The acute phase of inflammatory response involved in the wound-healing process after excimer laser treatment.
OBJECTIVE
To evaluate the participation of proinflammatory cytokines in the acute phase of corneal wound-healing response after excimer laser treatment.


METHODS
The study included 68 myopic eyes up to -3.0 diopters divided into two groups: 1) eyes treated with laser in situ keratomileusis (LASIK) (n=31) and 2) eyes treated with photorefractive keratectomy (PRK) (n=37). Each group was then divided into three subgroups based on tear sampling times: before (0 hours), 1 hour after, and 24 hours after treatment. The tear fluid was sampled from lower lateral tear meniscus using a cellulose microsurgical sponge. The levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-8 in tear fluid were determined by flow cytometry method.


RESULTS
Statistical significance was observed in the concentrations of TNF-α (P=0.0421) and IL-1β (P=0.0225) between samples collected 1 and 24 hours after PRK treatment in favor of samples collected 1 hour after treatment. IL-6 concentration changes showed a significant increase in the PRK group in both time intervals following treatment compared to pretreatment (0 hour/1 hour, P=0.0031; 0 hour/24 hours, P=0.0059). For IL-8 concentrations, significant differences were observed between control and experimental groups in samples collected 1 hour after LASIK and 1 hour after PRK treatment (P<0.001 for both groups), and IL-8 concentrations between control and experimental groups in samples collected 24 hours after LASIK and 24 hours after PRK treatment were greater after PRK treatment (P=0.0005). Comparison of average concentration values of proinflammatory cytokines in all the tested samples between LASIK and PRK groups showed significantly higher levels of IL-1β in the LASIK group 24 hours after treatment (P=0.0134), and of IL-6 in the PRK group 24 hours after treatment (P=0.0031).


CONCLUSIONS
The acute phase of corneal wound healing after excimer laser treatment is defined by an intensive inflammatory response. After PRK treatment, there were increased concentrations of TNF-α and IL-1β in tear samples 1 hour after treatment, IL-6, 1 and 24 hours after treatment, and IL-8, 1 and 24 hours after treatment. After LASIK treatment, there were increased concentrations of IL-8 in tear samples 1 hour after treatment and IL-1β, 24 hours after treatment. Both PRK and LASIK methods are characterized with a significant inflammatory response. However, tear findings following PRK method showed more intensive inflammatory response than the findings after LASIK method.
Eye Clinic, Military Medical Academy, Belgrade, Serbia; Faculty of Medicine of the Military Medical Academy, University of Defense, Belgrade, Serbia.
Mirko
M
Resan
Eye Clinic, Military Medical Academy, Belgrade, Serbia; Faculty of Medicine of the Military Medical Academy, University of Defense, Belgrade, Serbia.
Miroslav
M
Vukosavljevic
Faculty of Medicine of the Military Medical Academy, University of Defense, Belgrade, Serbia; Department for Clinical and Experimental Immunology, Institute for Medical Research, Military Medical Academy, Belgrade, Serbia.
Danilo
D
Vojvodic
Eye Clinic ORASIS, Swiss Eye Research Foundation, Reinach AG, Switzerland.
Brigitte
B
Pajic-Eggspuehler
Faculty of Medicine of the Military Medical Academy, University of Defense, Belgrade, Serbia; Eye Clinic ORASIS, Swiss Eye Research Foundation, Reinach AG, Switzerland; Department of Physics, Faculty of Science, University of Novi Sad, Novi Sad, Serbia; Division of Ophthalmology, Department of Clinical Neurosciences, University Hospitals of Geneva, Switzerland.
Bojan
B
Pajic
LASIK; PRK; proinflammatory cytokines; tears; wound healing