LASIK矫治PRK术后屈光度欠矫及回退

目的　探讨准分子激光原位角膜磨镶术(LASIK)用于矫治屈光性角膜切削术(PRK)后欠矫及屈光度回退的效果。方法　2 6例(4 9眼)因PRK术后屈光度欠矫及回退再行LASIK矫治。49眼PRK术前的屈光度为-5 . 5 0D～-10 . 0 0D ,平均(-6 2 5±1 .5 0 )D ,PRK术后欠矫及回退的度数为-2. 2 5D～-5 . 75D ,平均(-3 0±1. 12 )D。观察LASIK矫治术后裸眼视力、屈光度、最佳矫正视力及并发症。术后随访6月以上。结果　裸眼视力≥0 .5者42眼(85. 71% ) ,其中≥1 .0者2 3眼(4 6 .94% )。实际屈光矫正度在预测矫正度的±0. 75以内者为43眼(87 .76% ) ,1眼发生角膜瓣下上皮植入。结论　PRK术后屈光欠矫及回退而残留的近视度数可以用LASIK手术矫治,且疗效好、安全性高,但远期效果尚需进一步观察。     

准分子激光角膜瓣背面磨镶术治疗LASIK术后屈光欠矫和回退

目的 探讨准分子激光角膜瓣背面磨镶术(LASUK)治疗准分子激光原位角膜磨镶术(LASIK)术后屈光欠矫和回退的疗效.方法 对LASIK后屈光欠矫和回退的14例(24眼)施行LASUK,观察术后视力、屈光度、角膜后表面及haze情况.结果 术后3个月视力和屈光度趋于稳定,术后无角膜浑浊,无继发性圆锥角膜.术后6个月,裸眼视力≥0.6和≥1.0者分别为24眼(100.00%)和18眼(75.00%).屈光度介于±1.00D者22眼(91.67%),19眼屈光度介于±0.50D之间,最佳矫正视力无下降者.结论 LASUK治疗LASIK术后屈光欠矫是安伞有效的.     

再次LASIK治疗屈光回退和欠矫38例分析

目的　探讨再次准分子激光原位角膜磨镶术 (LASIK)矫治屈光回退和欠矫的疗效。方法　收集 2 0 0 0年 12月～2 0 0 2年 8月因屈光回退和欠矫在我院行再次LASIK者 3 8例 ( 70眼 ) ,随访 1年 ,观察术中术后并发症 ,术眼的屈光度。探讨再次LASIK的安全性、疗效及手术时机。结果　 3 8例 ( 70眼 )术中术后无不良并发症发生 ,术后 1年裸眼视力达术前最佳矫正视力者 68眼 ( 97 14 %) ,残余屈光度在± 1 0 0D以内者 69眼 ( 98 5 7%) ,术后 3月和 6月屈光度分别为 ( -0 3 5± 1 12 )D和( -0 5 2± 1 0 1)D ,术后 1年无角膜膨隆或圆锥角膜发生。结论　在保留角膜基质床的厚度≥ 2 5 0 μm的前提下行再次LASIK ,安全性及有效性均较理想     

大龄近视患者准分子激光原位角膜磨镶术分析

目的　探讨大龄近视患者LASIK疗效、特点及需要加以关注的问题。方法　对 88例(16 4眼 )大龄 (年龄≥ 4 0岁 )近视患者进行LASIK治疗 ,并对术前屈光度、预矫屈光度、手术疗效等进行统计分析。结果　行LASIK治疗的大龄近视患者术前屈光度 (球镜等量 ) :轻度近视 (≤ -3D) 5眼 ,占 3% ,中度近视 (>- 3D ,≤ - 6D) 2 8眼 ,占 17% ,高度近视 (>- 6D ,≤ - 10D) 4 2眼 ,占 2 6 % ,超高度近视 (>- 10D) 89眼 ,占 5 4 %。为保证角膜的安全性 ,2 0例 (2 2 73% ) 39眼(2 3 78% )术前设计的预矫屈光度需低于术前屈光度。术后裸眼视力 0 0 6～ 1 5 ,平均 0 78± 0 39,其中裸眼视力≥ 0 5者为 6 1眼 ,占 78 2 1% ,裸眼视力≥ 1 0者 2 5眼 ,占 32 0 5 %。结论　大龄近视患者行LASIK治疗以高度、超高度近视患者为主 ,术前角膜厚度的仔细测量、预矫屈光度数的确定、激光切削直径的选择对减少眩光以及术后屈光度数回退 ,提高术后视力、改善视觉质量至关重要。     

准分子激光原位角膜磨镶术后再次手术原因探讨

目的分析准分子激光原位角膜磨镶术(LASIK)后再次手术的原因及其可行性。设计回顾性病例系列研究。研究对象46例(84眼)LASIK术后屈光回退患者。方法根据屈光回退的主要原因不同将患者分为三组:Ⅰ组为个体原因组14例(24眼),Ⅱ组为医源性原因组8例(11眼),Ⅲ组为单纯屈光度过高组24例(49眼)。再次LASIK手术采用直接掀瓣或重新切角膜瓣法,按预矫度数进行切削。主要指标视力、屈光度。结果再次LASIK术后随访6个月至1年,屈光度在±1D以内者69眼(82%),屈光度≤-1D者15眼。术后裸眼视力≥1.0者67眼(80%),裸眼视力≥0.5者79眼(94%)。再次LASIK术后复发屈光回退者I组10眼(41.7%),Ⅱ组无屈光回退,Ⅲ组复发屈光回退者5眼(10.2%)。三组均未发生角膜混浊和上皮植入等并发症。结论由于个体原因、医源性原因及单纯屈光度过高导致的LASIK术后屈光回退,再次LASIK手术均是安全的,且有较好的预测性。     

预留不同屈光度对LASIK手术患者的影响

目的:评价术前预留不同屈光度对LASIK手术患者的影响。方法:对486眼近视LASIK手术患者进行回顾性分析。按预留屈光度不同分成3组:Ⅰ组(全矫组)219眼,Ⅱ组(预留-0.25D组)215眼,Ⅲ组(预留-0.50D组)52眼。观察术前、手术后1,3和6mo裸眼远视力和等值球镜屈光度。结果:术后裸眼视力:各组术后各时间段与术前矫正视力间无显著差异。术后等值球镜屈光度:各组1mo与3mo,1mo与6mo比较有显著差异(P<0.05)。术后3,6moⅢ组和Ⅰ组、Ⅱ组间比较有显著差异(P<0.05)。结论:术前预留-0.25D以内屈光度6mo内对近视LASIK手术患者裸眼远视力和屈光无明显影响,术前预留-0.50D术后3mo开始影响患者术后屈光,达到预防老视的目的。     

LASIK治疗RK后屈光欠矫临床观察

目的评价准分子激光原位角膜磨削术(LASIK)治疗放射状角膜切开术(RK)术后屈光欠矫的临床效果。方法对34眼(21人)RK术后残余近视、散光患者行LASIK治疗,年龄20～38岁,残余球镜屈光度-2.00～-13.00D(-5.87D±2.65D),柱镜屈光度0～3.5D(-1.15D±0.94D)。结果术后6个月屈光稳定,裸眼视力≥术前矫正视力32眼(94.12％),所有眼屈光度在术前预期矫正±1.00D以内。1眼最佳矫正视力较术前下降l行。无角膜瓣移位、脱失、角膜混浊等并发症。结论LASIK治疗RK后屈光欠矫安全、有效、预测性好。     

准分子激光原位角膜磨镶术远期疗效观察

目的　探讨准分子激光原位角膜磨镶术 (laserinsitukeratomileusis,LASIK)治疗近视的远期疗效。方法　按近视屈光度数 - 1 5 0～ - 6 0 0D、- 6 12～ - 12 0 0D和 - 12 12～ - 2 5 0 0D将716例 (12 85只眼 )近视患者分为A、B和C 3个组行LASIK ,术后平均随访时间 2 6 7个月 ,对资料进行总结和分析。结果　术后 2年 ,屈光度数 <± 1 0 0D者A组为 93 4 % ,B组为 86 7% ,C组为 6 5 5 % ;屈光度数 <± 0 5 0D者A组为 84 4 % ,B组为 79 7% ,C组为 4 2 1%。裸眼视力≥ 0 5者A组为99 6 % ,B组为 93 8% ,C组为 6 2 6 % ;裸眼视力≥ 1 0者A组为 90 4 % ,B组为 6 8 6 % ,C组为 2 7 2 %。39只眼因屈光度数回退或欠矫 ,2只眼因角膜上皮植入再次行LASIK。结论　LASIK可有效治疗轻度至超高度近视 ,手术安全、预测性好 ,远期随访 2年疗效稳定。     

掀瓣行LASIK提升术的临床疗效分析

目的：探讨采用掀瓣行二次准分子激光原位角膜磨镶术(LASIK)治疗LASIK术后欠矫和回退的有效性及安全性。 方法：对LASIK术后因欠矫和屈光回退的近视眼患者25例36眼采用掀开原角膜瓣的方法,对瓣下基质床行再次准分子激光消融。术后随访1a,观察视力、屈光度及手术并发症。 结果：再次术后1,3,6,12mo,平均裸眼视力（UCVA）从术前的0.39±0.16分别提高为0.92±0.17,1.01±0.16,1.03±0.16,1.04±0.18,术前UCVA与术后各时间点比较均具有极显著差异(P<0.01);术前平均等效球镜度数为-1.87±0.64D,术后12mo的等效球镜度数平均为0.21±0.43D,两者比较有极显著性差异(P<0.01)。 结论：采用掀瓣的LASIK提升术治疗LASIK术后欠矫和屈光回退,此方法是安全、有效的。     

LASIK手术屈光预测性与年龄的关系

目的探讨LASIK手术屈光预测性与年龄的关系。设计回顾性病例系列。研究对象362例(703眼)LASIK手术患者。方法按年龄将患者分为18～30岁,31～34岁,35～39岁,≥40岁4组,于LASIK术前,术后1、10天,1、3、6个月,1、2年用自动验光仪结合显然验光的方法检查患者的屈光状态,并与预期屈光度进行比较。根据患者术前屈光状态,分为中低度组(≤-6.00D)、高度组(-6.25～-12.00D)、超高度组(≥-12.25D)。术后2年屈光度数≥-1.00D者为回退眼。主要指标屈光度。结果<40岁各组术后6个月屈光度(-0.32D±0.07D,-0.15D±0.06D,-0.20D±0.14D)与预期屈光度(-0.07D±0.04D,-0.19D±0.06D,-0.25D±0.07D)比较差异无统计学意义(P值分别为0.059,0.368,0.546),而≥40岁组的术后6个月屈光度(-0.25D±0.48D)与预期屈光度(-0.88D±0.60D)比较差异有统计学意义(P=0.001);不同年龄组间回退率比较差异有显著性;中低度、高度、超高度近视组间比较,回退率差异有统计学意义,近视回退量与术前屈光度呈正相关;57.83%患者回退发生于术后6个月内。结论LASIK手术屈光预测性受年龄、屈光度、术后时间等因素影响,对于年龄较大的高度近视患者应严格掌握手术适应证,并根据年龄、术前屈光度、用眼习惯等调整预期矫正度数。(眼科,2007,16:333-335)     

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 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.     

CustomCornea wavefront retreatment after conventional laser in situ keratomileusis

PURPOSE: To evaluate the safety and efficacy of performing laser in situ keratomileusis (LASIK) retreatment using the Alcon CustomCornea system in patients who had prior myopic LASIK using conventional (nonwavefront) software. SETTING: Private practice ophthalmology clinic, St. Paul, Minnesota, USA. METHODS: In this prospective interventional trial, consecutive patients having CustomCornea retreatment following conventional LASIK were evaluated. Main outcome measures were uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refractive error, and higher-order aberrations (HOAs). RESULTS: Fourteen eyes of 10 patients were evaluated, with a mean follow-up of 5.3 months (range 6.2 to 15.4 months). Mean UCVA improved from 20/50 (logMAR) to 20/26 (P<.001). Mean spherical equivalent changed from -1.45 diopters (D) to +0.52 (P<.00001). Total aberrations, HOAs, defocus, and spherical aberration improved significantly. No eye lost a line of BCVA; 4 eyes (28.6%) gained 1 line, and 1 eye (7.1%) gained 2 lines. Ten eyes (71.4%) were within 0.5 D of emmetropia. Four eyes were overcorrected by 1.00 to 2.00 D. Risk factors for overcorrection included increased HOAs, higher spherical aberration, and not using the surgeon's offset at the time of surgery. CONCLUSIONS: Wavefront retreatment following conventional LASIK is safe and effective. Care must be taken when treating patients with higher amounts of total aberration, especially spherical aberration. Refractive results are closer to emmetropia when the surgeon's offset is used.     

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.     

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

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

The safety and efficacy of photorefractive keratectomy after laser in situ keratomileusis

PURPOSE: To determine the safety and efficacy of performing photorefractive keratectomy (PRK) in corneas previously treated with laser in situ keratomileusis (LASIK) surgery. METHODS: Fifteen eyes of 14 patients who had initially received LASIK for the treatment of myopia and compound myopic astigmatism were evaluated. Variables included existence of and/or type of flap complication associated with the original LASIK procedure, refractions before and after (3 and 6 months) PRK, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and the development of complications after PRK such as haze, scarring, double vision, or ghosting. RESULTS: All 15 eyes were available for analysis at 6 months. Eleven eyes had experienced flap complications during the initial LASIK procedure and 4 eyes had experienced complications in the LASIK postoperative period. Characteristics prior to performing PRK included 11 myopic and 4 hyperopic eyes. By 6 months after PRK treatment, 87% of eyes had UCVA > or = 20/40, 53% had > or = 20/25, and 40% had > or = 20/20. All eyes had BSCVA of > or = 20/30, with 73% being > or = 20/20. No eye had lost 2 lines of BSCVA and only 1 eye lost 1 line of BSCVA. Sixty percent of eyes were within 1.0 diopters (D) of emmetropia, and 40% were within 0.5 D of emmetropia. A trend towards undercorrection and surgical induction of astigmatism as confirmed by vector analysis was noted. No eye developed significant haze or scarring. CONCLUSIONS: Photorefractive keratectomy may be a safe procedure to perform in corneas previously treated with LASIK surgery. Results show good reduction of refractive error and improvement of UCVA and BSCVA. A significant undercorrection of astigmatism was attributed to surgically induced astigmatism. Further studies are necessary to determine the long-term safety and stability of outcomes.     

Hyperopic LASIK retreatments with the Technolas laser

PURPOSE: To evaluate the safety, efficacy, and predictability of hyperopic LASIK retreatments. METHODS: This retrospective, consecutive, non-comparative, observational study included 85 eyes that underwent hyperopic LASIK retreatment with 1-year follow-up. Complete ophthalmic examination included distance uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), cycloplegic refraction, and pachymetry. Patients were divided into two groups according to the preoperative spherical equivalent refraction: group 1, < or = +3.9 diopters (D) and group 2, > or = +4.0 D. RESULTS: The UCVA improved from 0.31 +/- 0.2 to 0.7 +/- 0.2 in group 1 and from 0.2 +/- 0.2 to 0.6 +/- 0.2 in group 2 following retreatment. Mean spherical equivalent refraction improved from +2.8 +/- 0.85 to +0.2 +/- 0.9 in group 1 and from +5.3 +/- 0.9 to +0.3 +/- 1.3 in group 2 after retreatment. In group 1, 32 (72.7%) of 44 eyes had BSCVA > or = 20/25, and in group 2, 24 (58.5%) of 41 eyes had BSCVA > or = 20/25. After primary hyperopic LASIK, 25 (56.8%) of 44 eyes in group 1 and 19 (46.3%) of 41 eyes in group 2 maintained BSCVA or gained > or = 1 lines postoperatively in contrast to 21 (47.7%) of 44 eyes in group 1 and 22 (53.9%) of 41 eyes in group 2 after retreatment. In group 1, 11 (25%) of 44 eyes lost > or = 2 lines of BSCVA after initial hyperopic LASIK compared to 14 (31.8%) of 44 eyes after retreatment. In group 2, 10 (24.4%) of 41 eyes lost > or = 2 lines of BSCVA after initial hyperopic LASIK compared to 12 (29.2%) of 41 eyes after retreatment. After hyperopic LASIK retreatment, 31 (70.5%) of 44 eyes in group 1 and 19 (46.4%) of 41 eyes in group 2 were within +/- 0.5 D of emmetropia. Safety was 0.9 in both groups and efficacy was 0.8 and 0.7 in groups 1 and 2, respectively. Complications included epithelial ingrowth of 1 to 3 mm (30%) and flap edge melting (2%). CONCLUSIONS: Hyperopic LASIK retreatment improved the refractive results of initial hyperopic LASIK surgery with 20% to 30% of eyes gaining > or = 1 lines of BSCVA. The loss of BSCVA was greater after primary hyperopic LASIK than after retreatment.     

Laser in situ keratomileusis with the VISX Star laser for myopia over -10.0 diopters.

PURPOSE: To evaluate the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) for myopia over -10.00 diopters (D). SETTING: The Eye Institute of Utah, Salt Lake City, Utah, USA. METHODS: The prospective study included 332 eyes of 183 patients having LASIK with the VISX Star laser to correct myopia of -10.00 to -18.00 D. The eyes were divided into 3 groups according to the preoperative refraction: Group A (n = 208), -10.00 to -11.90 D; Group B (n = 94), -12.00 to -14.00 D; Group C (n = 30), -14.10 to -18.00 D. The mean follow-up was 12.0 months +/- 5.6 (SD) (range 6 to 37 months). RESULTS: Overall, the mean spherical equivalent decreased 96%, from -11.69 +/- 1.46 D preoperatively to -0.37 +/- 0.80 D postoperatively. The mean astigmatism decreased 72%, from 1.66 +/- 1.22 D to 0.46 +/- 0.53 D. At the last visit, 84.0% of eyes were within +/-1.00 D of emmetropia and 96.4% were within +/-2.00 D. An overcorrection of more than +1.00 D was experienced by 1.8% of patients. The uncorrected visual acuity (UCVA) was 20/20 or better in 45.8% of eyes and 20/40 or better in 89.5%. Six eyes (1.8%) lost 2 or more lines of best corrected visual acuity; this included 1 eye in which iatrogenic keratectasia developed 18 months after LASIK retreatment. Retreatment was done in 37.0% of eyes at a mean of 6.3 +/- 5.3 months (3 to 32 months) after the initial treatment. At the last examination, 86.0% of eyes in Groups A and B and 70.0% in Group C were within +/-1.00 D of emmetropia. A significant difference was found between Groups A and C (P =.032). The UCVA was 20/20 in 52.0% of Group A eyes, 38.0% of Group B eyes, and 23.0% of Group C eyes. The difference between Groups A and C was significant (P =.001), but the difference between Groups A and B was not (P =.055). CONCLUSIONS: In this study, LASIK was effective in correcting myopia up to -14.00 D. The efficacy, predictability, and safety were significantly less in eyes with myopia greater than -14.00 D.     

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.     

准分子激光原位角膜磨镶术手术治疗超高度近视合并散光

目的观察准分子激光原位角膜磨镶术（LASIK）治疗超高度近视合并散光的临床效果。方法采用准分子激光原位角膜磨镶术治疗52例（101眼）超高度近视合并散光患者,球镜度-10.00D～-14.00D,散光-0.50～-4.50DC。结果术后1天、1、3、6月裸眼视力与术前预期最佳矫正视力符合率分别为78.2%、85.1%、92.1%、87.1%;术后6个月,实际矫正屈光度与术前预期矫正符合率球镜93.1%、柱镜87.1%。结论LASIK治疗超高度近视合并散光,视力恢复快,安全可靠。