DAILY DISPOSABLE BENEFITS

Daily Disposable Lenses in Urban Environments

Some research has found that a daily disposable lens can improve vision and comfort both indoors and out in urban environments.

Dr. Rah is the manager, Global Medical Affairs, Vision Care, Bausch + Lomb.

By Marjorie J. Rah, OD, PhD, FAAO

The urban environment plays a role in the health of those who work or live in these areas. The World Health Organization (WHO) reported that “research in recent decades consistently indicates the adverse effects of outdoor air pollution on human health, and the evidence points to air pollution stemming from transport as an important contributor to these effects,” (Krzyzanowsk et al, 2005). The health of tens of thousands of individuals is affected by the air pollution from road transportation (Krzyzanowsk et al, 2005; Kunzli et al, 2000) including mortality, non-allergic respiratory conditions, allergic illness and symptoms (such as asthma), cardiovascular disease, cancer, pregnancy, birth outcomes, and male fertility (Kunzli and Perez, 2009).

In the eye, airborne toxins result in watering, burning, and redness of the eye (Saxena et al, 2003). Andres et al (1988) found a decrease in lacrimal pH with increased levels of air pollution that was based on the change in sulfur dioxide (SO₂) concentration, the chief contaminating agent in the atmosphere. They reported that of subjects with normal eyes who spent approximately eight hours each day in different levels of air pollution (SO₂), the percentage having problems associated with contact lens wear increased when the level of atmospheric SO₂ increased. Nitrogen dioxide (NO₂—an oxidative environmental pollutant), high temperature, and wind speed also have been associated with conjunctivitis and other eye surface diseases (Rozanova et al, 2009; Bourcier et al, 2003). Additionally, according to Rozanova et al, “The most common eye condition due to air pollution described in literature is dry eye syndrome.”

The Indoor Urban Environment

Environmental ocular sensitivities are not limited to air pollution. Environmental factors that affect people’s ocular health can be encountered both indoors and outdoors. Ocular irritation is one of the most frequently reported symptoms in relation to working in office-like environments (Rozanova et al, 2009). Low relative humidity conditions have been shown to exacerbate the development of eye irritation symptoms, in particular if the pre-corneal tear film has been altered by working conditions such as viewing a computer screen (Wolkoff et al, 2006). Another manifestation of the health-related effects in the urban environment is the condition known as sick building syndrome (SBS). SBS is a group of symptoms “reported by workers in modern office buildings, hypothesized to occur when the supply of outdoor air is reduced, because of the accumulation of contaminants arising from within the building,” (Menzies et al, 1993). It has been estimated that approximately 25 million workers in 1.2 million commercial buildings in the United States have symptoms of SBS (Backman and Haghighat, 1999). Studies of SBS have shown a high correlation between ocular discomfort and poor indoor-air quality, and it has been associated with contact lens discomfort (Backman and Haghighat, 1999).

The Needs, Symptoms, Incidence, Global Eye Health Trends (NSIGHT) study, a comprehensive survey of 3,800 vision-corrected patients worldwide, investigated patients’ sensitivity to pollution, pollen, light quality, air conditioning, computer use, and long days. The results showed that between 50 percent and 80 percent of contact lens-wearing patients experience these sensitivities (Table 1).

A Daily Disposable Contact Lens in the Urban Environment

Contact lens-wearing patients who have environmental sensitivities may be well-suited to daily disposable lens wear. Utilization of available products may make a marked contribution to improving the vision, comfort, and product satisfaction of patients requiring vision correction who may be sensitive to the urban environment and to frequent use of technological devices.

Research using the SofLens Daily Disposable (Bausch + Lomb) lens has shown some promising results for these patients. A 20-investigator, multisite study was conducted in which 216 eligible and consenting subjects, aged 15 to 40 years, were dispensed SofLens Daily Disposable lenses. The IRB-approved protocol required eligible subjects to use technology devices (eg, PDAs, computers, electronic game consoles, hand-held electronic devices, electronic book readers, etc.) for an average of four hours per day over a week’s time for a minimum of four days each week. After seven days, subjects completed an online survey to evaluate lens performance. The results showed that 85 percent of patients felt that the SofLens Daily Disposable lenses deliver crisp, sharp vision even while using a computer or other technological device, and 74 percent felt that the lenses help reduce fatigue when in front of a computer, video, or PDA screen for a long period of time. (Table 2).

A similar 28-investigator, multi-site study was conducted in which 215 eligible subjects, aged 18 to 40 years, were dispensed SofLens Daily Disposable lenses following informed consent. The IRB-approved protocol required that eligible subjects live and/or work in an urban environment, feel challenged by harsh, drying outdoor conditions (i.e. dust, pollution, smog), and feel that being in an urban environment had a negative effect on their lens-wearing experience. After seven days, subjects completed an online survey to evaluate lens performance. Results from this study revealed that 82 percent of patients agreed that SofLens Daily Disposable lenses helped maintain crisp, clear vision in dusty and polluted environments, 76 percent agreed that they alleviated irritation in urban environments, and 73 percent of urban environment consumers felt that SofLens Daily Disposable lenses make them less aware that they are wearing lenses (Table 2).

Conclusion

Urban and technological environments have been shown to have an impact on ocular symptoms and health. Although these environmental sensitivities can result in contact lens discomfort (Andres et al, 1988; Backman and Haghighat, 1999), SofLens Daily Disposable lenses have been shown to positively impact the lens-wearing experience for patients using computer, video, or PDA screens. In addition, these contact lenses also helped to maintain crisp clear vision and to reduce ocular irritation in urban environments. CLS

For references, please visit www.clspectrum.com/references.asp and click on document #205.