Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You and Your Team.

Learn More →

Laser-Assisted In Situ Keratomileusis Posterior Ablation Platform

Laser-Assisted In Situ Keratomileusis Posterior Ablation Platform A laser-assisted in situ keratomileusis posterior ablation platform was developed to improve the ease and quality of the undersurface ablation of the flap technique. This ergonomic instrument combines a fixation ring with a platform that provides a physiologically spherical and smooth, low-reflective surface to extend the turned flap during the undersurface ablation of the flap retreatment. It was used successfully in 17 enhancement procedures when there was insufficient posterior stroma for additional treatment but adequate flap stroma. The result was improved globe stabilization and stromal smoothness during ablation. An efficacy index of 1 was achieved day 1 postoperatively in a greater percentage of eyes (88.2%) than without its use (29.4%; P = .001). The L-PAP appears to facilitate UAF procedures and prompt visual recovery.Undersurface ablation of the flap (UAF) effectively reduces low-refractive errors after laser-assisted in situ keratomileusis (LASIK) in eyes with sufficient flap stroma.Considering the risk of keratectasia after primary LASIK and in-the-bed retreatment,this posterior stromal sparing technique may be advantageous.However, satisfactory globe stabilization and stromal smoothness during ablation are more difficult to achieve with UAF than with conventional LASIK enhancements.To make UAF procedures easier and more refined, the LASIK posterior ablation platform (L-PAP) was devised. The rationale behind this development was to improve both the comfort of the procedure for the surgeon and the patient and also the quality of the surface undergoing ablation so that more patients might benefit from a retreatment technique conceived to prevent future keratectasia.The aims of this study were therefore to describe the L-PAP and to evaluate its use clinically.METHODSThis study followed the principles outlined in the Declaration of Helsinki. All candidates received detailed information about the potential risks and benefits of the procedure, and all provided informed consent. This project was approved by the University of Navarra clinic review committee.The L-PAP is a novel, reusable instrument that combines the functions of a globe fixation ring and a unique platform upon which the reflected lenticule can be extended (Figure, A). The instrument consists of a ring mounted on an angled handle, which allows the surgeon to comfortably hold the instrument in a nasal, superior, or oblique position without obscuring the viewing area of the microscope. The 12-mm inner diameter of the ring facilitates enhanced fixation of the eyeball during ablation, enabling 1-handed globe stabilization. Patient comfort is improved by the even distribution of pressure against the conjunctiva and sclera (the ring features a total of 15 smooth teeth). The convexity of the platform is devised to match the normal corneal curvature (Figure, B), and the finish is glass-beaded to provide a surface of low reflectivity for maximum ease of use under the surgical microscope lighting.Figure.A, The laser-assisted in situ keratomileusis posterior ablation platform (L-PAP) consists of a ring mounted on a swivel handle for nasal, superior, or oblique approaches. B, Details of the head show the platform featuring a physiologically spherical and smooth, low-reflective surface to extend the turned flap during the undersurface ablation of the flap procedure. C, The procedure begins with the marking of the optical axis and the pararadial and 180° meridian lines. The flap is lifted while the eye is deviated downward so that the corneal visual axis mark aligns with the laser beam. D, A drop of lubricant is instilled on the platform, which is then slipped under the flap. The stromal bed adjacent to the hinge is covered with a laser-assisted in situ keratomileusis shield. A blunt-angled instrument may be used to further smooth the flap stroma. E, A mirror-pattern ablation with a 5-mm optical zone is performed. The finish of the L-PAP allows for easy recognition of the corneal visual axis mark for correct centration. The ablated surface appears fairly smooth when it is extended over the L-PAP. F, Intraoperative view of the same undersurface of the flap technique without the use of the L-PAP shows a suboptimal surface for ablation due to the presence of undulations on the flap stroma.Undersurface ablation of the flap retreatment procedures were performed in 17 eyes according to the previously described indications (postretreatment flap thickness >150 &mgr;m to preserve the Bowman layer) and technique.Briefly, the optical axis was carefully marked (Figure, C), and further corneal marks were placed in the 180° meridian for toric ablations. A flap rhexis techniquewas used to elevate the flap. Intraoperative pachymetrywas performed to verify the corneal thickness. Adequate exposure of the flap stroma was achieved by requesting that the patient look downward in superiorly hinged procedures (n = 15) and temporally in nasally hinged procedures (n = 2). The platform was moistened with 1.75% unpreserved methylcellulose to provide a lubricated surface for the health of the corneal epithelium and to increase the surface tension for achieving enhanced flap adhesion to the L-PAP (Figure, D). The exposed stromal bed was covered by a particulate-free LASIK shield to avoid the most peripheral ablation of the transition zone. With the aid of a blunt-angled instrument (spatula or forceps) or a blunt-tipped LASIK spear, the flap was outwardly flattened over the convexity of the platform to resolve folds. After accurate centration of the laser-aiming beam on the marked visual axis, photoablation was performed with the eye-tracker turned off (Figure, E). In every case, the full correction was administered using a 5-mm optical zone. The formula β = 180°−α was used to calculate new axis orientation (β) from the original axis orientation of the cylinder (α) for toric ablations on the flap stroma.RESULTSThe average ± SD patient age was 35.9 ± 9.2 years (range, 27-55 years). The mean spherical equivalent refraction before retreatment was −1.0 ± 0.59 diopter (D) (range, −0.5 to −2.0 D) and decreased to −0.06 ± 0.14 D (range, 0 to −0.5 D) 6 months after UAF enhancement (P = .001, paired ttest). The average refractive astigmatism before enhancement was −0.47 ± 0.35 D (range, 0 to −1.0 D) and decreased to −0.07 ± 0.25 D (range, 0 to −1.0 D) at 6 months (P = .001, paired ttest). Before retreatment, 6 (35.3%) of 17 eyes had an uncorrected visual acuity of 20/25 or better, and 6 months postoperatively, 15 (88.2%) of 17 eyes achieved 20/25 uncorrected visual acuity (P = .02, McNemar test). The efficacy and safety indicesof the procedure were 0.96 and 0.98, respectively. No retreated eye lost or gained 2 or more lines of best-corrected visual acuity.The mean central corneal thickness decreased from 446 ± 18 μm (range, 405-472 μm) before retreatment to 432 ± 20 μm (range, 388-456 μm) at 6 months (P = .001, paired ttest). The average central cap thickness before UAF was 182 ± 12 μm (range, 160-228 μm) and decreased to 168 ± 11 μm (range, 152-206 μm) at 6 months (P = .001, paired ttest).In every case, L-PAP was successfully used without encountering any major difficulty or complication. Some eyes with tight palpebral fissures required full ocular deviation for complete insertion of the ring. In only 1 (5.9%) of 17 cases, the patient reported some discomfort due to the pressure created by the L-PAP. Globe stabilization was generally better than before using the L-PAP, and the procedures tended to proceed more quickly. Stromal smoothness during ablation improved substantially with the use of the L-PAP (Figure, E and F). In addition, the postoperative visual recovery seemed to be more rapid. The proportion of eyes that achieved an uncorrected visual acuity that was equal to the pre-UAF best-corrected visual acuity (efficacy index = 1)was analyzed 1 day postoperatively and compared with another 17 eyes that were group-matched for age, sex, and refractive error and that underwent UAF without the L-PAP.An efficacy index of 1 was attained in 15 (88.2%) of 17 procedures in which L-PAP was used and in 5 (29.4%) of 17 procedures when no specific instrumentation was used (P = .001, Fisher exact test). Tangential topographic analysis disclosed well-centered ablations in relation to the entrance pupil in every case.COMMENTThe L-PAP was successfully used in every attempted UAF surgery and provided improved globe stabilization and stromal smoothness during ablation. In addition, an efficacy index of 1 was achieved on the first postoperative day in a greater proportion of eyes than without its use.Formerly, patients often had difficulty maintaining fixation during UAF.Although patient cooperation continues to play an important role in these procedures, the L-PAP ring meliorates this. In turn, procedures tend to take less time. Furthermore, more rapidly performed surgeries are associated with less corneal epithelial dehydration, which helps maintain a wrinkle-free stromal surface for the ablation of the posterior flap and diminishes the degree of superficial epitheliopathy, which allows quicker visual recovery.With L-PAP, because the flap is extended over a surface that resembles the curvature of the physiologic central cornea, the smoothness and quality of the ablative surface are surpassed (Figure, E). Previously,the flap was laid out on the bulbar conjunctiva, but the flatter curvature of the limbus and sclera compared with that of the central cornea led to wrinkling of the upward exposed flap stromal surface (Figure, F). When the platform of the instrument is moistened with a lubricating fluid, the flap maintains adequate epithelial hydration that further helps in achieving a wrinkle-free surface during the ablative procedure and allows the flap to remain folded back because of the associated increase in surface tension. Beyond that, applying outward posterior pressure to the LASIK flap lying over the platform with a blunt-angled instrument or a blunt-tipped LASIK spear resolves intraoperative flap folds. All these improvements permit a superior-quality ablative procedure that provides more rapid early visual rehabilitation, as the statistical analysis of this series showed.In summary, this new instrument is an ergonomically designed combination of a fixation ring with a platform that provides a physiologically spherical and smooth low-reflective surface to extend the turned flap during LASIK enhancement procedures. This facilitates treating the stroma at the back of the flap in the UAF retreatment technique, a surgical approach conceived to save stromal bed tissue and thus prevent future keratectasia.Early experience indicates that this novel instrument simplifies and upgrades the UAF procedure.Correspondence:Miguel J. Maldonado, MD, PhD, Department of Ophthalmology, University Clinic, University of Navarra, Avenida Pío XII, 36, 31080 Pamplona, Spain (mjmaldonad@unav.es).Submitted for Publication:December 15, 2003; final revision received January 20, 2005; accepted February 8, 2005.REFERENCESMJMaldonadoUndersurface ablation of the flap for laser in situ keratomileusis retreatment.Ophthalmology20021091453146412153795SDMcLeodTAKislaNCCaroTTMcMahonIatrogenic keratoconus: corneal ectasia following laser in situ keratomileusis for myopia.Arch Ophthalmol200011828228410676799NSJabburWJStarkWRGreenCorneal ectasia after laser-assisted in situ keratomileusis.Arch Ophthalmol20011191714171611709027TKohnenIatrogenic keratectasia: current knowledge, current measurements.J Cataract Refract Surg2002282065206612498819RJOuELShawBJGlasgowKeratectasia after laser in situ keratomileusis (LASIK): evaluation of the calculated residual stromal bed thickness.Am J Ophthalmol200213477177312429260LSpadeaGPalmieriLMoscaRFascianiEBalestrazziIatrogenic keratectasia following laser in situ keratomileusis.J Refract Surg20021847548012160161TSeilerKKoufalaGRichterIatrogenic keratectasia after laser in situ keratomileusis.J Refract Surg1998143123179641422IGPallikarisGDKymionisNIAstyrakakisCorneal ectasia induced by laser in situ keratomileusis.J Cataract Refract Surg2001271796180211709254CArgentoMJCosentinoATytiunGRapettiJZarateCorneal ectasia after laser in situ keratomileusis.J Cataract Refract Surg2001271440144811566530WALyleGJJinLaser in situ keratomileusis with the VISX Star laser for myopia over –10 diopters.J Cataract Refract Surg2001271812182211709256HSGeggelARTalleyDelayed onset keratectasia following laser in situ keratomileusis.J Cataract Refract Surg19992558258610198868MGMulhernPICondonMO’KeefeMyopic and hyperopic laser in situ keratomileusis retreatments: indications, techniques, limitations, and results.J Cataract Refract Surg2001271278128711524201ARaniBRMurthyNSharmaPosterior corneal topographic changes after retreatment LASIK.Ophthalmology20021091991199512414404MJMaldonadoLRuiz-OblitasJMMunueraDAlisedaAGarcía-LayanaJMoreno-MontañésOptical coherence tomography evaluation of the corneal cap and stromal bed features after laser in situ keratomileusis for high myopia and astigmatism.Ophthalmology2000107818810647724JJPérez-SantonjaMMedranoJMRuiz-MorenoCCardona-AusinaJLAlióFlaprhexis circular: una técnica minuciosa para el retratamiento tras LASIK.Arch Soc Esp Oftalmol20017630330811373706MJMaldonadoJRJuberíasRRodríguez-CondeCorneal flap thickness and tissue laser ablation in myopic LASIK.Ophthalmology20021091042104312045038DDKochTKohnenSAObstbaumESRosenFormat for reporting refractive surgical data.J Cataract Refract Surg1998242852879559453 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png JAMA Ophthalmology American Medical Association

Laser-Assisted In Situ Keratomileusis Posterior Ablation Platform

JAMA Ophthalmology , Volume 123 (7) – Jul 1, 2005

Loading next page...
 
/lp/american-medical-association/laser-assisted-in-situ-keratomileusis-posterior-ablation-platform-8os6GGBSRP
Publisher
American Medical Association
Copyright
Copyright 2005 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.
ISSN
2168-6165
eISSN
2168-6173
DOI
10.1001/archopht.123.7.988
pmid
16009842
Publisher site
See Article on Publisher Site

Abstract

A laser-assisted in situ keratomileusis posterior ablation platform was developed to improve the ease and quality of the undersurface ablation of the flap technique. This ergonomic instrument combines a fixation ring with a platform that provides a physiologically spherical and smooth, low-reflective surface to extend the turned flap during the undersurface ablation of the flap retreatment. It was used successfully in 17 enhancement procedures when there was insufficient posterior stroma for additional treatment but adequate flap stroma. The result was improved globe stabilization and stromal smoothness during ablation. An efficacy index of 1 was achieved day 1 postoperatively in a greater percentage of eyes (88.2%) than without its use (29.4%; P = .001). The L-PAP appears to facilitate UAF procedures and prompt visual recovery.Undersurface ablation of the flap (UAF) effectively reduces low-refractive errors after laser-assisted in situ keratomileusis (LASIK) in eyes with sufficient flap stroma.Considering the risk of keratectasia after primary LASIK and in-the-bed retreatment,this posterior stromal sparing technique may be advantageous.However, satisfactory globe stabilization and stromal smoothness during ablation are more difficult to achieve with UAF than with conventional LASIK enhancements.To make UAF procedures easier and more refined, the LASIK posterior ablation platform (L-PAP) was devised. The rationale behind this development was to improve both the comfort of the procedure for the surgeon and the patient and also the quality of the surface undergoing ablation so that more patients might benefit from a retreatment technique conceived to prevent future keratectasia.The aims of this study were therefore to describe the L-PAP and to evaluate its use clinically.METHODSThis study followed the principles outlined in the Declaration of Helsinki. All candidates received detailed information about the potential risks and benefits of the procedure, and all provided informed consent. This project was approved by the University of Navarra clinic review committee.The L-PAP is a novel, reusable instrument that combines the functions of a globe fixation ring and a unique platform upon which the reflected lenticule can be extended (Figure, A). The instrument consists of a ring mounted on an angled handle, which allows the surgeon to comfortably hold the instrument in a nasal, superior, or oblique position without obscuring the viewing area of the microscope. The 12-mm inner diameter of the ring facilitates enhanced fixation of the eyeball during ablation, enabling 1-handed globe stabilization. Patient comfort is improved by the even distribution of pressure against the conjunctiva and sclera (the ring features a total of 15 smooth teeth). The convexity of the platform is devised to match the normal corneal curvature (Figure, B), and the finish is glass-beaded to provide a surface of low reflectivity for maximum ease of use under the surgical microscope lighting.Figure.A, The laser-assisted in situ keratomileusis posterior ablation platform (L-PAP) consists of a ring mounted on a swivel handle for nasal, superior, or oblique approaches. B, Details of the head show the platform featuring a physiologically spherical and smooth, low-reflective surface to extend the turned flap during the undersurface ablation of the flap procedure. C, The procedure begins with the marking of the optical axis and the pararadial and 180° meridian lines. The flap is lifted while the eye is deviated downward so that the corneal visual axis mark aligns with the laser beam. D, A drop of lubricant is instilled on the platform, which is then slipped under the flap. The stromal bed adjacent to the hinge is covered with a laser-assisted in situ keratomileusis shield. A blunt-angled instrument may be used to further smooth the flap stroma. E, A mirror-pattern ablation with a 5-mm optical zone is performed. The finish of the L-PAP allows for easy recognition of the corneal visual axis mark for correct centration. The ablated surface appears fairly smooth when it is extended over the L-PAP. F, Intraoperative view of the same undersurface of the flap technique without the use of the L-PAP shows a suboptimal surface for ablation due to the presence of undulations on the flap stroma.Undersurface ablation of the flap retreatment procedures were performed in 17 eyes according to the previously described indications (postretreatment flap thickness >150 &mgr;m to preserve the Bowman layer) and technique.Briefly, the optical axis was carefully marked (Figure, C), and further corneal marks were placed in the 180° meridian for toric ablations. A flap rhexis techniquewas used to elevate the flap. Intraoperative pachymetrywas performed to verify the corneal thickness. Adequate exposure of the flap stroma was achieved by requesting that the patient look downward in superiorly hinged procedures (n = 15) and temporally in nasally hinged procedures (n = 2). The platform was moistened with 1.75% unpreserved methylcellulose to provide a lubricated surface for the health of the corneal epithelium and to increase the surface tension for achieving enhanced flap adhesion to the L-PAP (Figure, D). The exposed stromal bed was covered by a particulate-free LASIK shield to avoid the most peripheral ablation of the transition zone. With the aid of a blunt-angled instrument (spatula or forceps) or a blunt-tipped LASIK spear, the flap was outwardly flattened over the convexity of the platform to resolve folds. After accurate centration of the laser-aiming beam on the marked visual axis, photoablation was performed with the eye-tracker turned off (Figure, E). In every case, the full correction was administered using a 5-mm optical zone. The formula β = 180°−α was used to calculate new axis orientation (β) from the original axis orientation of the cylinder (α) for toric ablations on the flap stroma.RESULTSThe average ± SD patient age was 35.9 ± 9.2 years (range, 27-55 years). The mean spherical equivalent refraction before retreatment was −1.0 ± 0.59 diopter (D) (range, −0.5 to −2.0 D) and decreased to −0.06 ± 0.14 D (range, 0 to −0.5 D) 6 months after UAF enhancement (P = .001, paired ttest). The average refractive astigmatism before enhancement was −0.47 ± 0.35 D (range, 0 to −1.0 D) and decreased to −0.07 ± 0.25 D (range, 0 to −1.0 D) at 6 months (P = .001, paired ttest). Before retreatment, 6 (35.3%) of 17 eyes had an uncorrected visual acuity of 20/25 or better, and 6 months postoperatively, 15 (88.2%) of 17 eyes achieved 20/25 uncorrected visual acuity (P = .02, McNemar test). The efficacy and safety indicesof the procedure were 0.96 and 0.98, respectively. No retreated eye lost or gained 2 or more lines of best-corrected visual acuity.The mean central corneal thickness decreased from 446 ± 18 μm (range, 405-472 μm) before retreatment to 432 ± 20 μm (range, 388-456 μm) at 6 months (P = .001, paired ttest). The average central cap thickness before UAF was 182 ± 12 μm (range, 160-228 μm) and decreased to 168 ± 11 μm (range, 152-206 μm) at 6 months (P = .001, paired ttest).In every case, L-PAP was successfully used without encountering any major difficulty or complication. Some eyes with tight palpebral fissures required full ocular deviation for complete insertion of the ring. In only 1 (5.9%) of 17 cases, the patient reported some discomfort due to the pressure created by the L-PAP. Globe stabilization was generally better than before using the L-PAP, and the procedures tended to proceed more quickly. Stromal smoothness during ablation improved substantially with the use of the L-PAP (Figure, E and F). In addition, the postoperative visual recovery seemed to be more rapid. The proportion of eyes that achieved an uncorrected visual acuity that was equal to the pre-UAF best-corrected visual acuity (efficacy index = 1)was analyzed 1 day postoperatively and compared with another 17 eyes that were group-matched for age, sex, and refractive error and that underwent UAF without the L-PAP.An efficacy index of 1 was attained in 15 (88.2%) of 17 procedures in which L-PAP was used and in 5 (29.4%) of 17 procedures when no specific instrumentation was used (P = .001, Fisher exact test). Tangential topographic analysis disclosed well-centered ablations in relation to the entrance pupil in every case.COMMENTThe L-PAP was successfully used in every attempted UAF surgery and provided improved globe stabilization and stromal smoothness during ablation. In addition, an efficacy index of 1 was achieved on the first postoperative day in a greater proportion of eyes than without its use.Formerly, patients often had difficulty maintaining fixation during UAF.Although patient cooperation continues to play an important role in these procedures, the L-PAP ring meliorates this. In turn, procedures tend to take less time. Furthermore, more rapidly performed surgeries are associated with less corneal epithelial dehydration, which helps maintain a wrinkle-free stromal surface for the ablation of the posterior flap and diminishes the degree of superficial epitheliopathy, which allows quicker visual recovery.With L-PAP, because the flap is extended over a surface that resembles the curvature of the physiologic central cornea, the smoothness and quality of the ablative surface are surpassed (Figure, E). Previously,the flap was laid out on the bulbar conjunctiva, but the flatter curvature of the limbus and sclera compared with that of the central cornea led to wrinkling of the upward exposed flap stromal surface (Figure, F). When the platform of the instrument is moistened with a lubricating fluid, the flap maintains adequate epithelial hydration that further helps in achieving a wrinkle-free surface during the ablative procedure and allows the flap to remain folded back because of the associated increase in surface tension. Beyond that, applying outward posterior pressure to the LASIK flap lying over the platform with a blunt-angled instrument or a blunt-tipped LASIK spear resolves intraoperative flap folds. All these improvements permit a superior-quality ablative procedure that provides more rapid early visual rehabilitation, as the statistical analysis of this series showed.In summary, this new instrument is an ergonomically designed combination of a fixation ring with a platform that provides a physiologically spherical and smooth low-reflective surface to extend the turned flap during LASIK enhancement procedures. This facilitates treating the stroma at the back of the flap in the UAF retreatment technique, a surgical approach conceived to save stromal bed tissue and thus prevent future keratectasia.Early experience indicates that this novel instrument simplifies and upgrades the UAF procedure.Correspondence:Miguel J. Maldonado, MD, PhD, Department of Ophthalmology, University Clinic, University of Navarra, Avenida Pío XII, 36, 31080 Pamplona, Spain (mjmaldonad@unav.es).Submitted for Publication:December 15, 2003; final revision received January 20, 2005; accepted February 8, 2005.REFERENCESMJMaldonadoUndersurface ablation of the flap for laser in situ keratomileusis retreatment.Ophthalmology20021091453146412153795SDMcLeodTAKislaNCCaroTTMcMahonIatrogenic keratoconus: corneal ectasia following laser in situ keratomileusis for myopia.Arch Ophthalmol200011828228410676799NSJabburWJStarkWRGreenCorneal ectasia after laser-assisted in situ keratomileusis.Arch Ophthalmol20011191714171611709027TKohnenIatrogenic keratectasia: current knowledge, current measurements.J Cataract Refract Surg2002282065206612498819RJOuELShawBJGlasgowKeratectasia after laser in situ keratomileusis (LASIK): evaluation of the calculated residual stromal bed thickness.Am J Ophthalmol200213477177312429260LSpadeaGPalmieriLMoscaRFascianiEBalestrazziIatrogenic keratectasia following laser in situ keratomileusis.J Refract Surg20021847548012160161TSeilerKKoufalaGRichterIatrogenic keratectasia after laser in situ keratomileusis.J Refract Surg1998143123179641422IGPallikarisGDKymionisNIAstyrakakisCorneal ectasia induced by laser in situ keratomileusis.J Cataract Refract Surg2001271796180211709254CArgentoMJCosentinoATytiunGRapettiJZarateCorneal ectasia after laser in situ keratomileusis.J Cataract Refract Surg2001271440144811566530WALyleGJJinLaser in situ keratomileusis with the VISX Star laser for myopia over –10 diopters.J Cataract Refract Surg2001271812182211709256HSGeggelARTalleyDelayed onset keratectasia following laser in situ keratomileusis.J Cataract Refract Surg19992558258610198868MGMulhernPICondonMO’KeefeMyopic and hyperopic laser in situ keratomileusis retreatments: indications, techniques, limitations, and results.J Cataract Refract Surg2001271278128711524201ARaniBRMurthyNSharmaPosterior corneal topographic changes after retreatment LASIK.Ophthalmology20021091991199512414404MJMaldonadoLRuiz-OblitasJMMunueraDAlisedaAGarcía-LayanaJMoreno-MontañésOptical coherence tomography evaluation of the corneal cap and stromal bed features after laser in situ keratomileusis for high myopia and astigmatism.Ophthalmology2000107818810647724JJPérez-SantonjaMMedranoJMRuiz-MorenoCCardona-AusinaJLAlióFlaprhexis circular: una técnica minuciosa para el retratamiento tras LASIK.Arch Soc Esp Oftalmol20017630330811373706MJMaldonadoJRJuberíasRRodríguez-CondeCorneal flap thickness and tissue laser ablation in myopic LASIK.Ophthalmology20021091042104312045038DDKochTKohnenSAObstbaumESRosenFormat for reporting refractive surgical data.J Cataract Refract Surg1998242852879559453

Journal

JAMA OphthalmologyAmerican Medical Association

Published: Jul 1, 2005

References