Associations between Subjective Happiness and Dry Eye Disease: A New Perspective from the Osaka Study

<div><p>Importance</p><p>Dry eye disease has become an important health problem. A lack of concordance between self-reported symptoms and the outcome of dry eye examinations has raised questions about dry eye disease.</p><p>Objective</p><p>To explore the association between subjective happiness and objective and subjective symptoms of dry eye disease.</p><p>Design</p><p>The study adopted a cross-sectional design.</p><p>Setting</p><p>All the employees of a company in Osaka, Japan.</p><p>Participants</p><p>672 Japanese office workers using Visual Display Terminals (age range: 26–64 years).</p><p>Methods</p><p>The dry eye measurement tools included the Schirmer test, conjunctivocorneal staining, the tear film break-up time, as well as the administration of a dry eye symptoms questionnaire. Happiness was measured by the Subjective Happiness Scale.</p><p>Main Outcome Measures</p><p>Dry eye examination parameters, dry eye symptoms questionnaires, and the Subjective Happiness Scale score.</p><p>Results</p><p>Of the 672 workers, 561 (83.5%) completed the questionnaires and examinations. The mean Subjective Happiness Scale score was 4.91 (SD = 1.01). This score was inversely correlated with the dry eye symptom score (r = -0.188, p < 0.001), but was not associated with objective findings which include conjunctivocorneal staining, low Schirmer test score, or low tear film break-up time. The level of subjective happiness was the lowest in the group without objective results, but reported subjective symptoms of dry eyes (p < 0.05).</p><p>Conclusions and Relevance</p><p>There is evidence of the relationship between subjective happiness and self-reported symptoms of dry eyes. Findings of this study revealed a new perspective on dry eye disease, including the potential for innovative treatments of a specific population with dry eye disease.</p></div

Comparison of dry eye symptom scores between objective and subjective classifications.

<p>SD = standard deviation.</p

Correlation of SHS score with objective findings from dry eye examinations and subjective symptom scores.

<p><i>Note</i>. SHS = Subjective Happiness Scale; SD = standard deviation; <i>r</i> = Pearson’s correlation coefficient; BUT = breakup time.</p><p>Correlation of SHS score with objective findings from dry eye examinations and subjective symptom scores.</p

Adjusted result of the Subjective Happiness Scale score: dry eye, gender, age, and body mass index.

<p><i>Note</i>: SHS = Subjective Happiness Scale; SE = Standard error.</p><p>Adjusted result of the Subjective Happiness Scale score: dry eye, gender, age, and body mass index.</p

Comparison of SHS score between objective and subjective classifications.

<p>SD = standard deviation.</p

Age, gender, and the Subjective Happiness Scale scores of the participants.

<p><i>Note</i>. p-values reported pertain to the results of an ANOVA; SD = standard deviation; SHS = Subjective Happiness Scale.</p><p>Age, gender, and the Subjective Happiness Scale scores of the participants.</p

Comparison of Subjective Happiness Scale and dry eye symptom scores.

<p><i>Note</i>. DED = Dry eye disease; SHS = Subjective Happiness Scale</p><p>Comparison of Subjective Happiness Scale and dry eye symptom scores.</p

<i>Tet-mev-1</i>/Dox(+) have dry eye disease.

<p>A, Aqueous tear production: Aqueous tear quantity values of <i>Tet-mev-1</i>/Dox(+) were significantly lower than those in the other types of mice (n≥6, ANOVA Tukey's test, p = 0.0024). B, <i>Tet-mev-1</i>/Dox(+) mice had more corneal fluorescein staining than in the other mice. C, The corneal fluorescein staining score of <i>Tet-mev-1</i>/Dox(+) was significantly worse than that in the other types of mice (all n = 8, ANOVA Tukey's test, p<0.00001).</p

Lacrimal gland in <i>Tet-mev-1 mice</i> with Dox has functional depression of mitochondria and excessive O₂⁻production.

<p>A, The activity of complexes I and II in WT/Dox(+) vs. <i>Tet-mev-1</i> mice/Dox(+). NADH-cytochrome c oxidoreductase was applied as an enzymatic indicator of complex I activity, and succinate-coenzyme Q oxidoreductase as an enzymatic indicator of complex II activity. Although there were no differences in the activity of complex I between these mice, complex II was significantly decreased in <i>Tet-mev-1 mice</i> with Dox. (WT: n = 5, <i>Tet-mev-1</i>: n = 3, NS, not significant; *P<0.01 [Student's t-test]). The vertical bars indicate the standard deviation of the separate experiments. B, Production of O₂⁻ in the lacrimal gland was significantly increased in <i>Tet-mev-1</i>/Dox(+) compared with that in the other types of mice. (n≥5, *P = 0.0014 [Kruskal-Wallis test]). The vertical bars indicate the standard deviation of the separate experiments. C, Carbonyl protein content of the lacrimal gland by ELISA. Each value shows the ratio of <i>Tet-mev-1</i> and WT for the relative amount of carbonyl protein in <i>Tet-mev-1 mice</i> with or without Dox (n = 4, *P = 0.004 [Student's t-test]). D, Immunohistochemical staining of 8-OHdG: <i>Tet-mev-1</i>/Dox(+) shows more positive nuclei (brown, indicated by the arrow) than the other types of mice.</p