Impact of Environmental Exposure on Ocular Surface Balance: A Comparative Study.

Abstract

Purpose: Environmental factors such as high temperatures, low humidity, ultraviolet radiation, wind, and dust can harm ocular surface health, increasing dry eye disease risk, especially in harsh climates like central Saudi Arabia. Thus, the purpose of this study is to investigate the impact of outdoor environmental exposure on ocular surface stability by comparing ocular surface parameters between participants exposed to harsh outdoor conditions and those in indoor environments in central Saudi Arabia.

Patients and methods: A cross-sectional study was conducted in May 2024 with 40 male participants divided equally into two groups: those exposed to outdoor environments and those in indoor settings. Clinical assessments included Non-Invasive Keratographic Break-Up Time (NIKBUT) to evaluate tear film stability, lipid layer thickness measurement, meibomian gland evaluation using meiboscore and gland expressibility, Tear Meniscus Height (TMH), conjunctival redness grading, and the Ocular Surface Disease Index (OSDI) questionnaire. Data were analysed to identify the differences between the groups; a P-value less than 0.05 was considered statistically significant.

Results: Participants exposed to outdoor environments exhibited significantly shorter NIKBUT (12.35± ± 6.76 seconds) compared to indoor participants (18.50± ± 8.54 seconds), P = 0.016, indicating increased tear film instability. The outdoor group had higher lipid layer thickness (1.60± ± 0.50 units; P < 0.009), greater meiboscores (1.25± ± 0.44; P < 0.010), and increased conjunctival redness scores compared to those in indoor environments (P = 0.016). No significant differences were observed in TMH or meibomian gland expressibility between the groups. Although OSDI scores were higher in the outdoor-exposed group, this difference did not reach statistical significance.

Conclusion: Exposure to harsh outdoor environments adversely affects ocular surface health, increasing the risk of dry eye disease among individuals in central Saudi Arabia. Implementing protective measures like UV-protective eyewear and regular eye examinations can help mitigate these effects.