bluuebunny/crossref_metadata_2025_split huggingface dataset:
From Wavefront Device to Laser: An Alignment Method for Complete Registration of the Ablation to the Cornea
Authors: Chernyak Dimitri A 
Published: December 2019

ABSTRACT
PURPOSE: When customized laser refractive surgery is based on a wavefront measurement, correct registration of the laser ablation to the prescribed treatment area is vital. If the treatment is not ablated exactly where it was measured, the error could negate some benefits of the procedure. Currently, treatments are aligned to the pupil center, which has been shown to shift between measurement and treatment. This article describes an alignment method that uses an image-based coordinate system to compensate for shifts of the pupil center as well as eye Io rotation.
METHODS: Images of patients' eyes were taken during wavefront measurements and again when patients were in position for surgery. An image-processing method, which matches multiple ocular landmarks in both image sets, was used to align the laser beam to the ablation target.
RESULTS: Analyses of the data collected from both instruments suggest that alignment errors caused by movement of the pupil center and cyclorotation could be significantly reduced by using the proposed alignment method.
CONCLUSIONS: Because the pupil center undergoes significant movement with changes in lighting conditions, it is unsuitable as the sole alignment point for custom ablations. Several reference points are necessary to compensate for changing pupil size as well as the cyclotorsional eye position changes that occur between wavefront measurement and laser procedure. By providing multiple points for alignment, the registration method described herein increases safety and effectiveness of wavefront-based laser vision correction. [J Refract Surg. 2005;21:463-468.]
Moria M2 Single Use Microkeratome Head in 100 Consecutive LASIK Procedures
Authors: Kanellopoulos A John , Pe Lawrence H , Kleiman Lynda 
Published: December 2019

ABSTRACT
PURPOSE: To evaluate the safety and efficacy of the Moria M2 single use 130 microkeratome head in consecutive LASIK procedures for correction of myopia and myopic astigmatism.
METHODS: One hundred eyes of 55 patients underwent LASIK in which the flaps were created with the Moria M 2 microkeratome using the single use 130 head and excimer laser ablation was done with the Allegretto Wavelight laser. Flap parameters measured were: thickness, diameter, hinge length, and overall quality. Preoperative uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, wavefront aberrations, and low contrast sensitivity were compared to postoperative values at 6-month follow-up.
RESULTS: Mean flap thickness was 145 ?17. 5 ?im, mean flap diameter was 8.5?0.40 mm, and mean hinge cord length was 4. 05 ?0.35 mm. At 6-month follow-up, UCVA improved from 20/200 (?0.24) to 20/18.5 (?0.12) and BSCVA improved from 20/20.5 (?0.18) to 20/17.5 (?0.11).
CONCLUSIONS: The Moria M2 single use 130 microkeratome head appears to be safe and effective in performing LASIK procedures. [J Refract Surg. 2005;21:476-479.]
Late Bilateral Keratectasia After LASIK in a Low Myopic Patient
Authors: Lifshitz Tova , Levy Jaime , Klemperer Itamar , Levinger Shmuel 
Published: December 2019

ABSTRACT
PURPOSE: To report a rare case of late bilateral ectasia developing after LASIK for low myopia without preoperative risk factors.
METHODS: A 21-year-old man underwent bilateral uneventful LASIK for low myopia of -2.75 diopters in both eyes. Preoperative corneal pachymetry was 531 µm in the right eye and 526 µm in the left eye. The total ablation depth was 46.8 µm in the right eye and 42.2 µm in the left eye. Preoperative corneal topography was normal and did not reveal forme fruste keratoconus.
RESULTS: Twenty-four months postoperatively, the patient developed bilateral inferior keratectasia of +0.50 -3.00 × 72° in the right eye and +1.00 -2.75 × 99° in the left eye.
CONCLUSIONS: Late keratectasia may follow LASIK for low myopia despite a thorough preoperative work-up. [J Refract Surg. 2005;21:494-496.]
Influence of Exposure Time and Pupil Size on a Shack-Hartmann Metric of Forward Scatter
Authors: Donnelly William J , Applegate Raymond A 
Published: December 2019

ABSTRACT
PURPOSE: To determine the influence of exposure time and pupil size on a Shack-Hartmann (S/H) derived metric of forward scatter (MAX_SD) using a physical model of nuclear cataract.
METHODS: A physical model eye was developed and mounted to a S/H wavefront sensor. The eye model consisted of a lens, variable pupil, simulated cataract, and retina. Located behind the pupil, a cuvette contained one of five polystyrene microsphere solutions simulating five levels of nuclear cataract severity. Cataract severity was described using a S/H derived metric of forward scatter (MAX_SD), which measures aspects of forward scatter contained in the S/H lenslet point spread functions (PSF). To determine the impact of exposure time and pupil size, measurements of MAXSD were regressed against cataract severity for three different exposure times and three different pupil sizes.
RESULTS: MAX_SD was well correlated to cataract severity. Exposure time had the largest influence, and pupil size had the smallest influence on the forward scatter metric. When pupil size and exposure time were allowed to vary and image saturation was allowed to occur, MAX_SD explained 83% of the variance in cataract severity. Excluding images where saturation occurred, holding optimal exposure time constant, and varying pupil size, MAX_SD explained 97% of the variance in cataract severity.
CONCLUSIONS: The ability of the forward scatter metric derived from S/H measurements to predict cataract severity for a longitudinal study is optimized by selecting a patient-specific exposure at the initial cataract assessment to avoid saturation and maximize the dynamic range of the system. This patient-specific exposure should be used in all future visits. [J Refract Surg. 2005;21:S547-S551.]
Errors in Zernike Transformations and Non-modal Reconstruction Methods
Authors: Neal Daniel R , Baer C David , Topa Daniel M 
Published: December 2019

ABSTRACT
PURPOSE: Wavefront aberrometers often represent the wavefront in terms of Zernike polynomials. The fit coefficients for these polynomials are pupil-size dependent; hence it is desirable to be able to calculate polynomial coefficients at a different pupil size from the initial measurement.
METHODS: We developed a method for scaling the Zernike fit coefficients for different sized pupils and compared them to the coefficients calculated by reanalyzing the original data. We evaluated cases where the initial set of Zernike coefficients was an accurate representation of the data as well as cases where the Zernike polynomials fit the data poorly.
RESULTS: The rescaling methods work well in all cases with a good original fit (as measured by the gradient root-mean-square [RMS] fit error). Rescaling and reanalyzing also agree well over a small scaling range. However, if the original fit was poor, large errors result if the rescaling is more than ~25%.
CONCLUSIONS: Rescaling works well and is useful as long as the RMS fit error can be evaluated. The RMS difference between the zonal reconstruction and the Zernike fit is useful for determining this fit error. [J Refract Surg. 2005;21:S558-S562.]
Combined Flap Undersurface and Bed LASIK for High Myopia
Authors: Li Li Wei , Mei Wang Qin , Jun Fang Xue 
Published: December 2019

ABSTRACT
PURPOSE: To discuss the predictability, stability, and safety of LASIK for high myopia using laser treatment on both the flap undersurface and bed (both-sided LASIK).
METHODS: One hundred twenty-one eyes of 63 patients underwent flap undersurface and bed LASIK for high myopia. Postoperative uncorrected visual acuity (UCVA), refraction, and topography were evaluated up to 12 months. The safety and injury indices in both-sided LASIK were compared with that of conventional LASIK.
RESULTS: In both-sided LASIK, the largest diopter correction on the undersurface of the corneal flap was -6.00 diopters (D), correlating to an ablation of 44.62 µm. The mean thickness of residual corneal stroma bed was 283.87 ± 19.83 µm after the laser treatment. Postoperative UCVA was close to the preoperative best spectacle-corrected visual acuity (BSCVA). The mean BSCVA was significantly better (P<.05) than preoperatively at each time point (1 week, 1, 3, and 6 months, and 1 year) after surgery. Postoperative corneal topography was normal in all cases. The safety and injury indices for conventional LASIK in both-sided LASIK eyes were calculated by programming the excimer laser as though conventional treatments would be performed to calculate the theoretical bed ablation. The safety factor of both-sided LASIK was higher than that calculated for conventional LASIK (P<.05); the injury index was lower than that calculated for conventional LASIK (P<.05).
CONCLUSIONS: Surgery on high myopia by bothsided LASIK is safe and effective. [J Refract Surg. 2005;21(Suppl):S606-S609.]
LASIK Enhancement Using Excimer Laser Ablation on the Back of the Flap
Authors: Grim Millicent , Sheard Janine , Martin Lynn 
Published: December 2019

ABSTRACT
PURPOSE: To report our surgical technique for LASIK enhancement by ablating the underside of the flap.
METHODS: Surgical case report of clinical outcomes in three eyes of two patients who had an initial laser ablation in the bed with subsequent enhancements on the underside of the flap.
RESULTS: Following LASIK enhancement on the back of the flap, two eyes gained one line of best spectacle-corrected visual acuity (BSCVA) after treatment compared to preoperatively, going from 20/15 to 20/12, and one eye maintained BSCVA at 20/20.
CONCLUSIONS: Excimer laser ablation of the underside of the flap is a viable alternative to treat corneas with minimal residual tissue whether primary or enhancement procedures are needed. A surgical learning curve exists with this technique. [J Refract Surg. 2005;21(Suppl): S610-S613.]
Screening Patients With the Corneal Navigator
Authors: Klyce Stephen D , Karon Michael D , Smolek Michael K 
Published: December 2019

ABSTRACT
PURPOSE: To present a corneal topography screening device for the detection of corneal ectasias and various refractive procedures based on corneal topography patterns.
METHODS: A database of corneal topography patterns were analyzed and used to "train" a neural network on nine different corneal topography patterns using nineteen corneal topography indices of corneal shape and power.
RESULTS: Sample normal and corneal topographies were recognized correctly.
CONCLUSIONS: The use of the corneal navigator to screen various corneal topographies aids clinical diagnosis. [J Refract Surg. 2005;21(Suppl):S617-S622.]
Retinal Nerve Fiber Layer Changes After LASIK Evaluated With Optical Coherence Tomography
Authors: Dementyev Dmitriy D , Kourenkov Vyacheslav V , Rodin Alexander S , Fadeykina Tatyana L , Martinez Tatyana E Diaz 
Published: December 2019

ABSTRACT
PURPOSE: To determine whether the increase in intraocular pressure (IOP) during LASIK suction can induce a decrease in retinal nerve fiber layer thickness assessed by optical coherence tomography (OCT).
METHODS: Nineteen patients (38 eyes) were enrolled in the study. Intraocular pressure was normal at all preand postoperative examinations. Retinal nerve fiber layer thickness was measured using OCT-3 Stratus prior to and 1 week and 3 months after LASIK. Laser in situ keratomileusis was performed using the Bausch & Lomb Hansatome microkeratome and the NIDEK EC-5000 excimer laser. Optical coherence tomography mean retinal nerve fiber layer thickness values before and after LASIK were compared using the Student paired t test.
RESULTS: Mean patient age was 27.8 years (range: 18 to 33 years). Mean preoperative spherical equivalent refractive error was -4.9 diopters (D) (range: -2.0 to -8.5 D). Mean time of microkeratome suction was 30 seconds (range: 20 to 50 seconds). Preoperatively, the mean retinal nerve fiber layer thickness obtained by OCT was 104.2±9.0 µm; at 1 week postoperatively the mean thickness was 101.9±6.9 µm, and 106.7±6.1 µm at 3 months postoperatively. Mean retinal nerve fiber layer thicknesses obtained by OCT were not significantly different between preoperative and 1 week and 3 months after LASIK (P≥.05).
CONCLUSIONS: Laser in situ keratomileusis performed on young myopic patients does not have a significant effect on retinal nerve fiber layer thickness determined by OCT. Further studies are required to reveal the risk of possible optic nerve or retinal nerve fiber layer damage by elevated IOP during LASIK. [J Refract Surg. 2005;21(Suppl):S623-S627.]
Five Techniques for Improving Outcomes of Hyperopic LASIK
Authors: Zaldivar Roberto , Orcherow Susana , Bains Harkaran S 
Published: December 2019

ABSTRACT
PURPOSE: To determine whether five changes to our hyperopic LASIK protocol produced better outcomes.
METHODS: Five changes, both technical and surgical, were instituted for the treatment of hyperopia. These five changes were nomogram refinements accounting for accommodation, use of a 7.0-mm optical zone and a 9.5-mm transition zone, a targeted mean flap diameter of 10.5 mm, sequential interruption of the laser ablation, and cleaning of the interface. The study comprised 43 eyes undergoing LASIK for hyperopia or hyperopic astigmatism with a mean preoperative spherical equivalent refraction of +2.28 diopters (D), a mean sphere of +1.93 D (range: +4.25 to +0.25 D), and mean cylinder of +1.10 D (range: +4.50 to +0.25 D). The NIDEK CXII excimer laser was used for all treatments.
RESULTS: From 1 day to 3 months postoperatively, the mean hyperopic shift was <0.50 D. Postoperatively, the number of patients achieving a distance best spectacle-corrected visual acuity (BSCVA) of 20/20 gradually increased to 93% by 3 months. The number of eyes that achieved 20/15 increased by 11.7% compared to preoperatively. Eighty-eight percent of eyes maintained or gained lines of BSCVA. Four patients lost 1 line of BSCVA. One patient lost >1 line of vision due to visually significant microstriae.
CONCLUSIONS: The outcomes support the observation that five surgical and technical modifications to the hyperopic LASIK procedure result in excellent visual quality and refractive outcomes and a low rate of regression. [J Refract Surg. 2005;21(Suppl):S628-S632.]
Wavefront-guided LASIK With the NIDEK NAVEX Platform for the Correction of Myopia and Myopic Astigmatism With 6-month Follow-up
Authors: Venter Jan 
Published: December 2019

ABSTRACT
PURPOSE: To assess safety, efficacy, predictability, stability, and change in higher order aberrations after wavefront-guided LASIK for myopia and myopic astigmatism using the NIDEK NAVEX platform.
METHODS: Wavefront-guided LASIK was performed in 93 eyes in a 6-month trial with a goal of emmetropia. Treated eyes had a mean subjective manifest spherical equivalent refraction of -4.08±1.99 D diopters (D), with a range of -9.50 to -0.38 D of myopia and -4.50 to 0.00 D of astigmatism. An early nomogram with the OPDCAT software program provided by the manufacturer was used in all procedures. Safety, efficacy, predictability, stability, and change in higher order aberrations were evaluated at 6 months.
RESULTS: At 6 months, 100% eyes were within ±1.0 D of emmetropia and 95% eyes were within ±0.5 D. Uncorrected visual acuity (UCVA) of ≥1.0 was achieved in 89% of eyes, and 38% of eyes achieved UVCA of ≥1.2. No eyes lost ≥2 lines of best spectacle-corrected visual acuity (BSCVA), 25% of eyes gained 1 line, 3% gained 2 lines, and 1% gained ≥2 lines of BSCVA. Higher order root-mean-square (RMS) values increased by 19% on average between pre- and postoperative measurements. Eyes treated with higher order aberrations of <0.3 RMS showed on average an increase of 40% on preoperative values, whereas eyes with significant aberrations showed a decrease in aberrations following wavefront treatment.
CONCLUSIONS: Wavefront-guided ablation using the NIDEK NAVEX platform is safe, effective, and predictable. However, patients with low amounts of aberrations showed an increase in aberrations following wavefront treatment, therefore, wavefront treatment may not be indicated or beneficial to every patient. [J Refract Surg. 2005;21(Suppl):S640-S645.]
Incidence of Complications During Flap Creation in LASIK Using the NIDEK MK-2000 Microkeratome in 26,600 Cases
Authors: Carrillo Carlos , Chayet Arturo S , Dougherty Paul J , Montes Miguel , Magallanes Roberto , Najman Jacobo , Fleitman Jacobo , Morales Alfredo 
Published: December 2019

ABSTRACT
PURPOSE: To evaluate the incidence of intraoperative complications using the NIDEK MK-2000 microkeratome during flap creation in LASIK.
METHODS: The incidence of intraoperative flap complications during LASIK using the NIDEK MK-2000 microkeratome was retrospectively studied in 26,600 procedures performed in 5 outpatient excimer laser surgery centers.
RESULTS: A total of 65 (0.244%) complications were identified: 23 (0.086%) eyes had free caps, 13 (0.049%) eyes had an incomplete pass, 13 (0.049%) eyes had an epithelial defect, 11 (0.041%) eyes had buttonhole, and 5 (0.019%) eyes had irregular flap. The remaining 26,535 (99.756%) eyes had uneventful flap creation.
CONCLUSIONS: Use of the NIDEK MK-2000 microkeratome resulted in a low incidence of intraoperative complications, making it a safe and reliable device for creating flaps during LASIK. [J Refract Surg. 2005;21(Suppl): S655-S657.]
Comparison of LASIK Outcomes With the Alcon LADARVision4000 and the VISX STAR S2 Excimer Lasers Using Optimized Nomograms
Authors: Gailitis Raymond P 
Published: December 2019

ABSTRACT
PURPOSE: To evaluate the difference in clinical outcomes between LASIK patients treated with the Alcon LADARVision4000 laser and the VISX STAR S2 laser using optimized nomograms.
METHODS: Data from 572 UVSIK surgeries of two groups that were sequentially performed by one surgeon were retrospectively reviewed. The first group of 286 eyes were the last cases performed with the VISX STAR S2 laser. Following these surgeries, a second group of 286 eyes were the first cases performed with the Alcon LADARVision4000 laser, after an initial 50-eye adaptation period. Treatments were guided by the Refractive Surgery Consultant software.
RESULTS: For myopic eyes 3 months postoperatively, the percentage of eyes with uncorrected visual acuity (UCVA) ^20/20, accuracy of treatment within ?0.5 D, and loss of s=2 lines of best spectacle-corrected visual acuity (BSCVA) for the LADARVision4000 and STAR S2, respectively was: 89% vs 63%, 84% vs 80%, and 0.8% vs 3.8%. For hyperopic eyes 3 months postoperatively, the percentage of eyes with UCVA ^ 20/20, accuracy of treatment within ?0.5 D, and loss of >2 lines of BSCVA for the LADARVision4000 and STAR S2, respectively was: 74% vs 33%, 69% vs 74%, and 2% vs 18.5%.
CONCLUSIONS: Although good results are evident for both platforms, superior results were observed with the Alcon l_ADARVision4000 laser. [J Refract Surg. 2005;21:683-690.]
LASIK for Myopia With the Zeiss Meditec MEL 80
Authors: Goes Frank Josef 
Published: December 2019

ABSTRACT
PURPOSE: To prospectively evaluate a new high-speed, small spot-scanner laser for the correction of myopia and myopic astigmatism.
METHODS: Seventy-six consecutive eyes with myopia and myopic astigmatism between -1.00 and -8.25 diopters (D) and up to -2.75 D astigmatism underwent LASIK treatment using the MEL 80 laser (Carl Zeiss M?dit?e, Jena, Germany). Parameters evaluated were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), residual refractive error, regression of correction, and aberrometry.
RESULTS: Mean preoperative BSCVA was 20/20, which improved to 20/18 postoperatively. Postoperative UCVA was 20/20 at 1 month and 20/18 at 1 year. Uncorrected visual acuity ≥20/20 was achieved in 58 (83%) of 70 eyes at 1 month and in 60 (88%) of 68 eyes at 1 year. The average refractive error before LASIK was -4.41±1.98 D. The mean residual refractive error was 0.14±0.31 D at 1 month and 0.13±0.30 D at 1 year. At 1-month and 1-year follow-up, respectively, 66 (94%) of 70 eyes and 65 (96%) of 68 eyes were within ±0.50 D of intended refractive correction. No eye lost two lines. At 1 month 17% of eyes and at 1 year 13% of eyes gained two lines or more. Between 1- month and 1-year follow-up, 100% of eyes were stable. Mean rootmean-square high order aberration changed from 0.20 µm preoperative Iy to 0.28 µm postoperatively.
CONCLUSIONS: The MEL 80 is effective and safe in the treatment of myopia and myopic astigmatism. [J Refract Surg. 2005;21:691-697.]
Comparison of Ablation Centration After Bilateral Sequential Versus Simultaneous LASIK
Authors: Lin Jane-Ming , Tsai Yi-Yu 
Published: December 2019

ABSTRACT
PURPOSE: To compare ablation centration after bilateral sequential and simultaneous myopic LASIK.
METHODS: A retrospective randomized case series was performed of 670 eyes of 335 consecutive patients who had undergone either bilateral sequential (group 1) or simultaneous (group 2) myopic LASIK between July 2000 and July 2001 at the China Medical University Hospital, Taichung, Taiwan. The ablation centrations of the first and second eyes in the two groups were compared 3 months postoperatively.
RESULTS: Of 670 eyes, 274 eyes (137 patients) comprised the sequential group and 396 eyes (198 patients) comprised the simultaneous group. Three months postoperatively, 220 eyes of 110 patients (80%) in the sequential group and 236 eyes of 118 patients (60%) in the simultaneous group provided topographic data for centration analysis. For the first eyes, mean decent ration was 0.39±0.26 mm in the sequential group and 0.41 ±0.19 mm in the simultaneous group (P= .30). For the second eyes, mean decentration was 0.28±0.23 mm in the sequential group and 0.30±0.21 mm in the simultaneous group (P=. 36). Decentration in the second eyes significantly improved in both groups (group 1, P =.02; group 2, P<.01). The mean distance between the first and second eyes was 0.31±0.25 mm in the sequential group and 0.32±0.18 mm in the simultaneous group (P=.33). The difference of ablation center angles between the first and second eyes was 43.2 ±48.3° in the sequential group and 45.1±50.8° in the simultaneous group (P =.42).
CONCLUSIONS: Simultaneous bilateral LASIK is comparable to sequential surgery in ablation centration. [J Refract Surg. 2005;21:705-708.]
Effect of Topical Vitamin E on Ethanol-induced Corneal Epithelial Apoptosis
Authors: Bilgihan Kamil , Konuk Onur , Hondur Ahmet , Akyürek Nalan , Özogul Candan , Hasanreisoglu Berati 
Published: December 2019

ABSTRACT
PURPOSE: Ethanol is used to loosen the corneal epithelium before photoablation in laser subepithelial keratomileusis (LASEK). In this study, the apoptotic index of corneal epithelium after ethanol exposure and the effects of topical vitamin E were evaluated.
METHODS: The study was performed on 28 rabbit eyes in four groups. Group 1 comprised the controls. In group 2, 20% ethanol was applied topically for 20 seconds. In group 3, topical vitamin E was applied following 20% ethanol application. In group 4, only topical vitamin E was applied. Apoptosis was evaluated with TUNEL assay and transmission electron microscopy.
RESULTS: Epithelial apoptosis was detected in all specimens in group 2. No apoptosis was detected in other groups except for one eye in group 1. The apoptotic index in group 2 was statistically higher than other groups (P<.001).
CONCLUSIONS: Topical vitamin E can prevent ethanol-induced apoptosis in the corneal epithelium in rabbits. [J Refract Surg, 2005;21:761-763.]