Exploring the prevalence of dry eye disease in Hong Kong population

Purpose : Dry eye disease (DED) is an ocular condition that cause discomfort, visual disturbances, and potential harm to the ocular surface. However, the percentage of individuals affected by DED varies across studies due to the utilization of different criteria. This study is to investigate the prevalence of DED in Hong Kong Chinese population, employing the criteria established by the Tear Film and Ocular Surface Society (TFOS).

Methods : Chinese residents (≥ 13 years old) who lived in Hong Kong for ≥ 3 years were invited to participate in this study in between September 2021 to April 2023, through open advertisement. The temperature and humidity of the examination room were controlled at 23-25oC and approximately 50%, respectively. Measurements were performed after 10 minutes of adaptation in the room. The examination procedures and diagnosis of DED were strictly following the TFOS DEWS II Diagnostic methodology report. Ocular Surface Disease Index (OSDI) and 5-Item Dry Eye questionnaires were performed using Qualtrics XM platform. Non-invasive tear breakup time (NITBUT) and tear meniscus height (TMH) (Keratograph 5M, Oculus), lipid layer thickness (IDRA, SBM), schirmer test, tear osmoloarity (TearLab), and ocular surface integrity (slit lamp examination) were examined. Subjects diagnosed with DED must have an OSDI score ≥ 13 and any of the following in either eye: a) TBUT < 10 s; b) osmolarity ≥ 308 or between-eye difference > 8; c) positive ocular surface (corneal and conjunctival) desiccations.

Results : 617 (73% female) subjects aged 13-88 years old (mean 46 years) were enrolled, with 59% TFOS defined DED. The percentages of DED that were similar across all age groups. When analyzing by individual eyes, 271 eyes (44%) were defined with DED when only the right eyes were chosen. The DED eyes had significantly higher OSDI (27.27 vs 8.51, p < 0.001) and DEQ-5 (9.23 vs 5.36, p < 0.001) scores, shorter first (8.50 vs 10.08 s, p < 0.001) and average (11.48 vs 12.59, p = 0.009) NITBUT, and higher osmolarity score (302.97 vs 299.71, p = 0.01), compared to the non-DED eyes. Other parameters, including TMH, lipid layer thickness, and schirmer test, did not show significant differences between DED and non-DED eyes.

Conclusions : This large-scale study revealed a higher prevalence (59%) of DED in Hong Kong population, compared to western countries. The eyes diagnosed with DED using TFOS criteria showed a higher osmolarity and shorter NITBUT.