A Multimodal Analysis of Serum and Tear Crystallization Patterns in Patients with Obesity

Objectives: The study examined tear and serum alterations using the ferning test and quantified the number of branches formed during the controlled drying of these biological fluids (tears and serum), in order to identify a potential diagnostic patterning test in individuals with obesity. Methods: A total of 61 patients aged between 25 and 72 years were enrolled (median age [interquartile range] = 39.0 [26] years). BMI values ranged from 19.1 to 47.5 kg/m², with a median BMI (interquartile range) of 29.3 (12.1) kg/m². Results: The Kruskal-Wallis test showed statistically significant differences among at least two Schirmer classes with respect to the number of branches observed in dried tears at a brightness threshold of 220 (H(2) = 8.485, p = 0.014). According to the Dunn post hoc test, Schirmer Class 1 showed a markedly lower number of branches compared with Classes 2 and 3 (p < 0.031 and p < 0.021), whereas no significant difference was found between Classes 2 and 3. The Kruskal-Wallis test further suggested the presence of statistically significant differences in the number of branches in dried serum, quantified using ImageJ2 at a brightness threshold of 190, across visceral fat classes (H(2) = 9.583, p = 0.008). Dunn's post hoc tests revealed that the number of branches in serum analyzed at a brightness threshold of 190 was significantly higher in visceral fat class 3 compared to class 1 (p_holm = 0.006), while no statistically significant differences were observed between classes 1 and 2 or between classes 2 and 3 (p_holm > 0.05). Conclusions: In addition to other obesity-specific complications patients with obesity exhibit an increased risk of developing dry eye syndrome. The combined assessment of DPT in both the tear film and serum may represent a new method for analyzing obesity-associated biomarkers. Further studies are required to determine the sensitivity and specificity of these approaches in diagnosing systemic alterations induced by excess adipose tissue.