Inflammatory and Anti-Inflammatory Response of the Ocular Surface After Excimer Laser Treatment

Background/Objectives: The goal of this study was to show the consistency between the inflammatory and anti-inflammatory response in the early postoperative period after corneal refractive surgery (LASIK and PRK), represented by the levels of specific cytokines in the tear film. Materials/Methods: A total of 68 myopic eyes (31 in the LASIK and 37 in the PRK group) had 3 samples of tear film taken, one before surgery (t₀), another 1 h after surgery (t₁) and the third 24 h after surgery (t₂). The tear samples were then analyzed by flow cytometry in order to determine the levels of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, IFN-γ, TNF-α) and the levels of anti-inflammatory cytokines (IL-4, IL-10). Results: A statistically significant positive correlation was found between the concentrations of all pro-inflammatory cytokines (IL-1β, IL-6, IL-8, IFN-γ, TNF-α) and all anti-inflammatory cytokines (IL-4, IL-10), respectively, for both t₁ and t₂ in the group of eyes that underwent LASIK. In the PRK group, there was a statistically significant positive correlation for all cytokines (pro-inflammatory and anti-inflammatory) at t₁; however at t_2, there was no correlation between IL-1β and IL-10, IL-6 and IL-10, IL-8 and IL-10, and IFN-γ and IL-10. In contrast, for other correlations between pro-inflammatory and anti-inflammatory cytokines in the same observation time (t₂), a positive correlation was observed. Conclusions: There is a consistency between the inflammatory and anti-inflammatory responses in the early postoperative period after refractive surgery, which persists longer after LASIK compared to PRK. This difference may explain the different clinical courses in patients after undergoing these procedures.