Comparison of early changes in ocular surface markers and tear inflammatory mediators after femtosecond lenticule extraction and FS-LASIK

AIM:To compare the short-term impacts of femtosecond lenticule extraction(FLEx)and femtosecond laser-assisted laser in situ keratomileusis(FS-LASIK)on ocular surface measures and tear inflammatory mediators.METHODS:This prospective comparative nonrandomized clinical study comprised 75 eyes(75 patients).Totally 20 male and 15 female patients(age 21.62±3.25 y)with 35 eyes underwent FLEx,and 26 male and 14 female patients(age 20.18±3.59 y)with 40 eyes underwent FS-LASIK.Central corneal sensitivity,noninvasive tear breakup time,corneal fluorescein staining,Schirmer I test,tear meniscus height,and ocular surface disease index were evaluated in all patients.Tear concentrations of nerve growth factor(NGF),interleukin-1α(IL-1α),transforming growth factor-β1(TGF-β1),tumor necrosis factor-α(TNF-α),interferon-γ(IFN-γ),and matrix metalloproteinase-9(MMP-9)were assessed by multiplex antibody microarray.All measurements were performed preoperatively,and 1 d,1 wk,and 1 mo postoperatively.RESULTS:Patients who underwent FLEx exhibited a more moderate reduction in central corneal sensation and less corneal fluorescein staining than those in the FS-LASIK group 1 wk after the procedure(P<0.01).NGF was significantly higher 1 d and 1 wk after surgery in the FS-LASIK group than in the FLEx group(P<0.01).By contrast,compared to those in the FLEx group,higher postoperative values and slower recovery of tear TGF-β1,IL-1α,and TNF-αconcentrations were observed in the FS-LASIK group(P<0.01).Tear concentrations of NGF,TGF-β1,TNF-α,and IL-1αwere correlated with ocular surface changes after FLEx or FS-LASIK surgery.CONCLUSION:There is less early ocular surface disruption and a reduced inflammatory response after FLEx than after FS-LASIK.NGF,TGF-β1,TNF-α,and IL-1αmay contribute to the process of ocular surface recovery.

Corneal flap morphological analysis using anterior segment optical coherence tomography in laser in situ keratomileusis with femtosecond lasers versus mechanical microkeratome

AIM: To assess and compare the flap morphology using anterior segment optical coherence tomography (AS-OCT) in laser in situ keratomileusis (LASIK) with Femto LDV femtosecond lasers versus Hansatome mechanical Microkeratome. METHODS: AS-OCT (Visante) was used to compare 1 month postoperatively the morphology of the flaps created with Femto LDV femtosecond lasers or Hansatome Microkeratome. The intendedfiap thickness was 110 mu m and 160 mu m respectively. The thickness of twenty-five points across each flap, which were 0mm, 1.5mm, 2.5mm, and 3.5mm to the corneal vertex on the horizontal, vertical, 45 degrees and 135 degrees meridian respectively, was evaluated. RESULTS: One month postoperative, the central flap thickness in the Femto LDV group was 107.43 +/- 4.70 mu m, while 125.90 +/- 17.50 mu m in the Hansatome group. The difference between the actual and the expectedfiap thickness was 5.61 +/- 3.84 mu m and 31.52 +/- 12.27 mu m, respectively. The Hansatome group had presented a statistically significant result (P<0.001). Flap morphology showed a more regular planar shape in the Femto LDV group and a meniscus shape in the Hansatome group. CONCLUSION: AS-OCT is a direct and fast procedure to assess the flap morphology. The morphology by AS-OCT showed that the flaps created with Femto LDV femtosecond laser were more accurate and regular than the flaps created with Hansatome microkeratome.