Investigation on the prevalence of dry eye syndrome in military pilots and risk factors analysis

Objective To investigate and analyze the prevalence of dry eye syndrome and risk factors in military pilots in order to provide references for improving aeromedical supports. Methods Cross-sectional study was applied on conducting questionnaire survey as consensus obtained from 846 military pilots. The suspected dry eye syndrome cases were diagnosed by the tests of slit lamp, break-up time (BUT), Schirmer I test (SIT), corneal fluorescein staining (FL) and tarsal glands function. The pilots were grouped by aircraft type (fighter, helicopter, transporter and bomber), by flying hours ( 2 000 h), by if the long-term usage of antibiotic eye drops and by if the play time of computer or smart phone ≥4 h/d. The prevalence of dry eye syndrome was compared among groups. Results Eight hundred and forty-three valid questionnaires out of 846 were collected. The available ratio was 99.65%. The prevalence of the dry eye syndrome was 8.07%. The common self-repoiled symptoms were dryness (80.88%), foreign body sensation (41.18%), visual fatigue (36.76%), visual acuity fluctuation (22.06%) and red eyes (14.71%). The comparisons among different aircraft type groups showed no statistical significance(χ2=3.16, P>0.05). The comparisons among different flying hours groups were statistically significant (χ2=49.85, P 2 000 h flying hours group was much higher than that in other two flying hours groups. The pilots with antibiotic eye drops for long time had significantly higher prevalence than those without the long-term usage (χ2=20.68, P<0.01). The pilots using computer or smart phone longer than 4 h/d showed significantly higher prevalence (χ2=18.33, P<0.01). Conclusions The prevalence of dry eye syndrome in military pilots increases with flying hours. Eye dryness is the main symptom. Using computer or smart phone for long time is one of the major risk factors that could lead to the dry eye syndrome in military pilots. Key words: Dry eye syndromes; Risk factors; Questionnaires; Military pilots