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  • Modifying Indoor Environments May Improve Dry Eye

    By Lynda Seminara
    Selected and Reviewed By: Neil M. Bressler, MD, and Deputy Editors
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    Journal Highlights

    JAMA Ophthalmology, August 2020

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    Most studies of dry eye syndrome involve the outdoor environment, but the ocular surface is sensitive to indoor conditions as well. Huang et al. assessed the relationship between dry eye and indoor atmosphere and found the biggest offenders to be high humidity and strong concentration of particulate air pollutants.

    For this prospective cross-sectional study, the researchers included 97 vet-erans with a wide array of dry eye metrics. The participants were recruit­ed from the Miami Veterans Affairs Healthcare eye clinic in 2017 and 2018. Dry eye metrics were assessed in the clinic first, then inside the home within the following week. A handheld particle counter was used for the latter. Dry eye symptoms were documented from standard questionnaires, and physical signs were determined from ocular surface exams. Indoor environmental metrics included temperature, humid­ity, and the mass and count of particu­late matter.

    Eighty-one of the 97 participants were male; mean age was 58.2 years. Overall, their dry eye symptoms were moderate, with a mean Ocular Surface Disease Index (OSDI) score of 31.2. High humidity was correlated with worse symptoms and signs, including poorer OSDI (r = 0.30; p = .01) and Schirmer score (r = −0.25; p = .03), more inflammation (r = 0.32; p = .01), more meibomian gland dropout (r = 0.27; p = .02), and less eyelid vascularity (r = 0.27; p = .02).

    In multivariate analyses, which were adjusted for demographics, co­morbidities, and other factors, partic­ulate matter of 2.5 μm or less (PM2.5) was linked to dry eye. For example, each per-unit increase in instrumented PM2.5 level corresponded to a 1.59 in­crease in OSDI score (p = .002), a 0.39 decrease in Schirmer score (p = .04), a 0.07 increase in meibomian gland dropout (p = .02), and a 0.06 increase in inflammation (p = .009).

    The finding of higher humidity causing dryer eyes is contradictory to studies in which low humidity was deemed the greater culprit. High hu­midity may increase microbial growth and the mass and size of particulate matter, said the authors. Their findings suggest that indoor environmental ma­nipulations, such as regulating humid­ity and reducing airborne pollutants, may help some individuals with dry eye. (Also see related commentary by Ian J. Saldanha, MBBS, MPH, PhD, in the same issue.)

    The original article can be found here.