A study of medical databases in the US has found that residents of polluted cities such as New York, Chicago and Los Angeles are at greater risk of dry eye syndrome. The best contact lenses for dry eyes could be the new ortho-k overnight contact lenses which correct short-sightedness while you sleep. The lenses are removed during the day, to give perfect unaided vision for up to 36 hours.

Dry eye syndrome occurs when there is insufficient tear volume and residents of our polluted cities who wear daytime contact lenses are particularly vulnerable as the pollution is trapped behind their lens. Tears are produced to lubricate the eye and the tear film has three distinct layers, which aim to capture water and increase dwell time on the eye. These layers can be disrupted by medication, ageing and environmental conditions and this causes dry patches to form on the surface of the eyes. Treatments for hay fever can also cause dry eye discomfort since medications that block histamine receptors to reduce allergic conditions have a drying effect, reducing mucus and aqueous production within the tear film.

Using data from the National Veterans Administrative (VA) Database, the National Climatic Data Center and NASA, researchers examined the health records of 606,708 veterans who visited one of 394 VA eye clinics to receive treatment for dry eye syndrome between 2006 and 2011. Study subjects in and around New York City were found to be three to four times more likely to be diagnosed with dry eye symptoms compared to those in areas with relatively little air pollution.

Eye care is particularly important for city dwellers, who are exposed, not just to glare and UV light but also to dust, pollen and wind, all of which can irritate the eyes. Many short-sighted people wear daytime contact lenses but suffer from watery eyes and are unaware that it may be a symptom of dry eye, which can also cause a scratchy, gritty or smarting feeling. Some people have resorted to laser surgery to correct short-sightedness and found out the hard way that it is not a permanent solution for their problem eyesight. So the new overnight contact lenses are an ideal solution for city dwellers and could be the best contact lenses for dry eyes.

Ortho-k is a unique new treatment for short-sightedness where small custom-designed contact lenses are only worn overnight while sleeping. This makes these lenses the best contact lenses for dry eyes because no contact lenses are needed during the day. The lenses gently flatten the surface of the eyes under the mild pressure of closed eyelids and this ensures that light entering the eyes focuses directly on the retina rather than in front of it. The wearer enjoys perfect natural vision all day long as the correction effect lasts for over 24 hours.