Comparison of Ocular Surface and Tear Film Parameters in Smokers versus Non-Smokers in Palestine

ABSTRACT Background Smoking is a significant global public health challenge, strongly associated with the rise of noncommunicable diseases and preventable deaths, particularly in conflict zones like Gaza. Aim To compare the different types of dry eye disease between smokers and non-smokers. Methods This cross-sectional study included 426 participants. Using a proportional stratified sampling approach, 80 participants were identified as smokers, which began in March 2022. An age- and gender-matched control group consisting of 80 participants was included for comparative analysis. Dry eye symptoms were assessed using the Arab-Ocular Surface Disease Index (Arab-OSDI) alongside several clinical tests. Dry eye was defined by an Arab-OSDI score of ≥ 13 and at least one positive clinical sign. Results Smokers had an average Arab-OSDI score of 17.09 ± 16.21 compared to 10.58 ± 10.65 in the control group (p = 0.046). The three ocular surface signs demonstrated statistically significant correlations in the expected directions (TBUT–STT: r ≈ 0.28; TBUT–CFS: r ≈ −0.24; STT–CFS: r ≈ −0.14; all p < 0.01). These inter-correlations were anticipated given the physiological relationships among the measures, and they were appropriately accounted for within the analytical model; therefore, they did not influence or confound the model estimates. Mild dry eye was observed in 13.6% of smokers and 7.4% of controls, while severe dry eye was present in 9.9% of smokers and 2.5% of controls. The overall frequency of dry eye was higher in smokers (25.9%) than in controls (11.1%) (p = 0.014). Aqueous deficient dry eye (ADDE) was more common among smokers (19.8%) compared to controls (8.6%; p = 0.041), as was mixed dry eye (p = 0.034). Conclusion Smokers exhibit a higher frequency of dry eye, with significantly elevated Arab-OSDI scores and higher incidences of ADDE and mixed dry eye associated with smoking.