Femtosecond laser in situ keratomileusis for consecutive hyperopia after radial keratotomy

PURPOSE: To assess the use of the femtosecond laser for laser in situ keratomileusis (LASIK) in eyes with consecutive hyperopia after radial keratotomy (RK). SETTING: Private ambulatory surgical center, Valencia, Spain. METHODS: This prospective noncomparative interventional case series study included 13 eyes of 9 patients with secondary hyperopia after previous RK. The patients were operated on with the IntraLase femtosecond laser (IntraLase Corp.) and the Star S2 excimer laser (Visx, Inc.). Postoperative uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, flap thickness, flap diameter, and complications were evaluated at 6 months. RESULTS: The mean spherical equivalent (SE) decreased from 2.00 diopters (D)+/-0.40 (SD) to -0.41+/-0.61 D, with 8 eyes (61.5%) within+/-0.50 D of the targeted refraction. Twelve eyes (92.3%) had a UCVA of 20/40 or better, and 3 eyes (23.1%) lost 1 line of BSCVA. A mean change in SE of 0.10 D was observed at the 6-month follow-up. The mean flap thickness and diameter were 117+/-14 microm and 9.18+/-0.12 mm, respectively. Most complications were in eyes with more than 8 RK incisions than in eyes with 8 RK incisions. These complications were multiple intraoperative incision openings (100% versus 28.6%, respectively), interface inflammation (66.6% versus 0%, respectively), haze (83.3% versus 14.3%, respectively), and loss of BSCVA (50% versus 0%, respectively). CONCLUSIONS: The femtosecond laser provided large, thin corneal flaps for hyperopic LASIK. However, the procedure should be avoided in eyes with more than 8 RK incisions because of the increased risk for multiple intraoperative incision openings, interface inflammation, haze, and loss of BSCVA.     

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

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

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

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

Topography-based screening for previous laser in situ keratomileusis to correct myopia and hyperopia

PURPOSE: To develop a screening tool based on corneal topography to detect previous myopic and hyperopic laser in situ keratomileusis (LASIK). METHODS: Clinical data from three private clinics were analyzed in a university setting. A total of 476 topographies (Orbscan II) were randomly selected (1 topography per patient): 338 from unoperated corneas, 81 from corneas that had LASIK to correct myopia, and 57 from corneas that had LASIK to correct hyperopia. The LASIK procedures were performed using a Technolas excimer laser (217C or 217Z) and a Hansatome microkeratome. The first set of algorithms (VESm and VESh) calculated the volume summation between the anterior corneal surface and the best-fit sphere in the central and mid-peripheral regions. The second set of algorithms (DCm and DCh) calculated the mean anterior tangential curvature difference between the central and mid-peripheral regions. RESULTS: The features VESm and DCm for the screening of a myopic LASIK yield, respectively, sensitivity rates of 92.7% and 95.1% and specificity rates of 94.9% and 96.5%. The features VESh and DCh for the screening of a hyperopic LASIK gave sensitivity rates of 93.1% for both and specificity rates of 94.8% and 97.1%. The performance of those features was superior to clinical assessment using topography color maps. CONCLUSIONS: Criteria based on Orbscan II corneal topography are proposed for the detection of previous hyperopic and myopic LASIK performed with a Technolas excimer laser (version 217C or 217Z).     

Laser in situ keratomileusis for primary hyperopia

PURPOSE: To evaluate the efficacy, predictability, stability, and safety of hyperopic laser in situ keratomileusis (H-LASIK) over a 24-month period and analyze topographic changes after H-LASIK to assess topographic pseudokeratectasia (TPKE) following H-LASIK. SETTING: Eye Institute of Utah, Salt Lake City, Utah, USA. METHODS: This prospective study included 139 eyes of 77 patients having H-LASIK for primary hyperopia. The mean follow-up was 15.6 months +/- 7.6 (SD) (range 6 to 48 months). One hundred twenty-two eyes (88%) were followed at 1 year and 36 eyes (26%) at 24 months. Topographic pseudokeratectasia was defined as 1 or more positive keratoconus screening findings in an eye with topographic central or inferior steepening detected by the Topography Modeling System but without corneal thinning or progressive change. RESULTS: The mean spherical equivalent manifest refraction was +2.39 +/- 0.99 diopter (D) preoperatively and -0.05 +/- 0.61 D at the last visit. Ninety-one percent of eyes were within +/-1.00 D of emmetropia and 71% of the eyes were within +/-0.50 D. Uncorrected visual acuity of 20/20 or better was present in 42%, 20/25 in 63%, and 20/40 or better in 93% of eyes. Loss of 2 lines of BSCVA occurred in 2 eyes (1.4%). In 1 eye, ischemic optic neuropathy occurred, and in another, choroidal neovascularization developed postoperatively. Topographic pseudokeratectasia was detected in 28% to 56% of eyes postoperatively. No significant difference between postoperative visual and refractive outcome, regression, or irregularity was found between the eyes with or without TPKE. CONCLUSION: Hyperopic LASIK appears to be an effective, predictable, and safe procedure to correct low to moderate primary hyperopia. Topographic pseudokeratectasia, which was observed after H-LASIK with a keratoconus-like topographic pattern in otherwise normal eyes, may represent a relatively static condition.     

Laser in situ keratomileusis for recurrent hyperopia following laser thermal keratoplasty

PURPOSE: Laser thermal keratoplasty (LTK) has its main indication in the correction of hyperopia. However, regression of refractive effect following LTK is a limitation. Laser in situ keratomileusis (LASIK) may provide a good alternative to correct residual refractive errors. METHODS: Fifty hyperopic eyes with varying amounts of regression after LTK underwent LASIK. The Chiron Automated Corneal Shaper microkeratome was used to make a flap of 160 microm and laser ablation was performed with the Technolas 217 Planoscan excimer laser. Postoperative follow-up was 6 months. RESULTS: Mean spherical equivalent refraction improved from +2.92+/-1.60 D to +0.36+/-1.48 D. Mean best spectacle-corrected visual acuity changed from 0.78+/-0.14 before LASIK to 0.76+/-0.16 D 6 months after LASIK. Mean uncorrected visual acuity changed from 0.37+/-0.16 to 0.66+/-0.24. Forty-two percent (21 eyes) were within +/-0.50 D of intended correction, 60% (30 eyes) were within +/-1.00 D, and 76% (38 eyes) were within +/-2.00 D. After LASIK, confluent haze between previous LTK spots was observed in most eyes, as LASIK ablation took place at the sites of the LTK spots. CONCLUSIONS: LASIK after LTK is a good alternative for hyperopic regression. Predictability and efficacy are less than with primary LASIK for hyperopia, but the procedure is equally safe.     

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.     

准分子激光角膜原位磨镶术治疗近视的临床研究

目的     

Laser in situ keratomileusis for spherical hyperopia and hyperopic astigmatism using the NIDEK EC-5000 excimer laser

PURPOSE: To assess the efficacy, predictability, and safety of LASIK for the surgical correction of low to moderate hyperopia and hyperopic astigmatism using the NIDEK EC-5000 excimer laser. METHODS: In a multicenter United States Food and Drug Administration (FDA) regulated study of LASIK, 7 centers enrolled 293 eyes with manifest refraction sphere that ranged from +0.50 to +6.00 diopters (D) with or without astigmatism up to 3.00 D. The intended outcome was plano in all eyes. Patients were treated bilaterally. One year postoperative outcomes are reported. RESULTS: The mean spherical equivalent refraction (MRSE) for all eyes changed from +2.61 +/- 1.19 D (range: +0.50 to +6.63 D) preoperatively to +0.35 +/- 0.54 D (range: -1.63 to +2.00 D) 1 year postoperatively. Overall, 61% (170/279) of eyes achieved distance uncorrected visual acuity (UCVA) of 20/20 or better, 82% (228/279) of eyes saw 20/25 or better, and 99% (277/279) of eyes saw 20/40 or better. Refractive accuracy was demonstrated as 63.1% (176/279) of eyes achieved a MRSE within +/- 0.50 D and 90.3% (252/279) of eyes within +/- 1.00 D. Less than 2% (4/279) of eyes lost 2 lines of distance best spectacle-corrected visual acuity. Stability of refraction was demonstrated by 6 months, with a mean hyperopic shift of < 0.03 D from 3 to 6 months. CONCLUSIONS: The NIDEK EC-5000 corrected hyperopia and hyperopic astigmatism with UCVA, refractive accuracy, 1-year stability, and safety that surpassed all FDA criteria.     

小光斑飞点扫描准分子激光角膜原位磨镶术治疗近视疗效观察

目的评价小光斑飞点扫描准分子激光系统应用于准分子激光角膜原位磨镶术(LASIK)治疗近视的疗效.方法将79例150只眼按术前屈光度分三组,Ⅰ组-0.50～-6.00D,Ⅱ组-6.25～-10.00D,Ⅲ组-10.25～-14.00D,对LASIK术后超过3个月的患者的视力、屈光度、切削区大小、偏中心情况进行随访分析.结果术后3个月时,三组的裸眼视力均达0.5以上,达1.0或以上者分别为83.1%、79.6%、50.0%,1.2或以上者分别为48.3%、38.8%、8.3%,有27眼(18%)的术后裸视和40眼(26.7%)的术后最好矫正视力分别大于术前最好矫正视力.三组术后屈光度在预期矫正度±1.0D以内者分别为100%、95.9%、91.7%,±0.5D以内者分别为88.8%、86.5%、83.3%,平均实际切削区直径为(7.35±0.33)mm,平均偏中心(0.22±0.21)mm.结论使用小光斑高速飞点扫描准分子激光系统的LASIK治疗近视的初期临床结果较好,较大的切削光区和良好的中心定位可有效减少手术并发症和提高术后的预测性.     

Excimer laser assisted in situ keratomileusis for hyperopia

Purpose:To evaluate hyperopic surgical correction with 6.0 mm optical zonehyperopic laser in situ keratomileusis (LASIK) after various refractive procedures.Setting:Buzard Eye Institute, Las Vegas, Nevada, USA.Methods:This study followed 14 eyes of 14 patients who had hyperopic LASIK with a VISX Star laser. Mean follow-up was 8 months. The patients represented a variety of preoperative situations, including primary radial keratotomy (RK) (5 eyes), primary automated lamellar keratectomy (ALK) (2 eyes), primary LASIK (3 eyes), congenital hyperopia (1 eye), and combinations of ALK, RK, and LASIK. In all patients, a toroidal or “doughnut-shaped” ablation was constructed with the use of a 3.5 mm diameter soft contact lens as a blocking agent centrally with a 6.0 mm outside beam diameter.Results:Mean preoperative spherical equivalent was +1.33 diopters (D) ± 0.5 (SD)(range +0.50 to +1.88 D). The mean spherical equivalent was −0.32 ± 1.20 D (range −1.25 to +2.63 D) at 1 month postoperatively and −0.15 ± 0.60 D (range −1.13 to +1.25 D) at the last follow-up. Uncorrected visual acuity of 20/40 was obtained by 13 eyes (93%). No eye lost 2 or more lines of best corrected visual acuity at last follow-up. Four eyes required a postoperative LASIK enhancement procedure to correct induced myopia. No significant complications were seen.Conclusion:Hyperopic LASIK with the technique used in this study appeared safe, predictable, and stable. It represents a simple way to add hyperopic correction to existing laser systems.     

小光斑LASIK治疗高度近视临床分析

目的　评价小光斑飞点扫描式准分子激光系统应用于准分子激光角膜原位磨镶术 (LASIK)治疗高度近视的疗效。方法　 197(3 86眼 )按术前屈光度分成 2组 ,A组 :-6.2 5D～ 10 .0D ,2 89眼 ;B组 :-10 .2 5D～ -2 7.5D ,97眼。观察术后视力、屈光度、偏中心情况及并发症。结果　术后 3月 ,两组的裸眼视力达 0 .5以上者分别为 99.3 1%、84.5 4% ;1 0以上者分别为95 .85 %、70 .10 %。两组的术后最佳矫正视力下降者分别为 1.3 8%、6.19%。平均屈光度A组 (-0 .13± 0 .5 7)D ,B组 (-3 .77±1.2 2 )D ,其中≤± 0 .5D的分别是 86.16% ,42 .2 7%。切削区均匀 ,偏离中心 0～ 0 .71mm ,平均 (0 .2 0± 0 .19)mm ,术后无严重并发症发生。结论　使用小光斑飞点扫描准分子激光系统的LASIK治疗高度近视近期效果良好。     

准分子激光原位角膜磨镶术治疗远视眼

目的 :评价LASIK治疗远视眼的有效性、可预测性和安全性。方法 :用LASIK治疗 54只远视眼 ,屈光度 1 0 0～ 6 0 0D ,术后平均随访一年。对裸眼和矫正视力、屈光稳定性和并发症等进行了分析。结果 :至术后一年时 ,平均残余屈光度为 0 2 9± 0 78D ,屈光度在± 0 5D和± 1 0D以内者分别占 61 1 % ( 33只眼 )和 83 3% ( 45只眼 )。裸眼视力达到 0 5以上者占 92 6% ( 50只眼 ) ,1 0以上者 63 0 % ( 34只眼 )。 1只眼 ( 1 9% )最佳矫正视力下降 2行 ,2只眼 ( 3 7% )增加 2行。 2只眼 ( 3 7% )有眩光。结论 :LASIK可用于治疗 1 0 0～ 6 0 0D的远视眼且具有较好的预测性和安全性。对手术技术和激光治疗程序的不断改进将有助于进一步提高手术的可预测性和稳定性     

准分子激光原位角膜磨镶术治疗远视

目的　评价准分子激光原位角膜磨镶术 (LASIK)治疗的效果和安全性。方法　对 16例 ( 3 0眼 )远视行LASIK。术前远视度数为 3 5 0～ 12 .5D ,平均 ( 7 0 9± 2 .62 )D。术后随访观察 12月。结果　术中无严重并发症 ,术后 3月屈光度基本稳定 ,术后 12月残余屈光度在 1 0 0D和 2 0 0D以内的分别占 40 0 0 % ( 12眼 )和 63 3 3 % ( 19眼 ) ,裸眼近视力≥ 0 .5者 3 0眼 ( 10 0 0 0 % ) ,≥ 1 0者 2 4眼 ( 80 0 0 % ) ,裸眼远视力≥ 0 .5者 2 6眼 ( 86 67% ) ,≥ 1.0者 9眼 ( 3 0 0 0 % ) ,1眼 ( 3 3 3 % )最佳矫正视力下降一行 ,5眼 ( 16 67% )有眩光。结论　LASIK治疗远视安全有效。治疗软件进一步完善及治疗参数进一步的调整将有助于提高手术的可预测性和稳定性     

Laser in situ keratomileusis for high myopia with the VISX star laser

PURPOSE: To evaluate the results of laser in situ keratomileusis (LASIK) for spherical and spherocylindrical myopia (range, 9-22 diopters [D]) with the VISX Star laser, (VISX Inc., Santa Clara, CA). DESIGN: Non-comparative, single-surgeon interventional case series. PARTICIPANTS: Two hundred ninety eyes of 175 patients. METHODS: Consecutive patients who underwent LASIK in the study range with the VISX Star laser were evaluated for early (approximately 1 month) and late (after 9 months) outcomes. Both single procedure outcomes and results after reoperation for refractive enhancement were included. MAIN OUTCOME MEASURES: Outcome measures included uncorrected visual acuity, manifest refraction, refractive predictability, refractive stability, best spectacle-corrected visual acuity (BSCVA), results of reoperations, and complications. RESULTS: At the early postoperative examination, approximately 1 month after surgery, 285 of 290 eyes (98.3%) were examined. Uncorrected visual acuity of 20/40 or better occurred in 209 of 285 (73.3%) eyes, and 198 of 285 (69.5%) eyes had a manifest spheroequivalent between +/-1.00 D. Subsequently, 60 eyes (20.7%) underwent reoperation for refractive enhancement. Late results, beyond 8 months from the initial surgery and including reoperations, were available in 195 of 290 eyes (67.2%). Uncorrected visual acuity results of 20/40 or better were found in 166 of 195 eyes (85.1%) and of 20/25 or better in 99 of 195 eyes (50.8%). Manifest spheroequivalent results were +/-2.00 D in 187 of 195 eyes (95.9%) and +/-1.00 D in 148 of 195 eyes (75.9%). In a paired-cohort analysis of 131 single-procedure eyes seen at both intervals, refractive stability (change in manifest refractive spheroequivalent of less than 1.00 D) was present in 101 of 131 eyes (77.1%) between the two observation intervals. Overall, approximately 3.6% eyes lost 2 lines or more of BSCVA, and other complications (flap wrinkling and epithelial ingrowth) were reported in 2% of eyes. Improvement in BSCVA of 1 line or more occurred in 5.6% eyes. CONCLUSIONS: Laser in situ keratomileusis for high myopia with the VISX Star laser provided satisfactory refractive and visual results that compare well with other reports in the literature. Subjective results and other measures of visual function need further evaluation.     

Changes in intraocular pressure after laser in situ keratomileusis for myopia,hyperopia, and astigmatism

PURPOSE: Reports have shown that photorefractive keratectomy changes intraocular pressure (IOP) in myopic eyes by changing the thickness and curvature of the cornea. Changes in intraocular pressure after laser in situ keratomileusis (LASIK) for hyperopia led the authors to evaluate IOP after LASIK for various refractive errors. METHODS: The measurement of intraocular pressure with a Goldman applanometer in the central cornea was evaluated before and 3 months after LASIK in 100 eyes of 55 patients with various refractive errors. Corneal thickness (pachymetry) and corneal topography were evaluated. RESULTS: After LASIK, a significant decrease of intraocular pressure was observed in most eyes: mean 11.9 +/- 3.2 mmHg before and 9.8 +/- 2.6 mmHg at 3 months after surgery (P < .001). Mean decrease in IOP was 2.75 +/- 3.3 mmHg (P < .0001) for myopic eyes, 2.28 +/- 2.43 mmHg (P < .001) for hyperopic eyes, and 1.47 +/- 2.5 mmHg (P < .0012) for astigmatic eyes. IOP reduction was not significantly correlated to the amount of ablation (r = 0.05) or to corneal thickness. CONCLUSION: Intraocular pressure decreased in myopic, hyperopic, and astigmatic eyes after LASIK. The reduction was not correlated to the amount of tissue removed or to flattening or steepening of the central cornea.     

激光角膜原位磨镶术治疗远视的实验研究

目的：评价激光角膜原位磨镶术（ＬＡＳＩＫ）治疗对高度远视的效果和安全性。方法：选择日本大耳兔１２ 只,根据左右眼将其分为两组。应用吸引环和微型角膜刀在兔角膜上做一带蒂角膜瓣,用Ｋｅｒａｔｏｍ Ⅱ准分子激光仪对左眼角膜基质床行预期矫正度数为＋５．００Ｄ、右眼＋８．００Ｄ的激光切削,分别于术前、术后３ 天、２ 周、１ 月、２ 月、３ 月对术眼进行了角膜地形图和裂隙灯检查和记录,同期随机处死一只兔子,取角膜标本进行光镜和电镜的病理学观察。结果：裂隙灯检查所有术眼无严重并发症,＋ ５．００Ｄ组和＋８．００Ｄ组术后３ 个月时的平均角膜中央屈折力变化分别是＋４ ．５２±１．０３Ｄ和＋８．６４±０．８４Ｄ,散光较术前增加０．３６Ｄ 和０ ．８４Ｄ。两组都在术后２ 周～１ 个月时出现回退（ Ｐ＜ ０．０１） 。术后１ 月～３ 月的平均角膜屈折力的差别无统计学意义（ Ｐ＜ ０．０５） 。与预期的光学区直径５．５ｍｍ 相比,两组实际得到的平均光学区直径只有３．９１ｍｍ 和３ ．９３ｍｍ 。实验表明双区域切削方式同样可以应用于ＬＡＳＩＫ治疗高度近视。病理学观察表明病理损伤后的愈合过程与ＬＡＳＩＫ 治疗近视相近。结论：ＬＡＳＩＫ治疗中、高度远视有明显疗效且具     

Laser in situ keratomileusis for myopia and compound myopic astigmatism using the Technolas 217 scanning-spot laser

PURPOSE: To evaluate the safety, efficacy, predictability, and visual results of laser in situ keratomileusis (LASIK) using the Bausch & Lomb Technolas(R) 217 scanning-spot laser for the treatment of myopia and compound myopic astigmatism. SETTING: Stanford Eye Laser Center, Stanford, California, USA. METHODS: In a prospective study, 110 eyes of 58 patients with a mean spherical equivalent (SE) of -4.87 diopters (D) +/- 2.5 (SD) (range -1.0 to -11.4 D) had LASIK for myopia and compound myopic astigmatism using the Technolas 217 scanning-spot laser. The primary outcome variables included preoperative and postoperative best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity (UCVA), achieved versus attempted correction, vector analysis of astigmatism, and complications. RESULTS: One hundred ten eyes were available for analysis at 3 months. The mean SE refraction was reduced 95% (mean -0.23 +/- 0.4 D), and astigmatism was reduced 70% (mean 0.28 +/- 0.3 D). One day postoperatively, 100% of eyes had a UCVA of 20/40 or better, 96% had 20/25 or better, 77% had 20/20 or better, and 39% had 20/15 or better. At the 3-month examination, 100% of eyes had a UCVA of 20/40 or better, 95% had 20/25 or better, 83% had 20/20 or better, and 48% had 20/15 or better. Ninety percent of eyes were within +/-0.5 D of emmetropia. No eye lost 2 or more lines of BSCVA. CONCLUSIONS: The Technolas 217 scanning-spot laser produced excellent postoperative UCVA and BSCVA. It was predictable, safe, and effective for the treatment of myopia and compound myopic astigmatism. Long-term follow-up is needed to assess the stability of the procedure.