WaveLight FS200 Femtosecond Laser Research Articles

High hyperopic LASIK with reduction of corneal prolateness to control-induced spherical aberration.

To evaluate visual outcomes of high hyperopic laser in situ keratomileusis (LASIK), using corneal aspherization to control the induced spherical aberration. Fondation Ophtalmologique Adolphe de Rothschild, Paris, France. Prospective interventional case series. Prospective interventional study of consecutive high hyperopes (≥+3 diopters [D] of spherical equivalent [SE]) undergoing LASIK with the WaveLight FS200 femtosecond and EX500 excimer laser platform. An aspheric ablation profile (planned change in corneal asphericity ΔQ = +0.2) was delivered using the Custom-Q nomogram on an optical zone of ≥6.5 mm centered near the corneal vertex. Uncorrected corrected distance visual acuity (UDVA) and corrected distance visual acuity, as well as changes in SE, corneal asphericity (ΔQ), and higher-order aberrations, were analyzed preoperatively and on day 1, 1, 3, 6, and 12 months. 117 eyes of 63 patients (mean age of 30.1 ± 5.6 years) were included. Preoperatively and at 12 months postoperatively, the mean SE was 5.1 ± 1.1 D and 0.00 ± 0.7 D, respectively. 88% of eyes achieved 0 logMAR or better UDVA at 12 months. 1 month postoperatively, there was a statistically significant induction of positive spherical aberration decreasing progressively and significantly until the last visit (preop SA4 = 0.09 ± 0.11 μm, day 1 SA4 = 0.30 ± 0.32 μm, 12 months SA4 = 0.08 ± 0.21 μm, P = .056). 2 eyes needed enhancement at 12 months. LASIK for high levels of hyperopia showed good outcomes mainly due to aspheric-customized ablation profile with a change of ΔQ = +0.2 in corneal asphericity.

The Accuracy of Flap Thickness and Diameter in LASIK Using a Femtosecond Laser.

To evaluate the resultant thickness of the WaveLight FS200 (Alcon Vision, LLC) created LASIK flap compared to intended thickness at the surgical visit, using the WaveLight EX500 (Alcon Vision, LLC) pachymeter and the resultant flap diameter compared to intended diameter. This single arm, prospective, single surgeon study assessed the accuracy of the intended flap thickness and diameter, after successful bilateral LASIK surgery. The WaveLight FS200 femtosecond laser was used to create all flaps with an intended thickness of 120 μm. Flap thickness was calculated by subtracting the stromal bed thickness after flap lift from the preoperative corneal thickness using the WaveLight EX500 on-board optical pachymeter. Flap diameter was determined using digital analysis. A total of 58 subjects (116 eyes) completed the study. The calculated mean flap thickness was 120.6 ± 9.0 μm (range 102 to 143 μm) using the EX500 pre- and post-flap pachymetry measurements. There was no statistically significant difference between the planned and achieved flap thickness (p > 0.05). The mean difference in flap diameter between planned and actual was 0.02 ± 0.05 mm. Corneal thickness measured by Pentacam at up to 2 months preoperatively versus EX500 just prior to surgery was similar, with EX500 measuring 2 μm less on average than the Pentacam. The results suggest that the WaveLight FS200 laser is reliable for LASIK flap thickness and diameter and accurately created flaps at the intended thickness and the intended diameter.

A morphological comparison between sub-bowman keratomileusis flap and femtosecond laser-assisted flap in LASIK surgery for myopia

Abstract Purpose: Comparison between the SBK microkeratome versus femtosecond laser in flap creation during LASIK surgery for myopia. Materials and Methods: This is a prospective comparative nonrandomized interventional clinical study that included 60 eyes of 30 patients in each group. Patients were randomized to receive either the SBK microkeratome or femtosecond laser technique according to a randomization computer software. The patient’s ages ranged from 18 to 46 years in the FS200 laser group and from 20 to 44 years in the SBK group. The WaveLight FS200 femtosecond laser and the Moria SBK microkeratome were both used to generate flaps in the 60 eyes of 30 patients (Moria SA, Antony, France). About 1 month after surgery, AS-OCT was utilized to measure the thickness of five locations on each flap that was 0, 1.5 mm from the corneal vertex on the horizontal and vertical axes. Hinge size and flap diameter were measured using a caliper 1 month after surgery. Uncorrected visual acuity and best corrected visual acuity were measured at 1 day, 1 week, and 1 month postoperative in each group. Any related complications were recorded in each group. For side-cut angles, scans were done across the temporal side of the flap, and then images were transferred to Draw editor software, and measurements were recorded and analyzed 1 month after surgery using AS-OCT. Results: The mean obtained central corneal flap thickness in both eyes in the FS200 laser group was 117.4 µ ± 4.18 SD, and 84.90 µ ± 3.74 SD in the SBK group, which was statistically significant (P < 0.05). The mean achieved Hinge size in both eyes in the FS200 laser group was 3.47 ± 0.26 mm, and 4.81 ± 0.63 mm (P < 0.05) in the Moria SBK group. The mean achieved flap diameter in the FS200 laser group was 7.95 ± 0.43 mm, and 9.15 ± 0.21 mm in the SBK group (P < 0.05). In the FS200 laser group, the average side cut angle was 126.93°9.56°, while in the SBK group, it was 37.18°6.93° (P < 0.05). Conclusion: In the two study groups, there was a statistically significant difference in the side cut angles that were intended and actually achieved. In comparison to the SBK group, the FS200 laser group had better predictability of flap thickness. There were reported complications in the SBK group, while femtosecond laser technology has shown better postoperative flap uniformity with no reported complications.

Measurement of the Intraocular Pressure Elevation During Laser-Assisted In Situ Keratomileusis Flap Creation Using a Femtosecond Laser Platform.

PurposeThe purpose of this study was to measure the intraocular pressure (IOP) elevation during laser assisted in situ keratomileusis (LASIK) flap creation using the WaveLight FS200 femtosecond (FS) laser platform.MethodsWe conducted an ex vivo experimental study in an animal model. The WaveLight FS200 FS laser platform was used to perform the corneal LASIK flap in freshly enucleated porcine eyes. We measured the changes in IOP from the application of the suction ring (suctioning phase) through the creation of the lamellar corneal flap (cutting phase). The IOP was recorded using a manometric technique with direct cannulation to the anterior chamber.ResultsNine freshly enucleated porcine eyes were included in the study. The mean baseline IOP before the procedure was 20.33 ± 5.9 mm Hg. The mean IOP increase over baseline IOP was 32.33 ± 11.3 mm Hg at the suctioning phase, and 38.22 ± 11.3 mm Hg at the cutting phase. The total surgical time needed to complete the procedure was 29.5 ± 4.4 seconds.ConclusionsThe WaveLight FS200 FS laser platform produces a low to moderate increase in IOP during LASIK flap creation.Translational RelevanceThe WaveLight FS200 is a safe FS laser platform because it induces a low to moderate IOP increase during LASIK flap creation.

Analysis and Causation of All Inaccurate Outcomes After WaveLight Contoura LASIK with LYRA Protocol.

PurposeThis study analyzes every eye that had an outcome greater than 0.25D of sphere or astigmatism from planned goal after treatment with WaveLight Contoura with LYRA Protocol.MethodsThe study included 266 consecutive eyes treated with LASIK Contoura using the LYRA Protocol. All LASIK procedures were performed on the WaveLight EX500 excimer laser. Flaps were created with either the Alcon WaveLight FS200 femtosecond laser or the Moria M2 microkeratome. Eyes that were off by >0.25 diopters (D) sphere or cylinder from the targeted goal within 3 months after surgery were identified and analyzed for cause. Topographical, higher-order aberration, and epithelial maps were created.ResultsCauses for inaccurate outcomes were biomechanical corneal change from LASK flap creation (9.78% of total eyes), pre-operative epithelial compensation of corneal higher-order aberration (4.1% of total eyes), changes to lamellar corneal tension from laser ablation causing a hyperopic shift (1.9% of total eyes), epithelial thickening over the ablation area post-operatively causing a refractive change (1.5% of total eyes), and posterior astigmatism (0.75%).ConclusionThe causes of the majority of inaccurate outcomes have not been properly defined and must be incorporated into further improving outcomes. Current and planned advances in technology do not address the majority of these causes.

Biomechanical Changes to the Cornea from LASIK Flap Creation Resulting in Inaccurate Ablations and Suboptimal Refractive Outcomes with Topographic-Guided Ablation.

PurposeThis study documents a biomechanical corneal change related to corneal flap creation in certain patients leading to an irregular ablation pattern and an inaccurate refractive outcome.MethodsThis retrospective study included consecutive eyes treated with primary LASIK Contoura using the LYRA Protocol. All LASIK procedures were performed on the WaveLight EX500 excimer laser. Flaps were created with either the Alcon WaveLight FS200 femtosecond laser or the Moria M2 microkeratome. Eyes that were off by greater than or equal to 0.50 diopters (D) sphere or cylinder from the targeted goal within 3 months after surgery were identified. Topographical, higher order aberration, and epithelial maps were created. Of these eyes, approximately 10% of eyes were found to have undergone a biomechanical change upon flap creation that led to an inaccurate outcome.ResultsSix representative cases are presented that demonstrate the biomechanical change, outcomes, and treatment. All patients demonstrated an elliptical, irregular ablation pattern on post-operative topography, lateralized the thinnest point of the cornea relative to the corneal apex on Pentacam pachymetry maps, and irregular corneal epithelial thickening at the periphery of the elliptical ablation.ConclusionA biomechanical change during flap creation can occur in certain types of corneas during LASIK flap creation and subsequent treatment with topographic-guided ablation leading to an irregular ablation and suboptimal refractive outcomes.

Relationship between the offset of a laser-assisted flap using the WaveLight FS200 femtosecond laser and the clinical results

Objective To evaluate the relationship between the offset of a laser-assisted flap using the WaveLight FS200 femtosecond laser and the clinical results after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). Methods In this prospective cohort study, 125 patients who underwent FS-LASIK for myopia by WaveLight FS200 femtosecond laser from June 2017 to July 2018 at the Tungwah Ophthalmic Center were divided into two groups according to the offset of the corneal flap from the pupil center: the no-offset group (57 eyes) and the certain-offset group (68 eyes); the baseline data, including age, sex, uncorrected visual acuity(UCVA), spherical degree, and central corneal thickness were matched in the two groups.UCVA, residual astigmatism, spherical degree, corneal curvature and aberration were observed 1 week and 1 month after surgery.The study protocol was approved by the Ethics Committee of Tungwah Hospital of Sun Yat-Sen University (No.2017DHLL004). Written informed consent was obtained from each subject prior to entering the study cohort. Results UCVA, corneal curvature, spherical degree, spherical and corneal aberration between the two groups were not significantly different (all at P>0.05). One week after surgery, the residual astigmatism was ≤-0.50 D in 50 eyes (87.7%, 50/57)and >-0.50 D in 7 eyes (12.3%, 7/57) in the no-offset group; the residual astigmatism was ≤-0.50 D in 50 eyes (73.5%, 50/68) and >-0.50 D in 18 eyes (26.5%, 18/68) in the no-offset group.The residual astigmatism between the two groups 1 week after surgery was significantly different (χ2=3.902, P=0.048), and there was no significant difference in residual astigmatism 1 month after surgery (χ2=2.031, P=0.068). The trefoil of the no-offset group was statistically less than of the certain-offset group at 1 week and 1 month after surgery (0.05[0.04, 0.08]vs.0.06[0.04, 0.10]; 0.05[0.03, 0.07]vs.0.06[0.05, 0.09])(Z=-2.245, P=0.022; Z=-2.370, P=0.018). The spherical aberration and coma were not significantly different between the two groups at 1 week and 1 month after surgery (both at P>0.05). Conclusions The offset from femtosecond laser-assisted flap by WaveLight FS200 has no effect on long-term visual acuity or residual astigmatism.Some patients may have different visual experiences because of the residual astigmatism and higher order aberration during the early postoperative stage. Key words: Laser/therapeutic use; Femtosecond laser; Corneal flap; Corneal curvature; Higher order aberration

Flap thickness and side-cut angle using sub-Bowman keratomileusis microkeratome, 200-kHz femtosecond laser system, and Moria M2 microkeratome

Purpose The aim of this study was to compare the thickness and side-cut angle of corneal flap in candidates undergoing laser-assisted in situ keratomileusis using sub-Bowman keratomileusis (SBK) microkeratome, femtosecond (FS) laser, or Moria M2 microkeratome (MK). Patients and methods This prospective clinical study included 60 eyes of 30 patients. They were divided into three groups (20 eyes in each group). The study was conducted from January 2019 till December 2019. Corneal flaps were created using Moria SBK microkeratome, Alcon Wavelight FS-200 FS laser, or Moria MK. Heidelberg anterior segment optical coherence tomography was done 1 month postoperatively to assess the central flap thickness and side-cut angle. Results The mean error cut angle was −39.00±19.00, 24.75±12.56, and −25.65±10.31° in the SBK, FS, and MK groups, respectively (P Conclusion There was a statistically significant difference between the intended and achieved side-cut angle in the three groups. Flap thickness was more predictable in the SBK and FS group, with an insignificant difference between the intended and achieved flap thickness, whereas in the MK group, the difference was statistically significant.

Study of Accuracy of Corneal Flap Thickness by Using Femtosecond Laser Technology

Background- LASIK is the most popular surgery to correct the refractive errors nowadays. It is proved to be safe, effective and well predictable. It is important to produce a uniform flap with a narrow SD from the intended thickness. The Integrated optical pachymetry is a convenient and useful feature of the EX500 excimer laser which can be used to measure flap thickness intraoperatively.Objectives: this study aimed to detect the accuracy of Allegretto Wavelight FS200™ platform in creation of different corneal flap thicknesses. Patients and Methods: sixty eyes of 30 myopic patients were included in our study, the patients were operated by 2 different surgeons from June 2017 till December 2017. The patients were distributed randomly into 3 studied groups. Group I (20 eyes with intended fs flap 100um), group II (20 eyes with intended fs flap 110um) and group III (20 eyes with intended fs flap 120um). All participants were subjected to full medical history taking, uncorrected distance visual acuity, slit-lamp microscopy, corneal topography using oculus® pentacam device, manifest and cycloplegic refraction, corrected distance visual acuity, fundus bio-microscopy examination using 90 D lens. Results: inthis study 100μm thickness group (Group A) showed the lowest difference between the mean result and the intended flap (-0.35um) followed by the 120um group (Group C) with difference of (-2.9um) between the mean result and the intended flap thickness followed by the 110μm group (group B) with the highest difference (-3.45um) from the intended flap thickness. Conclusion: the flaps made with the Wavelight FS200 femtosecond laser were predictable and uniform more predictable in group A than in group C and B, but with no statistical significance between the three studied groups (P=0.402).

High incidence of rainbow glare after femtosecond laser assisted-LASIK using the upgraded FS200 femtosecond laser

BackgroundTo compare the incidence of rainbow glare (RG) after femtosecond laser assisted-LASIK (FS-LASIK) using the upgraded FS200 femtosecond laser with different flap cut parameter settings.MethodsA consecutive series of 129 patients (255 eyes) who underwent FS-LASIK for correcting myopia and/or astigmatism using upgraded WaveLight FS200 femtosecond laser with the original settings was included in group A. Another consecutive series of 129 patients (255 eyes) who underwent FS-LASIK using upgraded WaveLight FS200 femtosecond laser with flap cut parameter settings changed (decreased pulse energy, spot and line separation) was included in group B. The incidence and fading time of RG, confocal microscopic image and postoperative clinical results were compared between the two groups.ResultsThere were no differences between the two groups in age, baseline refraction, excimer laser ablation depth, postoperative uncorrected visual acuity and refraction. The incidence rate of RG in group A (35/255, 13.73%) was significantly higher than that in group B (4/255, 1.57%) (P < 0.05). The median fading time was 3 months in group A and 1 month in group B (P > 0.05).The confocal microscopic images showed wider laser spot spacing in group A than group B. The incidence of RG was significantly correlated with age and grouping (P < 0.05).ConclusionsThe upgraded FS200 femtosecond laser with original flap cut parameter settings could increase the incidence of RG. The narrower grating size and lower pulse energy could ameliorate this side effect.

Does femtosecond laser assisted penetrating keratoplasty lead to less astigmatism in keratoconus patients, compared with conventional penetrating keratoplasy?

PurposeVisual impairing including high irregular astigmatism is a well‐known problem after penetrating keratoplasty (PK). The femtosecond (FS) laser technique allows completely new trephination methods such as the zig‐zag, top hat or the mushroom cutting profiles, which result in a more rapid and stable wound healing. In the present study we compare conventional PK and FS laser PK concerning astigmatism and visual outcome in keratoconus patients 2 years postoperativelyMethodsA total of 67 patients were operated with PK between September 2013 and June 2015 at Oslo University Hospital, Norway. All patients were examined 2 years after surgery. Ten keratoconus patients who were operated with FS laser‐assisted PK (FS group) were included, using Alcon Wavelight FS200 Femtosecond Laser, and compared with a control group who underwent conventional PK (n = 20). Controls were matched for diagnosis, age, gender and time of operation. Postoperative results regarding astigmatism and visual outcome were compared.ResultsAt the 2 years follow‐up, the mean logMAR BCVA was 0.17 ± 0.14 in the FS‐group and 0.16 ± 0.19 in the control group (p = 0.89). The mean spherical equivalent was ‐1.91 ± 4.58 in the FS‐group, and ‐3.08 ± 2.81 in the control group (p = 0.39). The mean subjective and corneal cylinder was ‐6.08 ± 2.50 and 7.71 ± 3.78 in the FS‐group, compared to ‐4.89 ± 2.57 (p = 0.24) and 5.73 ± 3.84 in the control group (p = 0.21), respectively. K‐mean was 44.00 D ± 3.99 in the FS‐group and 44.98 D ± 1.63 in the control group (p = 0.50). ECD was 1456 cells/mm²± 325 in the FS‐group, and 1679 cells/mm²± 475 in the control group (p = 0.22).ConclusionsEven though the study included relatively few eyes, the findings confirm previous studies. No significant difference in astigmatism or visual outcome was found between the two groups 2 years postoperatively.

Accuracy of Alcon WaveLight® EX500 optical pachymetry during LASIK.

PurposeTo study the accuracy and reliability of optical pachymetry using the Alcon WaveLight EX500 during laser-assisted in situ keratomileusis (LASIK).Materials and methodsThis was a retrospective chart review of 90 eyes from 45 patients who had undergone LASIK (mean age 35.2±8.2 years; 19 males, 26 females). The WaveLight FS200 femtosecond laser was programmed to cut LASIK flaps at a desired depth of 120 μm. Optical low-coherence reflectometry (WaveLight EX500) was used to measure central corneal thickness prior to lifting the flap, and the residual stromal bed immediately after excimer ablation. Flap thickness (FT) was calculated using simple subtraction. Optical coherence tomography (OCT) was used to measure central corneal thickness, flap thickness, and residual stromal bed in the postoperative period and the results compared to intraoperative measurements.ResultsMean programmed FS200 FT was 119 μm. Mean FT using EX500 optical pachymetry was 109 μm. The difference between FS200- programmed and EX500-measured FT was 9 μm (P<0.001). There was also a significant difference between the EX500 and OCT FT (109 μm vs 119 μm, respectively; P<0.001).ConclusionFT values calculated using intraoperative EX500 optical pachymetry were significantly lower than programmed FS200 values or OCT measurements.

Assessment of refractive outcome of femtosecond-assisted LASIK for hyperopia correction.

IntroductionLaser vision correction for hyperopia is challenging. The purpose of the study was to assess the refractive outcomes of femtosecond-assisted laser in situ keratomileusis (LASIK) for hyperopic correction using wavefront-optimized ablation profiles.MethodsThis retrospective case series study included 20 Egyptian patients (40 eyes) with hyperopia or hyperopic astigmatism with a mean manifest refraction spherical equivalent (MRSE) of +2.55D±1.17 (range from +1.00 to +6.00) who had uneventful femtosecond-a assisted LASIK with wavefront-optimized aspheric ablation profile using refractive surgery suite (WaveLight FS200 Femtosecond Laser and WaveLight EX500 Excimer Laser) performed in the Research Institute of Ophthalmology and International Eye Hospital, Giza, Egypt. Statistical analysis was done using Microsoft Excel (Microsoft Corporation, Seattle, WA, USA).ResultsThe procedure significantly reduced the MRSE and cylinder post-operatively (95% were ± 0.50D and 100% ± 1.00 D), with stability of refraction and UDVA over the follow-up period (up to 12 months) after surgery. No eye lost any line of the CDVA, which reflects the excellent safety profile of the procedure; on the other hand, one eye (5%) gained one line and one eye (5%) even gained two lines. There were no significant complications during the procedure.ConclusionsFemtosecond-assisted laser in situ keratomileusis for hyperopia showed predictable, effective, and safe refractive outcomes that were stable through 12 months. Longer follow-up period is required to detect any further regression

Comparison of efficacy, safety, and predictability of laser in situ keratomileusis using two laser suites.

PurposeThe main aim of this study was to compare the efficacy, safety, and predictability of femtosecond laser-assisted in situ keratomileusis performed by two different laser suites in the treatment of myopia for up to 6 months.MethodsIn this two-site retrospective nonrandomized study, myopic eyes that underwent laser-assisted in situ keratomileusis using IntraLase FS 60 kHz formed group 1 and those using WaveLight FS200 femtosecond laser system formed group 2. Ablation was performed with Visx Star S4 IR and WaveLight EX500 Excimer lasers, respectively, in groups 1 and 2. Both groups were well matched for age, sex, and mean level of preoperative refractive spherical equivalent (MRSE). Uncorrected distance visual acuity, corrected distance visual acuity, and MRSE were evaluated preoperatively and at 1 week, 1 month, and 6 months after treatment.ResultsFifty-six eyes of 28 patients were included in the study. At 6-month follow-up postop, 78.6% of eyes in group 1 and 92.8% of eyes in group 2 achieved an uncorrected distance visual acuity of 20/20 or better (P=0.252). 35.7% and 50% in group 1 and group 2, respectively, gained one line (P=0.179). No eye lost lines of corrected distance visual acuity. Twenty-five eyes in group 1 (92.7%) and 27 eyes in group 2 (96.3%) had MRSE within ±0.5 D in the 6-month follow-up (P>0.999). The mean efficacy index at 6 months was similar in group 1 and group 2 (mean 1.10±0.12 [standard deviation] vs 1.10±0.1) (P=0.799). The mean safety index was similar in group 1 and group 2 (mean 1.10±0.10 [standard deviation] vs 1.10±0.09) (P=0.407). Conclusion: The outcomes were excellent between the two laser suites. There were no significant differences at 6-month follow-up postop between the two laser systems.

Comparison of corneal flaps created by Wavelight FS200 and Intralase FS60 femtosecond lasers.

To assess and compare the morphology of corneal flaps created by the Wavelight FS200 and Intralase FS60 femtosecond lasers in laser in situ keratomileusis (LASIK). Four hundred eyes of 200 patients were enrolled in this study and divided into Wavelight FS200 groups (200 eyes) and Intralase FS60 groups (200 eyes). Fourier-domain optical coherence tomography (RTVue OCT) was used to measure the corneal flap thickness of 36 specified measurements on each flap one week after surgery. Results were used to analyze the regularity, uniformity and accuracy of the two types of LASIK flaps. The mean thickness of corneal flap and central flap was 105.71±4.72 µm and 105.39±4.50 µm in Wavelight FS200 group and 109.78±11.42 µm and 109.15 ±11.59 µm in Intralase FS60 group, respectively. The flaps made with the Wavelight FS200 femtosecond laser were thinner than those created by the Intralase FS60 femtosecond laser (P=0.000). Corneal flaps in the 2 groups were uniform and regular, showing an almost planar configuration. But the Wavelight FS200 group has more predictability and uniformity of flap creation. The mean deviation between achieved and attempted flap thickness was smaller in the Wavelight FS200 group than that in the Intralase FS60 group, which were 5.18±3.71 µm and 8.68±7.42 µm respectively. The deviation of more than 20 µm was 0.2% measurements in Wavelight FS200 group and 8.29% measurements in Intralase FS60 group. The morphologies of flaps created by Wavelight FS200 are more uniform and thinner than those created by Intralase FS60.

Clinical analysis of complications of LASIK using the WaveLight FS200 femtosecond laser

To explore the incidence of intraoperative and early postoperative complications associated with the WaveLight FS200 femtosecond laser-assisted flap creation in LASIK surgery. A consecutive series of 400 patients (786 eyes) who underwent LASIK using the WaveLight FS200 femtosecond laser from March 2011 to December 2012 were included in this retrospective study. Intraoperative and early postoperative complications were described and analyzed. The intraoperative complications included suction loss (two eyes, 0.25%), incomplete flap creation (one eye, 0.13%), severe opaque bubble layers (three eyes, 0.38%), anterior chamber gas bubbles (eight eyes, 1.02%), skip lines (12 eyes, 1.53%), and corneal epithelial defects (eight eyes, 1.02%). The early postoperative complications included canal bleeding (eight eyes, 1.02%), diffuse lamellar keratitis (23 eyes, 2.93%), haze (six eyes, 0.76% ), and flap dislocation (one eye, 0.13% ). Intraoperative and early postoperative complications of LASIK using the WaveLight FS200 were relatively mild. All patients could obtain satisfactory clinical results with proper treatment.

Comparison of laser in situ keratomileusis flaps created by 2 femtosecond lasers.

To compare flap morphology created by the WaveLight FS200 femtosecond laser and the VisuMax femtosecond laser, assessing the uniformity, accuracy, and predictability of flap creation. A total of 400 eyes had corneal flaps created with the WaveLight FS200 femtosecond laser (200 eyes) or the VisuMax femtosecond laser (200 eyes). The desired flap thickness was 110 μm. At 1 week postoperatively, all eyes were evaluated with RTVue Fourier-domain optical coherence tomography. Dimensions of the flaps were tested for their regularity, uniformity, accuracy, and predictability comparison. One week after surgery, the central flap thickness and the mean flap thickness of the FS200 group were 105.4 ± 3.4 μm and 105.7 ± 2.6 μm, respectively. They were both thinner than those of the VisuMax group, which were 110.8 ± 3.9 μm and 111.3 ± 2.3 μm, respectively. The mean deviation between the achieved and attempted flap thickness of the FS200 group (5.2 ± 1.9 μm) was greater than that of the VisuMax group (3.2 ± 1.8 μm). Flap thickness measurements at 36 points in both groups were close to the intended thickness. Morphology of the flaps in the 0-, 45-, 90-, and 135-degree lines created by the FS200 femtosecond laser and VisuMax femtosecond laser were uniform and regular. Flap dimensions created by the WaveLight FS200 femtosecond laser and VisuMax femtosecond laser were uniform and regular. Although the flap thickness created by the FS200 was less than that created by the VisuMax, measurements of both femtosecond lasers were close to the intended thickness.

Comparison of corneal flap thickness using a FS200 femtosecond laser and a moria SBK microkeratome.

To evaluate differences in flap thickness resulting from use of an Alcon Wavelight FS200 femtosecond laser and a MORIA SBK microkeratome when making a 110-µm-thick corneal flap and to identify the potential factors that affect corneal flap thickness. A prospective case study was performed on 120 eyes of 60 patients who were divided into two groups for LASIK, each group consisting of 60 eyes (30 patients). The corneal flaps were created using an Alcon Wavelight FS200 femtosecond laser or a MORIA SBK microkeratome. The central corneal flap thickness was calculated by subtraction pachymetry. Age, central corneal thickness (CCT), spherical equivalent refraction, mean keratometry, and corneal diameter were recorded preoperatively for analysis. Cutting of all flaps was easily performed without intraoperative complications. In the Alcon Wavelight FS200 femtosecond laser group, the mean right and left corneal flap thicknesses were 114.0±6.6 µm (range: 98-126) and 111.4±7.6 µm (range: 98-122), respectively. The difference (2.6±9.1 µm) in the corneal flap thickness between the right and left eyes was not significant (t=1.59, P=0.12). Stepwise regression analysis indicated that the resulting corneal flap thickness was unrelated to the patient's age, preoperative CCT, spherical equivalent refraction, mean keratometry, or corneal diameter. In the MORIA SBK microkeratome group, the mean right and left corneal flap thicknesses were 110.6±7.4 µm (range: 97-125 µm) and 108.2±6.1 µm (range: 78-123 µm), respectively. The difference in the corneal flap thickness between the right and left eyes (2.4±6.5µm) was not significant (t=2.039, P=0.0506). The corneal flap thickness was positively correlated with the preoperative CCT through stepwise regression analysis (r=0.297, P=0.021). The corneal flap thickness was not related to age, spherical equivalent refraction, mean keratometry, or corneal diameter. The corneal flap thickness was estimated using the following equation: Tflap=67.77+0.076 CCT (F=5.63, P=0.021). Both the Alcon Wavelight FS200 femtosecond laser and the MORIA SBK microkeratome produced 110-µm-thick corneal flaps. The central corneal flap thickness was positively correlated with the preoperative CCT in MORIA SBK microkeratome surgery.

Measurement and comparison of corneal flap thickness between Wavelight FS200 femtosecond laser and Moria 90 microkeratome LASIK by OCT

Background Lasein situ keratomileusi(LASIK) imainstream surgery forefractive correction,and femtosecond laseimuch often used to create thin corneal flap.The measuremenof OPTOVUE RTVue-100 OCto flap and stromal bed thicknesseofferuseful basifoLASIK.Ican be used in measuring the thicknesand shape of the corneal flap.Buthe study on the comparison of flap thicknesbetween WavelighFS200 femtosecond laseand MoriM2 microkeratome 90 μm-knife (Mori90 microkeratome) LASIK by OCilack.Objective The aim of thitrial wato compare the featureof corneal flapcreated by the WavelighFS200 femtosecond laseand Mori90 microkeratome.Methodpiloand prospective study wadesigned.Written informed consenwaobtained from each patienprioto LASIK.Sixty righeyeof 60 patientwith myopiomyopiastigmatism were enrolled in thiclinical trial.The patientwere randomized into the FS200 femtosecond lasegroup and Mori90 microkeratome group with matching demography.RTVue OCwaused to measure flap thicknesusing 10 settingon the 60 eye1 month afteoperation.The featureof the LASIK flapwere analyzed based on the measuring outcomes.ResultThe central flap thickneswa(112±3) μm and the mean flap thickneswa(112 ±3) μm in the FS200 femtosecond lasegroup,which wasignificanlowethan the central flap thicknesa(121±7) μm and the mean flap thicknesa(128±11) μm in the Mori90 microkeratome group respectively (P=0.031,0.030).Corneal flapin the FS200 femtosecond lasegroup showed flashape and thain the Mori90 microkeratome group wameniscushape.The central flap thickneswanoevidently differenfrom thaof peripheral thicknesin the FS200 femtosecond lasegroup (P =0.320).However,in the Mori90 microkeratome group,the central flap thickneswaobviously thinnethan thain the peripheral thicknes(P=0.038).The mean deviation between the actual and predicted flap thicknes(110 μm) wa(3±4)μm in the FS200 femtosecond lasegroup and (17±10) μm in the Mori90 microkeratome group,showing significandifference between them (P =0.009).ConclusionRTVue OCdeterminethathe shape of flapcreated by the FS200 femtosecond laseimore uniform and closeto the expected thicknesof 110 μm than the onecreated by the Mori90 microkeratome.OPTOVUE RTVue-100 OCiuseful tool to evaluate the flap shape and thicknesafteLASIK. Key words: Fourier-domain optical coherence tomography; Femtosecond laser; Cornea; Refractive surgery; Laser in situ keratomileusis; Flap thickness

Unilateral Rainbow Glare After Uncomplicated Femto-LASIK Using the FS-200 Femtosecond Laser

To report a case of rainbow glare following femtosecond laser-assisted LASIK (femto-LASIK) with the Wavelight FS-200 femtosecond laser (Alcon Laboratories, Inc., Fort Worth, TX). A patient was treated bilaterally for myopia with femto-LASIK using the FS-200 femtosecond laser. Postoperatively, he complained of rainbow glare in his right eye. Three months postoperatively, the induced grating pattern (hyperreflective spot-like zones corresponding to the surgeon-programmed spot and line separation distance of the FS-200 femtosecond laser) was demonstrated with confocal microscopy at the level of the flap interface in the right eye. This is the first report of rainbow glare following femto-LASIK with the FS-200 femtosecond laser documented with in vivo confocal microscopy.