准分子激光屈光性角膜切削术和激光原位角膜磨镶术治疗中低度近视的对比研究

目的：比较准分子激光屈光性角膜切削术（ＰＲＫ） 和激光原位角膜磨镶术（ＬＡＳＩＫ） 治疗中低度近视的临床效果。方法：中、低度近视４００ 例（７１０ 眼） ,其中ＰＲＫ 组３４３ 眼,平均屈光度－４ ．１８±１．２４Ｄ。ＬＡＳＩＫ 组３６７ 眼,平均屈光度－ ４．７５±１．１０Ｄ。两组均于手术后１、３、６、１２ 个月复查视力、屈光度、角膜地形图及角膜上皮下基质混浊等并发症情况。结果：ＰＲＫ组欠矫＞ －１．００Ｄ者９．０３％ ,ＬＡＳＩＫ组为４ ．８０ ％ （Ｐ＜ ０．０１） 。角膜上皮下或层间混浊（Ｈａｚｅ）发生率：ＰＲＫ组０ 级８６ ．５９％ ,１ 级１１．３７％ ,２ 级２ ．０４％ ,３ 级以上无。ＬＡＳＩＫ组０ 级９５．１０％ ,１ 级２．４５％ ,２ 级以上无。结论：ＬＡＳＩＫ术式较之ＰＲＫ术式具有术后视力恢复快而稳定,用药少,痛苦少,并发症少,欠矫率低等优点,中低度近视治疗应首选ＬＡＳＩＫ方法治疗。     

准分子激光原位角膜磨镶术后眼压测量值的变化

目的 探讨准分子激光原位角膜磨镶术（ＬＡＳＩＫ）后眼压测量值的变化。方法 采用非接触式眼压计对３４０只眼（１７６例患者）行ＬＡＳＩＫ手术后行眼压测量。结果 ＬＡＳＩＫ后眼压测量值明显低于术前（ｔ＝５６．１１８,Ｐ〈０．００１）。按术前屈光度将患眼分成４组。Ⅰ组：－３．００￣－６．００Ｄ;Ⅱ组：－６．００￣－９．００Ｄ;Ⅲ组：－９．００￣－１２．００Ｄ;Ⅳ组：－１２．００Ｄ以上,每组术后眼压测量值均     

非球面切削LASIK治疗—10D以上高度近视

为评估非球面切削准分子激光原位角膜磨镶术（ＬＡＳＩＫ）治疗－１０Ｄ以上高度近视的有效性及安全性。采用ＳＣＭＤ气动式角膜切割刀及ＳＣＨＷＩＮＤＫＥＲＡＴＯＭ—Ｆ型准分子激光系统，利用Ｕｌｔｒａｖｉｓｉｏｎ非球面切削程序对－１０Ｄ以上高度近视（等值球镜－１０．２５～－３０．００Ｄ）１１７例１８０只眼行ＬＡＳＩＫ手术，其中屈光度－１０．２５Ｄ～－１５．００Ｄ（Ａ组，超高度近视）７８只眼，平均－１２．６２±１．５２Ｄ；屈光度－１５．５０Ｄ～－３０．００Ｄ（Ｂ组，极高度近视）１０２只眼，平均－１９．１８±３．３８Ｄ。术后随访观察６个月以上。结果：术后６个月裸眼视力≥１．０者Ａ、Ｂ二组分别达５７．７％及２５．５％，裸眼视力≥０．５者分别达９４．９％及７６．５％；屈光度在±１．００Ｄ以内的分别达４１．０％及１９．６％，在±３．００Ｄ以内的分别达８３．３％及５１．０％。Ａ、Ｂ二组各有１眼（分别占１．３％及１．０％）术后３个月有黄斑出血，６个月时的最佳矫正视力与术前相比，低于２行以上。结论：非球面切削ＬＡＳＩＫ手术对于矫治－１０Ｄ以上高度近视有很好的疗效，影响手术安全性的主要因素为视网膜并发症。     

准分子激光屈光性角膜切削术与激光原位角膜磨镶术治疗中低度近视的对比

目的对准分子激光屈光性角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ，ＰＲＫ）和准分子激光原位角膜磨镶术（ｌａｓｅｒａｓｓｉｓｔｅｄｉｎｓｉｔｕｋｅｒａｔｏｍｉｌｌｅｕｓｉｓ，ＬＡＳＩＫ）治疗中、低度近视的疗效进行前瞻性对比研究。材料和方法术前屈光度为－１．２５～－６．００Ｄ的近视５６９只眼，其中１３７只眼接受ＬＡＳＩＫ手术，４３２只眼接受ＰＲＫ手术，随访６－１６个月（平均８．９±２．６个月）。在术后１周、１个月、３个月、６个月和１２个月复查。结果ＬＡＳＩＫ组术后屈光状态较ＰＲＫ稳定，回退幅度较ＰＲＫ小，术后６个月时，ＬＡＳＩＫ组和ＰＲＫ组分别有９４％和８７％屈光度在±１．００Ｄ内（ｐ＜０．０５），分别有８４％和７１％屈光度在±０．５０Ｄ以内（ｐ＜０．０１）。ＬＡＳＩＫ组术后视力恢复较ＰＲＫ快，术后１周的平均裸眼视力超过１．０，术后６个月时，ＬＡＳＩＫ和ＰＲＫ组中裸眼视力０．５或以上者分别占１００％和９４％（ｐ＜０．０１），裸眼视力１．０以上者分别占８６％和７２％（ｐ＜０．０１）。结论ＬＡＳＩＫ不仅适合治疗高度近视，也适合治疗中、低度近视。对于中、低度近视，ＬＡＳＩＫ的疗效优于ＰＲＫ。     

准分子激光屈光性角膜切削术和激光原位角膜磨镶术治疗中低度近？…

目的：比较准分子激光屈光性角膜切削术（ＰＲＫ）和激光原位角膜磨镶术（ＬＡＳＩＫ）治疗中低度近视的临床效果。方法：中、低度近视４００例（７１０眼）,其中ＰＲＫ组３４３眼,平均屈光度－４．１８±１．２４Ｄ。ＬＡＳＩＫ组３６７眼,平均屈光度－４．７５±１．１０Ｄ。两组均于手术后１、３、６、１２个月复查视力、屈光度、角膜地形图及角膜上皮下基质混浊等并发症情况。结果：ＰＲＫ组欠矫〉－１．００Ｄ者９．０３％,     

准分子激光原位角膜磨镶术治疗近视的并发症

目的 分析准分子原位角膜磨镶术（ｅｘｃｉｍｅｒ ｌａｓｅｒ ｉｎ ｓｉｔｕ ｋｅｒａｔｏｍｉｌｕｓｉｓ,ＬＡＳＩＫ）治疗近视的并发症,探讨其发生原因及预防措施。方法 ６６２例（１２６５只眼）近视患者（－２．００～２５．００Ｄ）按屈光度分为３组：Ａ组７２６只眼,≤－６．００Ｄ;Ｂ组２８７只眼,－６．２５～－１０．００Ｄ）;Ｃ组２５２只眼,〉－１０．００Ｄ;行ＬＡＳＩＫ后均随访１２个月,观察及分析其并     

准分子激光屈光性角膜切削术治疗近视和近视散光一年临床…

采用ＶＩＳ×２０／２０型准分子激光仪对１６９例（２８１眼）近视患者进行屈光性角膜切削术（ＰＲＫ）。术前等值球镜屈光度为－１．７５－１６．００Ｄ（－８．１９Ｄ±１．５２Ｄ）分为两组：Ｉ组：－１．７５－－６．００Ｄ，１５３眼，ＩＩ组：－６．２５－－１６．００Ｄ，１２８眼，随访一年以上，术后１年实际矫正屈光度在预测矫正度±１．００Ｄ者在Ⅰ，Ⅱ，组分别为８７．６％，５４．７％，裸眼视力≥０．５，１．０者在     

准分子激光屈光性角膜手术后角膜地形图与临床屈光度变化的关系

目的：分析和探讨准分子激光屈光性角膜术后角膜地形图角膜闪表面曲率变化与临床屈光度变化的关系。方法：对近视度为－１．５０～－２．４００Ｄ的患者１７６例３２７眼行ＰＲＫ或ＬＡＳＩＫ治疗,观察６个月以上。按实矫屈光度分为二组：Ｉ组－１．５０～－６．００Ｄ有１２４眼;Ⅱ组－６．２５～－２０．００Ｄ有２０３眼;并将屈光回退患者９１眼作为Ⅱ组。经计算机得出角膜曲率变化与临床屈光度变化的散点图及相关系数ｒ值。结     

准分子激光原位角膜磨镶术后欠矫的再治疗

对２４例（３６只眼）行准分子激光原位角膜磨镶术（ｅｘｃｉｍｅｒｌａｓｅｒｉｎｓｉｔｕｋｅｒａｔｏｍｉｌｅｕｓｉｓ,ＬＡＳＩＫ）后屈光欠矫的患眼,再行原瓣下准分子激光角膜切削术。其中２只眼在ＬＡＳＩＫ术后１个月内施行,３４只眼在术后３～５个月内施行。３６只眼行ＬＡＳＩＫ前的屈光度数为：－５．００～－１７．８７Ｄ,平均－１０．７５±３．４１Ｄ,ＬＡＳＩＫ后欠矫的度数为：－１．２５～－５．５０Ｄ,平均－３．１２±１．１６Ｄ。再手术后,随诊３～６个月。２６只眼（７２．２％）的裸眼视力达到术前矫正视力,２只眼的裸眼视力较术前矫正视力增加一行,８只眼的矫正视力较术前下降一行。术后角膜瓣平整,角膜界面清晰,因此,ＬＡＳＩＫ后屈光欠矫可于术后３～６个月内于原角膜瓣下的基质层再行准分子激光角膜切削术,手术简便、安全、有效。     

PRK治疗近视术后2年随访分析

目的：评价准分子激光屈光性角膜切削术（ＰＲＫ）治疗轻、中、高度近视眼的临床效果。方法：对在我院接受ＰＲＫ治疗的２３９只近视眼的术后２年随访结果进行统计分析结果：Ⅰ组术前近视－１．００～－６．００Ｄ（等值球境，下同），术后２年裸眼视力≥１．０者占８７．１％，≥０．５者占９７．０％，剩余屈光度为－０．３４±０．３９Ｄ，９５．０％，角膜已完全恢复透明；Ⅱ组术前近视－６．２５～－１２．００Ｄ，术后２年裸眼视力≥１．０者占４７．８％，≥０．５者占８８．４％，剩余屈光度为－０．７７±０．６３Ｄ，７８．２％角膜已完全恢复透明。结论：ＰＲＫ治疗－１２．００Ｄ以下，特别是－６．００Ｄ以下近视眼安全有效，预测性及稳定性好     

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.     

准分子激光原位角膜磨镶术治疗高度近视

目的评价准分子激光原位角膜磨镶术治疗高度近视的疗效。方法采用LASIK治疗高度近视186例308眼,按术前屈光度将患者分为2组。对1a随访结果进行统计分析。结果A组术前近视-6.0～-10.0D(等值球镜,下同)术后1a裸眼视力达到0.5和1.0者分别为95.76%和77.58%,剩余屈光度为-0.32D±0.46D。B组术前近视-10.25～-20.00D,术后1a裸眼视力达0.5和1.0者分别为62.24%和37.06%.剩余屈光度-0.92D±1.13D。结论LASIK治疗高度近视安全有效,并有较好的预测性和稳定性。     

Laser in situ keratomileusis to correct residual myopia after cataract surgery

PURPOSE: To evaluate the effectiveness, predictability, and safety of laser in situ keratomileusis (LASIK) for correcting residual myopia after cataract surgery with intraocular lens implantation. METHODS: Twenty-two eyes of 22 patients underwent LASIK for the correction of residual myopia after cataract surgery. LASIK was carried out using the Chiron Automated Corneal Shaper and the NIDEK EC-5000 excimer laser. In all eyes, the follow-up was 12 months. RESULTS: Before LASIK, 1 eye (4.5%) had an uncorrected visual acuity of 0.5 or better; 12 months after LASIK, 10 eyes (45.4%) achieved this level of visual acuity and 0 eyes achieved 1.00 or better. Before LASIK, mean refraction was -2.90 +/- 1.80 D; 12 months after LASIK it decreased significantly to 0.40 +/- 0.60 D (P < .01). In 18 eyes (81.8%) at 12 months after LASIK, spherical equivalent refraction was within +/-1.00 D of emmetropia; 11 eyes (50%) were within 0.50 D. No vision-threatening complications occurred. CONCLUSION: LASIK with the Automated Corneal Shaper and Nidek EC-5000 excimer laser was an effective, predictable, stable, and safe procedure for correcting residual myopia after cataract surgery. No intraocular lens or cataract incision related complications occurred when LASIK was performed at least 3 months after phacoemulsification.     

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

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

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.     

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.     

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.     

Corneal wavefront-guided ablation with the Schwind ESIRIS laser for myopia

PURPOSE: To evaluate the outcome of corneal wavefront-guided LASIK for the treatment of myopia and myopic astigmatism. METHODS: This study included 56 myopic virgin eyes of 28 patients with a mean spherical equivalent refraction of -4.40 +/- 1.83 diopters (D) (range: -1.25 to -9.75 D) and astigmatism < 2.50 D. The corneal wavefront aberrations were analyzed using a corneal topography system. The preoperative corneal wavefront aberration data obtained from the above analyses combined with manifest refraction were used to generate a customized ablation profile. The safety, efficacy, and predictability of the correction, contrast sensitivity, and corneal higher order wavefront aberrations were evaluated. RESULTS: At 1-year follow-up, the mean residual spherical equivalent refractive error was -0.15 +/- 0.3 D (range: 0 to -1.25 D) and mean cylinder was -0.54 +/- 0.34 D (range: 0 to -1.50 D). Ninety-five percent of eyes were in the residual refractive error range of +/- 0.50 D and uncorrected visual acuity improved by 1.00 D or better in 94% of eyes. The safety index and efficacy index were 1.13 and 0.92, respectively. After treatment, corneal higher order wavefront aberrations with a 6-mm pupil diameter increased significantly (paired sample t test, P < .01), and contrast sensitivity with glare had small reductions at high spatial frequencies. Changes in spherical-like aberration (R = 0.708, P < .001) and higher order wavefront aberration (R = 0.449, P = .001), except for coma-like aberration (P = .238), were positively correlated with the amount of achieved correction. CONCLUSIONS: Evaluation of clinical results showed that corneal wavefront-guided LASIK for the correction of myopia and myopic astigmatism was safe and effective. There was an increase in all higher order aberrations postoperatively.     

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.     

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

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