Clinical Research Of Femtossecond Lasser Cataraact Surgery

Objective: To investigate the safety and effectiveness of femtosecond laser-assisted cataract surgery and femtosecond laser corneal relaxing incisions(CRI) in reducing corneal astigmatism during cataract surgery.Methods:Eighty-seven patients(114 eyes) were enrolled in the study between December 2013 and May 2014 in Shanxi Eye Hospital. Forty-four patients(60 eyes) underwent femtosecond laser-assisted cataract surgery. Forty-three patients(54 eyes) underwent 2.2mm coaxial microincision cataract surgery. Intraoperative complication rates and phaco energy parameters were recorded. Visual acuity, central corneal thickness and cornea endothelial cell loss was analyzed between groups. In 27 eyes of 27 patients undergoing femtosecond laser cataract surgery(femto group), aqueous humor of 100 μl was collected after laser treatment. In 15 eyes of 15 subjects undergoing routine cataract surgery(control group), aqueous humor of 100 μl was also collected. The Human Interleukin 1β ELISA Kit, Human Interleukin 6ELISA Kit, and Human Prostaglandin E2 ELISA Kit were used to determine the concentrations of IL-1β, IL-6 and PGE2 in the aqueous humor. IOP of 32 patients(39 eyes) were measured using a rebound tonometer(i Care PRO) at different time points(at baseline before the suction application and 30 seconds up to 10 minutes after the suction ring and corneal contact lens were removed). Using the Len Sx laser, in 48 eyes, CRIs were placed at diameter of 8 mm with a depth of 90%. The length of CRI was determined based on the AMO LRI calculator. Corneal astigmatism was measured before and 1 and 3 months after the surgery. Vector analyses were performed. The with-the-wound(WTW) and again-the-wound(ATW) changes were calculated along the meridian of the relaxing incisions.Results:U/S Total Time and cumulative dissipated energy(CDE) were reduced dramatically compared to conventional cataract surgery group(P=0.007; P=0.003) In the femtosecond laser-assisted cataract surgery group, 78.33% incision was easily to be opened, the rest of them needed extra effort to open. 93.33% of the capsule buttons were free floating and 6.67% were incomplete and a manual capsulorrhexis was required to complete the capsulotomy. For IL-1β, IL-6, and PGE2, respectively, the mean concentration values in aqueous humor were 25.6 pg/ml, 24.6pg/ml, and 64.2 pg/ml in the femto group, and 17.1 pg/ml, 15.2pg/ml, and 45.7 pg/ml in the control group Concentrations of IL-1β,IL-6, and PGE2 were significantly higher in the femto group than those in the control group(all P<0.01). There were no significant correlations between concentrations of IL-1β, IL-6, or PGE2 and age, cataract densities, suction time, or laser time(all P>0.05). The mean baseline IOP was 18.09 ± 2.91 mm Hg before suction was applied. Mean IOP values following the suction ring removal was higher at 30 seconds(21.61± 10.55 mm Hg(P=0.188)) than baseline, although this did not reach statistical significance. The IOP decreased to 17.34 ± 5.50 mm Hg at 1 minute(P=0.351) and 16.80 ± 5.55 mm Hg at 2 minutes(P=0.028), returned to the baseline IOP level at 3 minutes and remained constant up to 10 minutes(all P>0.05). At postoperative 1 and 3 months, respectively, the mean keratometric astigmatism was reduced significantly from 1.42 ± 0.43 D to 0.79 ± 0.39 D and 0.78 ± 0.38 D(both P<0.05). Compared to preoperative corneal astigmatism, percentages of eyes within 0.5 D of corneal astigmatism significantly increased from 2% to 50% at 3 months postoperatively. At 1 month and3 months postoperatively, SIA was 1.14 ± 0.63 D and 1.05 ± 0.56 D; EM was 0.30 ± 0.50 D and 0.42 ± 0.46 D; CI was 0.78 ± 0.38 and 0.72 ± 0.32; ER was 0.60 ± 0.34 and 0.57 ± 0.32 respectively. AE was 1.67 ± 29.84°(-80.78° ~ 89.77°)at 1 month;AE was 2.14 ± 18.24°(-41.80°~47.73°)at 3 months。SIA was 1.25 ± 0.58 D of ATR group, which was bigger than 0.86 ± 0.50 D of WTR group at 3 months. The mean value of DV、ER and ME was smaller in ATR group. CI of ATR group was 0.83 ± 0.25, which was bigger than 0.57 ± 0.30 in WTR group. The depth of CRIs was 78.6% and 78.9% at 1 month and 3 months postoperatively, which was smaller than 90%.Conclusions:Femtosecond laser capsulotomy and lens fragmentation reduce ultrasound usage over conventional surgery significantly. The new surgery appears to be more safe and efficient compared to conventional cataract surgery in short term postoperatively. Inflammatory cytokines IL-1β, IL-6, and prostaglandin E2 significantly increased after femtosecond laser cataract surgery, the reason should be studied in the future. Femtosecond laser pretreatment with the curved applanation patient interface appeared to be safe and well tolerated. But the fluctuations of intraocular pressure was noticed after the suction. Whether or not the fluctuations of IOP will have the influence on the cataract patients who has the myopia or intraocular hypertension should be observed in a long term. Femtosecond laser CRIs were effective in reducing corneal astigmatism during cataract surgery. A nomogram is proposed. The long-term effect of femtosecond laser CRIs should be evaluated.