Comparison of Tear Cytokines and Clinical Outcomes Between Off-flap and On-flap Epi-LASIK With Mitomycin C

Department of Ophthalmology, Peking University Third Hospital, Beijing, China.
Journal of refractive surgery (Thorofare, N.J.: 1995) (Impact Factor: 3.47). 09/2012; 28(9):632-8. DOI: 10.3928/1081597X-20120815-01
Source: PubMed


To compare tear cytokines and clinical outcomes between off-flap and on-flap epi-LASIK eyes and explore the possible mechanism for the clinical differences.
This double-masked, randomized study enrolled 18 myopic patients who underwent off-flap epi-LASIK with mitomycin C (MMC) in 1 eye and on-flap epi-LASIK with MMC in the contralateral eye. Tears were collected from each eye preoperatively and 2 hours, 1 day, and 5 days postoperatively. Concentrations of multiple tear cytokines were measured by a multiplex immunobead assay. Uncorrected distance visual acuity (UDVA), refraction, haze scores, pain scores, and percentage of corneal epithelial healing were evaluated.
Compared with the on-flap group, the off-flap group had outcomes of better UDVA and higher percentages of epithelial healing at 5 days after surgery (P<.001) and lower levels of haze at 1 month after surgery (P=.049). Preoperatively, no significant differences were noted in the release rate of all tear cytokines between groups. At 2 hours postoperatively, the release rate of tear basic fibroblast growth factor (bFGF), platelet-derived growth factor-BB (PDGF-BB), interleukin-8 (IL-8), and tumor necrosis factor alpha (TNF-α) in the off-flap group were significantly lower than those in the on-flap group (P=.011, .017, .048, and .041, respectively).
Off-flap epi-LASIK with MMC offers faster corneal epithelial healing and visual recovery, and temporary less haze than on-flap epi-LASIK with MMC. The lower tear levels of bFGF, PDGF-BB, IL-8, and TNF-α in the offflap group 2 hours after surgery may suggest a possible mechanism for the clinical differences.

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