ABSTRACT Objective The purpose of this study was to assess the levels of interleukin‐6 (IL‐6) and tumour necrosis factor‐alpha (TNF‐α) in the tears and serum of patients with age‐related macular degeneration, as well as to identify the factors associated with IL‐6 and TNF‐α levels in tears. Methods This was a comparative, cross‐sectional study involving age‐related macular degeneration patients and a control group. Tear samples were collected using Schirmer paper strips, while 3 mL of blood was obtained from each patient. IL‐6 and TNF‐α levels in tears and serum were measured using a commercial human enzyme‐linked immunosorbent assay (ELISA) kit. The study analysed the effects of duration of age‐related macular degeneration, disease stage, and smoking status on IL‐6 and TNF‐α levels in tears, aiming to determine their associations. Results A total of 142 patients were recruited for this study, including 56 patients with early age‐related macular degeneration, 56 patients with late neovascular age‐related macular degeneration, and 30 patients in the control group. Age‐related macular degeneration patients exhibited significantly higher mean levels of IL‐6 in both tears and serum, as well as TNF‐α in serum, compared to the control group, both before and after adjusting for covariates (21.97 ± 10.95 vs. 16.06 ± 10.00 pg/mL, p = 0.008 and p = 0.014; 12.00 ± 6.04 vs. 8.53 ± 4.13 pg/mL, p = 0.004 and p = 0.004; 18.58 ± 7.90 vs. 13.61 ± 4.86 pg/mL, p = 0.001 and p = 0.004, respectively). Within the age‐related macular degeneration group, the mean IL‐6 level in serum was significantly higher in patients with late neovascular age‐related macular degeneration compared to those with early age‐related macular degeneration (13.89 ± 6.08 vs. 10.11 ± 5.41 pg/mL, p = 0.001). The levels of IL‐6 and TNF‐α in tears were not associated with the duration of age‐related macular degeneration, the stages of age‐related macular degeneration, or smoking status. Conclusion There are significantly higher levels of IL‐6 in both tears and serum, whereas tears and serum TNF‐α serve as non‐specific biomarkers for age‐related macular degeneration. This study could serve as a basis for future research.
Rosli et al. (Tue,) studied this question.