Advances in Photoprotection

Elma D. Baron, MD; Eugene B. Kirkland, BS; Diana Santo Domingo, MD

Disclosures

Dermatology Nursing. 2008;20(4):265-273. 

In This Article

Protective Clothing

Clothing is an easy and effective way of keeping safe in the sun. The protective value of clothing is measured in vitro by the UV protection factor (UPF), which conveys a fabric's ability to prevent the transmission of UV light. Unlike the sun-protection factor (SPF) afforded by sunscreens, which mainly represents protection against UVB, the UPF supposedly represents protection against both UVA and UVB (Edlich et al., 2004). UPF is influenced by qualities such as fabric type, color, thickness/tightness of the weave, and method in which the material is worn (Rai & Srinivas, 2007; Rosen, 1999). Denim, for example, has a UPF of 1,700 compared to cotton which has a UPF of 5 to 9. Typically, the UPF is higher for materials that are darker in color and those that have undergone fabric shrinkage after having been laundered (Kullavanijaya & Lim, 2005). However, color alone is not an accurate way of judging protection be cause UPF relies on factors such as dye type and concentration (Hatch & Osterwalder, 2006). Wearing clothes so that they do not hug the skin can increase UPF (Rai & Srinivas, 2007). Additionally, keeping fabrics from becoming wet or stretched prevents a drop in protective quality (Khazova, O'Hagan, & Grainger, 2007).

New fabrics are also now available providing better UV protection. Nylon made from BASF fibers is one example. It has the feel of cotton, but unlike cotton it has titanium dioxide particles dispersed within its fibers allowing for combined UVA/UVB protection. Incorporating inorganic sun screen particles into fabrics allows for greatly enhanced UPF. Similar innovations for commonly worn materials like cotton include the use of thin titanium layers and application of titanium hydrosol with fluorescent whitening agents (Hatch & Osterwalder, 2006). While such novel modifications are an effective solution, there are other alternatives for increasing the UPF of existing clothing.

A number of photoprotective laundry additives that act as sunscreens or optical brightening agents have been created to reduce UVR transmission. Rit Sun Guard®, which contains Tinosorb® FD, filters both UVA/UVB and lasts for approximately 20 washings. Cotton t-shirts with UPF of 5 show a six-fold increase in UPF after just one laundering with Rit Sun Guard and a ten-fold increase after two launderings in succession (Edlich et al., 2004). The use of optical whitening agents can likewise increase UPF through their fluorescent-like properties (re-emitting absorbed UVR in the visible spectrum); however, this augmented protection is limited by partial UVB coverage (Edlich et al., 2004; Van den Keybus, Laperre, & Roelandts, 2006). Therefore, combinations of these agents or simultaneous use with other photoprotective measures may prove to be the most effective.

Hats and sunglasses are other clothing accessories that allow for a more comprehensive approach to sun protection. Hats have an SPF up to 7 depending on the brim size and area of the face protected. A hat with a brim greater than 7.5 cm offers protection for the neck (SPF 5), chin (SPF 2), cheeks (SPF 3), and nose (SPF 7). Sunglass effectiveness, on the other hand, depends on factors such as size, shape, UV blocking ability, and reflection from the back of the lens (Kullavanijaya & Lim, 2005). The American Academy of Ophthalmology recommends that sunglasses block 99% of UVR, and those that comply with this standard are labeled accordingly. Appropriate UVR filtration by sunglasses is important because it prevents the development of certain ocular disorders including cancers of the eye/eyelid, cataracts, and possibly age-related macular degeneration (Young & Sands, 1998).

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