Comparison of the IntraLase femtosecond laser and mechanical keratomes for laser in situ keratomileusis

PURPOSE: To compare laser in situ keratomileusis (LASIK) results obtained with the femtosecond laser (IntraLase Corp.) to those obtained using 2 popular mechanical microkeratomes. SETTING: Private practice, Greensboro, North Carolina, USA. METHODS: This retrospective analysis compared LASIK outcomes with the femtosecond laser to those with the Carriazo-Barraquer (CB) microkeratome (Moria, Inc.) and the Hansatome microkeratome (Bausch & Lomb, Inc.). The 3 groups were matched for enrollment criteria and were operated on under similar conditions by the same surgeon. RESULTS: There were 106 eyes in the IntraLase group, 126 eyes in the CB group, and 143 eyes in the Hansatome group. One day postoperatively, the uncorrected visual acuity (UCVA) results in the 3 groups were similar; at 3 months, the UCVA and the best spectacle-corrected visual acuity results were not significantly different. A manifest spheroequivalent of +/-0.50 diopter (D) was achieved in 91% of eyes in the IntraLase group, 73% of eyes in the CB group, and 74% of eyes in the Hansatome group (P<.01). IntraLase flaps were significantly thinner (P<.01) and varied less in thickness (P<.01) than flaps created with the other devices. The mean flap thickness was 114 microm +/- 14 (SD) with the IntraLase programmed for a 130 microm depth, 153 +/- 26 microm with the CB using a 130 microm plate, and 156 +/- 29 microm with the Hansatome using a 180 microm plate. Loose epithelium was encountered in 9.6% of eyes in the CB group and 7.7% of eyes in the Hansatome group but in no eye in the IntraLase group (P =.001). Surgically induced astigmatism in sphere corrections was significantly less with the IntraLase than with the other devices (P<.01). CONCLUSIONS: The IntraLase demonstrated more predictable flap thickness, better astigmatic neutrality, and decreased epithelial injury than 2 popular mechanical microkeratomes.     

Randomized prospective clinical study comparing induced aberrations with IntraLase and Hansatome flap creation in fellow eyes: potential impact on wavefront-guided laser in situ keratomileusis

PURPOSE: To measure and compare the changes in objective wavefront aberration and subjective manifest refraction after laser in situ keratomileusis (LASIK) flap creation with a mechanical microkeratome and a femtosecond laser. SETTING: Private practice refractive surgery center, Irvine, California, USA. METHODS: This randomized prospective study comprised 9 patients (18 eyes) treated with a 2-step LASIK procedure: lamellar keratectomy with a Hansatome microkeratome (Bausch & Lomb) or the IntraLase femtosecond laser in fellow eyes followed by non-wavefront-guided (standard) excimer laser treatment with the Technolas 217A (Bausch & Lomb) excimer laser 10 weeks later. Fellow eyes were matched to within 0.75 diopter (D) sphere and 0.50 D cylinder. Patients were followed for 3 months after excimer laser treatment. Preoperative and post-flap creation wavefront aberrometry using a Hartmann-Shack aberrometer and manifest refraction were compared between the 2 groups. The same tests were performed 3 months after excimer laser ablation. RESULTS: Statistically significant changes were seen in defocus wavefront aberrations after Hansatome (P=.004) and IntraLase (P=.008) flap creation. A hyperopic shift in manifest refraction was noted in the Hansatome group after the creation of the corneal flap (P=.04); no statistically significant changes in manifest refraction were seen in the IntraLase group. Statistically significant changes in total higher-order aberrations (HOAs) (trefoil and quadrafoil Zernike terms) were seen after flap creation in the Hansatome group (P=.02). No significant changes in HOAs were noted after flap creation in the IntraLase group. After the flap was relifted and standard excimer laser ablation was performed, a statistically significant increase in coma occurred in the Hansatome group (P=.008). Standard refractive outcomes in the 2 groups were similar. CONCLUSIONS: The creation of the LASIK flap alone can modify the eye's optical characteristics in low-order aberrations and HOAs. A significant increase in HOAs was seen in the Hansatome group but not in the IntraLase group. This may have significant clinical implications in wavefront-guided LASIK treatments, which are based on measurements made before flap creation.     

Wavefront-guided ablation with Bausch and Lomb Zyoptix for retreatments after laser in situ keratomileusis for myopia

PURPOSE: To evaluate the efficacy of wavefront-guided ablation for treatment of residual refractive error and higher order aberrations after laser in situ keratomileusis (LASIK) for myopia. METHODS: Twenty-one eyes of 13 patients with residual refractive error after myopic LASIK were treated with a wavefront-guided ablation with the Zyoptix technique. In 13 eyes of 8 patients (Group A) we lifted the flap with an epitheliorhexis technique; in 8 eyes of 5 patients (Group B) we cut a new flap with a Hansatome microkeratome. RESULTS: Preoperative root mean square (RMS) values were 1.370 for second order aberrations, 0.382 for total higher order aberrations, 0.273 for third order, 0.243 for fourth order, and 0.052 for fifth order aberrations. Three months postoperatively, RMS values decreased significantly to 0.278 (second order), 0.189 (total higher order), 0.138 (third order), 0.107 (fourth order), and 0.038 (fifth order). Ablation depth was two times greater than needed with a standard Planoscan treatment. Patients in the microkeratome recut group showed a trend toward overcorrection, and residual astigmatism was higher (-0.75 +/- 0.58 D) than in the flap lift group (-0.25 +/- 0.29 D). CONCLUSIONS: Wavefront-guided ablation was an effective method to correct residual refractive error and higher order aberrations after myopic LASIK. Functional and refractive outcomes were better when we lifted the flap than when we recut the flap.     

Measurement of corneal curvature change after mechanical laser in situ keratomileusis flap creation and femtosecond laser flap creation

PURPOSE: To compare the change in corneal curvature from the predicted surgical radius (sculpted in the corneal stroma) and the measured postoperative radius of the first surface of the cornea after laser in situ keratomileusis (LASIK) for myopia correction using 2 methods of flap creation: mechanical microkeratome and femtosecond laser. SETTING: Vissum-Instituto Oftalmológico de Alicante, Alicante, Spain. METHODS: This retrospective consecutive nonrandomized comparative interventional case series included 85 eyes with myopia or myopic astigmatism treated using the Esiris excimer laser (Schwind). Patients were divided into 2 groups. One group had LASIK with an M2 microkeratome (Moria) (mechanical LASIK group) and the other, with a femtosecond laser (IntraLase FS, IntraLase Corp.) (femtosecond LASIK group). The relationship between the postsurgical corneal radius and the predicted sculpted radius as well as the mean value of the percentage change in the curvature radius were analyzed to obtain the effect on the refractive defect in each group. RESULTS: There were 44 eyes in the mechanical LASIK group and 41 eyes in the femtosecond LASIK group. A high correlation was found between the final corneal radius and the predicted sculpted radius in both groups (r(2) = 0.85). The mean percentage change in the curvature radius was -3.6% in the mechanical LASIK group and -1.6% in the femtosecond LASIK group (P<.001). The mean estimated refractive change was 1.2 diopters (D) and 0.8 D, respectively. CONCLUSIONS: The refractive change in corneal curvature, which related to the biomechanical response of the corneal surface after the flap cut and repositioning, was lower after femtosecond laser LASIK than after LASIK performed using a mechanical microkeratome. Estimations of refractive change induced by this response should be taken into account in surgery design.     

Wavefront analysis comparison of LASIK outcomes with the femtosecond laser and mechanical microkeratomes

PURPOSE: To evaluate differences related to ocular aberrations after customized LASIK for myopia using three different microkeratomes. METHODS: Charts of 410 patients who underwent customized LASIK with the Alcon LADARVision4000 excimer laser were reviewed. Patients were stratified according to the device used to create the flap: Moria M2 microkeratome, Bausch & Lomb Hansatome microkeratome, or IntraLase laser. The difference between the wavefront pre- and postoperative value received a positive or a negative sign if the change occurred toward or away from zero, respectively, and it was compared to preoperative minus postoperative manifest refraction spherical equivalent (MRSE). RESULTS: Patients showed increase in the aberration level after LASIK with the three devices used in this study. IntraLase spherical aberration change tended to be better than mechanical microkeratomes for higher MRSE values (IntraLase compared to Hansatome, P < or = .023 for MRSE values > or = 4.00 diopters [D]; IntraLase compared to Moria, P < or = .015 for MRSE values > or = 2.00 D). For total aberrations, the improvement values for IntraLase tended to be higher than those for Moria (IntraLase compared to Moria, P < or = .021 for MRSE values > or = 3.00 D). For total higher order aberrations, IntraLase values tended to be better than Moria and Hansatome microkeratomes (IntraLase compared to Hansatome, P < or = .047 for MRSE values between 3.00 and 8.00 D; IntraLase compared with Moria, P < or = .002 for MRSE values > or = 2.00 D). Change in coma root-mean-square was similar for the three groups. CONCLUSIONS: The findings suggest the femtosecond laser provides a better platform for LASIK than the commonly used microkeratomes analyzed in this study.     

Comparison of corneal aberration changes after laser in situ keratomileusis performed with mechanical microkeratome and IntraLase femtosecond laser: 1-year follow-up

PURPOSE: To compare corneal aberration changes 1 year after myopic laser in situ keratomileusis (LASIK) performed with a mechanical microkeratome and IntraLase femtosecond laser. METHODS: Twenty four eyes of 15 patients underwent LASIK with the Hansatome microkeratome, and 23 eyes of 13 patients underwent LASIK with the IntraLase femtosecond laser. A standard ablation was performed with the Bausch & Lomb Technolas 217 excimer laser. Topography data were used to calculate corneal aberrations with a 3.0 mm and 5.00 mm pupil, before and 12 months after surgery. The increasing factor (IF), defined as the ratio between the postoperative and preoperative mean value of the optical aberration, was calculated. The method of Mulhern et al was used to evaluate the centration of ablation. The comalike aberration was correlated with the decentration of ablation. The Student t test was used for the statistical anaylsis. RESULTS: The postoperative mean decentration of ablation was <0.5 mm. The comalike aberration appeared to be positively correlated with the decentration of ablation in both groups with a 5.0-mm pupil (P < 0.05). With a 3.00-mm pupil, the comalike aberration changed in the Hansatome group, whereas with a 5.00-mm pupil, all aberrations statistically significantly changed in both groups (P < 0.05). The IF similarly increased in 2 groups for spherical-like aberration, whereas IF greatly increased for total and comalike aberrations in the Hansatome group. CONCLUSIONS: Wavefront corneal aberrations change significantly 1 year after myopic LASIK performed with the Hansatome microkeratome as well as with IntraLase femtosecond lasers. Both of the procedures induce higher-order aberrations in the anterior corneal surface, but the amount of comalike aberration increases more with the Hansatome mechanical microkeratome.     

Bitoric laser in situ keratomileusis for astigmatism

PURPOSE: To evaluate the efficacy, predictability, and safety of bitoric laser in situ keratomileusis (LASIK) for the correction of mixed astigmatism. SETTING: Instituto Oftalmológico de Alicante, Alicante, Spain. METHODS: This prospective study included 28 eyes of 21 patients with mixed astigmatism who had bitoric LASIK using the Hansatome microkeratome (Bausch & Lomb Surgical) and the Chiron Technolas 217 excimer laser (Bausch & Lomb Surgical). The main outcome measures were uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), defocus equivalent, blur strength, and refraction. RESULTS: Six months after bitoric LASIK, the mean UCVA was 0.70 +/- 0.23 (SD). The percentage of eyes with a UCVA of 20/40 or better was 78.6% and of 20/20, 21.4%. There was a statistically significant increase in the mean BCVA from 0.71 +/- 0.19 before surgery to 0.83 +/- 0.15 at 6 months (P =.0004). Three eyes (10.7%) lost 1 line of BCVA; 19 eyes (67.9%) gained 1 or more lines. The mean preoperative astigmatism of -4.04 +/- 1.13 diopters (D) was reduced to -0.67 +/- 0.79 D after surgery. The defocus equivalent was less than 1.00 D in 75.0% of eyes and less than 0.50 D in 64.3%. Vector analysis showed that the mean achieved correction was 97.4% of the intended correction. CONCLUSIONS: Bitoric LASIK was a safe, effective, and predictable procedure in the treatment of mixed astigmatism. It is a means to improving BCVA in a significant percentage of patients.     

Evaluation of iris recognition system for wavefront-guided laser in situ keratomileusis for myopic astigmatism

PURPOSE: To evaluate the visual and refractive outcomes of wavefront-guided laser in situ keratomileusis (LASIK) using an iris recognition system for the correction of myopic astigmatism. SETTING: Centre for Eye Research Australia, Melbourne Excimer Laser Research Group, and Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia. METHODS: A comparative analysis of wavefront-guided LASIK was performed with an iris recognition system (iris recognition group) and without iris recognition (control group). The main parameters were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity, amount of residual cylinder, manifest spherical equivalent (SE), and the index of success using the Alpins method of astigmatism analysis 1 and 3 months postoperatively. A P value less than 0.05 was considered statistically significant. RESULTS: Preoperatively, the mean SE was -4.32 diopters (D) +/- 1.59 (SD) in the iris recognition group (100 eyes) and -4.55 +/- 1.87 D in the control group (98 eyes) (P = .84). At 3 months, the mean SE was -0.05 +/- 0.21 D and -0.20 +/- 0.40 D, respectively (P = .001), and an SE within +/-0.50 D of emmetropia was achieved in 92.0% and 85.7% of eyes, respectively (P = .07). At 3 months, the UCVA was 20/20 or better in 90.0% and 76.5% of eyes, respectively. A statistically significant difference in the amount of astigmatic correction was seen between the 2 groups (P = .00 and P = .01 at 1 and 3 months, respectively). The index of success was 98.0% in the iris recognition group and 81.6% in the control group (P = .03). CONCLUSION: Iris recognition software may achieve better visual and refractive outcomes in wavefront-guided LASIK for myopic astigmatism.     

First clinical experience with the Alcon LADAR 6000 excimer laser

PURPOSE: To evaluate the reliability and ergonomics and to assess the first clinical results provided by the new LADAR 6000 excimer laser used to correct myopia and astigmatism, both by conventional and wavefront-guided ablation. METHODS: Seventy-four consecutive eyes from 37 patients underwent LASIK as the first field evaluation protocol of the Alcon LADAR 6000 excimer laser. Forty-six eyes were treated by wavefront-guided ablation to correct a manifest spheroequivalent refractive error (MSRE) of -0.50 to -9.75 diopters (D) (mean: -4.19 D, cylinder range: 0.0 to -3.50 D). Twenty-eight eyes were treated by conventional ablation to correct MSRE of -1.00 to -7.00 D (mean: -3.11 D, cylinder range: 0.0 to -1.75 D). Uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), MSRE, and wavefront measurements were assessed. Follow-up was 3 months for all eyes. RESULTS: Three months after surgery, all eyes were within +/- 1.00 D of intended correction. Forty-three (93.5%) eyes treated with wavefront-guided ablation and 25 (89.3%) eyes treated with conventional ablation were within +/- 0.50 D. All eyes reached > or = 20/25 UCVA. UCVA > or = 20/20 was reached in 45 (97.8%) wavefront-guided eyes and 26 (92.9%) conventional eyes; 37 (80.4%) wavefront-guided eyes and 17 (60.7%) conventional eyes had 20/16 UCVA. None of the eyes treated lost > or = 2 lines of BSCVA. CONCLUSIONS: The LADAR 6000 excimer laser results proved to be at least as accurate, predictable, and safe as the results currently achieved with the LADARVision4000 excimer laser. The improved microscope illumination enhances visibility for better consistency and ease of use. The better ergonomics and software design of this platform improved patient flow.     

Prospective randomized trial of wavefront-guided laser in situ keratomileusis with the CustomCornea and CustomVue laser systems

PURPOSE: To compare visual function, safety, and higher-order aberrations (HOAs) after wavefront-guided laser in situ keratomileusis (LASIK) with the LadarVision CustomCornea (Alcon Laboratories, Inc.) and Star S4 CustomVue (Visx) laser systems. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Seventy-eight eyes of 39 patients with myopia with or without astigmatism were randomized for LASIK treatment in 1 eye with the CustomCornea laser; the other eye was treated with the CustomVue laser. Patients were followed for 6 months after surgery. The primary outcome measures were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and changes in HOAs. RESULTS: At 6 months, the mean logarithm of the minimum angle of resolution (logMAR) UCVA was -0.0135 +/- 0.07 (SD) in the CustomVue group and 0.0417 +/- 0.12 in the CustomCornea group (P = .023). Eighty-eight percent of eyes in the CustomVue group had 20/20 or better UCVA compared with 67% in the CustomCornea group (P<.02). At 6 months, 91% of eyes in the CustomVue group and 79% in the CustomCornea group were within +/-0.50 diopter (D) of emmetropia (P<.1); 88% and 50%, respectively, were within +/-0.25 D (P<.001). Both platforms led to a small increase in total HOAs. The CustomVue system reduced trefoil and induced less of an increase in total HOAs, whereas the CustomCornea platform increased trefoil but induced less of an increase in spherical aberrations and coma. CONCLUSIONS: Both laser systems were effective, safe, and predictable. Wavefront-guided LASIK with the CustomVue system resulted in better visual acuity, with more eyes having 20/20 acuity than in the CustomCornea group.     

Wavefront-guided laser in situ keratomileusis retreatment for consecutive hyperopia and compound hyperopic astigmatism

PURPOSE: To evaluate the efficacy, predictability, and safety of wavefront-guided laser in situ keratomileusis (LASIK) using the Visx CustomVue excimer laser (Advanced Medical Optics) in eyes with consecutive hyperopia and compound hyperopic astigmatism after LASIK. SETTING: Stanford University School of Medicine, Department of Ophthalmology, Stanford, California, USA. METHODS: This retrospective analysis included 19 eyes of 16 patients who had wavefront-guided LASIK for consecutive hyperopia and compound hyperopic astigmatism after initial LASIK surgery. Primary outcome variables, including uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), higher-order aberration (HOA) analysis, and spherical equivalence, were evaluated at 1 and 3 months. Nine eyes of 7 patients were available for all visits. RESULTS: The mean patient age was 51.7 years +/- 3.77 (SD) (range 44 to 55 years). The mean preoperative manifest refractive spherical equivalent (MRSE) was 0.99 +/- 0.32 diopters (D) (range 0.50 to 1.50 D) and the mean 3-month postoperative MRSE, -0.04 +/- 0.66 D (range -1.50 to 0.75 D). At 1 month, 57.9% of eyes had a UCVA of 20/20 or better and 78.9% of 20/25 or better; 84.2% were within +/-1.00 D of emmetropia. At 3 months, 66.7% of eyes had a UCVA of 20/20 or better and 88.9% of 20/25 or better; 88.9% were within +/-1.00 D of emmetropia. No eye lost 2 or more lines of BSCVA at 1 or 3 months. CONCLUSION: Wavefront-guided LASIK was an effective, predictable, and safe procedure for consecutive hyperopia and compound hyperopic astigmatism after LASIK.     

In vivo corneal confocal microscopy comparison of intralase femtosecond laser and mechanical microkeratome for laser in situ keratomileusis

PURPOSE: To assess and compare corneal modifications induced by IntraLase PulsionFS femtosecond laser and mechanical microkeratome Hansatome for laser in situ keratomileusis (LASIK) using the new-generation Heidelberg Retina Tomograph II (HRT II)/Rostock Cornea Module confocal microscope. METHODS: In this case-control study, 24 eyes of 12 patients were examined with the HRT II in the follow-up of IntraLase femtosecond laser for LASIK myopic surgery. Twenty eyes of 10 patients were also examined after microkeratome Hansatome-LASIK surgery. In both groups, the patients underwent the first follow-up examination on day 7 and the last 12 months after surgery. Morphologic modifications of corneal architecture were evaluated, and comparisons were made between the two flap-formation techniques. RESULTS: Evaluation of both groups on day 7 showed keratocyte transformation, most likely related to cellular activation beneath the interface. The flap margin after the IntraLase technique appeared microscopically as a clear-cut edge that included the epithelial plug. At month 2, secondary fibrosis, adjacent to the still well-defined IntraLase flap edge, was observed. This reaction diminished with time, leaving a fibrotic scar adjacent to a wound constriction originating from the surrounding stroma. The flap margin of the mechanical microkeratome had the appearance of a less clearly identified fibrotic scar with no epithelial plug. CONCLUSIONS: This study reveals morphologic similarities between the interfaces obtained by femtosecond laser and mechanical microkeratome, probably because the same excimer laser performed the photoablation. However, the IntraLase flap margin showed greater fibrotic scarring than that induced by the mechanical microkeratome.     

Comparison of Collamer toric implantable [corrected] contact lens implantation and wavefront-guided laser in situ keratomileusis for high myopic astigmatism

PURPOSE: To compare the postoperative visual outcomes after implantation of a Collamer toric implantable contact lens (ICL) and after wavefront-guided laser in situ keratomileusis in high myopic astigmatism. SETTING: Department of Ophthalmology, Kitasato University, Kanagawa, Japan. METHODS: This study comprised 30 eyes (18 patients) having toric ICL implantation and 24 eyes (17 patients) having wavefront-guided LASIK (Technolas 217z) to correct high myopic astigmatism (manifest spherical equivalent [SE] or=1.0 D). The safety, efficacy, predictability, stability, and adverse events were assessed preoperatively and 1 week and 1, 3, and 6 months postoperatively. RESULTS: At 6 months, the mean safety index was 1.28+/-0.25 (SD) in the ICL group and 1.01+/-0.16 in the LASIK group and the mean efficacy index, 0.87+/-0.15 and 0.83+/-0.23, respectively. All eyes in the ICL group and 71% of eyes in the LASIK group were within +/-1.00 D of the targeted SE correction at 6 months. The mean change in manifest refraction from 1 week to 6 months was -0.04+/-0.24 D in the ICL group and -0.60+/-0.49 D in the LASIK group. There were no significant complications in the ICL group; 2 eyes (8.3%) in the LASIK group required enhancement ablations. CONCLUSION: Toric ICL implantation was better than wavefront-guided LASIK in eyes with high myopic astigmatism in almost all measures of safety, efficacy, predictability, and stability, suggesting that toric ICL implantation may become a viable surgical option to treat high myopic astigmatism.     

Changes in the refractive index of the human corneal stroma during laser in situ keratomileusis. Effects of exposure time and method used to create the flap

PURPOSE: To compare the refractive index and calculated stromal bed hydration lifting the flap before and after photoablation during uneventful laser in situ keratomileusis (LASIK) using a microkeratome (M2, Moria) or a femtosecond laser (IntraLase, IntraLase Corp.) to create the flap. SETTING: Vissum-Instituto de Oftalmológico de Alicante, Alicante, Spain. METHODS: Uneventful LASIK was performed in 76 eyes of 49 patients. Flaps were created using a microkeratome (57 eyes) or a femtosecond laser (19 eyes). On lifting the flap, the refractive index of the stroma was measured using a customized manual Abbé refractometer. The measurement was repeated immediately after photoablation. Treatment time was noted. Hydration was calculated using the Fatt-Harris equation. RESULTS: Before LASIK, the mean refractive index was 1.366+/-0.0049 (SD) in the microkeratome group and 1.374+/-0.0047 in the femtosecond group. After LASIK, it was 1.382+/-0.0066 and 1.391+/-0.0102, respectively. The increase after ablation was statistically significant in both groups (P<.001). The increase in the refractive index linearly correlated with treatment time (microkeratome: r=0.355, P=.007; femtosecond, r=0.506, P=.027). Before photoablation, the refractive index was significantly lower in the microkeratome group than in the femtosecond group (P<.001). There was no significant difference in age between the 2 groups. CONCLUSIONS: Photoablation increased the refractive index of the stroma, and the increase was influenced by treatment time. Hydration of the stroma was 1.8 mgm/mgm greater in the microkeratome group than in the femtosecond laser group.     

Femtosecond laser in situ keratomileusis for consecutive hyperopia after radial keratotomy

PURPOSE: To assess the use of the femtosecond laser for laser in situ keratomileusis (LASIK) in eyes with consecutive hyperopia after radial keratotomy (RK). SETTING: Private ambulatory surgical center, Valencia, Spain. METHODS: This prospective noncomparative interventional case series study included 13 eyes of 9 patients with secondary hyperopia after previous RK. The patients were operated on with the IntraLase femtosecond laser (IntraLase Corp.) and the Star S2 excimer laser (Visx, Inc.). Postoperative uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, flap thickness, flap diameter, and complications were evaluated at 6 months. RESULTS: The mean spherical equivalent (SE) decreased from 2.00 diopters (D)+/-0.40 (SD) to -0.41+/-0.61 D, with 8 eyes (61.5%) within+/-0.50 D of the targeted refraction. Twelve eyes (92.3%) had a UCVA of 20/40 or better, and 3 eyes (23.1%) lost 1 line of BSCVA. A mean change in SE of 0.10 D was observed at the 6-month follow-up. The mean flap thickness and diameter were 117+/-14 microm and 9.18+/-0.12 mm, respectively. Most complications were in eyes with more than 8 RK incisions than in eyes with 8 RK incisions. These complications were multiple intraoperative incision openings (100% versus 28.6%, respectively), interface inflammation (66.6% versus 0%, respectively), haze (83.3% versus 14.3%, respectively), and loss of BSCVA (50% versus 0%, respectively). CONCLUSIONS: The femtosecond laser provided large, thin corneal flaps for hyperopic LASIK. However, the procedure should be avoided in eyes with more than 8 RK incisions because of the increased risk for multiple intraoperative incision openings, interface inflammation, haze, and loss of BSCVA.     

Femtosecond laser in situ keratomileusis after radial keratotomy

PURPOSE: To assess the safety, efficacy, and predictability of femtosecond laser in situ keratomileusis (LASIK) in eyes with previous radial keratotomy (RK). SETTING: Hospital Virgen del Consuelo de Valencia, Valencia, and Vissum Instituto Oftalmológico de Alicante, Alicante, Spain. METHODS: This prospective study comprised 11 eyes of 7 patients with residual low myopia after previous RK who had surgery with the IntraLase femtosecond laser (IntraLase Corp.) and the Star 2 excimer laser (Visx, Inc.). Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), defocus equivalent, refraction, flap thickness, flap diameter, and intraoperative complications were evaluated over a minimum 6-month follow-up. RESULTS: Although the RK incisions opened in all eyes when the flap was lifted, LASIK was successfully completed in all cases. Mean flap thickness was 119 microm +/- 13 (SD). There were no cases of slipped flaps, microstriae, or epithelial ingrowth. Defocus equivalent was reduced from a mean of 2.51 +/- 0.62 diopters (D) to 0.52 +/- 0.28 D; 7 eyes (63.6%) were within +/-0.50 D, and 11 eyes (100%) were within +/-1.00 D. All eyes had 20/40 or better UCVA, although 2 eyes (18.1%) lost 1 line of BSCVA. CONCLUSIONS: The femtosecond laser was safely used to create thin LASIK flaps in eyes with previous RK. An increased postoperative inflammatory response may explain the loss of BSCVA in some cases. Efficacy and predictability of the procedure were comparable to those of LASIK after RK with mechanical microkeratomes.     

Randomized comparison of custom laser in situ keratomileusis with the Alcon CustomCornea and the Bausch & Lomb Zyoptix systems: one-month results

PURPOSE: To compare the early visual results of custom laser in situ keratomileusis (LASIK) outcomes for two different excimer laser systems. METHODS: This is a preliminary report of an ongoing prospective study that evaluated 30 patients (60 eyes) who were randomized to one of two custom LASIK treatment groups: 15 patients (30 eyes) with the Alcon CustomCornea laser system (Alcon Laboratories Inc, Fort Worth, Tex) and 15 patients (30 eyes) with the Bausch & Lomb Zyoptix laser system (Bausch & Lomb, Rochester, NY). These matched patients were required to qualify for treatment with both custom laser systems. All flaps were created with the IntraLase femtosecond laser (IntraLase Corp, Irvine, Calif) using a superior hinge. Early outcome measures are uncorrected visual acuity (UCVA) at 1 day, 1 week, and 1 month postoperative; manifest refractions at 1-month follow-up; and a comparison of 1-month postoperative UCVA to preoperative best spectacle-corrected visual acuity (BSCVA). Wavefront, topography, contrast sensitivity, and subjective questionnaires were also performed and will be reported after 3-month follow-up. RESULTS: At 1 month, the percentage of eyes with UCVA of 20/20 and 20/40 were similar with 93% and 100%, respectively, for CustomCornea eyes and 90% and 97%, respectively, for Zyoptix eyes. A difference between the two groups is in the percentage of eyes with UCVA of 20/16, 20/12.5, and 20/10 with 80%, 47%, and 13%, respectively, for CustomCornea and 70%, 10%, and 0%, respectively, for Zyoptix. The mean residual spherical equivalent refraction was +0.01 +/- 0.34 diopters (D) for CustomCornea and -0.04 +/- 0.38 D for Zyoptix. The two groups are similar at +/-1.00 D of intended correction, with CustomCornea 100% and Zyoptix 97%. However, +/-0.25 D the CustomCornea group was 10% more accurate at 73% versus 63% for the Zyoptix group. The efficiency ratio (postoperative UCVA compared to preoperative BSCVA) was greater for the CustomCornea group at 20/20, 20/16,20/12.5, and 20/10 levels. CONCLUSION: Custom LASIK with CustomCornea and Zyoptix is safe and effective and produces excellent early visual outcomes. This study demonstrates that current standard metrics for reporting refractive surgery visual outcomes are not adequate for evaluating wavefront-guided laser vision correction procedures. Amending the standard reporting metrics to include visual outcomes at the 20/16, 20/12.5, and 20/10 levels; accuracy at the +/-0.25 D of attempted; and postoperative UCVA compared to preoperative BSCVA will improve our ability to analyze wavefront-guided outcomes.     

飞秒激光和微型角膜刀制瓣LASIK术后共焦显微镜检查比较

背景 飞秒激光制作准分子激光角膜原位磨镶术(LASIK)角膜瓣技术日渐成熟,术后角膜创伤愈合及神经纤维的再生成为关注热点.目的 对比分析FEMTO LDV飞秒激光及Hansatome机械角膜刀制瓣对LASIK后角膜细胞的影响.方法 采用前瞻性病例对照研究设计.纳入2010年3-7月在武警河南总队医院眼科连续收治的行LASIK的近视患者38例38眼,分为FEMTO LDV组20例20眼(采用FEMTOLDV飞秒激光制瓣)及Hansatome组18例18眼(采用Hansatome微型角膜刀制瓣),两组患者性别、年龄、术前等效球镜度等资料相匹配.分别于术前及术后1周、1个月、3个月应用共焦显微镜检测角膜中央及角膜瓣边缘的形态学变化,并比较两种制瓣方式术后角膜细胞形态学的异同.观察两组患者的术后视力、屈光度变化和裂隙灯下表现.结果 本研究中两组术眼术后1个月最佳矫正视力均≥1.0.FEMTO LDV组平均等效球镜度为(+0.21±0.48)D,Hansatome组为(-0.04±0.54)D,两组屈光度结果接近.FEMTO LDV组术后1周角膜上皮有增厚表现,但与术前比较差异无统计学意义(t=1.63,P＞0.05).FEMTO LDV组术后1周、1个月和3个月浅基质细胞密度较术前均明显减少,差异均有统计学意义(t=-27.99、-25.49、-28.87,P＜0.01).Hansatome组术后1周角膜上皮厚度为(56.73±2.47)μm,较术前值(51.16±1.11)μm明显增加,差异有统计学意义(t=9.29,P＜0.05),3个月时接近术前厚度;Hansatome组术后1周、1个月和3个月浅基质细胞密度较术前明显减少,差异均有统计学意义(t=-17.57、-14.13、-19.63,P=0.00).所有眼均可在切削面见到高反光颗粒,FEMTO LDV组术后1周、1个月和3个月切削面高反光颗粒密度均明显少于Hansatome组,差异均有统计学意义(t=-13.505、-11.900、-14.084,P＜0.01).术后1周时两组均观察到角膜细胞形态改变,切削界面后见激活的基质细胞,3个月时激活细胞减少.FEMTO LDV组术后3个月可见完整的神经纤维,而Hansatome组神经纤维短小.术后3个月,FEMTO LDV组周边角膜基质高反光,并有不规则纤维化,而Hansatome组角膜瓣边缘基质反光较弱.结论 与Hansatome机械角膜刀制瓣LASIK比较,FEMTO LDV飞秒激光制瓣LASIK术后神经纤维再生较早,角膜瓣边缘瘢痕化改变较明显,显示出较强的愈合过程.     

Very high-frequency digital ultrasound measurement of the LASIK flap thickness profile using the IntraLase femtosecond laser and M2 and Carriazo-Pendular microkeratomes

PURPOSE: To evaluate the corneal aberrometric outcomes and corneal flap thickness profile after LASIK using three different devices for lamellar keratotomy: Moria M2 microkeratome, SCHWIND Carriazo-Pendular microkeratome, and IntraLase femtosecond laser. METHODS: Sixty-six myopic eyes of 33 patients who underwent LASIK with the SCHWIND ESIRIS excimer laser were enrolled in this study. Lamellar keratotomy was performed using three different devices that were assigned randomly to each patient: the Moria M2 microkeratome, SCHWIND Carriazo-Pendular microkeratome, and IntraLase femtosecond laser. The intended flap depth was 110 microm in all cases. Flap thickness profile, corneal aberrations, contrast sensitivity, and refractive outcomes were evaluated. RESULTS: Mean central flap thickness was 117.50 +/- 7.80, 118.08 +/- 8.34, and 115.95 +/- 6.22 microm for the M2, Carriazo-Pendular, and IntraLase systems, respectively. No significant differences were found among the groups. Nasal thicknesses were significantly larger for the M2 flaps compared to IntraLase (P < .05) and Carriazo-Pendular flaps (P = .046 only at 3-mm position). Temporal thicknesses were larger for the M2 flaps, although only differences between M2 and Carriazo-Pendular flaps reached statistical significance. Larger superior and inferior thicknesses were also observed for M2 flaps, although no statistically significant differences were found. Regarding corneal aberrometry, no statistically significant differences were observed in coma-like (P = .138) and spherical-like root-mean-square (P = .300). CONCLUSIONS: The M2, Carriazo-Pendular, and IntraLase systems create flaps of predictable thickness during lamellar keratotomy in LASIK. Additionally, the Carriazo-Pendular and IntraLase devices create flaps with a planar profile.     

Conventional vs wavefront-guided LASIK using the LADARVision4000 excimer laser

PURPOSE: To compare outcomes after LASIK surgery using the conventional LADARVision4000 laser and the wavefront-guided LADARWave CustomCornea wavefront system. METHODS: A prospective study was performed involving 140 myopic eyes receiving conventional or CustomCornea LASIK between May and October 2003. The preoperative manifest spherical equivalent refraction was limited to myopia < or = -7.00 diopters (D). The preoperative manifest cylinder was limited to < or = -2.50 D of astigmatism. Patients were evaluated for 3 months following surgery. Results evaluated were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity, manifest refraction, dilated wavefront measurements, contrast sensitivity, and patient responses to subjective questionnaires. RESULTS: For the CustomCornea eyes at 3 months, 80% (70/87) had UCVA > or = 20/20 and 95% (83/87) had UCVA > or = 20/25. For the conventional eyes at 3 months, 45% (9/20) had UCVA > or = 20/20 and 80% (16/20) had UCVA > or = 20/25. At the 3-month postoperative visit, 85% (74/87) of the CustomCornea eyes and 55% (11/20) of the conventional eyes were within +/- 0.50 D of their intended correction. At 1 and 3 months, the CustomCornea treated eyes had a statistically significant lower mean increase in higher order aberrations than conventionally treated eyes (P < .05). CONCLUSIONS: CustomCornea wavefront-guided LASIK surgery appears safe and effective and provides clinical benefits that appear to exceed those of conventional LADARVision surgery.