Laser in situ keratomileusis for myopic astigmatism with the Nidek EC-5000 laser

PURPOSE: We studied the efficacy, predictability, and safety of laser in situ keratomileusis (LASIK) for moderate to high simple and compound myopic astigmatism. METHODS: Ninety-two eyes of 46 consecutive patients who had LASIK for myopic astigmatism (64 eyes, astigmatism 3.00 to 9.00 D; myopia 0 to -20.00 D), or simple myopia (28 eyes, myopia -4.00 to -20.00 D; astigmatism 0 to 0.50 D) were retrospectively studied. Mean baseline spherical equivalent refraction (SE) in the myopia group was -8.11 +/- 3.94 D and in the astigmatism group, -8.55 +/- 4.49 D. All eyes underwent LASIK using the Nidek EC-5000 laser by the same surgeon. RESULTS: At 6 months after LASIK in the myopia group versus the astigmatism group, 24 eyes (85%) vs. 54 eyes (84%) were available for follow-up, 12 eyes (50%) vs. 13 eyes (24%) had uncorrected visual acuity (UCVA) of 20/20, 19 eyes (79%) vs. 44 eyes (81%) had UCVA of 20/40, 8 eyes (33%) vs. 18 eyes (33%) had SE within +/- 0.50 D, 15 eyes (62%) vs. 39 eyes (72%) had SE within +/- 1.00 D, and mean SE was -1.22 +/- 1.17 D vs. -0.74 +/- 1.46 D. Mean astigmatism (vertexed to the corneal plane) in the astigmatism group was 2.77 D at 0 degrees before surgery and 0.32 D at 7 degrees at 6 months. None of the myopic eyes and three of the astigmatic eyes (5%) lost > or = 2 lines of best spectacle-corrected visual acuity. CONCLUSION: LASIK with the Nidek EC-5000 laser for myopic astigmatism was reasonably effective, predictable, and safe. Astigmatism was under-corrected with the nomogram implemented in this study.     

Laser in situ keratomileusis for myopia and hyperopia using the Lasersight 200 laser in 300 consecutive eyes

PURPOSE: To evaluate effectiveness, safety, predictability, and short-term stability of laser in situ keratomileusis (LASIK) using the LaserSight Compac-200 Mini excimer laser with software version 9.0, for all refractive errors. METHODS: One hundred fifty consecutive patients (300 eyes) that received bilateral LASIK for myopia, hyperopia, and astigmatism were studied prospectively. A new 9.0 software version applying a modified nomogram that takes advantage of bilateral surgery was used. Follow-up at 6 months was available for 267 eyes (89%). RESULTS: Six months postoperatively, 131 eyes (96.32%) in the low to moderate myopia group (-1.00 to -5.99 D; n=136) had a spherical equivalent refraction within +/-1.00 D, and 123 eyes (90.44%) were within +/-0.50 D of emmetropia. In the high to extreme myopia group (-6.00 to -25.00 D; n=114), 97 eyes (87.08%) had a spherical equivalent refraction within +/-1.00 D and 78 eyes (68.42%) were within +/-0.50 D of emmetropia. In the hyperopia group (+1.00 to +6.00 D; n=50), 44 eyes (88%) had a postoperative spherical equivalent refraction within +/-1.00 D, and 31 eyes (62%) were within +/-0.50 D of emmetropia. Mean change in spherical equivalent refraction at 6 months was less than -0.50 D in the low to high myopia groups and -1.16 +/- 0.55 D in the extreme myopia group. At 6 months follow-up, uncorrected visual acuity was 20/20 or better in 73 eyes (54%) in the low to moderate myopia groups and 21 eyes (18%) in the high to extreme myopia groups. In the hyperopia group at 6 months follow-up, uncorrected visual acuity was 20/20 or better in 31 eyes (62%) and 20/40 or better in 41 eyes (82%). Only two eyes had a temporary loss of two or more lines of spectacle-corrected visual acuity due to corneal folds that were surgically treated. Six months after LASIK, no eye had lost any lines of best spectacle-corrected visual acuity in this series. CONCLUSIONS: Our modified LASIK nomogram with the 9.0 software of the LaserSight 200 excimer laser (with a larger and smoother ablation pattern) resulted in safe and effective outcomes for the treatment of low to high myopia, astigmatism, and hyperopia.     

激光角膜上皮瓣下磨镶术和激光原位角膜磨镶术治疗中高度近视的对比研究

目的比较激光角膜瓣下磨镶术(LASEK)和激光原位角膜磨镶术(LASIK)治疗中高度近视的临床效果. 方法中高度近视患者198例(394只眼).其中LASEK手术治疗93例(184只眼), LASIK手术治疗105例(210只眼). 结果术后1天,LASIK 组28 %裸眼视力达到1.0,LASEK组无1例裸眼视力达到1.0.术后1周、1、3、6月裸眼视力大于或等于1.0者,两组比较差异无显著性 (P=0.36,P=0.58,P=0.44,P=0.64).角膜地形图分析平均角膜中央屈光力与周边屈光力的差异,LASEK组(0.69)明显小于LASIK组(2.62).结论 LASEK手术矫正中高度近视均有良好的治疗效果,是一种安全、有效、预测性好的屈光手术.     

Laser in situ keratomileusis for different degrees of myopia

PURPOSE: To determine the efficacy, predictability, stability and safety of laser in situ keratomileusis (LASIK) in treating patients with different degrees of myopia. METHODS: We enrolled 386 eyes of 200 consecutive patients who underwent LASIK and divided them into four groups according to their degree of preoperative spherical equivalent (SE). Group 1 eyes ranged between - 1.00 and - 3.99 dioptres (D) (low myopia). Group 2 eyes ranged between - 4.00 and - 5.99 D (moderate myopia). Group 3 eyes ranged between - 6.00 and - 9.99 D (high myopia). Group 4 eyes were over - 9.99 D (extreme myopia). Follow-up was at 1 day, 1 week and 1, 3, 6, 12 and 18 months postoperatively. RESULTS: Our study included 386 eyes of 200 patients with SE ranging from - 3.00 to - 16.00 D (mean - 7.14 +/- 2.87 D). All eyes were seen at 1 day postoperatively. A total of 360 eyes (93%) were examined at 1 week, 330 eyes (85%) at 1 month, 281 eyes (73%) at 3 months, 247 eyes (64%) at 6 months, 199 eyes (52%) at 12 months and 142 eyes (37%) at 18 months. The postoperative data from 1 day to 12 months were used because of the low follow-up rate at 18 months postoperatively. Group 1 consisted of 30 eyes. The mean SE was - 3.52 +/- 0.43 D preoperatively and - 0.40 +/- 0.58 D at 1 month, - 0.46 +/- 0.60 D at 6 months and - 0.42 +/- 0.50 D at 12 months postoperatively. Uncorrected visual acuity (UCVA) was 20/40 or better in 95% of eyes at 1 day and in 100% of eyes at 6 and 12 months postoperatively. Group 2 consisted of 151 eyes. The mean SE was - 5.36 +/- 0.67 D preoperatively and - 0.54 +/- 0.78 D at 1 month, - 0.56 +/- 0.90 D at 6 months and - 0.55 +/- 0.82 D at 12 months postoperatively. Uncorrected VA was 20/40 or better in 95% of eyes at 1 day and in 100% of eyes at 6 and 12 months postoperatively. Group 3 consisted of 167 eyes. The mean SE was - 8.15 +/- 0.94 D preoperatively and - 0.58 +/- 0.90 D at 1 month, - 0.67 +/- 1.00 D at 6 months and - 0.64 +/- 0.95 D at 12 months postoperatively. Uncorrected VA was 20/40 or better in 90% of eyes at 1 day and in 98% of eyes at 6 and 12 months postoperatively. Group 4 consisted of 38 eyes. The mean SE was - 11.09 +/- 1.10 D preoperatively and - 1.25 +/- 1.20 D at 1 month, - 1.13 +/- 1.30 D at 6 months and - 1.20 +/- 1.25 D at 12 months postoperatively. Uncorrected VA was 20/40 or better in 78% of eyes at 1 day, in 94% at 6 months and in 90% at 12 months postoperatively. Intraoperative complications (free cap) occurred in two eyes and postoperative complications were observed in three eyes, making the total complications rate 1.29% (5/386). Seven eyes lost one Snellen line of BCVA, five lost two lines and two lost more than two lines (total: 3.64%, 14/386). CONCLUSION: In conclusion, LASIK is effective, predictable and safe for correcting myopia but is more accurate for correcting myopia up to -10.00 D. With more improvement in algorithms and ablation profile, we believe that LASIK can offer better results for higher myopia.     

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 versus laser-assisted subepithelial keratectomy for the correction of high myopia

PURPOSE: To compare the visual and refractive outcomes of laser in situ keratomileusis (LASIK) and laser-assisted subepithelial keratectomy (LASEK) in the treatment of high myopia. SETTING: Institute of Vision Research, Department of Ophthalmology, College of Medicine, Yonsei University, and Balgeunsesang Ophthalmology Clinic, Seoul, South Korea. METHODS: Four hundred seventy eyes of 240 patients with manifest refraction spherical components greater than -6.00 diopters (D) were assigned to 2 groups: 324 eyes (167 patients) were treated with LASIK and 146 eyes (73 patients), with LASEK. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), remaining refractive error, corneal haze, and complications were followed in both groups for 12 months. RESULTS: At 12 months, the mean spherical equivalent (SE) was within +/-0.50 D of emmetropia in 205 eyes (63.3%) in the LASIK group and 81 eyes (55.5%) in the LASEK group and within +/-1.00 D in 261 eyes (80.6%) and 104 eyes (71.2%), respectively. The UCVA was 20/25 or better in 269 LASIK eyes (83.0%) and 111 LASEK eyes (76.0%). There was more than a 1-line loss of BSCVA in 4 LASIK eyes (1.2%) and 21 LASEK eyes (14.3%). The between-group differences in SE, magnitude of cylinder, UCVA, and haze were statistically significant (P<.05). CONCLUSIONS: Both LASIK and LASEK were safe and effectively treated eyes with high myopia. Laser in situ keratomileusis provided superior results in visual predictability and corneal opacity.     

Laser in situ keratomileusis for hyeropia and hyperopic astigmatism.

PURPOSE: To evaluate the efficacy, stability, and safety of laser in situ keratomileusis (LASIK) for hyperopia and hyperopic astigmatism using a prospective clinical trial. METHODS: LASIK was performed using the Automatic Corneal Shaper and the Keracor 117C excimer laser on 192 hyperopic eyes with astigmatism of less than 1.00 D (spherical group) and 164 hyperopic eyes with corneal astigmatism of 1.00 to 7.50 D (toric group). RESULTS: At 12 months after LASIK, 110 eyes were available for follow-up examination. In low spherical hyperopia (+1.00 to +3.00 D), 13 eyes (55%) were within +/-0.50 D of emmetropia and none lost 2 or more lines of spectacle-corrected visual acuity. In low toric hyperopia (+1.00 to +3.00 D), 14 eyes (61%) were within +/-0.50 D and none lost 2 or more lines of spectacle-corrected visual acuity. In moderate spherical hyperopia (+3.10 to +5.00 D) 9 eyes (44%) were within +/-0.50 D and none lost 2 or more lines of spectacle-corrected visual acuity and in moderate toric hyperopia (+3.10 to +5.00 D) 5 eyes (36%) were within +/-0.50 D and 2 eyes (14%) lost 2 or more lines of spectacle-corrected visual acuity. In high spherical hyperopia (+5.10 to +9.00 D), 6 eyes (38%) were within +/-0.50 D and 2 eyes (13%) lost 2 or more lines of spectacle-corrected visual acuity, and in high toric hyperopia (+5.10 to +9.50 D) 4 eyes (31%) were within +/-0.50 D and 2 eyes (15%) lost 2 or more lines of spectacle-corrected visual acuity. CONCLUSIONS: LASIK seems to be reasonably effective and safe in spherical hyperopia of +1.00 to +5.00 D but less effective for hyperopic astigmatism. For hyperopia greater than +5.00 D, loss of spectacle-corrected visual acuity occurred in a significant number of eyes and accuracy was sufficiently poor to advise against LASIK in these eyes.     

A control-matched comparison of laser epithelial keratomileusis and laser in situ keratomileusis for low to moderate myopia

PURPOSE: To compare the visual and refractive outcomes of laser epithelial keratomileusis (LASEK) and laser in situ keratomileusis (LASIK) for the treatment of low to moderate myopia. DESIGN: Retrospective, nonrandomized, control-matched study. METHODS: The charts of 2257 eyes that underwent LASEK or LASIK treatment were reviewed. Patients who were 21 years of age or older having between -0.75 and -6.00 diopters (D) of myopia with up to -2.25 D of astigmatism were included. One hundred twenty-two LASEK-treated eyes were matched with 122 LASIK-treated eyes having preoperative spheres, cylinders, and spherical equivalent (SE) within +/-0.50 D. Both groups had similar preoperative best spectacle-corrected visual acuity (BSCVA), laser platform, and follow-up durations. Outcome measures were visual and refractive results. RESULTS: Preoperatively, the mean SE was -3.50 +/- 1.40 D for LASEK and -3.50 +/- 1.42 D for LASIK (P = .59). Postoperatively, the mean logarithm of minimum angle of resolution (logMAR) uncorrected visual acuity (UCVA) was 0.01 +/- 0.08 (20/21) for LASEK and 0.06 +/- 0.12 (20/23) for LASIK; the mean SE was -0.15 +/- 0.40 D for LASEK and -0.37 +/- 0.45 D for LASIK; and the mean logMAR of BSCVA was -0.03 +/- 0.06 (20/19) for LASEK and -0.02 +/- 0.05 (20/19) for LASIK. No eye lost 2 or more lines of BSCVA in both groups. CONCLUSIONS: Slight differences in the visual and refractive results between LASEK and LASIK were observed, despite the use of the same nomogram. Both procedures were safe, effective, and predictable. Nomogram adjustment may be necessary for LASIK surgeons adopting surface ablation.     

Laser in situ keratomileusis versus surface ablation: visual outcomes and complications

PURPOSE: To compare the visual outcomes and complications of laser in situ keratomileusis (LASIK) with those of surface treatment by laser-assisted subepithelial keratectomy (LASEK), photorefractive keratectomy with mechanical epithelial removal (M-PRK), and transepithelial photorefractive keratectomy (T-PRK). SETTING: Tertiary care eye center. METHODS: This retrospective review comprised all cases of LASIK, LASEK, M-PRK, and T-PRK performed at King Khaled Eye Specialist Hospital between July 1, 2004, and June 30, 2005. Separate statistical analyses were performed for eyes with low to moderate myopia (spherical equivalent [SE] less than -6.00 diopters [D]) and high myopia (SE -6.00 to -11.25 D). RESULTS: Of 696 eyes that met the inclusion criteria, 464 had LASIK, 104 had LASEK, 69 had M-PRK, and 59 had T-PRK. Eyes with low to moderate myopia had a statistically significantly smaller mean difference between logMAR final postoperative uncorrected visual acuity (UCVA) and preoperative best spectacle-corrected visual acuity (BSCVA) after T-PRK and M-PRK than after LASIK or LASEK. A higher percentage of eyes with high myopia had a final UCVA within +/-2 lines of the preoperative BSCVA with T-PRK than with LASIK, LASEK, or M-PRK. There were more major non-flap-related complications after LASEK than after LASIK, M-PRK, or T-PRK. CONCLUSIONS: In eyes with low to moderate myopia, T-PRK and M-PRK provided slightly better visual outcomes than LASIK or LASEK. In eyes with high myopia, T-PRK provided better visual outcomes than LASIK, LASEK, and M-PRK. Laser in situ keratomileusis was associated with the most major postoperative complications.     

准分子激光角膜原位磨镶术治疗近视

目的 评价准分子激光角膜原位磨镶术（ＬＡＳＩＫ）在治疗近视眼中的作用。方法 将６７８例（９２８只眼）近视眼患者（－２．００￣－２０．００Ｄ）分为３组：Ｉ组为－２．００￣－６．００Ｄ、Ⅱ组为－６．１０￣－１０．００Ｄ及Ⅲ组为－１０．１０￣－２０．００Ｄ,均采用ＬＡＳＩＫ进行治疗,术后平均随访１年（６￣１８个月）,并对其资料进行分析。结果 Ｉ组：术后１年时平均残余屈光度为－０．２４±０．５０Ｄ,屈光度     

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.     

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.     

Laser in situ keratomileus using the LaserSight 200 laser: results of 950 consecutive cases.

PURPOSE: To examine the refractive outcome in 950 consecutive eyes having laser in situ keratomileusis (LASIK) by 1 surgeon with experience in keratomileusis. SETTING: Outpatient excimer laser surgical facility. METHODS: This study comprised 950 consecutive eyes of 475 patients having LASIK as a primary procedure with a LaserSight 200 excimer laser (8.51 software). A nasal hinged flap and a Chiron microkeratome were used. Preoperative cycloplegic refraction was done only in patients younger than 25 years and in all hyperopic cases. Subjective preoperative and postoperative manifest refractions were done after autorefractometry in all cases. In cases of hyperopia, the software was modified by adding 30% to the refractive error. Enhancement results are not included. RESULTS: Of the 950 eyes, 893 (94.00%) were myopic and 57 (6.00%), hyperopic. In the low myopia group (1.00 to 3.99 D) of 223 eyes (24.97%), mean spherical equivalents (SEs) were -2.90 D +/- 0.56 (SD) preoperatively, -0.46 +/- 0.6 D 3 months postoperatively, and -0.41 +/- 0.5 D 6 months postoperatively. In the moderate myopia group (4.00 to 5.99 D) of 205 eyes (22.96%), respective mean SEs were -4.90 +/- 0.7 D, -0.90 D +/- 0.9 D, and -0.67 +/- 0.7 D. In the high myopia group (6.00 to 9.99) of 266 eyes (25.30%), the respective means were -7.70 +/- 1.3 D, -0.76 +/- 0.99 D, and -0.60 +/- 0.8 D. In the extreme myopia group (10.21 to 30.00) of 199 eyes (22.28%), the respective means were -13.30 +/- 2.9 D, -1.30 +/- 1.4 D, and -1.13 +/- 1.3 D. For the entire myopic group, the mean astigmatism was +1.55 +/- 1.38 D, +1.09 +/- 0.92 D, and +0.87 +/- 0.77 D, respectively. The low hyperopia group (1.00 to 2.99 D) of 39 eyes (68.42%) had a mean preoperative SE of +1.80 +/- 0.59 D and mean postoperative SEs of +1.00 +/- 0.76 D at 3 months and +1.16 +/- 0.52 D at 6 months. The respective means in the moderate hyperopia group (3.00 to 6.00) of 18 eyes (31.57%) were +4.62 +/- 1.19 D, +3.71 +/- 1.12 D, and +4.00 +/- 1.07 D. CONCLUSIONS: Laser in situ keratomileus for myopia using the LaserSight 200 excimer laser was stable with time and safe for the correction of different degrees of myopia. In the hyperopic group, marked regression occurred in a large percentage of patients. Thus, we will not perform LASIK for hyperopia until the software improves.     

Effect of preoperative keratometry on refractive outcomes after laser in situ keratomileusis

PURPOSE: To evaluate the effect of preoperative keratometry on the refractive outcome after laser in situ keratomileusis (LASIK) for myopia. SETTING: University Eye Clinic, Prince of Wales Hospital, Hong Kong, China. METHODS: In this retrospective study, the records of patients who had LASIK for myopia greater than -6.0 diopters (D) using the Chiron Automated Corneal Shaper and the Schwind Keratome-F excimer laser were reviewed. RESULTS: Laser in situ keratomileusis was performed in 167 eyes of 103 patients (mean age 34.7 years +/- 7.5 [SD]). Preoperative myopic spherical equivalent (SE) refraction was -9.0 +/- 2.0 D (range -6.0 to -13.9 D). Three months after surgery, SE refraction was -0.04 +/- 1.1 D (range +2.3 to -3.3 D); uncorrected visual acuity > or = 20/40 was present in 91.8% of 110 eyes in which emmetropia was the postoperative goal. Mean preoperative keratometry was 43.9 +/- 1.5 D (range 40.3 to 48.1 D). When eyes were stratified by the degree of preoperative myopia in 1.0 D steps, a trend toward greater undercorrection was noted in eyes with preoperative keratometry < 43.5 D than in those with steeper keratometry (> 44.5 D) in all myopia groups except the -7.0 to -7.9 D group. This difference was statistically significant in eyes with a preoperative SE of -10.0 to -10.9 D and -11.0 to -11.9 D. CONCLUSIONS: Preoperative keratometry appeared to influence the refractive outcome after myopic LASIK. Eyes with flatter corneas tended to have greater undercorrection than eyes with similar myopia and steeper corneas. Validation of these findings in larger data sets using the methodology described may improve the predictability of current LASIK nomograms, particularly in eyes with high myopia.     

Visual outcomes of wavefront-guided laser in situ keratomileusis in eyes with moderate or high myopia and compound myopic astigmatism

PURPOSE: To evaluate the safety, efficacy, and clinical outcomes of wavefront-guided laser in situ keratomileusis (LASIK) surgery for the treatment of moderate to high myopia and compound myopic astigmatism. SETTING: Stanford University School of Medicine, Department of Ophthalmology, Stanford, California, USA. METHODS: This retrospective study included patients with moderate (-6.0 to -8.0 diopters [D]) and high (greater than -8.00) myopia treated with wavefront-guided LASIK using the WaveScan linked to the CustomVue system (AMO USA, Inc.). Eyes were analyzed preoperatively and 1, 3, and 12 months postoperatively. RESULTS: The mean patient age was 38.4 years +/- 7.14 (SD). Eighty-nine eyes of 45 patients were evaluated at 3 months and 50 eyes of 25 patients at 12 months. No eye was retreated during the study. The mean manifest refraction spherical equivalent was -8.10 +/- 0.98 D (range -6.00 to -10.63 D) preoperatively and -0.33 +/- 0.55 D (range -1.625 to 1.375 D) 12 months postoperatively. Ninety percent of the eyes were within +/-1.00 D of the intended correction and 64.0%, within +/-0.50 D. For all eyes, the safety index was 1.00 and the efficacy index, 1.18. CONCLUSION: The data support the safety and efficacy of correcting moderate to high myopia and compound myopic astigmatism using wavefront-guided LASIK.     

Comparison between LASEK with mitomycin C and LASIK for the correction of myopia of -7.00 to -13.75 D

PURPOSE: To compare laser epithelial keratomileusis (LASEK) and LASIK for the correction of high myopia. METHODS: A prospective, single-masked study was conducted. Patients treated with LASEK to correct myopia > or = -7.00 diopters (D) (spherical equivalent manifest refraction) with a cylinder < or = -3.50 D (LASEK group) were compared to patients treated with LASIK (LASIK group) using the same excimer laser (Technolas 217C). Mitomycin C (MMC) 0.02% was applied for 1 minute in all LASEK-treated eyes. RESULTS: A total of 228 consecutive eyes were included in the study (114 in each group, matched for preoperative refraction). The mean preoperative spherical equivalent manifest refraction was -8.72 +/- 1.20 D in the LASEK group and -8.74 +/- 1.20 D in the LASIK group (range: -7.00 to -13.75 D) (P = .9). Uncorrected visual acuity (UCVA) was significantly lower in LASEK eyes 1, 7, and 30 days postoperatively (P = .0001 for each comparison). No significant differences were found at 3 months postoperatively in UCVA (P = .3), best spectacle-corrected visual acuity (BSCVA) (P = .2), or in the safety (P = .6) and efficacy (P = .8) indices. Uncorrected visual acuity was 1.0 or better in 34.2% of LASEK eyes and 44.7% of LASIK eyes. Spherical refraction was +0.25 +/- 0.6 D after LASEK and -0.06 +/- 0.5 D after LASIK (P = .0001). Sixty-eight percent of LASEK eyes and 79% of LASIK eyes were within +/- 0.50 D of intended refraction. No LASEK eye versus 7 LASIK eyes lost 2 lines of BSCVA. Eight LASEK eyes gained 2 or more lines of BSCVA versus 1 LASIK eye. CONCLUSIONS: Visual improvement after LASEK with intraoperative MMC was significantly slower than after LASIK. Visual outcomes (UCVA, BSCVA, and safety and efficacy indices) 3 months after surgery were similar with both techniques for the correction of high myopia. Ten percent more eyes after LASIK were within +/- 0.50 D of intended refraction.     

Clinical outcome of wavefront-guided laser in situ keratomileusis in eyes with moderate to high myopia with thin corneas

PURPOSE: To evaluate the clinical outcome of wavefront-guided laser in situ keratomileusis (LASIK) for the treatment of moderate to high myopia associated with a thin cornea. SETTING: Enaim Laser Medical Center, Tel Aviv, Israel. METHODS: This retrospective study included 98 eyes of 49 patients with moderate to high myopia (-5.20 to -10.35 diopters [D]) and thin corneas (456 to 498 mum) treated with wavefront-guided LASIK (Zyoptix, Bausch & Lomb) and followed for 36 months. Preoperative wavefront analysis was performed with a Hartmann-Shack aberrometer, and treatment was performed with the Technolas 217 z excimer laser system (Bausch & Lomb). Final refraction data, uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), optic zone size, ablation depth, optical aberrations, and night glare complaints were evaluated. RESULTS: Mean patient age was 28 years +/- 7 (SD), and mean preoperative spherical equivalent refraction was -7.06 D (range -5.20 to -10.35 D). Final UCVA ranged between 6/6 and 6/30. The safety index of the technique was 1.03, and the efficacy index was 0.67. Undercorrection of more than 0.50 D was observed in 41.3% of the high-myopic eyes (-7.00 to -10.35 D, n = 58) compared with 10% in the moderately myopic eyes (-5.00 to -6.75 D, n = 40). A significant reduction in spherical aberration (Z(4)0) was found 12 months postoperatively in all eyes. Night glare was documented in 4 eyes (4%) in the high myopia group. There were no cases of corneal ectasia. CONCLUSION: Zyoptix was safe in eyes with moderate to high myopia with relatively thin corneas (<498 microm). For myopia between -7.00 D and -10.35 D, a small optical zone (4.3 to 5.6 mm) may be applied as night glare was relatively rare, but significant undercorrection should be expected.     

近视患者LASIK术后夜间眩光的相关因素

目的:探讨近视患者LASIK术后发生夜间眩光的术前相关因素。方法:将665例(1257眼)近视患者按屈光度分为两组:组Ⅰ(低、中度近视)-1.00～-6.00D;组Ⅱ(高度近视)-6.25～-14.25D。以ObscanⅡ眼前节分析系统测量术前暗光下瞳孔直径,所有手术均为标准的LASIK手术,术后3mo调查患者夜间眩光情况。结果:低、中度近视组术前暗光下瞳孔直径6.81±0.50mm,高度近视组6.98±0.57mm,两组差异有显著性(P=0.001)。低、中度近视组58眼(7.9%)发生夜间眩光,高度近视组为137眼(26.2%),两组差异有显著性(P=0.000)。低、中度近视组发生眩光眼和无眩光眼在术前暗光下瞳孔直径上差异有显著性(P=0.000),拟矫正屈光度上差异无显著性(P=0.104);高度近视组在暗光下瞳孔直径和拟矫正屈光度上差异均具有显著性(P=0.001,0.002)。结论:LASIK术后夜间眩光与术前暗光下瞳孔直径有关,高度近视患者也与拟矫正屈光度有关。     

LASIK术后Sirius光线追踪法与IOLMaster法测量人工晶状体度数比较

目的对比Sirius光线追踪法和IOLMaster法测量准分子激光原位角膜磨镶术（LASIK）后人工晶状体（IOL）度数的一致性。方法前瞻性临床研究。收集近视和近视散光患者89例（89眼）,根据术前等效球镜度（SE）分为轻中度近视组（≤-6.0 D,59眼）和高度近视组（＞-6.0 D,30眼）,对LASIK术前和术后1个月患者分别行Sirius角膜地形图和IOLMaster检查。术前使用IOLMaster自带的Haigis公式,术后使用Haigis和Haigis-L公式计算IOL度数,分别与Sirius光线追踪法计算所得IOL度数进行比较（IOL型号分别为Alcon SN60WF和AMO Tecnis ZA9003）。采用Bland-Altman对测量结果进行一致性分析。结果Bland-Altman分析显示术前Sirius光线追踪法与Haigis公式测量IOL度数在轻中度近视组2种型号IOL 95％一致性界限（LoA）分别为（-0.78～+0.84）D、（-0.57～+1.21）D,均有3％的点在各自的95%LoA外,组内相关系数（ICC）分别为0.976、0.945;高度近视组95％LoA分别为（-0.83～+0.69）D、（-0.57～+0.93）D,均有3％的点在各自的95%LoA外,ICC分别为0.981、0.979。术后Sirius法与Haigis公式对比：轻中度近视组95％LoA分别为（-0.27～+2.59）D、（-0.50～+3.30）D,均有5％的点在各自的95％LoA外,ICC分别为0.641、0.584;高度近视组95％LoA分别为（-0.48～+2.78）D、（-0.17～+3.17）D,分别有10％、7％的点在各自的95％LoA外,ICC分别为0.622、0.651。术后Sirius光线追踪法与Haigis-L公式对比：轻中度近视组95％LoA分别为（-1.02～+0.58）D、（-1.10～+0.77）D,分别有0、2％的点在各自的95％LoA外,ICC分别为0.986、0.955;高度近视组95％LoA分别为（-2.36～+0.80）D、（-1.98～+1.22）D,分别有7％、10％的点在各自的95％LoA外,ICC分别为0.667、0.638。结论Sirius光线追踪法与Haigis公式计算未手术眼IOL度数有较好的一致性,与Haigis-L公式计算轻中度近视LASIK术后IOL度数有较好的一致性,与Haigis-L公式计算高度近视LASIK术后IOL度数的一致性较差。