Laser in situ keratomileusis for the correction of residual ametropia after penetrating keratoplasty

PURPOSE: To evaluate the safety, efficacy, and predictability of excimer laser in situ keratomileusis (LASIK) to correct residual myopia and astigmatism after penetrating keratoplasty (PKP). SETTING: Buzard Eye Institute, Las Vegas, Nevada, USA. METHODS: Twenty-six eyes had LASIK at least 1 year after PKP. All eyes were followed for at least 6 months after LASIK; 22 eyes were followed for 12 months. Sutures were removed at a mean of 13 months post PKP. Laser in situ keratomileusis was performed with the Chiron Automated Corneal Shaper microkeratome (Bausch & Lomb) and the Visx Star excimer laser. Before LASIK, the mean spherical equivalent (SE) was -4.94 diopters (D) +/- 2.79 (SD) and the mean astigmatism was 2.71 +/- 2.33 D; all eyes had regular astigmatism or slightly decentered, irregular astigmatism. RESULTS: At the last follow-up, the mean postoperative uncorrected visual acuity (UCVA) was 20/30, the mean SE was -0.35 +/- 0.65 D, and the mean residual astigmatism was 1.06 +/- 0.67 D. Eighty-six percent of patients had an SE within +/-1.00 D of emmetropia and a UCVA of 20/40 or better. Ten eyes (39%) had 1 or more enhancements, which were performed a mean of 6 months after the primary LASIK. Significant complications such as wound dehiscence, epithelial ingrowth, and corneal decompensation did not occur. At the last follow-up, 18% of patients lost 1 line of best corrected visual acuity and 27% gained 1 line. CONCLUSION: Laser in situ keratomileusis appeared to be a reliable and safe procedure to correct residual myopia and astigmatism after PKP.     

Chalazion as a cause of decreased vision after LASIK.

PURPOSE: To describe a post-LASIK patient with decreased vision and a chalazion of the upper eyelid. METHODS: A 46-year-old man was referred with decreased vision of 1 month's duration. He underwent bilateral uncomplicated LASIK for myopic astigmatism 1.5 years and bilateral enhancements 1 year previously. He had 20/20 uncorrected vision in both eyes after those procedures. He developed a chalazion of his right central upper eyelid 1 month prior with simultaneous blurring of vision. On our examination, his uncorrected visual acuity was 20/60 in the right eye. Complete eye examination including refraction, computerized corneal topography, and pachymetry were done. RESULTS: With a manifest refraction of +1.25 +0.50x80, the visual acuity in the right eye improved to 20/20. Computerized corneal topography revealed circular central corneal flattening in both eyes, much greater in the right eye than the left eye. The location of the chalazion with the right eye closed corresponded to the area of central corneal flattening. The central power from the corneal topography was 39.4 D OD and 40.8 D OS. He was diagnosed as having acquired hyperopia associated with chalazion-induced central corneal flattening of the right eye. Chalazion-induced hyperopic change on topography disappeared, and his uncorrected vision improved to 20/20 in the left eye as the chalazion resolved completely. CONCLUSION: In post-LASIK patients with decreased vision and topography changes late after surgery, periocular masses should be considered in the differential diagnosis. Decreased corneal thickness and rigidity after LASIK might be a predisposing factor to external compression-induced curvature changes.     

Recovery of uncorrected visual acuity after laser in situ keratomileusis or photorefractive keratectomy for low myopia

PURPOSE: To compare uncorrected visual acuity and refractive error in patients undergoing photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) between 1 week and 6 months after surgery. METHODS: All eyes underwent PRK or LASIK with the VisX StarS2 excimer laser. We retrospectively analyzed data from 77 random eyes of 77 patients in the PRK group and 76 eyes of 76 patients in the LASIK group. All eyes had a low myopic refractive error (spherical equivalent range, -0.88 diopters (D) to -5.13 D; mean PRK. -2.8 +/- 0.20 D: LASIK, -2.5 +/- 0.22 D). Uncorrected visual acuity and manifest refractive error were evaluated 1 week, 1 month, and 6 months after surgery. RESULTS: Each eye undergoing PRK was paired with an eye undergoing LASIK for a similar level of spherical equivalent. Mean uncorrected visual acuity after 1 week was 0.85 +/- 0.06 (20/25, logMAR 0.12 +/- 0.04) for the PRK group and 1.01 +/- 0.06 (20/20, logMAR 0.01 +/- 0.03) for the LASIK group (p < 0.001). Mean spherical equivalent after 1 week was 0.23 +/- 0.12 D for the PRK group and -0.02 +/- 0.07 D for the LASIK group (p = 0.02). Mean uncorrected visual acuity after 1 month was 1.03 +/- 0.05 (20/20, logMAR 0.02 +/- 0.03) for the PRK group and 1.05 +/- 0.05 (20/20. -0.02 +/- 0.03) for the LASIK group (p = 0.16). Mean spherical equivalent after I month was 0.19 +/- 0.10 D for the PRK group and -0.02 +/- 0.09 D for the LASIK group. This difference was statistically significant (p = 0.02), but was unlikely to be clinically significant. Mean uncorrected visual acuity after 6 months was 1.05 +/- 0.06 (20/20, logMAR -0.01 +/- 0.03) for the PRK group and 1.06 +/- 0.05 (20/20, logMAR -0.14 +/- 0.03) for the LASIK group (p = 0.41). Mean spherical equivalent after 6 months was 0.02 +/- 0.08 D for the PRK group and 0.00 +/- 0.08 D for the LASIK group (p = 0.35). CONCLUSION: Uncorrected visual acuity 1 week after surgery is significantly better in eyes undergoing LASIK than in eyes undergoing PRK. Both procedures provide functional vision by 1 week after surgery. The difference does not relate to refractive error, which was similar between the two groups, but to differences in healing of the epithelium. By 1 month after surgery, there is no difference in mean uncorrected visual acuity between eyes that undergo PRK or LASIK for low myopia.     

Laser in situ keratomileusis for myopia of -1.50 to -6.00 diopters

PURPOSE: To evaluate the results of laser in situ keratomileusis (LASIK) for the correction of low and moderate myopia and astigmatism using the Nidek EC-5000 excimer laser with a modified algorithm. METHODS: Three hundred and ninety-six eyes of 257 patients with myopia ranging from -1.50 to -6.00 D and astigmatism of no more than 4.00 D were included. Manifest spherical equivalent refraction, uncorrected and spectacle-corrected visual acuity were assessed at 1 month (357 eyes, 90%), 3 months (220 eyes, 56%), and 6 months (168 eyes, 42%) after LASIK. RESULTS: Mean preoperative spherical equivalent refraction was -3.60 +/- 1.27 D and mean cylinder was -1.01 +/- 1.08 D. Mean postoperative spherical equivalent refraction was -0.12 +/- 0.31 D and mean cylinder was -0.19 +/- 0.33 D. At 6 months follow-up, 158 eyes (94%) had a mean postoperative spherical equivalent refraction within +/- 0.50 D of emmetropia; 168 eyes (100%) were within +/- 1.00 D. Uncorrected visual acuity was 20/20 or better in 81% (136 eyes) and 20/40 or better in 100%. Two eyes (1.2%) lost 1 line of spectacle-corrected visual acuity due to a decentered ablation. No eye lost 2 or more lines of spectacle-corrected visual acuity. CONCLUSION: Our modified LASIK algorithm with the Nidek EC-5000 excimer laser resulted in safe and predictable outcomes for treatment of low and moderate amounts of myopia and astigmatism.     

Laser in situ keratomileusis after penetrating keratoplasty

PURPOSE: To assess the outcomes of laser in situ keratomileusis (LASIK) after penetrating keratoplasty (PKP). SETTING: Hospital de Clínicas de Porto Alegre, Department of Ophthalmology, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil. METHODS: Fourteen eyes of 13 patients who had LASIK after PKP were retrospectively reviewed. The interval between LASIK and PKP was at least 1 year, and the follow-up after LASIK was also at least 1 year. All patients had a stable refractive error for a minimum of 6 months after all sutures were removed, regular and symmetric topographic astigmatism, and a minimal ultrasonic central corneal pachymetry of 500 microm. The Chiron Automatic Corneal Shaper and the Meditec Aesculap MEL 60 excimer laser were used. RESULTS: At 12 months, mean myopia decreased from -5.33 diopters (D) +/- 4.22 (SD) to 0.19 +/- 1.71 D, mean hyperopia decreased from +5.04 +/- 3.32 D to + 0.42 +/- 0.46 D, and mean astigmatism decreased from 5.37 +/- 2.12 D to 2.82 +/- 2.42 D (47.5% of mean percentage reduction). Retreatment was necessary in 42.9% of eyes because of cylindrical undercorrection. Uncorrected visual acuity improved in 11 eyes (78.6%). Best spectacle-corrected visual acuity improved in 6 eyes (42.8%) and was maintained in 4 eyes (28.6%); 5 eyes (35.7%) lost 1 Snellen line. Intraoperative complications included 1 buttonhole flap. Postoperative complications included interface epithelial ingrowth at the periphery (2 eyes) and pseudophakic retinal detachment 2 years after LASIK (1 eye). CONCLUSION: Laser in situ keratomileusis after PKP safely and predictably corrected the spherical component of the refraction. However, the predictability of LASIK in correcting post-PKP astigmatism was poor.     

Laser in situ keratomileusis to correct myopia, hypermetropia and astigmatism after penetrating keratoplasty for keratoconus: a series of 27 cases.

BACKGROUND: Excimer laser treatment has been shown to be effective and safe in correcting anisometropia following penetrating keratoplasty (PKP). In this report we review our experience with excimer laser in situ keratomileusis (LASIK) to correct refractive myopia, hypermetropia and astigmatism in patients who had undergone PKP for keratoconus. METHODS: We reviewed the records of 22 patients (27 eyes) who had undergone LASIK to correct myopia, hypermetropia or astigmatism, in simple or combined forms, following corneal transplantation for keratoconus. LASIK was performed at a hospital in Curitiba, Brazil, between September 1998 and February 2000. The eyes were classified into two groups: those with a negative spherical equivalent and those with a positive spherical equivalent. LASIK was performed using the Moria LSK microkeratome and the Nidek EC-5000 excimer laser. RESULTS: The mean length of follow-up was 9.52 months for the 23 eyes with myopia and 5.75 months for the 4 eyes with hypermetropia. The mean refractive spherical equivalent in the myopic eyes was -5.27 (standard deviation [SD] 1.91) dioptres before LASIK and -0.45 D (SD 1.68 D) at the last follow-up visit. The corresponding values in the eyes with hypermetropia were +5.18 D (SD 1.46 D) and + 1.18 D (SD 0.94 D). The rate of regression of astigmatism in the myopic eyes was 76%. After surgery 18 (78%) of the myopic eyes and all the hypermetropic eyes had an uncorrected visual acuity of 20/40 or better. The best spectacle-corrected visual acuity was better than 20/25 in 22 (95.7%) of the myopic eyes and all the hypermetropic eyes. One eye lost 1 line of best spectacle-corrected Snellen visual acuity, and one eye lost 6 lines secondary to epithelial ingrowth. Wound dehiscence, intraoperative flap complications, graft rejection or other complications did not develop in this series. INTERPRETATION: In this series, LASIK proved to be relatively safe and effective in correcting refractive errors after PKP for keratoconus.     

Laser in situ keratomileusis retreatment for residual myopia and astigmatism

PURPOSE: To evaluate the visual and refractive results of laser in situ keratomileusis (LASIK) retreatment on eyes with residual myopia with or without astigmatism. METHODS: LASIK retreatment was performed on 35 eyes of 23 patients for correction of residual myopia, with or without astigmatism, with a mean manifest spherical equivalent refraction of -2.17+/-0.82 D (range, -1.00 to -3.87 D) and mean refractive astigmatism of -0.55+/-0.61 D (range, 0 to -1.75 D). Retreatment was performed 3 to 18 months after primary LASIK (mean, 5.1+/-2.6 mo). The corneal flap of the previous LASIK was lifted and laser ablation was performed using the Chiron-Technolas Keracor 116 excimer laser. Follow-up was 12 months for all eyes. RESULTS: At 1 year after retreatment, manifest spherical equivalent refraction was reduced to a mean -0.23+/-0.28 D (range, 0 to -0.87 D), and refractive astigmatism was reduced to a mean -0.16+/-0.25 D (range, 0 to -0.75 D). Thirty-two eyes (91.5%) had a manifest spherical equivalent refraction within +/-0.50 D of emmetropia, and 33 eyes (94.3%) had 0 to 0.50 D of refractive astigmatism. Uncorrected visual acuity was 20/20 or better in 11 eyes (31.4%). Spectacle-corrected visual acuity was not reduced in any eye after retreatment. There were no significant complications. CONCLUSION: LASIK retreatment was effective for correction of residual myopia or astigmatism after primary LASIK. Refractive results were predictable with good stability after 3 months. Lifting the flap during LASIK retreatment was relatively easy to perform and did not result in visual morbidity in eyes treated from 3 up to 18 months after primary LASIK.     

Subclinical inflammation after laser in situ keratomileusis in corneal grafts

PURPOSE: To evaluate postoperative inflammatory reaction in the eye after laser in situ keratomileusis (LASIK) in corneal grafts. SETTING: Department of Ophthalmology, Helsinki University Central Hospital, Helsinki, Finland. METHODS: Ten eyes of 9 patients with penetrating keratoplasty (PKP) and significant postoperative refractive errors and astigmatism had LASIK 22 months or more after the PKP. All patients were treated with the VISX Star excimer laser and the Bausch & Lomb Hansatome microkeratome. Preoperative and early postoperative inflammation was evaluated by quantifying the aqueous flare intensity with a laser flare photometer (Kowa FM-500). A full ophthalmic assessment was also performed before LASIK and up to 6 months postoperatively. RESULTS: The inflammatory response was mild and limited to the first postoperative hour. The mean anterior chamber flare increased from 6.0 photons/millisecond (ph/ms) preoperatively to 14.0 ph/ms at 1 hour and then decreased to 6.7 ph/ms (hour 3), 6.8 ph/ms (day 1), and 8.2 ph/ms (day 7). The mean spherical equivalent (SE) refraction decreased from -3.81 diopters (D) (range -9.63 to -0.25 D) to -0.46 D (range -1.13 to +0.38 D), and the mean preoperative astigmatism decreased from 3.0 D (range 6.5 to 0.5 D) to 0.7 D (range 0.0 to 2.0 D). At the last examination, 9 eyes were within +/-1.0 D (6 within +/-0.5 D) and all were within +/-1.5 D of the intended SE refraction. Three eyes achieved full cylinder correction, and 7 were within +/-1.0 D of the intended correction. Eight eyes had a best corrected visual acuity of 20/40 or better (unchanged or gain of 1 to 4 lines [6], loss of 1 line [1], and loss of 3 lines [1]), and 8 had an uncorrected visual acuity of 20/50 or better. CONCLUSIONS: Uneventful LASIK induced subtle, short-lasting anterior chamber flare when measured by the laser flare meter. In corneal grafts, LASIK appeared to be a safe and effective procedure for residual refractive errors.     

Characteristics of sixty myopic eyes with pre-laser in situ keratomileusis retinal examination and post-laser in situ keratomileusis retinal lesions

PURPOSE: A survey of eyes with pre-laser in situ keratomileusis (LASIK) retinal examinations and characteristics of post-LASIK retinal breaks and retinal detachments (RDs). METHODS: A survey of worldwide vitreoretinal surgeons (424 physicians). Surveyed information included demographics, best-corrected visual acuity, degree of myopia, pre- and post-LASIK retinal findings, follow-up time, and treatment outcome. RESULTS: Sixty eyes with pre-LASIK retinal examinations developed post-LASIK retinal breaks and RDs. There was an average of 2.3 breaks per eye, yielding a total of 140 breaks in the 60 eyes. Forty eyes also had RDs besides the retinal breaks. Large percentages of eyes had substantial myopia (mean myopia, -9.5 +/- 5.8 diopters [D]) and complex vitreoretinal complications. Forty percent developed vitreoretinal complications within 6 months after LASIK. The 20 eyes that developed more extensive RDs (>3 clock hours) had a significantly higher mean myopia than did the 6 eyes that developed limited RD (< or = 3 clock hours) within 12 months after LASIK (-8.92 +/- 6.82 D versus -3.50 +/- 1.97 D, P = 0.03). There were significant statistical differences in distribution of retinal breaks and tears between the temporal and nasal quadrants (P < 0.001, P < 0.001, respectively, chi2, but not between the superior and inferior quadrants. CONCLUSION: Distributions of retinal breaks in this study were comparable with results found in non-LASIK eyes in young myopes. Treatment for post-LASIK vitreoretinal complications was highly successful. The vulnerability of such highly myopic eyes for vitreoretinal complications warrants their close monitoring.     

Relation of pre-LASIK and post-LASIK retinal lesions and retinal examination for LASIK eyes

AIMS: Analysis of highly myopic eyes (mean myopia -11 D) with post-LASIK vitreoretinal complications (breaks, retinal detachment) that also had pre-LASIK vitreoretinal pathology (lattice, breaks). METHODS: Retrospective case series. RESULTS: 67 eyes in 56 patients with pre-LASIK retinal examination developed post-LASIK vitreoretinal complications. 17 of the 67 eyes (25.4%) had pre-LASIK vitreoretinal pathology. 10 of the 17 eyes that underwent pre-LASIK prophylactic retinal treatment still developed post-LASIK lesions. They developed adjacent to pre-LASIK lesions for 15 of 17 eyes (88.2%), and outside of quadrant(s) of pre-LASIK lesions for five eyes (29.4%). CONCLUSION: Pre-LASIK retinal examination may predict locations of certain post-LASIK retinal lesions that may develop in highly myopic eyes with pre-LASIK vitreoretinal pathology, but prophylactic treatment may not prevent all post-LASIK vitreoretinal complications.     

Laser in situ keratomileusis for compound myopic astigmatism using the Meditec MEL 70 G-Scan excimer laser

PURPOSE: To determine the safety, efficacy, predictability, and stability of laser in situ keratomileusis (LASIK) in treating patients with myopic astigmatism using the Meditec MEL 70 G-Scan excimer laser. METHODS: Seventy-four eyes of 42 patients with myopia ranging from -4.50 to -9.88 D and astigmatism ranging from 0.50 to 4.00 D who underwent LASIK with the Meditec MEL 70 G-Scan excimer laser and the Summit Krumeich-Barraquer microkeratome were studied. Patients were followed for 1 year. RESULTS: Mean baseline spherical equivalent refraction was -7.12 +/- 1.70 D and cylinder was 1.62 +/- 1.72 D. At 12 months, mean postoperative spherical equivalent refraction was -0.49 +/- 0.57 D and mean refractive cylinder was 0.59 +/- 0.32 D. Mean change in spherical equivalent refraction between 1 and 12 months after surgery was -0.09 +/- 0.31 D, toward myopia. At baseline, no eyes had best spectacle-corrected visual acuity (BSCVA) of 20/20 or better, and 65% had 20/40 or better. At 12 months after surgery, 10% of eyes had BSCVA of 20/20 or better and 88% of eyes had 20/40 or better. The unusually low postoperative BSCVA results were thought to be due to amblyopia or existence of a higher percentage of some optical aberrations in this group of eyes. Mean uncorrected visual acuity was -1.38 +/- 0.42 LogMAR units (20/400) at baseline and -0.29 +/- 0.25 LogMAR units (20/40) at the 12-month postoperative examination. No eyes lost two or more lines of spectacle-corrected visual acuity. No vision threatening complications were observed. CONCLUSIONS: LASIK with the Meditec MEL 70 G-Scan excimer laser appeared to be safe, effective, reasonably predictable, and stable for correction of myopic astigmatism with a spherical component between -4.25 and -8.25 D and a cylindrical component between 0.50 and 4.00 D. However, astigmatism was slightly undercorrected with the algorithm used.     

Topographic centration of ablation after LASIK for myopia using the CustomVue VISX S4 excimer laser

PURPOSE: To determine the ablation centration, efficacy, predictability, and safety of CustomVue LASIK using the VISX S4 excimer laser for the treatment of myopia and myopic astigmatism. METHODS: A retrospective review of 20 myopic eyes of 12 patients treated with LASIK CustomVue VISX S4 was conducted. Corneal topography was used to determine ablation centration. Primary outcome variables including manifest refraction, best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity (UCVA), and complications were evaluated at 3 months postoperatively. RESULTS: Mean decentration (from ablation zone to entrance pupil) was 0.23 +/- 0.08 mm at 3 months postoperatively. No eyes were decentered > 0.5 mm. Preoperatively, the mean spherical equivalent refraction was -4.81 +/- 11.39 diopters (D) (range: -6.75 to -2.25 D). At 3 months postoperatively, mean spherical equivalent refraction was -0.63 +/- 0.25 D (range: -2.00 to 0.25 D). Nineteen (95%) of 20 eyes had UCVA of 20/40 and 16 (80%) of 20 eyes had UCVA of 20/20 at 3 months postoperatively. Fourteen (70%) eyes were within +/- 0.50 D and 18 (90%) eyes were within +/- 1.00 D of emmetropia. No eye lost > 1 line of BSCVA. CONCLUSIONS: Wavefront-guided LASIK using the CustomVue VISX S4 for myopic eyes results in minimal decentration ablation and effective, predictable, and safe visual outcomes.     

Rehabilitation time after simultaneous bilateral photorefractive keratectomy for low to moderate myopia

PURPOSE: To evaluate the visual acuity rehabilitation time after simultaneous bilateral photorefractive keratectomy (PRK) using a flying small spot laser. SETTING: Eye Tech Medical Laser, Tel Aviv, Israel. METHODS: In this prospective interventional nonrandomized clinical trial, 42 consecutive eyes (21 patients) with myopia ranging from -0.75 to -5.50 diopters (D) (mean -2.75 D +/- 1.18 [SD]) and astigmatism up to -2.75 D (mean -0.64 +/- 0.55 D) were treated with bilateral simultaneous PRK using the ESIRIS excimer laser (Schwind). Main outcome measures were uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and manifest refraction up to 12 weeks after surgery. Both eyes of each patient were examined at the same follow-up after initial treatment. RESULTS: Within 2 weeks and 1 month of the laser procedure, the UCVA was at least 20/40 in 1 eye in 85.7% of patients (18 patients) and 100% of patients (21 patients), respectively. After 2 weeks, UCVA was at least 20/20, 20/25, and 20/40 in 7.1%, 40.5%, and 80.9% of eyes. The final mean manifest spherical equivalent 12 weeks post laser treatment was -0.10 +/- 0.26 D, with a mean sphere of +0.02 +/- 0.22 D and a mean cylinder of -0.24 +/- 0.37 D. No eye had a BCVA loss during the follow-up. CONCLUSION: Simultaneous bilateral PRK using a flying small spot excimer laser for low to moderate myopia allowed most patients to return to most daily tasks in a couple of weeks without compromising safety.     

Laser in situ keratomileusis for undercorrection after radial keratotomy.

PURPOSE: To assess the safety and efficacy of excimer laser in situ keratomileusis (LASIK) in treating residual myopia and/or astigmatism following refractive keratotomy. METHODS: Fourteen eyes that had previously undergone radial and/or arcuate keratotomy were included. The surgeries were performed using the Chiron Automated Microkeratome and the VISX 20/20B excimer laser. RESULTS: Average follow-up was 12.64+/-5.02 months. Mean spherical equivalent refraction was reduced from -3.48+/-3.52 D preoperatively to -0.04+/-0.87 D postoperatively. At the last follow-up examination there were 8 eyes (57.1%) with a refraction within+/-0.50 D, and 10 eyes (71.4%) within +/-1.00 D of emmetropia. Uncorrected visual acuity was 20/20 or better in 4 eyes (28.6%) and 20/40 or better in 10 eyes (71.4%). Vector analysis of the astigmatic correction showed an index of success of 80%. There was no significant loss (> or = or =2 lines) of spectacle-corrected visual acuity. We observed interface epithelial ingrowth in one eye. CONCLUSIONS: The correction of residual myopia and/or astigmatism with LASIK in eyes with prior refractive keratotomy proved to be safe and effective. Careful preoperative evaluation may help to avoid complications such as reopening of incisions during surgery or postoperative ingrowth of epithelium beneath the corneal flap.     

Two-stage laser in situ keratomileusis to correct refractive errors after penetrating keratoplasty

PURPOSE: To evaluate the effect of a two-stage laser in situ keratomileusis (LASIK) procedure on eyes with high astigmatism and/or anisometropia after penetrating keratoplasty. METHODS: Eleven postoperative penetrating keratoplasty eyes were included in a prospective, non-controlled study. All patients had at least 4.00 D of astigmatism and/or at least 3.00 D of anisometropia and were spectacle and contact lens intolerant. Two-stage LASIK was performed; in the first stage a hinged corneal flap 160 microm in thickness and 9 mm in diameter was created. After stabilization of corneal shape (1 to 3 months after keratotomy), the corneal flap was lifted and laser refractive treatment (second stage) was performed. RESULTS: After the first stage, a statistically significant reduction in refractive astigmatism (P<.01) was recorded. In all eyes but one, best spectacle-corrected visual acuity was maintained or improved after the procedure. Three months after the second stage, refractive astigmatism in 8 of 11 eyes (73%) was within +/- 1.00 D, and spherical equivalent refraction in 9 of 11 eyes (82%) was within +/- 1.00 D of intended correction. Preoperative irregular astigmatism persisted in three patients (3 eyes) who could not be corrected within +/- 1.00 D of refractive astigmatism and/or +/- 1.00 D of intended spherical equivalent refraction. In one eye, an interface infiltrate developed shortly after creation of the flap, and resulted in limited melting. CONCLUSIONS: A two-stage LASIK procedure improved visual acuity and refraction in postoperative penetrating keratoplasty eyes with high astigmatism and/or anisometropia. Complications were uncommon but can lead to loss of vision.     

Toric laser in situ keratomileusis for myopic astigmatism using an ablatable mask

BACKGROUND: To assess the results of toric laser in situ keratomileusis (LASIK) correction of myopic astigmatism. METHODS: A prospective study was performed over a 20 week period for consecutive patients treated for myopic astigmatism. Spectacle-corrected visual acuity, uncorrected visual acuity, spectacle refraction, videokeratography, and complications were recorded. Vector analysis was performed by the ASSORT program. RESULTS: Sixty-five eyes of 42 patients underwent toric LASIK with a Summit Technologies Apex Plus excimer laser. Mean preoperative spherical equivalent refraction at the spectacle plane was -6.24 +/- 2.42 D (range, -1.63 to -14.63 D) and mean pre-operative refractive cylinder magnitude was 1.99 +/- 1.35 D (range, 0.75 to 7.00 D); mean attempted refractive cylinder correction was 1.90 +/- 1.00 D. Six months after LASIK (43 eyes followed), mean spherical equivalent refraction at the spectacle plane was -0.40 +/- 0.55 D and 31 eyes (72.1%) were within +/- 0.50 D of emmetropia. At 6 months, mean refractive cylinder magnitude was 0.74 +/- 0.70 D, mean surgically induced astigmatism was 1.46 +/- 0.86 D, mean absolute angle of error was 10.33 degrees, mean astigmatic correction index was 0.93 +/- 0.36 D, and mean index of success was 0.46 +/- 0.39. Uncorrected visual acuity was 6/12 or better in 34 eyes (79.1%) and 6/6 in 15 eyes (35%); spectacle- corrected visual acuity was 6/9 or better in 41 eyes (95.35%). Six eyes (14.0%) lost 1 line of spectacle-corrected visual acuity at 6 months and one eye (2.3%) lost 2 lines. Ten eyes (23.3%) gained 1 line at 6 months. CONCLUSION: Toric LASIK with an ablatable mask using the Summit Apex Plus excimer laser is a safe and relatively accurate procedure for the correction of myopic astigmatism.     

Nomogram adjustment of laser in situ keratomileusis for myopia and myopic astigmatism with the Alcon LADARVision system

PURPOSE: To evaluate the visual and refractive results of conventional (non-wavefront) laser in situ keratomileusis (LASIK) for treatment of myopia and myopic astigmatism using the Alcon LADARVision 4000 excimer laser system and nomogram adjustment techniques. METHODS: A retrospective analysis of 499 eyes that had LASIK for myopia and myopic astigmatism was performed. Preoperative manifest spherical equivalent refraction ranged from -0.43 to -6.00 D and preoperative astigmatism ranged from 0 to -4.75 D. Patients were evaluated during 3 months following surgery. RESULTS: One month after surgery, 72% of eyes examined (298/415 eyes) had uncorrected visual acuity (UCVA) of 20/20 or better. Three months after surgery, 83% of eyes examined (216/261 eyes) had UCVA of 20/20 or better. One and three months after surgery, 82% and 83% of eyes, respectively, were within +/-0.50 D of attempted correction; 97% of eyes were within +/-1.00 D at both 1 and 3 months. No eye lost more than 1 line of best spectacle-corrected visual acuity (BSCVA) at 3 months after surgery. At the 3-month examination, 83% of eyes had UCVA better than or equal to preoperative BSCVA. CONCLUSIONS: Conventional LASIK to correct myopia and myopic astigmatism was safe and effective using the Alcon LADARVision 4000 excimer laser system. Outcomes were substantially improved throughout development of an accurate nomogram, derived from continually updated regression analysis of previous refractive results.     

Laser in situ keratomileusis versus photorefractive keratectomy in the correction of myopic astigmatism

PURPOSE: To evaluate retrospectively the effectiveness of astigmatism correction in eyes treated with laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). METHODS: Patients with low to moderate myopia with astigmatism ranging from +0.25 to +4.50 diopters were included in the study. PRK was performed on 62 eyes and LASIK on 70 eyes. Six-month data were analyzed with regard to astigmatism power, astigmatism axis, spherical equivalent, uncorrected visual acuity, vector astigmatism change, and topographic corneal regularity. RESULTS: Mean astigmatism magnitude change was 0.54 +/- 0.76 in PRK-treated eyes and 0.60 +/- 0.67 in LASIK-treated eyes (61% versus 64% change, respectively, p = 0.61) at 6 months after surgery. Mean spherical correction change was -2.79 +/- 1.51 for PRK and -2.90 +/- 1.03 for LASIK (p = 0.63). Mean spherical equivalent change was -2.5 +/- 1.57 for PRK and -2.6 +/- 1.23 for LASIK (p = 0.73). Mean change in astigmatism axis was 20.8 +/- 73.1 for PRK and 33.8 +/- 81.7 for LASIK (p = 0.34). Mean change in uncorrected visual acuity (LogMar) was 0.84 +/- 0.26 for PRK and 0.89 +/- 0.23 for LASIK (p = 0.21). Mean vector-corrected astigmatism change was 0.88 +/- 0.66 for PRK and 0.95 +/- 0.59 for LASIK (p = 0.51). Mean vector-corrected astigmatism axis for PRK was 86.9 +/- 59 degrees and for LASIK 83.8 +/- -47.6 degrees (p = 0.75). CONCLUSION: There was no significant difference in astigmatism correction between PRK and LASIK at 6 months after surgery.     

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

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

Topographic- and wavefront-guided customized ablations with the NIDEK-EC5000CXII in LASIK for myopia

PURPOSE: To assess refractive outcomes, changes in the total higher order root mean square (RMS) aberration, and changes in higher order wavefront aberrations after LASIK for myopia and myopic astigmatism with the NIDEK Advanced Vision Excimer Laser platform (NAVEX) using either an aspheric or topography-based or whole eye wavefront ablation algorithm. METHODS: This was a retrospective study of 1459 eyes that underwent LASIK for myopia and myopic astigmatism. The mean preoperative spherical equivalent refraction was -4.68 diopters (D) (range: -0.50 to -9.63 D) with astigmatism up to -4.50 D. Treatments were classified into three categories depending on the type of ablation algorithm used--optimized aspheric transition zone (OATz) denoted eyes that underwent aspheric treatment zones; customized aspheric treatment zone (CATz) denoted eyes that underwent customized ablations based on corneal topography; and OPDCAT denoted eyes that underwent customized ablation based on the whole eye wavefront profile. Follow-up data are reported at 3 months (69%) and 12 months (17%) postoperatively. RESULTS: Three months after LASIK, the predictability (10.5 D from target refraction) was 80% for OATz, 91% for CATz, and 76% for OPDCAT. Of all eyes, 96% were within +/- 1.0 D of intended refraction 3 months postoperatively and 100% after 12 months (87% +/- 0.5 D). In the aspheric and custom groups, a notable improvement of uncorrected visual acuity was noted between 3 and 12 months after LASIK. No eye lost >1 line of best spectacle-corrected visual acuity. Mean higher order RMS increased in all groups. CONCLUSIONS: The data support that the treatment of myopia and myopic astigmatism is safe and effective with NAVEX. Customized ablation based on corneal topography rather than on total wavefront error was more predictable.