[The prevalence of allergic conjunctivitis based on outpatients in Baotou area]

Objective: To explore the prevalence and influencing factors of allergic conjunctivitis in Baotou area at different times. Methods: A cross-sectional study was conducted in January 2021, 111 patients with allergic conjunctivitis who were admitted to the Department of Ophthalmology, the Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology in 2020 were selected as the research subjects. The basic information, allergic conditions, living habits and other information of the patients were obtained by self-made questionnaire. The pollen concentration and allergy related indicators(allergic duration and frequency, eye itching score, eye burn score, eye foreign body sensation score, tears score and the total scores) of 2019 and 2020 were analyzed by paired sample t-test. The pollen concentration of 2019 and 2020 were analyzed by Wilcoxon signed rank test. The allergy related indicators of different genders were analyzed by independent sample t-test. The allergy related indicators of different ages were analyzed by one-way analysis of variance. The relationship between the length of wearing masks and the allergy related indicators were analyzed by Spearman correlation analysis. Results: Among the 111 patients with allergic conjunctivitis, 54 were males and 57 were females, ranging in age from 8 to 69 years old, with a median age of 35 years old and an average age of (36.77±13.18) years old. The average pollen concentration in Baotou in 2019 was (125.35±222.64) grains/1 000 square millimeter, and the average pollen concentration in Baotou in 2020 was (107.38±137.29) grains/1 000 square millimeter. There was no significant difference in pollen concentration between the two years(Z=-0.178, P=0.859). The severity of allergic indicators in all patients in 2020 is significantly lower than in 2019(t values were 4.701,3.587,2.582,3.661,4.444,2.784,2.555,3.886,respectively, with P<0.05). The severity of allergic indicators in male patients is lower than that of female patients (t values were -1.558, -1.257, -3.41, -3.085, -2.335, -2.897, -2.652, -4.124, respectively). The prevalence of allergic conjunctivitis dose not vary significant with age (P values were 0.504, 0.095, 0.499, 0.265, 0.284, 0.655, 0.421, 0.976, respectively). In 2020, the average time that patients wear masks is (6.55±3.28) h/d, and there is a correlation with the difference in allergy duration (r=0.191, P=0.045). Conclusion: The severity of allergic conjunctivitis in Baotou in 2020 was significantly improved compared with that in 2019, which may be related to masks wearing.