zeiss on 0845 3007788.
References
1 Zeiss external wearer trial with 106 spectacle lens wearers in 2018.
2 Mecherikunnel AT & Richmond JC. NASA Technical Memorandum 82021. Spectral Distribution of Solar Radiation. 1980. https://ntrs.nasa.gov/search.jsp?R=19810016493
3 Rifai K, Hornauer M, Buechinger R, Schoen R, Barraza-Bernal M, Habtegiorgis S, Glasenapp C, Wahl S, Mappes T. Efficiency of ocular UV protection by clear lens solutions. Biomedical Optics Express. 2018;9(4):1948-1963.