Pollen count compared with severity of symptoms and signs of dry eye disease in Norway

Abstract

PurposeTo investigate whether pollen counts are associated with severity of symptoms and signs of dry eye disease (DED) in Oslo, Norway.MethodsThe mean daily number of birch or grass pollen grains per cubic meter of air (pollen count) in Oslo from 2012 to 2015 between March and September were provided by The Norwegian University of Science and Technology and The Norwegian Asthma‐ and Allergy Association. Four hundred and twelve DED patients that were examined for the first time on the same day as pollen data were available were included. Symptoms of DED were measured by the Ocular Surface Disease Index (OSDI) self‐report questionnaire and signs of DED included measurements of tear osmolarity, tear film break‐up time, blink interval, ocular protection index, Schirmer I, staining, meibum expressibility and meibum quality from the right eye. Symptoms and signs, as well as the composite score for dry eye severity level (DESL), were compared with pollen count using Pearson's and Spearman's correlations, Chi square test and Mann‐Whitney U‐test.ResultsBirch pollen was generally only detectable during April and May, whereas grass pollen was normally detectable during June. Neither birch (rs = −0.13; p = 0.81) nor grass (rs = 0.06; p = 0.38) pollen were associated with symptoms of DED as measured by the OSDI. Except Schemer I test, which surprisingly was negatively related to grass pollen count (rs = −0.15; p = 0.02), neither pollen types correlated with DESL or any signs of DED. Only 5.6% of the patients reported the use of systemic prescription drugs against allergy, thus the weak association between pollen counts and severity of DED appear not to have been confounded by concomitant use of anti‐allergy medications.ConclusionsThe severity of symptoms and signs of DED in Oslo, Norway does not seem to be strongly associated with either birch or grass pollen count.