Excimer laser correction of moderate to high astigmatism with a non‐wavefront‐guided aberration‐free ablation profile: Six‐month results

PURPOSE: To evaluate the postoperative clinical outcomes and higher‐order aberrations (HOAs) in eyes with astigmatism greater than 2.00 diopters (D) that had laser in situ keratomileusis (LASIK) using a non‐wavefront‐guided aberration‐free ablation profile. SETTINGS: Private practice. METHODS: This retrospective study evaluated the 6‐month results of LASIK for astigmatism greater than 2.00 D. Standard examinations and preoperative and postoperative wavefront analyses were performed. Aspheric treatments with a non‐wavefront‐guided ablation profile were planned using software integrated into the Amaris flying‐spot excimer laser system, which was used to perform the ablations. The LASIK flaps were created using an LDV femtosecond laser. Clinical outcomes were predictability, refractive outcomes, safety, efficacy, and wavefront aberration. RESULTS: At 6 months, 84% of the 50 eyes evaluated achieved 20/20 or better uncorrected distance visual acuity (UDVA) and 40% achieved 20/16 or better UDVA. Forty‐four percent of eyes were within ±0.25 D of the attempted astigmatic correction, and 78% were within ±0.50 D. The mean SE was −0.12 D ± 0.25 (SD) and the mean astigmatism, 0.50 ± 0.26 D. Corrected distance visual acuity (CDVA) improved in 36% of eyes; 4% of eyes lost 1 line of CDVA. The predictability slope for astigmatism was 0.97 and the intercept, −0.15 D. There were no clinically relevant changes in any aberration metric from preoperatively to postoperatively. CONCLUSIONS: Excimer laser LASIK using a non‐wavefront‐guided aberration‐free ablation profile yielded excellent visual outcomes. The preoperative astigmatism was reduced to subclinical values with no clinically relevant induction of HOA.

[1]  W. F. Harris,et al.  Representation of dioptric power in Euclidean 3‐space , 1991, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[2]  Y. Morad,et al.  Excimer laser photoastigmatic refractive keratectomy: eighteen-month follow-up. , 1998, Ophthalmology.

[3]  H. Taylor,et al.  Excimer laser correction of astigmatism with multipass/multizone treatment , 1998, Journal of cataract and refractive surgery.

[4]  M. Mrochen,et al.  Wavefront‐optimized ablation profiles: Theoretical background , 2004, Journal of cataract and refractive surgery.

[5]  One year follow-up of photoastigmatic keratectomy (PARK) with the VISX 20/20 excimer laser. , 1996, Ophthalmic surgery and lasers.

[6]  Michael Mrochen,et al.  Simulation of eye-tracker latency, spot size, and ablation pulse depth on the correction of higher order wavefront aberrations with scanning spot laser systems. , 2005, Journal of refractive surgery.

[7]  J. Garbus,et al.  Photorefractive keratectomy to create toric ablations for correction of astigmatism. , 1991, Archives of ophthalmology.

[8]  Sergio Barbero,et al.  Increase in corneal asphericity after standard laser in situ keratomileusis for myopia is not inherent to the Munnerlyn algorithm. , 2003, Journal of refractive surgery.

[9]  D. Azar,et al.  Analysis of customized corneal ablations: theoretical limitations of increasing negative asphericity. , 2002, Investigative ophthalmology & visual science.

[10]  C. Munnerlyn,et al.  Photorefractive keratectomy: A technique for laser refractive surgery , 1988, Journal of cataract and refractive surgery.

[11]  A. Calossi.  Corneal asphericity and spherical aberration. , 2007, Journal of refractive surgery.

[12]  C. Barraquer,et al.  Results of laser in situ keratomileusis in hyperopic compound astigmatism. , 1999, Journal of cataract and refractive surgery.

[13]  T. Seiler,et al.  Influence of corneal curvature on calculation of ablation patterns used in photorefractive laser surgery. , 2001, Journal of refractive surgery.

[14]  J. Wollensak,et al.  Side effects in excimer corneal surgery , 2005, Graefe's Archive for Clinical and Experimental Ophthalmology.

[15]  RENZO MATTIOLI,et al.  Corneal Geometry Reconstruction with the Keratron Videokeratographer , 1997, Optometry and vision science : official publication of the American Academy of Optometry.

[16]  Enrique Hita,et al.  Correction factor for ablation algorithms used in corneal refractive surgery with gaussian-profile beams. , 2005, Optics express.

[17]  Samuel Arba-Mosquera,et al.  Geometrical analysis of the loss of ablation efficiency at non-normal incidence. , 2008, Optics express.

[18]  Laser in Situ Keratomileusis for Mixed Astigmatism Using a Modified Formula for Bitoric Ablation , 2008, European journal of ophthalmology.

[19]  Power vectors versus power matrices, and the mathematical nature of dioptric power. , 2007, Optometry and vision science : official publication of the American Academy of Optometry.

[20]  Jorge L Alió,et al.  Topography-guided laser in situ keratomileusis (TOPOLINK) to correct irregular astigmatism after previous refractive surgery. , 2003, Journal of refractive surgery.

[21]  E. Hita,et al.  Effect on laser-ablation algorithms of reflection losses and nonnormal incidence on the anterior cornea , 2002 .

[22]  P. Carpineto,et al.  Photorefractive keratectomy with aspheric profile of ablation versus conventional photorefractive keratectomy for myopia correction: Six‐month controlled clinical trial , 2006, Journal of cataract and refractive surgery.

[23]  G O Waring,et al.  Multiple regression and vector analyses of laser in situ keratomileusis for myopia and astigmatism. , 1999, Journal of refractive surgery.

[24]  U. Gabbay,et al.  One-year follow-up results of photorefractive keratectomy for low, moderate, and high primary astigmatism. , 1996, Ophthalmology.

[25]  W. F. Harris,et al.  Closed Surfaces of Constant Visual Acuity in Symmetric Dioptric Power Space , 2001, Optometry and vision science : official publication of the American Academy of Optometry.

[26]  L. Thibos,et al.  Standards for reporting the optical aberrations of eyes. , 2002, Journal of refractive surgery.

[27]  M. Azzolini,et al.  Photorefractive keratectomy to correct myopic or hyperopic astigmatism with a cross-cylinder ablation. , 1999, Journal of refractive surgery.

[28]  T. Seiler,et al.  Q‐factor customized ablation profile for the correction of myopic astigmatism , 2006, Journal of cataract and refractive surgery.

[29]  Theo Seiler,et al.  Correlation between corneal and total wavefront aberrations in myopic eyes. , 2003, Journal of refractive surgery.

[30]  David Huang,et al.  Spot size and quality of scanning laser correction of higher‐order wavefront aberrations , 2002, Journal of cataract and refractive surgery.

[31]  M. Arbelaez,et al.  Central ablation depth and postoperative refraction in excimer laser myopic correction measured with ultrasound, Scheimpflug, and optical coherence pachymetry. , 2009, Journal of refractive surgery.

[32]  K. Fry,et al.  Spherical aberration after laser in situ keratomileusis and photorefractive keratectomy: Clinical results and theoretical models of etiology , 2003, Journal of cataract and refractive surgery.

[33]  Theo Seiler,et al.  Clinical results of wavefront‐guided laser in situ keratomileusis 3 months after surgery , 2001, Journal of cataract and refractive surgery.

[34]  F. Zernike.  Diffraction theory of the knife-edge test and its improved form, the phase-contrast method , 1934 .

[35]  Junzhong Liang,et al.  Objective measurement of wave aberrations of the human eye with the use of a Hartmann-Shack wave-front sensor. , 1994, Journal of the Optical Society of America. A, Optics, image science, and vision.

[36]  Samuel Arba-Mosquera,et al.  Clinical effects of pure cyclotorsional errors during refractive surgery. , 2008, Investigative ophthalmology & visual science.

[37]  David Williams,et al.  Causes of spherical aberration induced by laser refractive surgery , 2005, Journal of cataract and refractive surgery.

[38]  O. Ibrahim.  Laser in situ keratomileusis for hyperopia and hyperopic astigmatism. , 1998, Journal of refractive surgery.

[39]  Lisa Toto,et al.  Prospective randomized comparison of wavefront-guided and conventional photorefractive keratectomy for myopia with the meditec MEL 70 laser. , 2004, Journal of refractive surgery.

[40]  R. Maloney,et al.  Excimer laser ablation rate and corneal hydration. , 1994, American journal of ophthalmology.

[41]  M. Cosentino,et al.  Treatment of hyperopic astigmatism , 1997, Journal of cataract and refractive surgery.

[42]  R Navarro,et al.  Ocular aberrations before and after myopic corneal refractive surgery: LASIK-induced changes measured with laser ray tracing. , 2001, Investigative ophthalmology & visual science.

[43]  Samuel Arba-Mosquera,et al.  Clinical outcomes of corneal vertex versus central pupil references with aberration-free ablation strategies and LASIK. , 2008, Investigative ophthalmology & visual science.

[44]  David R Williams,et al.  Effect of beam size on the expected benefit of customized laser refractive surgery. , 2003, Journal of refractive surgery.

[45]  M. Mrochen,et al.  [Aspheric optics: physical fundamentals]. , 2008, Der Ophthalmologe : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft.

[46]  B. Cochener,et al.  Excimer laser treatment of myopic astigmatism. A comparison of three ablation programs. , 1998, Ophthalmology.

[47]  W S Kim,et al.  Corneal Hydration Affects Ablation During Laser In Situ Keratomileusis Surgery , 2001, Cornea.

[48]  T. Seiler,et al.  Ocular optical aberrations after photorefractive keratectomy for myopia and myopic astigmatism. , 2000, Archives of ophthalmology.