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Study: Cold climate does not worsen discomfort in hydrogel lens wearers
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DENVER – Climate does not appear to be a factor in frequency of winter ocular surface symptoms, according to a study presented here at the American Academy of Optometry meeting.
“I thought this would be a perfect last-day Denver presentation,” said presenter Robin Chalmers, OD, FAAO, the author of the study.
Dr. Chalmers and colleagues sought to determine whether hydrogel contact lens wearers living in cold winter climates experienced different levels of ocular surface symptoms than their counterparts in mild climates. In addition, the study evaluated whether refitting these subjects with second-generation silicone hydrogel lenses would have an impact on the frequency of these symptoms.
The researchers looked at lens wearers in 17 of the coldest (n = 70) and 17 of the warmest (n = 94) clinical sites (28.9+2.8 vs. 54.9+4.8 degrees F, P = 0.019, t-test). These subjects were compared for baseline reports of frequency of ocular surface symptoms of discomfort, dry eyes, stinging or burning, foreign body sensation, and fluctuating vision and eye redness. This information was collected in January and February 2005. Using Wilcoxon’s signed ranks test, change in symptom frequency after 2 weeks use of senofilcon A or galyfilcon A lenses was compared in the climate zones.
The results showed that when comparing habitual hydrogel lenses in warm climates at baseline, there was no difference in frequency of any symptoms except foreign body sensation (34% of cold vs. 26% of mild climate dwellers, P < 0.05).
Refitting with second-generation silicone hydrogel lenses did have an impact on ocular surface symptoms. Two weeks after refitting with second-generation silicone hydrogel lenses, significantly fewer of the cold climate dwellers showed symptoms of discomfort (P < 0.0001), dryness (P < 0.0001), eye redness (P < 0.0001), foreign body sensation (P < 0.002), stinging and burning (P = 0.02) and fluctuating vision (P < 0.02). The mild climate dwellers reported a significant improvement in dryness (P = 0.0001), eye redness (P = 0.0001) and discomfort (P = 0.03).
Although the study did conclude that climate does not seem to affect the frequency of ocular surface discomfort among hydrogel lens wearers, Dr. Chalmers added a caveat regarding the sites used in the study.
“The mild climate areas that we looked at tended to be larger, urban areas,” she said. “So there may have been other aspects other than temperature, such as pollution.” Dr. Chalmers said further investigation is needed to study climate more precisely.