Laser-assisted subepithelial keratectomy retreatment after laser in situ keratomileusis

PURPOSE: To evaluate the efficacy and safety of laser-assisted subepithelial keratectomy (LASEK) retreatment after laser in situ keratomileusis (LASIK). SETTING: Mater Private Hospital, Dublin, Ireland. METHODS: In this retrospective study, 22 eyes of 20 patients had LASEK retreatment for residual refractive errors after LASIK. All patients who had the procedure between January 2004 and May 2007 were included in the study. The main outcome measures at the final follow-up visit were efficacy, predictability, safety, and stability. RESULTS: The mean spherical equivalent (SE) was -4.50 diopters (D)+/-2.88 (SD) (range -10.00 to +3.87 D) before LASIK and -1.23+/-0.95 D (range -2.50 to +2.00 D) after LASIK. The mean time between the initial LASIK procedure and LASEK enhancement was 56.2+/-24.3 months (range 6 to 84 months). The mean follow-up after retreatment was 6.68+/-6.47 months (range 3 to 24 months). At the final follow-up visit, 19 eyes (86.4%) had an uncorrected visual acuity of 20/30 or better and 17 eyes (77.3%) were within +/-1.00 D of the target refraction. No patient lost more than 1 line of best corrected visual acuity or developed corneal haze greater than grade 1. CONCLUSION: Results indicate that LASEK retreatment after LASIK is a safe and effective alternative when LASIK retreatment is deemed unsafe because there is not sufficient residual corneal stromal bed or when retreatment is required many years after LASIK and relifting the original flap is expected to be problematic.     

Analysis of the visual and refractive outcome following laser in situ keratomileusis (LASIK) retreatment over a four-year follow-up period

Purpose To evaluate the safety and refractive stability following LASIK retreatment over a four-year follow-up period. Methods In this retrospective study, 60 eyes of 52 patients underwent LASIK retreatment for residual refractive errors after LASIK. Retreatment was performed by lifting the original flap followed by laser ablation of the stromal bed. The main outcome measures at the latest follow-up visit were efficacy, predictability, safety and stability. The mean follow-up time after retreatment was 22.3 ± 10.5 (range 12–48 months). Results The baseline mean spherical equivalent (SE) was −4.85 ± 2.57 dioptres (D) (range +2.25 to −11.75 D). At the latest follow-up visit, the uncorrected visual acuity (UCVA) was 6/9 or better in 88% of the eyes, the mean SE was −0.33 ± 0.8 D (−2.50 to +2.25 D), and 77% of the eyes were within ±0.50 D of target refraction. None of the patients lost lines of best corrected visual acuity (BCVA) and 25 eyes (41%) gained one or more lines. Three eyes (5%) developed peripheral epithelial in-growth and none of the patients had corneal ectasias or retinal complications. Conclusion LASIK retreatment is a safe and effective procedure for correcting residual refractive errors after LASIK. After retreatment, the visual and refractive outcome remained stable during the four-year follow-up period of the study.     

Surface ablation after laser in situ keratomileusis: retreatment on the flap

PURPOSE: To evaluate the safety and efficacy of superficial laser ablation on the flap as a treatment for residual ametropia after laser in situ keratomileusis (LASIK). SETTING: Private practice refractive surgery center, Utrecht, The Netherlands. METHODS: This retrospective study comprised 18 eyes of 15 patients who had alcohol-assisted photorefractive keratectomy (PRK) or laser-assisted subepithelial keratectomy (LASEK) retreatment for residual ametropia after LASIK. All patients who had retreatment on the flap between June 2004 and June 2005 were included in the study. Retreatments were performed by wavefront-guided excimer laser surface ablation using the Visx Star S4 laser. Outcome measures included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), subjective refraction, and biomicroscopy at the 3-, 6-, and 12-month postoperative visits. RESULTS: The preoperative spherical equivalent (SE) refraction was -0.63 diopter (D) +/- 0.87 (SD) (range -2.00 to +1.38 D). The mean amount of ablated cornea was 21.3 +/- 7.4 microm. At 3 months, the mean UCVA was 0.83 +/- 1.5 lines (range 0.40 to 1.25), yielding an efficacy index of 0.87. At 6 months, the mean UCVA increased to 0.98 +/- 0.8 line (range 0.63 to 1.25) and the efficacy index, to 1.03. At 12 months, 6 eyes were lost to follow-up. The mean UCVA was 0.83 +/- 2.2 lines (range 0.20 to 1.25), with an efficacy index of 0.87. The mean BSCVA was 0.98 +/- 0.9 line (range 0.80 to 1.25) at 3 months and 1.05 +/- 0.6 line (range 0.80 to 1.25) at 6 months, yielding a safety index of 1.03 and 1.11, respectively. At 12 months, the mean BSCVA was 0.95 +/- 1.0 line (range 0.63 to 1.25), with a safety index of 1.0. At 6 months, no eye had lost lines of BSCVA, 11 eyes had no change, and 7 eyes gained 1 line. At 12 months, 2 eyes lost 1 line of BSCVA, 8 eyes had no change, and 2 eyes gained 1 line. The mean SE refraction was +0.10 +/- 0.27 D (range -0.25 to +0.63 D) at 3 months, +0.06 +/- 0.37 D (range -0.50 to +1.13 D) at 6 months, and +0.15 +/- 0.39 D (range -0.50 to +0.88 D) at 12 months. On biomicroscopic examination, 1 eye had prolonged grade 1 haze that disappeared before 6 months. Two eyes of 1 patient who had hyperopic retreatment developed late-onset haze 8 months postoperatively. Eyes with microstriae in the flap before retreatment showed significant improvement after retreatment. There were no sight-threatening complications. CONCLUSION: Wavefront-guided LASEK or alcohol-assisted PRK retreatment on the surface of a LASIK flap was safe and effective in correcting small amounts of residual myopia.     

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.     

Laser-in-situ-Keratomileusis zur Korrektur von Hyperopie und hyperopem Astigmatismus mit Scanning-Spot-Excimer-Laser

PURPOSE: The purpose of this investigation was to evaluate the safety, efficacy, predictability, stability and complications of LASIK for the treatment of hyperopia and hyperopic astigmatism using a scanning spot excimer laser. PATIENTS AND METHODS: A total of 64 consecutive LASIK operations (37 patients, mean age 41 years, range 22-68 years) have been evaluated. The Hansatome microkeratome producing a superior hinge (flap diameter 9.5 mm) and a scanning spot excimer laser with an optical zone of 6.0 mm were used. Examinations were performed preoperatively, after 1 day, 7 days, 1 month, 4 and 12 months. RESULTS: One year after the primary procedure only 1 eye lost 2 or more lines of best-corrected visual acuity, 91% were within +/-1 line and 4 eyes gained 2 lines. Of these eyes 50 (86%) reached an uncorrected visual acuity of > or=0.5, 32 (55%) > or=0.8, 16 (28%) > or=1.0, 24 eyes (41%) needed a refractive correction of +/-0.5 D, 44 eyes (76%) of +/-1.0 D and 55 eyes (95%) of +/-2.0 D. The mean spherical equivalent after 1 year was +0.17+/-0.85 D. CONCLUSIONS: LASIK is suitable for the correction of hyperopia (up to a maximum of +5 D) and for hyperopic astigmatism (up to a maximum of -5 D). However, results were better in lower hyperopia (up to +3 D) than in the moderate hyperopia. The refractive results showed overall a good stability during the 12-month study period, but higher regression occurred in a few cases.     

Laser in situ keratomileusis for residual myopia after photorefractive keratectomy

PURPOSE: To evaluate the efficacy and safety of laser in situ keratomileusis (LASIK) for myopic regression and undercorrection after photorefractive keratectomy (PRK). SETTING: The Eye Institute, Sydney, Australia. METHODS: Fifty eyes of 32 patients were treated by LASIK for residual myopia following primary PRK. The mean spherical equivalent refraction (SEQ) was -2.92 diopters (D) +/- 1.57 (SD) (range -0.75 to -7.88 D). The mean refractive cylinder was 0.96 +/- 0.74 D (range 0 to 3.50 D). For analysis, the eyes were divided into 2 groups: those with 0 or low corneal haze (Group 1) and those with severe corneal haze (Group 2). In Group 1, the SEQ was -1.99 +/- 0.79 D (range -0.75 to -3.75 D) and in Group 2, -3.77 +/- 1.62 D (range -0.75 to -7.90 D). The procedure was performed using the Chiron Automated Corneal Shaper and the Summit Apex Plus laser. The mean interval between PRK and LASIK was 25 months (range 9 to 59 months). The following parameters were studied before and after LASIK retreatment: SEQ, mean refractive cylinder, uncorrected visual acuity (UCVA), and best corrected visual acuity (BCVA). Complications after LASIK retreatment were evaluated. RESULTS: Six months after LASIK, the mean SEQ in all eyes was -0.65 +/- 0.86 D (range +1.50 to -3.35 D); 70.0% of eyes were within +/-1.00 D of emmetropia and the UCVA was 6/12 or better in 72.5%. The mean SEQ in Group 1 was -0.22 +/- 0.55 D (range -0.88 to -1.50 D) and in Group 2, -0.97+/- 0.92 D (range 0.12 to -3.25 D); the UCVA was 6/12 or better in 94.0% of eyes in Group 1 and in 56.0% in Group 2. No statistically significant between-group difference was found in lines of Snellen acuity lost or gained at 6 months. No eye lost more than 1 line of BCVA. CONCLUSIONS: Laser in situ keratomileusis appears to be a safe, effective, and predictable procedure for treating eyes with 0 or low haze with residual myopia after PRK. It is less predictable in eyes with severe haze.     

Safety and predictability of laser in situ keratomileusis enhancement by flap reelevation in high myopia

PURPOSE: To evaluate the safety and predictability of laser in situ keratomileusis (LASIK) retreatment following primary procedures for high myopia and astigmatism. SETTING: Corneal Diseases and Excimer Laser Research Unit, Department of Ophthalmology, University of Dundee, Dundee, United Kingdom. METHODS: This prospective observational study of retreatment comprised a cohort of 109 eyes having primary LASIK for high myopia and astigmatism with a spherical equivalent (SE) of -9.70 diopters (D) +/- 4.06 (SD). Twenty-four eyes (22%) with an initial myopic SE of -9.83 +/- 3.50 D, a comparable subset of the entire group (P < .05), had retreatment for residual myopia (-3.02 +/- 2.17 D) to improve uncorrected visual acuity (UCVA) by reelevating the corneal flap and ablating the stromal bed. RESULTS: The mean follow-up after retreatment was 12.8 +/- 5.1 months (range 1.5 to 24 months; 19 eyes >/=6 months, 13 eyes > or = 12 months). The mean myopic SE was reduced to +0.53 +/- 0.62 D at 1 week, +0.05 +/- 0.50 D at 1 month, +0.30 +/- 0.50 D at 6 months, and +0.18 +/- 0.42 D at the latest follow-up, 12.8 months. At the latest review, 62% of eyes were within +/-0.50 D of emmetropia and 100% were within +/-1.00 D. The mean refraction did not alter statistically between 1 week and subsequent times. The mean UCVA improved from 6/30 prior to retreatment to 6/9 at the latest follow-up. Uncorrected visual acuity of 6/6 or better, 6/9 or better, and 6/12 or better was achieved by 33.0%, 75.0%, and 95.8% of eyes, respectively. No significant complications that led to a loss of best corrected visual acuity were encountered, although retreatment procedures were more uncomfortable than primary procedures and self-limiting; epithelial ingrowth that did not threaten vision was common, and 2 patients complained of nighttime visual symptoms. CONCLUSIONS: Retreatment of residual myopia by reelevating the flap was relatively safe and predictable, with a low risk of sight-threatening complications. However, longer term studies may be required to detect late complications.     

Clear lens extraction with intraocular lens followed by photorefractive keratectomy or laser in situ keratomileusis

OBJECTIVE: To study photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) after clear lens extraction (CLE) with intraocular lens (IOL) implantation for hyperopia or astigmatism. DESIGN: Retrospective, noncomparative interventional case series. PARTICIPANTS: Sixty-five eyes (55 subjects) had CLE with posterior chamber IOL implants for hyperopia up to 12.25 diopters (D); 31 eyes were retreated with PRK, and 34 eyes were retreated with LASIK for residual ametropias. INTERVENTION: For PRK and LASIK, the refractive surgery was performed with the slit-scanning excimer laser Nidek EC-5000, Nidek Co., Tokyo, Japan. MAIN OUTCOME MEASURES: Manifest refraction, best-spectacle and uncorrected Snellen visual acuity, haze, and halos were evaluated before surgery and at 1, 3, 6, and 12 months postoperative. RESULTS: Forty-seven eyes were evaluated at the 12-month postoperative examination: 96% of these eyes had spherical equivalents (SE) within +/-2 D of emmetropia, 79% of eyes had SE within +/-1 D of emmetropia and 51% of eyes had SE within +/-0.50 D of emmetropia. Eighty-five percent of the eyes at 12 months postoperative had uncorrected visual acuity of 20/40 or better, and 46% of eyes had uncorrected visual acuity of 20/20 or better. Eighty-seven percent of the eyes at 12 months postoperative had uncorrected visual acuity within 1 Snellen line of their initial best spectacle-corrected visual acuity (BSCVA) before all treatment. No eye lost 2 Snellen lines of BSCVA at 3, 6, or 12 months after PRK or after LASIK. CONCLUSIONS: IOL implantation for CLE, although an invasive technique, resulted in better refractive outcomes without laser-related clinical complications after PRK or LASIK adjustment.     

Lift-flap retreatment after laser in situ keratomileusis

PURPOSE: To demonstrate the effectiveness of lifting the flap for retreatment of undercorrected eyes after laser in situ keratomileusis (LASIK). METHODS: We reviewed the results of 11 LASIK patients (12 eyes) who underwent retreatment for residual myopia by lifting the previously cut flap. This was followed by treatment with the Summit Apex excimer laser and repositioning of the flap. Average time prior to retreatment was 5 months (range, 1 to 9 mo). Follow-up was 100% at 3 months after retreatment. RESULTS: The average preoperative spherical equivalent refraction was -8.73 D; average prior to retreatment was -2.24 D (range, -0.67 to -5.75 D). At 1 month after retreatment, average deviation from intended correction was 0.08 D; at 3 months it was -0.12 D. Eleven of 12 treated eyes (92%) had uncorrected visual acuity of 20/40 or better and 4 eyes (33%) saw 20/20 or better without correction. Six eyes (50%) were within +/- 0.50 D of intended correction at 3 months. No patients lost any lines of spectacle-corrected visual acuity. CONCLUSION: Retreatment of residual myopia after LASIK by lifting the flap appears to be effective and associated with minimal complications.     

Laser in situ keratomileusis for consecutive hyperopia after myopic LASIK and radial keratotomy

PURPOSE: To evaluate and compare the efficacy, predictability, and safety of hyperopic laser in situ keratomileusis (H-LASIK) for the correction of consecutive hyperopia after myopic-LASIK (M-LASIK) and radial keratotomy (RK). SETTING: The Eye Institute of Utah, Salt Lake City, Utah, USA. METHODS: Seventy-seven eyes of 64 patients were studied. The eyes were divided into 2 groups based on the prior refractive procedures: in Group A (n = 34), H-LASIK was performed for overcorrection after M-LASIK and in Group B (n = 43), for overcorrection after RK. All eyes were included in the analysis of intraoperative and postoperative complications. Only eyes with a minimum follow-up of 6 months were included in the analysis of visual and refractive results. Among these 66 eyes, 30 were in Group A and 36 were in Group B. The mean follow-up in these eyes was 12.34 months +/- 5.95 (SD) (range 6 to 33 months). RESULTS: Overall, the mean spherical equivalent (SE) was +1.88 +/- 0.91 diopters (D) preoperatively and -0.37 +/- 0.65 D at the last visit. Eighty-three percent of eyes were within +/-1.00 D of emmetropia, and 66% were within +/-0.50 D. The uncorrected visual acuity (UCVA) was 20/20 in 39% of eyes and 20/40 or better in 92% of eyes. The preoperative SE was +1.43 +/- 0.59 D in Group A and +2.26 +/- 0.96 D in Group B; the difference in the preoperative SE was significant (P=.001). However, there was no statistically significant between-group difference in postoperative refraction and UCVA. One eye in Group B (3%) lost 2 or more lines of best corrected visual acuity. Corneal ectasia developed in 1 eye in Group B 11 months after H-LASIK. A sliver occurred in 1 eye in Group A after the flap was recut. CONCLUSION: Hyperopic LASIK was equally effective and predictable in treating consecutive hyperopia after overcorrected M-LASIK and overcorrected RK. The safety of the procedure in the RK group appeared to be inferior to that in the M-LASIK group. Although vision-threatening complications are rare after H-LASIK retreatment, corneal ectasia developed in 1 eye in the RK group.     

Retreatment after initial laser in situ keratomileusis

PURPOSE: To report the results of laser in situ keratomileusis (LASIK) retreatment in patients with primary undercorrection and with postoperative regression and to assess the efficacy and safety of LASIK retreatment. SETTING: The Eye Institute of Utah, Salt Lake City, Utah, USA. METHODS: The prospective study included 157 eyes of 108 patients. Using the VISX Star laser, retreatments were performed for undercorrection in 43 eyes (27%) and for regression in 114 eyes (73%). The mean follow-up was 15 months (range 6 to 28 months) after the initial surgery and 10 months (range 3 to 25 months) after the repeat LASIK procedure. RESULTS: Overall, the mean spherical equivalent (SE) was -6.11 +/- 2.35 diopters (D) (range -1.87 to -15.00 D) before LASIK and -1.28 +/- 0.57 D (range -0.50 to -3.25 D) prior to retreatment. At the last visit, it was -0.23 +/- 0.41 D (range -2.55 to 1.13 D). One hundred fifty-three eyes (97.5%) were within +/-1.00 D of emmetropia and 128 (81.5%), within +/-0.50 D. The uncorrected visual acuity was 20/20 or better in 68.8% of eyes and 20/40 or better in 98.1%. In all eyes, the best corrected visual acuity (BCVA) improved or remained within 1 line of the pre-revision level. However, 2 eyes (1.3%) lost 2 or more lines of pre-initial LASIK BCVA. Both eyes had a preoperative SE greater than -8.00 D; corneal irregularity was the cause of the decrease in vision. CONCLUSIONS: Several conclusions can be drawn from this study. First, LASIK retreatment is effective and safe for correcting undercorrection and regression after initial LASIK, and a good visual outcome is expected. Second, in most eyes, regression occurs within 6 months after the initial LASIK. However, regression can develop up to 2 years after LASIK. Third, multiple retreatments will be required in some patients. The outcome in these cases is promising.     

Laser in situ keratomileusis enhancement for consecutive hyperopia after myopic overcorrection.

PURPOSE: To assess the efficacy, predictability, and safety of laser in situ keratomileusis (LASIK) for the treatment of consecutive hyperopia after myopic LASIK. SETTING: Stanford University School of Medicine, Stanford, California, USA. METHODS: In a retrospective study, 36 eyes of 30 patients with consecutive hyperopia after myopic LASIK had LASIK retreatment using the VISX S2 excimer laser. Primary outcome variables including uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, complications, and vector analysis were evaluated preoperatively and 1 day and 3 months postoperatively. RESULTS: The mean spherical equivalent decreased from +1.52 diopters (D) +/- 0.55 (SD) (range +0.63 to +2.63 D) preoperatively to -0.10 +/- 0.52 D (range -1.25 to +1.50 D) 3 months after retreatment. The UCVA was 20/20 or better in 24 eyes (66.7%) and 20/40 or better in 34 eyes (94.4%). Twenty eyes (55.5%) were within +/-0.5 D of the intended correction and 34 eyes (94.4%), within +/-1.0 D. No eye lost 2 or more lines of BSCVA. One eye (2.8%) developed diffuse lamellar keratitis that resolved without sequelae, and 2 eyes (5.6%) developed nonprogressive epithelial ingrowth that did not require removal. CONCLUSIONS: Laser in situ keratomileusis retreatment for consecutive hyperopia following myopic LASIK was an effective, predictable, and safe procedure. Long-term follow-up is needed to assess stability.     

Cornea-sparing laser in situ keratomileusis: ablation on the flap

PURPOSE: To evaluate the safety and efficacy of laser ablation on the flap as a treatment for a refractive error. SETTING: Laser Sight Centres, Sydney, Australia. METHODS: In this noncomparative case series, 142 treatments were performed in 98 patients using cornea-sparing laser in situ keratomileusis (LASIK) with ablation of the corneal flap and, in some cases, also the stromal bed for spherical equivalent (SE) refractive errors from -0.50 diopter (D) to -12.38 D. The procedure was performed as a primary treatment in 104 eyes, an initial enhancement in 32 eyes, and a second enhancement in 6 eyes. Data were extracted for analysis by retrospective review of patients' charts. RESULTS: After LASIK, the mean SE was -0.20 D +/- 0.47 (SD) (range +0.87 to -2.35 D) excluding eyes with monovision. The 6 eyes with monovision had a mean SE of -1.90 D with myopia of -1.70 D (range -1.00 to -3.00 D) and mean astigmatism of -0.37 D (range 0 to -0.75 D). Excluding eyes with monovision, 97% of eyes achieved an uncorrected visual acuity of 6/12 or better and 64% of eyes, better than or equal to 6/6. Ninety-six percent were within +/-1.0 D of the intended correction (SE). The safety index was 1.02 and the efficacy index, 0.8. CONCLUSIONS: Laser ablation of the corneal flap achieved good visual results and enabled preservation of the posterior corneal stroma. This technique may aid the prevention of corneal keratectasia following LASIK.     

Recutting the cornea versus lifting the flap: comparison of two enhancement techniques following laser in situ keratomileusis

PURPOSE: To evaluate enhancement techniques following laser in situ keratomileusis (LASIK). METHODS: Recutting was performed on 263 eyes and the flap was lifted in 55 eyes that had LASIK for simple myopia or myopic astigmatism. The time interval between LASIK and retreatment was 340+/-46 days (range, 270 to 892 days) in the recutting group and 215+/-36 days (range, 53 to 617 days) in the flap lifting group. Mean spherical equivalent refraction, refractive cylinder, uncorrected and best spectacle-corrected visual acuity were examined prior to, and 1, 3, and 6 months after retreatment. RESULTS: Seventeen eyes were lost to follow-up in the lifting group and 53 eyes in the recutting group. In the recutting group, mean spherical equivalent refraction improved from -1.48+/-1.25 D to -0.49+/-0.88 D at 6 months. In the flap lifting group, mean spherical equivalent refraction improved from -1.05+/-1.49 D to -0.45+/-0.39 D at 6 months. Refractive cylinder did not change significantly in either group (P = .2). There was a significant increase in uncorrected visual acuity (UCVA) of 6/6 in each group. In the recutting group, UCVA of 6/6 increased from 3.8% to 65.2% at 6 months, and in the lifting group from 3.6% to 71.1% at 6 months. In the recutting group, seven free flaps and three macerated flaps that required removal occurred. One eye in the recutting group and two in the lifting group developed significant epithelial ingrowth. No patient lost more than one line of best spectacle-corrected visual acuity (BSCVA). CONCLUSION: Both procedures were safe, effective, and highly predictable for enhancements, but flap complications may be more likely with recutting.     

Partial flap during laser in-situ keratomileusis: pathogenesis and timing of retreatment

PURPOSE: To report the timing of retreatment and clinical outcomes in patients with a partial corneal flap during laser in-situ keratomileusis (LASIK), and to describe the causes of this complication. METHODS: Retrospective review of case records of four patients (4 eyes) who had a partial corneal flap during LASIK. RESULTS: The mean age of the four patients was 23 +/- 4.7 years, and mean preoperative spherical equivalent (SE) refraction was -9.1 +/- 3.1 D (range, -5.5 to -13 D). A 160 microns corneal flap was attempted during the initial treatment. Retreatment with a 180 microns corneal flap was performed at a mean of 5.1 +/- 1.6 weeks (range, 4 to 7.5 weeks) after the initial procedure. There were no intraoperative complications during retreatment. Post-LASIK mean SE refraction was -1.0 +/- 1.1 D (range, +0.38 to -2.0 D), after a mean follow up of 19 +/- 15.7 weeks (range, 7 to 42 weeks). Best spectacle-corrected visual acuity decreased in one eye from 6/5 to 6/6 and was maintained in the others. CONCLUSION: LASIK retreatment can be performed as early as one month after a partial flap, if the refraction is stable and a thicker corneal flap is created.     

Pathogenesis and management of laser in situ keratomileusis flap buttonhole

PURPOSE: To describe the clinical features and outcomes in patients who had a flap buttonhole during laser in situ keratomileusis (LASIK) and propose an etiopathogenic mechanism for this complication. SETTING: University Eye Center, Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China. METHODS: Retrospective review of case records of 6 patients (6 eyes) who had a flap buttonhole during LASIK. RESULTS: The mean patient age was 38.2 years +/- 4.1 (SD) and the mean preoperative spherical equivalent (SE) refraction, -8.13 +/- 4.04 diopters (D). Mean keratometry was 44.20 +/- 1.30 D. Retreatment was performed after a mean interval of 9.2 +/- 3.2 months. Final postoperative SE refraction was -0.44 +/- 0.58 D after a mean follow-up of 59.0 +/- 5.3 weeks. No patient experienced loss of best spectacle-corrected visual acuity. CONCLUSIONS: Retreatment of eyes that have a flap buttonhole during LASIK is associated with good visual outcomes. Flap buttonholes can produce alterations in refraction, so retreatment is best performed after the refractive error has stabilized. Microkeratome malfunction may be responsible for the occurrence of a flap buttonhole during LASIK in eyes that do not have significant corneal steepening.     

Results of resident-performed laser in situ keratomileusis

PURPOSE: To analyze the results of resident-performed laser in situ keratomileusis (LASIK). SETTING: Rush University Medical Center, Department of Ophthalmology, Chicago, Illinois, USA. METHODS: This retrospective study comprised 44 consecutive eyes of 22 patients who had LASIK performed from August 2000 through February 2002. Based on preoperative spherical equivalent, the eyes were divided into a low myopia group (A) (-1.0 to -6.0 diopter [D]) and a higher myopia group (B) (> -6.01 D). Preoperative and postoperative spherical equivalent (SE), best corrected visual acuity (BCVA), and uncorrected visual acuity (UCVA) were measured and analyzed within each group. Patients had at least 2 follow-up visits, with the second visit occurring between 1 and 9 months postoperatively. RESULTS: Preoperatively, the mean SE in Group A was -3.93 D +/- 1.53 (SD) and in Group B, -8.49 +/- 1.70 D. At the final visit, the SE in Group A decreased to -0.29 +/- 0.55 D and in Group B, -1.09 +/- 0.87 D. The UCVA in Group A at the final visit was 20/20 or better in 43% of eyes and 20/40 or better in 100% of eyes. In Group B, the UCVA was 20/20 or better in 31% of eyes and 20/40 or better in 75% of eyes. In all eyes, the BCVA improved by 1 line in 16% or remained the same in 84%. No eyes lost any lines of BCVA. The SE taken at the last visit was within +/-0.5 D in 69% of all eyes and within +/-1.0 D in 82% of all eyes. The incidence of patients needing retreatment in resident-performed LASIK surgery was 3 of 44 (6.8%). CONCLUSIONS: Laser in situ keratomileusis performed by residents is a safe and effective procedure for correction of refractive error. Postoperative UCVA, refractive error, retreatment rate, and loss of BCVA were consistent with published results from nonresident surgeons. These results also exceeded the U.S. Food and Drug Administration requirements for LASIK surgery.     

Conventional and wavefront-guided myopic LASIK retreatment

PURPOSE: To assess the clinical outcomes of conventional and wavefront-guided myopic laser in situ keratomileusis (LASIK) retreatment. DESIGN: Retrospective, nonrandomized case series. METHODS: The study comprised a cohort of 97 eyes having LASIK retreatment for residual myopia after primary LASIK. The eyes were divided into two groups: conventional retreatment (CR) group (n = 74) and wavefront-guided retreatment (WR) group (n = 23). The retreatment LASIK was performed using LADARVison 4000 with/without CustomCornea (Alcon Surgical, Orlando, Florida, USA). The mean follow-up was 8.9 +/- 5.8 months after retreatment (range three to thirty-six months). RESULTS: The mean pre-retreatment spherical equivalent (SE) was -0.93 +/- 0.41 diopters in the CR group and -0.84 +/- 0.48 diopters in the WR group (P = .409). At the last visit, the mean SE was -0.19 +/- 0.28 diopters and +0.32 +/- 0.47 diopters, respectively (P < .001). An SE of +/- 0.50 diopters was achieved in 92% (68 of 74) of CR eyes and 65% (15 of 23) of WR eyes. In the CR group, 85% eyes had a uncorrected visual acuity (UCVA) > or = 20/20 and 99% > or = 20/40, and in the WR group, 35% and 100%, respectively. None of the CR eyes and 17% (4 of 23) of WR eyes lost two lines of best spectacle-corrected visual acuity (BSCVA). Nine percent (7 of 74) of CR eyes and 30% of WR eyes (7 of 23) had optical symptoms before retreatment, the number was reduced to 1% (1 of 74) and 4% (1 of 23), respectively. CONCLUSIONS: In the study period with the current equipment, our results showed that conventional LASIK retreatment was superior to wavefront-guided LASIK retreatment in both efficacy and safety.     

飞秒激光制作角膜瓣的激光角膜原位磨镶术的临床观察

目的探讨应用飞秒激光制作角膜瓣的准分子激光角膜原位磨镶术（LASIK）的安全性、有效性和可预测性。方法应用VISX Stars 4准分子激光设备和Intralase飞秒激光仪,对屈光不正512例（1016眼）施行飞秒激光制作角膜瓣的LASIK手术。术后随访6～12个月,裂隙灯显微镜及角膜地形图仪检查角膜及角膜屈光改变情况。结果术后6个月的屈光状态,（等效球镜）为（1．00D～＋1．25D）,平均为（-0．25±0．75D）。923眼（90．85％）的裸眼视力大于或等于1．0,1002眼（98．62％）的裸眼视力等于或超过术前最佳矫正视力。术前与术后结果行t检验显示,二者差异有统计学意义（P〈0．01）。术中并发症有结膜下出血57眼（5．61％）,未见其他并发症。结论应用飞秒激光制作角膜瓣的LASIK手术是矫正屈光不正的安全和有效的方法,可预测性好。     

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.