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.     

Secondary laser in situ keratomileusis 1 year after primary LASIK for high myopia

PURPOSE: To report the results of the laser in situ keratomileusis (LASIK) using a second-cut hinged corneal flap to treat regression 1 year after primary LASIK for high myopia. SETTING: Istanbul University, Eye Research Center, Istanbul, Turkey. METHODS: Six eyes of 4 patients who had a mean myopic regression of -6.20 diopters (D) +/- 1.10 (SD) 1 year after primary LASIK were retreated with secondary LASIK performed using the Automated Corneal Shaper (Chiron Vision) and a 193 nm excimer laser (Chiron Technolas, Keracor 116). Fluence was 130 mJ/cm2 and the repetition rate, 10 Hz. RESULTS: Mean follow-up was 12.16 +/- 0.75 months. At the last follow-up, the mean spherical equivalent was -0.18 +/- 0.77 D (range +0.12 to -1.25 D). Two eyes (33.3%) remained within +/- 0.50 D of emmetropia; 5 eyes (83.3%) were within +/- 1.00 D of emmetropia. No patient lost best spectacle-corrected visual acuity. No complications occurred such as detachment of the former corneal flap and rolling, irregularity, or tearing of the new corneal flap. CONCLUSION: Secondary LASIK was an effective, safe method to treat regression after primary LASIK for high myopia.     

Efficacy of nonsimultaneous bilateral LASIK after nonsimultaneous bilateral penetrating keratoplasty

PURPOSE: To show if nonsimultaneous bilateral laser in situ keratomileusis (LASIK) is a safe and effective procedure for patients with bilateral penetrating keratoplasty (PKP). METHODS: Five patients (10 eyes), with keratoconus, underwent PKP separately in each eye. After an average PKP follow-up of 45.8 months per eye, (range, 19-92 months), each eye underwent 1-stage LASIK using the Visx Star S3 laser to correct its residual refractive error. We used the cycloplegic refraction as the target for the LASIK surgery. Each patient had his or her eyes done separately 3 weeks apart. RESULTS: Pre-LASIK myopia averaged -3.93 +/- 2.9 D, ranging from -10.00 to +0.75 D. Pre-LASIK astigmatism averaged -3.25 +/- 0.80 D, ranging from -1.75 to -4.50 D. Mean pre-LASIK keratometry was 45.4 +/- 2.6, ranging from 42.2 to 50.5. Uncorrected visual acuity pre-LASIK averaged 20/220, ranging from 20/60 to 20/400. Best-corrected spectacle visual acuity (BCSVA) pre-LASIK averaged 20/22, ranging from 20/20 to 20/30. Nine eyes had no complications. One eye had a flap buttonhole during LASIK, and surgery was aborted. No vision was lost in this eye. Mean follow-up after LASIK in the 9 eyes was 17 +/- 15.2 months, (range, 4-56 months). Mean post-LASIK ametropia in these 9 eyes was +0.25 +/- 0.45 D, ranging from -0.50 to +0.75 D. Average post-LASIK astigmatism was -0.33 +/- 0.38 D, ranging from 0 to -0.75 D. In the 9 treated eyes, uncorrected vision post-LASIK averaged 20/25, ranging from 20/20 to 20/30. BCSVA post-LASIK averaged 20/21, ranging from 20/20 to 20/25. No lines of visual acuity were lost in any of the eyes. CONCLUSION: Young patients who have had bilateral PKP, with good postoperative vision and low levels of myopia, astigmatism, and minimal wound override, are good candidates for bilateral nonsimultaneous LASIK. Further studies can now be done on the performance of bilateral simultaneous LASIK in patients who have had corneal transplant surgery in both of their eyes.     

Laser in situ keratomileusis for residual myopia after radial keratotomy and photorefractive keratectomy.

PURPOSE: To evaluate the visual outcome, stability, and complications of laser in situ keratomileusis (LASIK) for residual myopia after radial keratotomy (RK) and photorefractive keratectomy (PRK). SETTING: Dr. Agarwal's Eye Hospital, Chennai, India. METHODS: Twenty eyes that had LASIK treatment for residual myopia after RK (10 eyes) or PRK (10 eyes) were retrospectively analyzed. Laser in situ keratomileusis was performed after a mean period of 24.3 months +/- 0.75 (SD) in the RK group and 22.0 +/- 1.07 months in the PRK group. RESULTS: At the last follow-up, the mean spherical equivalent was reduced from -6.05 +/- 1.98 diopters (D) to -1.26 +/- 0.32 D (P <.05) in the RK group and from -3.38 +/- 1.30 D to -0.55 +/- 0.40 D (P <.005) in the PRK group. The mean uncorrected visual acuity improved from 20/300 (range 20/600 to 20/200) to 20/40 (range 20/60 to 20/20) (P <.05) and from 20/200 (range 20/800 to 20/80) to 20/25 (range 20/40 to 20/20) (P <.05), respectively. Two eyes in the RK group and 3 in the PRK group gained 1 line of best corrected visual acuity, and 2 eyes in the RK group lost 1 line. No sight-threatening complications such as a free flap, corneal ectasia, or a retinal complication occurred. There was no statistically significant difference in corneal haze before and after LASIK. Two eyes in the RK group required repositioning of the flap because of irregular apposition to the stromal bed. CONCLUSION: Laser in situ keratomileusis was safe, effective, and stable in the treatment of residual myopia after RK and PRK.     

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.     

Flap lift for LASIK retreatment in eyes with myopia

PURPOSE: To analyze the results achieved with LASIK retreatment after lifting the original flap in a large series of patients. DESIGN: Retrospective, noncomparative, interventional consecutive case series. PARTICIPANTS: Two thousand four hundred twenty-two consecutive eyes undergoing LASIK surgery for myopia, including 334 eyes submitted to flap lift for LASIK retreatment. MAIN OUTCOME MEASURES: Uncorrected visual acuity, best-corrected visual acuity, refractive error, and complications. RESULTS: LASIK retreatment was performed in 334 eyes (14%), and the mean time between initial procedure and retreatment was 8.2+/-6.2 months. The mean spherical equivalent (SE) improved from -1.2+/-0.6 diopters (D) (range, -4.2 to +1.2 D) before retreatment to +0.2+/-0.4 D (range, -3.1 to +1.1 D) after the retreatment. The uncorrected visual acuity (UCVA) after retreatment was 20/20 or better in 58% and 20/40 or better in 92% of eyes. The mean SE was within +/-1.0 D in 96% of the patients and within +/-0.5 D in 80.5% after retreatment. Eighteen eyes (5%) lost 1 line of best-corrected visual acuity, and 4 eyes (1%) lost 2 lines. CONCLUSIONS: LASIK retreatment surgery performed by relifting the flap was a useful procedure for correcting residual refractive errors after the primary LASIK procedure. It provided good uncorrected visual acuity, predictable results, good refractive stability, and few complications.     

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.     

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.     

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.     

Laser-assisted subepithelial keratectomy enhancement of residual myopia after primary myopic LASEK: six-month results in 10 eyes

PURPOSE: To determine whether residual myopia after primary laser-assisted subepithelial keratectomy (LASEK) can be corrected by repeated LASEK and whether this procedure is safe and effective. SETTING: University Eye Clinic, University of Regensburg, Regensburg, Germany. METHODS: Laser-assisted subepithelial keratectomy was performed in 10 eyes that had had primary LASEK for myopia. The initial mean spherical equivalent (SE) was -6.2 diopters (D) (range -2.5 to -8.0 D), and the residual mean SE was -1.6 D (range -1.0 to -3.0 D). The retreatment ratio was 7.6%. The exposure time of the corneal epithelium to alcohol (20% ethanol) was 30 seconds plus an additional 10 to 15 seconds in cases of strong epithelial adherence. Laser ablation was performed with a Keracor 117 excimer laser (Chiron Technolas). The follow-up after the second LASEK treatment was 6 months. RESULTS: The epithelial flap for repeated LASEK was successfully created in all 10 eyes. The postoperative course in the eyes was uneventful. Six months after LASEK enhancement, the SE refraction was within +/-0.5 D in all eyes. No eye lost more than 1 line of best corrected visual acuity, and the uncorrected visual acuity was 20/20 or better in 8 eyes. Significant haze was not observed after repeated LASEK (mean 0.35 before and 6 months after LASEK enhancement). CONCLUSIONS: Laser-assisted subepithelial keratectomy enhancement appears to be safe and effective for the correction of residual myopia after primary LASEK. Repeated epithelial flap preparation is possible without technical modifications.     

Laser in situ keratomileusis enhancement after radial keratotomy

PURPOSE: To present results of laser in situ keratomileusis (LASIK) enhancement after radial keratotomy (RK). METHODS: Sixteen eyes of 10 patients were treated with LASIK for residual myopia and hyperopia after RK. Mean preoperative spherical equivalent refraction was -3.14+/-3.04 D (range, -6.675 to +6.00 D). Best spectacle-corrected visual acuity was 20/20 in 9 eyes, 20/25 in 6 eyes, and 20/30 in 1 eye. Uncorrected visual acuity was better than 20/40 in only 2 eyes. Patients were followed at 1 day, 1 week, 1, 3, and 6 months, and 1 year. Mean follow-up was 8.3 months (range, 1 to 17 mo). RESULTS: All eyes received one LASIK enhancement. Mean final spherical equivalent refraction was +0.16+/-0.68 D (range, -1.00 to +1.75 D). No eyes experienced any visual loss. Five eyes gained 1 line of best spectacle-corrected visual acuity. Uncorrected visual acuity was 20/20 in 9 eyes, 20/25 in 6 eyes, and 20/30 in 1 eye. Two eyes of one patient had the previous RK incisions open. CONCLUSION: LASIK was an effective treatment for correction of residual myopia and hyperopia after RK.     

Outcomes of retreatment after laser in situ keratomileusis

OBJECTIVE: To evaluate the safety and efficacy of retreatment after myopic laser in situ keratomileusis (LASIK). DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: A total of 962 eyes of 566 patients underwent LASIK for up to -20.0 diopters (D) of myopia, of which 53 eyes (5.5%) were retreated. INTERVENTION: Retreatments were performed by lifting the original flap and using the Nidek EC-5000 excimer laser (Nidek Inc., Tokyo, Japan). MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA), fogged manifest refraction, and complications were evaluated 6 months after retreatment. RESULTS: Overall, 53 (5.5%) of 962 eyes underwent LASIK retreatment. Before retreatment, the mean spherical equivalent (MSE) was -1.7 +/- 1.1 D (range, +0.3 to -5.0 D), UCVA ranged from 20/25 to 20/400, and BCVA ranged from 20/20 to 20/50. Six months after retreatment, the MSE was -0.09 +/- 0.29 D, 48 (90.6%) eyes were within +/-0.5 D, and all eyes were within +/-1.0 D of the attempted correction. The UCVA improved to 20/20 or better in 21 (39.6%) eyes and 20/40 or better in 51 (96.2%) eyes. The BCVA was maintained in 33 eyes (62.3%), 15 eyes (28.3%) gained 1 line or more of vision, whereas 5 eyes (9.4%) lost 1 line. All eyes had a BCVA of 20/50 or better. No retreated eye lost two or more lines of BCVA. No complications were observed. CONCLUSION: Retreatment for low amounts of residual myopia performed by lifting the original flap within the first year after surgery after myopic LASIK is safe, effective, and predictable.     

Hyperopic laser in situ keratomileusis: primary and secondary treatments are safe and effective

PURPOSE: To retrospectively analyze the safety and efficacy of hyperopic laser in situ keratomileusis (LASIK) treatment of eyes with primary hyperopia and consecutive hyperopia after initial myopic treatment. METHODS: Thirty-two eyes of 19 patients with primary hyperopia (group 1) and 37 eyes of 26 patients with consecutive hyperopia after initial myopic LASIK overcorrection (group 2) that had LASIK for hyperopia with the Hansatome microkeratome and VISX S2 Smoothscan excimer laser with 6 months' follow-up after surgery were analyzed. Uncorrected visual acuity, best spectacle-corrected visual acuity, fogged manifest refraction, and corneal topography with corneal irregularity measurement (CIM) were evaluated 1 month, 3 months, and 6 months after surgery. RESULTS: In group 1, the mean preoperative cycloplegic spherical equivalent was +4.0 +/- 4.5 diopters (D) (range, +1.5 to + 8.75 D) and the 6-month postoperative cycloplegic spherical equivalent was +0.26 +/- 1.74 D (range, -3.00 to +2.75 D). Fifty-three percent of eyes (n= 17) in group 1 were within 1 D of emmetropia. Sixty-six percent of eyes (n= 21) had uncorrected visual acuity of at least 20/40. Three eyes (9%) lost two lines of best spectacle-corrected visual acuity. Changes in uncorrected visual acuity, best spectacle-corrected visual acuity, spherical equivalent, and the CIM topographic index 6 months after surgery were statistically significant compared with the preoperative values. In group 2, the mean preoperative cycloplegic spherical equivalent was +1.58 +/- 0.35 D (range, +0.125 to +2.75 D), and the mean postoperative cycloplegic spherical equivalent was -0.48 +/- 0.46 (range, -2.75 to +0.38 D). Eighty-six percent of eyes (n= 32) were within 1 D of emmetropia. Eighty-four percent of eyes (n= 31) in group 2 had uncorrected visual acuity of at least 20/40. One eye (2.7%) lost two lines of best spectacle-corrected visual acuity. Complications included an epithelial nest that resolved 3 months after surgery in one eye in group 2. CONCLUSIONS: LASIK is a relatively safe treatment of primary hyperopia and hyperopia resulting from overcorrection after initial LASIK treatment of myopia (consecutive hyperopia). Patients with high hyperopia (>5 D) are at risk for loss of two lines of best spectacle-corrected visual acuity. A reduction in the level of attempted correction appears to be necessary in the treatment of consecutive hyperopia.     

准分子激光原位角膜磨镶术治疗超高度近视远期疗效分析

目的探讨准分子激光原位角膜磨镶术(LASIK)治疗超高度(等效球镜度数>-10.00 D)近视的远期效果和安全性.方法对99例(173只眼)超高度近视行LASIK矫正,术前屈光度数-10.00～-23.50 D,平均(-13.7±3.6)D(等效球镜),其中-15.00 D以上41只眼.常规行裂隙灯显微镜、三面镜眼底检查、OrbscanⅡ眼前段分析系统、眼压、A超、角膜测厚、电脑验光、散瞳检影、主观验光等检查.术后随访18个月以上.结果术后18个月时裸眼视力≥0.5者148只眼(85.6%),最佳矫正视力高于或等于术前最佳矫正视力者147只眼(84.4%),未见术后最佳矫正视力较术前最佳矫正视力低于2行以上的眼;屈光度数稳定在±1.00 D以下者109只眼(63.0%),术前屈光度数在-14.75 D以下和-15.00 D以上达到±1.00 D内者的百分数分别为73.5%(97只眼/132只眼)和29.3%(12只眼/41只眼).术后角膜后表面前移,术后3个月时后表面顶点距理想球面的距离为(0.069±0.031)mm,18个月为(0.065±0.025)mm,均大于术前的(0.029±0.010)mm;角膜微皱褶2只眼,诉暗视力下降眩光6例(10只眼).结论 LASIK矫正超高度近视有效安全,同时在选择手术适应证方面应谨慎从之.对于屈光度数太高而角膜厚度偏薄者行LASIK应慎重,可考虑其他方法矫正如晶状体屈光手术或联合手术.(中华眼科杂志,2004,40816-818)     

Immediate transepithelial photorefractive keratectomy for treatment of laser in situ keratomileusis flap complications

PURPOSE: To study the role of photorefractive keratectomy (PRK) in the management of laser in situ keratomileusis (LASIK) flap complications. METHODS: A retrospective analysis was performed of seven patients (14 eyes) who had bilateral, simultaneous LASIK (single surgeon [TGA], Summit Apex Plus laser, Hansatome microkeratome in six patients [12 eyes], Automated Corneal Shaper keratome in one patient [two eyes]). One eye of each patient received PRK for a flap complication. The seven patients (four women, three men) had a mean age of 39.2 years (range, 22 to 64 yr). The uncomplicated LASIK eyes had moderate to high myopia (-2.25 to -8.75 D) and the eyes with LASIK flap complications had mild to moderate myopia (-1.50 to -5.75 D). Immediate transepithelial PRK was performed in all eyes after repositioning the defective flap. RESULTS: All seven patients had excellent visual outcome at 6 months follow-up; one patient required an enhancement (astigmatic keratotomy). Six of the seven LASIK eyes had best spectacle-corrected visual acuity of 20/20 or better and one LASIK eye had 20/25. In the transepithelial PRK eyes, six of the seven eyes had best spectacle-corrected visual acuity of 20/20 or better and one eye had 20/30. CONCLUSIONS: Immediate transepithelial PRK treatment of irregular and incomplete LASIK flaps at the time of surgery is an excellent therapeutic option to delayed surgical treatment.     

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.     

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.     

Comparison of two procedures: photorefractive keratectomy versus laser in situ keratomileusis for low to moderate myopia

PURPOSE: A prospective study was conducted to compare the effectiveness, safety, and stability of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) for correction of low to moderate myopia. METHODS: Forty-five patients with a manifest refraction (PRK, -4.54 +/- 0.80; LASIK, -4.82 +/- 1.10) from -1.50 to -6.00 diopters (D) were treated and followed-up for 6 months. In each case, 1 eye received PRK and the other LASIK. The first eye treated, and the surgical method used in the first eye, were randomized. Uncorrected and corrected visual acuity, manifest refraction, corneal haze, and topographic analysis of ablation decentration were examined. RESULTS: The uncorrected visual acuity was 20/20 or better in 35 PRK eyes (77.8%) and 28 LASIK eyes (62.2%) at 6 months (P =.107). At 6 months, 28 eyes (62.2%) that received PRK showed a spherical equivalent of within +/-0.5 D as compared with 24 eyes (53.4%) that received LASIK (P =.393). The amount of ablation decentration was 0.37 +/- 0.25 mm in PRK eyes and 0.49 +/- 0.38 mm in LASIK eyes at 3 months (P =.36). CONCLUSIONS: In our study, PRK and LASIK were found to be similarly effective and predictive of correction in low to moderate myopia. PRK has the advantage of less ablation decentration and is safer than LASIK, so we recommend PRK for eyes with low to moderate myopia.     

准分子激光角膜原位磨镶术矫治高度近视准分子激光屈光性角膜切削术后屈光回退的临床观察

目的评价准分子激光角膜原位磨镶术（LASIK）矫治高度近视准分子激光屈光性角膜切削术（PRK）后屈光回退的疗效。方法回顾性临床研究。对PRK术后2年以上、屈光回退且屈光度稳定的患者8例14眼行LASIK,对LASIK术后术眼进行评价。患眼PRK术前屈光度为-6.25～-12.50 D,PRK术后屈光度为-1.50～-6.25 D。随访观察LASIK矫正1年后术眼的裸眼视力、最佳矫正视力、屈光度、上皮下雾状混浊（haze）形成和角膜厚度的变化。结果所有患眼术后主观症状较轻。LASIK术后1年平均球镜度数为（-0.62±0.94）D。LASIK术后0.5≤裸眼视力〈0.8者4眼,≥0.8者9眼,1眼（7.1%）最佳矫正视力下降2行。4眼术后出现不同程度的haze,包括2级haze 3眼、3级haze 1眼。应用氟米龙滴眼液1个月后,haze及屈光回退减轻;术后1年,1级haze 2眼,2级haze 2眼,3级haze 1眼。LASIK术前角膜厚度为（467±38）μm,术后为（422±21）μm。结论高度近视PRK术后屈光回退行LASIK矫治是一种可行的方法,但少数患者术后可出现haze,仍需治疗。     

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.