Randomized comparison of custom laser in situ keratomileusis with the Alcon CustomCornea and the Bausch & Lomb Zyoptix systems: one-month results

PURPOSE: To compare the early visual results of custom laser in situ keratomileusis (LASIK) outcomes for two different excimer laser systems. METHODS: This is a preliminary report of an ongoing prospective study that evaluated 30 patients (60 eyes) who were randomized to one of two custom LASIK treatment groups: 15 patients (30 eyes) with the Alcon CustomCornea laser system (Alcon Laboratories Inc, Fort Worth, Tex) and 15 patients (30 eyes) with the Bausch & Lomb Zyoptix laser system (Bausch & Lomb, Rochester, NY). These matched patients were required to qualify for treatment with both custom laser systems. All flaps were created with the IntraLase femtosecond laser (IntraLase Corp, Irvine, Calif) using a superior hinge. Early outcome measures are uncorrected visual acuity (UCVA) at 1 day, 1 week, and 1 month postoperative; manifest refractions at 1-month follow-up; and a comparison of 1-month postoperative UCVA to preoperative best spectacle-corrected visual acuity (BSCVA). Wavefront, topography, contrast sensitivity, and subjective questionnaires were also performed and will be reported after 3-month follow-up. RESULTS: At 1 month, the percentage of eyes with UCVA of 20/20 and 20/40 were similar with 93% and 100%, respectively, for CustomCornea eyes and 90% and 97%, respectively, for Zyoptix eyes. A difference between the two groups is in the percentage of eyes with UCVA of 20/16, 20/12.5, and 20/10 with 80%, 47%, and 13%, respectively, for CustomCornea and 70%, 10%, and 0%, respectively, for Zyoptix. The mean residual spherical equivalent refraction was +0.01 +/- 0.34 diopters (D) for CustomCornea and -0.04 +/- 0.38 D for Zyoptix. The two groups are similar at +/-1.00 D of intended correction, with CustomCornea 100% and Zyoptix 97%. However, +/-0.25 D the CustomCornea group was 10% more accurate at 73% versus 63% for the Zyoptix group. The efficiency ratio (postoperative UCVA compared to preoperative BSCVA) was greater for the CustomCornea group at 20/20, 20/16,20/12.5, and 20/10 levels. CONCLUSION: Custom LASIK with CustomCornea and Zyoptix is safe and effective and produces excellent early visual outcomes. This study demonstrates that current standard metrics for reporting refractive surgery visual outcomes are not adequate for evaluating wavefront-guided laser vision correction procedures. Amending the standard reporting metrics to include visual outcomes at the 20/16, 20/12.5, and 20/10 levels; accuracy at the +/-0.25 D of attempted; and postoperative UCVA compared to preoperative BSCVA will improve our ability to analyze wavefront-guided outcomes.     

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.     

Simultaneous bilateral laser in situ keratomileusis: Safety and efficacy

ObjectiveTo compare the safety and efficacy of simultaneous bilateral to sequential bilateral laser in situ keratomileusis (LASIK) surgery for the correction of myopia.DesignRetrospective, nonrandomized, comparative trial.ParticipantsA total of 2142 consecutive simultaneous and sequential bilateral myopic LASIK surgery eyes operated from March 1996 through June 1998 for the correction of myopia were reviewed.InterventionTwo surgeons (HVG and JAV) performed myopic LASIK using the Nidek EC-5000 excimer laser and either the Chiron Automated Corneal Shaper or the Bausch & Lomb Hansatome microkeratome.Main outcome measuresThe incidence of intra- or perioperative complications for sequential and simultaneous bilateral LASIK for myopia was recorded. Refractive and visual outcomes at 3 to 6 months postoperative were analyzed. Deviations from targeted spherical equivalent (SE), uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), and retreatment rates are reported.ResultsLaser in situ keratomileusis was performed on the first eye of 1853 patients scheduled for simultaneous bilateral myopic LASIK. Of these, 28 (1.5%) first eyes had intraoperative or perioperative complications. The second eye surgery was cancelled in 11 cases, and 1842 second eyes completed simultaneous surgery; 13 (0.7%) intraoperative or perioperative complications occurred. Of these 41 complications in simultaneous cases, 1 eye lost 1 line of BCVA at 6 months follow-up. Two hundred eighty-nine patients were scheduled for sequential bilateral myopic LASIK. Five (1.8%) first eyes of the sequential cases had intraoperative complications compared with four (1.4%) sequential second eyes. There was no loss of BCVA in any sequential bilateral case with complications at a minimum at 6 months follow-up. There was no statistically significant difference between intra- and perioperative complication rates comparing simultaneous to sequential bilateral LASIK. Three to 6 months postoperative visual and refractive data were reviewed; except when comparing simultaneous first eye postoperative SE to sequential first eye, there was no statistically significant difference in refractive or visual outcomes, including deviation from targeted SE, UCVA, BCVA, and retreatment rates.ConclusionSimultaneous bilateral LASIK is as safe and effective as sequential surgery. Simultaneous bilateral LASIK may offer several benefits to the patient.     

大龄近视患者LASIK疗效分析

目的：探讨大龄近视患者LASIK特点及采用Monovision矫正方法设计的LASIK术后疗效。

方法：对104例186眼大龄近视患者(年龄≥40岁)采用Monovision矫正方法设计并进行LASIK手术,并对术前后视力、屈光度、手术疗效等进行统计分析。

结果：术后1mo,所有术眼的裸眼视力均明显提高(P<0.01),达到1.0的百分率分别为非主导眼83.7%(87/104),主导眼91.5%(75/82); 术后裸眼视力与术前最佳矫正视力比较,非主导眼差异不显著(P>0.05),而主导眼提高明显(P<0.01); 术后屈光度非主导眼为-0.70±0.12D,与术前欠矫设计量基本一致(P>0.05),主导眼为-0.04±0.28D,两组差异显著(P<0.01); 患者对远视力满意度100%、近视力满意度82.7%。

结论：大龄近视患者行LASIK治疗以高度、超高度近视患者为主,大屈光参差(>2.50D)患者占比例较高; 采用Monovision矫正方法设计的LASIK术对改善大龄患者术后视近功能、缓解视疲劳以及提高其视觉满意度是切实有效的,将这一临床经验用于个体化手术方案的设计可以使其更为完善。     

Influence of flap thickness on results of laser in situ keratomileusis for myopia

PURPOSE: To study whether flap thickness influences laser in situ keratomileusis (LASIK) results. METHODS: This comparative, non-randomized, retrospective study comprised 421 LASIK eyes (233 patients) with spherical equivalent refraction between -0.60 and -6.00 diopters (D). Laser in situ keratomileusis was performed with the Moria One manual microkeratome and the Chiron Technolas 217C laser. Depending on the flap thickness, the eyes were divided into three groups (group 1, flap thickness < or =100 microm; group 2, flap thickness > 100 microm and < 130 microm; and group 3, flap thickness > or = 130 pm). For each group uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity, residual spherical equivalent refraction, and keratometric power (D) were measured 1 day, 1 week, 1 month, and 6 months after LASIK. Complications, retreatment, and correlation between flap thickness and preoperative corneal thickness and keratometric power were also analyzed. RESULTS: One month postoperatively, UCVA was > or = 20/20 in 76% (96 eyes), 56% (79 eyes), and 61% (93 eyes) of eyes in the three group, respectively (P = .015). One month postoperatively, UCVA was > or = 20/25 in 88% (111 eyes), 76% (108 eyes), and 76% (116 eyes) of eyes in the three groups, respectively (P = .015). Complication rate and retreatment rate were not statistically different among the groups. At 6-month follow-up, no statistically significant differences were noted in UCVA between the groups. Significant correlations between flap thickness and preoperative corneal thickness (P < .0001) and between flap thickness and preoperative keratometric power (P < .05) were found. CONCLUSION: Patients with flaps < or = 100 pm had better functional results at 1 month than those with thicker flaps. It may be important to perform LASIK with thin flaps to save corneal tissue in the stromal bed.     

Hyperopic laser in situ keratomileusis to treat overcorrected myopic LASIK

PURPOSE: To evaluate the safety and efficacy of hyperopic laser in situ keratomileusis (LASIK) in treating hyperopia caused by overcorrected myopic LASIK and to evaluate a new technique to place the hyperopic treatment after lifting the initial myopic flap. SETTING: Open-access outpatient excimer laser surgical facility. METHODS: A retrospective analysis was performed of 54 eyes in 47 patients who had spherical hyperopic LASIK by 21 surgeons for the treatment of significant hyperopia after overcorrected LASIK for myopia. In 42 eyes, the initial LASIK flaps were lifted and in 12 eyes, new flaps were cut. The mean age of the 25 men (53%) and 22 women (47%) was 48.2 years +/- 8.4 (SD). Outcome measures included refractive error, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and complications. The mean follow-up was 2.97 months. RESULTS: In eyes in which postoperative emmetropia was attempted (n = 45), the mean spherical equivalent improved from +1.21 +/- 0.49 diopters (D) preoperatively to -0.38 +/- 0.50 D postoperatively (P <.001). The mean UCVA improved from 20/38.6 +/- 16.3 to 20/27.4 +/- 9.4 (P <.001). At the last follow-up, 69% of eyes were within +/-0.5 D and 96% were within +/-1.0 D of emmetropia; 42% had a UCVA of 20/20 and 96% had a UCVA of 20/40 or better. No eyes lost 2 or more lines of BSCVA. No vision-threatening complications occurred. Results in patients who had initial flaps lifted and those who had new flaps cut were statistically indistinguishable. On average, achieved hyperopic corrections were 18% greater than intended. CONCLUSION: Hyperopic LASIK was safe, predictable, and effective in the treatment of hyperopia caused by overcorrected myopic LASIK. Results were similar whether the original flap was lifted or a new one was cut.     

Conventional vs wavefront-guided LASIK using the LADARVision4000 excimer laser

PURPOSE: To compare outcomes after LASIK surgery using the conventional LADARVision4000 laser and the wavefront-guided LADARWave CustomCornea wavefront system. METHODS: A prospective study was performed involving 140 myopic eyes receiving conventional or CustomCornea LASIK between May and October 2003. The preoperative manifest spherical equivalent refraction was limited to myopia < or = -7.00 diopters (D). The preoperative manifest cylinder was limited to < or = -2.50 D of astigmatism. Patients were evaluated for 3 months following surgery. Results evaluated were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity, manifest refraction, dilated wavefront measurements, contrast sensitivity, and patient responses to subjective questionnaires. RESULTS: For the CustomCornea eyes at 3 months, 80% (70/87) had UCVA > or = 20/20 and 95% (83/87) had UCVA > or = 20/25. For the conventional eyes at 3 months, 45% (9/20) had UCVA > or = 20/20 and 80% (16/20) had UCVA > or = 20/25. At the 3-month postoperative visit, 85% (74/87) of the CustomCornea eyes and 55% (11/20) of the conventional eyes were within +/- 0.50 D of their intended correction. At 1 and 3 months, the CustomCornea treated eyes had a statistically significant lower mean increase in higher order aberrations than conventionally treated eyes (P < .05). CONCLUSIONS: CustomCornea wavefront-guided LASIK surgery appears safe and effective and provides clinical benefits that appear to exceed those of conventional LADARVision surgery.     

Results of laser in situ keratomileusis for myopia of -10 to -19 diopters with a Technolas 217 laser

PURPOSE: To evaluate the effectiveness, predictability, and safety of laser in situ keratomileusis (LASIK) for correcting myopia greater than -10.00 D. METHODS: Sixty-five eyes of 37 patients with myopia greater than -10.00 D underwent LASIK. Patients were evaluated on day 1, 1 week, 1, 3, and 6 months after surgery. Parameters evaluated were uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA), residual refractive error, regression of correction, and presence of any complication. RESULTS: Mean preoperative BSCVA was 0.745 +/- 0.234, which improved to 0.8070 +/- 0.237 postoperatively. The average preoperative UCVA was 0.022 +/- 0.02; postoperative UCVA at 6 months was 0.536 +/- 0.255. UCVA of 20/40 or better was achieved in 58% (38 eyes) and 20/20 or better in 26% (17 eyes). The average refractive error before LASIK was -12.64 +/- 2.16 D (range -10.00 to -19.00 D). Mean residual refractive error 1 week following LASIK was -0.63 +/- 1.36 D, which regressed to a mean -1.78 +/- 2.08 D at the end of 6 months. Nineteen eyes (29%) were within +/-0.50 D of intended refractive correction. CONCLUSION: LASIK was partially effective in the correction of high myopia. An initial overcorrection may be programmed to offset the effect of refractive regression.     

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.     

Natural history of central islands after laser in situ keratomileusis

PURPOSE: To assess the incidence and natural history of central islands following laser in situ keratomileusis (LASIK) and evaluate the association of central island characteristics with visual acuity. SETTING: Department of Ophthalmology, China Medical College Hospital, Taichung, Taiwan. METHODS: A consecutive series of 406 eyes of 212 patients who had LASIK was retrospectively evaluated. Uncorrected visual acuity (UCVA) was measured and corneal topography performed preoperatively and 1 week and 1, 3, 6, and 9 months postoperatively. Best spectacle-corrected visual acuity (BSCVA) was evaluated preoperatively and 1, 3, and 6 months postoperatively. RESULTS: The topographic images obtained at 1 week demonstrated central islands in 23 eyes of 20 patients (5.7%). No new cases of central island formation were identified after 1 week. Of the 23 eyes with central islands, the 6 month post-LASIK maps were available in 20 eyes of 18 patients. There was a significant difference in the size and power of the central islands between 1 week and 6 months. However, the power and size decreased slowly. Within 6 months, only 5 of 20 central islands (25.0%) had resolved. Eight eyes were undercorrected, and 1 eye lost 2 lines of BSCVA. Central islands larger than 1.8 mm or 3.0 diopters (D) were significantly correlated with lower UCVA. CONCLUSION: Most central islands that occur with LASIK persist more than 6 months. Large central islands (>/=1.8 mm or >/=3.0 D) are risk factors for lower UCVA. Preventive measures are necessary.     

Wavefront-guided laser in situ keratomileusis: early results in three eyes

PURPOSE: Wavefront optical aberrations induced by refractive corneal surgery correction of myopia are probably the reason for deterioration of visual performance in some eyes after surgery. Customized photoablation of the cornea to correct both the sphero-cylindrical refractive error as well as individual optical aberrations may improve postoperative visual acuity and visual performance. METHODS: In 3 eyes of 3 patients the wavefront deviations were measured by means of an aberrometer of the Tscherning-type. Based on these measurements an ablation pattern was determined and applied during a LASIK procedure using a Wavelight Allegretto scanning spot excimer laser with a spot size of 1 mm and a laser repetition rate of 200 Hz. The 3 eyes are part of a prospective study on wavefront-guided LASIK started in July 1999. RESULTS: At 1 month after LASIK, all 3 eyes had gained up to 2 lines of best spectacle-corrected visual acuity. Best spectacle-corrected visual acuity improved to 20/10 in all 3 eyes, uncorrected visual acuity was 20/10 in two eyes, and 20/12.5 in 1 eye 1 month postoperatively. The wavefront deviations were reduced by 27% on average. At 3 months, best spectacle-corrected visual acuity was 20/10 in 2 eyes and 20/12.5 in 1 eye. CONCLUSION: Wavefront-guided LASIK is a feasible approach in refractive corneal surgery. Optimized ablation patterns may further improve the visual results.     

Reoperations after myopic laser in situ keratomileusis

PURPOSE: To evaluate the results after enhancement of myopic laser in situ keratomileusis (LASIK) using the VISX Star excimer laser. SETTING: The Buzard Eye Institute, Las Vegas, Nevada, USA. METHODS: In this prospective study, 52 eyes of 40 patients had LASIK enhancement. The existing flap was lifted and the excimer laser treatment reapplied for the residual refractive error. The VISX Star excimer laser was used for the primary LASIK and the enhancement procedure. Retreatments for undercorrection, regression, and overcorrection were performed after 6 weeks and up to 40 weeks after the primary LASIK. Follow-up was 96% at 1 month, 67% at 6 months, and 71% at 12 months. RESULTS: Mean pre-enhancement spherical equivalent was -0.77 diopters (D) +/- 0.94 (SD) and mean uncorrected visual acuity (UCVA), 20/60. One year after the enhancement, mean spherical equivalent was -0.13 +/- 0.33 D, and mean UCVA was 20/25. Refraction remained stable during the 1 year follow-up, with no treatment required. After the enhancement, all patients had a UCVA of 20/40 or better. At 1 year, 3% of patients had lost 1 line of best corrected visual acuity and 32% had gained 1 line. No epithelial ingrowth was noted. CONCLUSION: Retreatment for LASIK beginning 6 weeks after the initial procedure proved to be effective with minimal complications and good results. The technique to raise and reposition the flap appeared safe, and complications were few.     

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.     

Nomogram adjustment of laser in situ keratomileusis for myopia and myopic astigmatism with the Alcon LADARVision system

PURPOSE: To evaluate the visual and refractive results of conventional (non-wavefront) laser in situ keratomileusis (LASIK) for treatment of myopia and myopic astigmatism using the Alcon LADARVision 4000 excimer laser system and nomogram adjustment techniques. METHODS: A retrospective analysis of 499 eyes that had LASIK for myopia and myopic astigmatism was performed. Preoperative manifest spherical equivalent refraction ranged from -0.43 to -6.00 D and preoperative astigmatism ranged from 0 to -4.75 D. Patients were evaluated during 3 months following surgery. RESULTS: One month after surgery, 72% of eyes examined (298/415 eyes) had uncorrected visual acuity (UCVA) of 20/20 or better. Three months after surgery, 83% of eyes examined (216/261 eyes) had UCVA of 20/20 or better. One and three months after surgery, 82% and 83% of eyes, respectively, were within +/-0.50 D of attempted correction; 97% of eyes were within +/-1.00 D at both 1 and 3 months. No eye lost more than 1 line of best spectacle-corrected visual acuity (BSCVA) at 3 months after surgery. At the 3-month examination, 83% of eyes had UCVA better than or equal to preoperative BSCVA. CONCLUSIONS: Conventional LASIK to correct myopia and myopic astigmatism was safe and effective using the Alcon LADARVision 4000 excimer laser system. Outcomes were substantially improved throughout development of an accurate nomogram, derived from continually updated regression analysis of previous refractive results.     

Comparison of photorefractive keratectomy and laser in situ keratomileusis for myopia of -6 D or less using the Nidek EC-5000 laser

PURPOSE: We compared the efficacy, predictability, and safety of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) for the surgical correction of low and moderate myopia. METHODS: A retrospective study was performed to evaluate uncorrected and spectacle-corrected visual acuity, and manifest refraction 1 year after PRK or LASIK. All procedures were done using an automatic microkeratome (Chiron Ophthalmic) and the Nidek EC-5000 excimer laser. RESULTS: PRK was performed in 75 eyes of 45 patients and LASIK in 133 eyes of 77 patients. Mean age for PRK patients was 32.8 years (range, 18 to 52 yr) and LASIK patients was 29.6 years (range, 18 to 49 yr). Mean preoperative spherical equivalent refraction for PRK patients was -3.28 D (range, -1.00 to -6.00 D) and LASIK, -3.86 D (range, -1.00 to -6.00 D). One year after surgery, mean spherical equivalent refraction for Group 1 (baseline, -1.00 to -3.00 D) PRK eyes was -0.18 +/- 0.61 D (range, -1.50 to +0.75 D) and for LASIK eyes, -0.08 +/- 0.61 D (range, -1.50 to +1.62 D), with no statistically significant difference. For Group 2 eyes (baseline, -3.25 to -6.00 D), mean spherical equivalent refraction for PRK eyes was -0.44 +/- 0.87 D (range, -2.00 to +2.12 D) and for LASIK eyes, -0.09 +/- 0.83 D (range, -1.50 to +1.75 D), with no statistically significant difference. The antilogarithm of the mean UCVA (antilogUCVA) in Group 1 for PRK was 0.79 +/- 0.21 (20/25) and for LASIK was 0.87 +/- 0.19 (20/23), with no statistically significant difference. The antilogUCVA in Group 2 for PRK eyes was 0.70 +/- 0.24 (20/28) and for LASIK eyes was 0.83 +/- 0.18 (20/24), with a statistically significant difference (0.7 vs. 0.83, P < .005). The percentage of eyes with a postoperative UCVA >20/40 in Group 1 for PRK was 91.5% (38 eyes) and for LASIK was 95% (50 eyes) (no statistically significant difference), and in Group 2 for PRK eyes, it was 82% (27 eyes) and 97.5% (78 eyes) for LASIK (statistically significant difference, P < .05). CONCLUSION: PRK and LASIK with the Nidek EC-5000 excimer laser are effective and safe for correcting low to moderate myopia, but LASIK eyes showed better results for moderate myopia in terms of uncorrected visual acuity.     

Effect of high-altitude exposure on myopic laser in situ keratomileusis

PURPOSE: To study the effect of high-altitude exposure on visual acuity after myopic laser in situ keratomileusis (LASIK). SETTING: Aconcagua, Mendoza, Argentina. METHODS: In the early postoperative period after uneventful myopic LASIK, 2 physicians prospectively assessed their visual acuity during an ascent of Aconcagua (22841 feet). The distance uncorrected visual acuity (UCVA) and peripheral oxygenation were measured at approximately every 2000 feet of altitude. RESULTS: Both climbers developed a moderate loss of distance UCVA but described normal near and pinhole acuity consistent with a myopic shift. The distance UCVA diminished to 20/100 in the right eye and 20/125 in the left eye of Climber A and to 20/160 and 20/30, respectively, of Climber B. The vision loss worsened with increased altitude, duration of exposure, and decreased peripheral oxygenation. One week after the climb, the manifest refraction demonstrated a small myopic shift in both eyes of Climber A; these subsequently resolved. CONCLUSIONS: Two climbers, 8 and 14 weeks after myopic LASIK, experienced vision loss consistent with a temporary myopic shift in the refractive error with ascent to high altitude. Climbers who have LASIK, particularly those in the early postoperative period, should be prepared for visual acuity fluctuations with high-altitude exposure.     

CustomVue laser in situ keratomileusis for myopia and myopic astigmatism using the Visx S4 excimer laser: Efficacy, predictability, and safety

PURPOSE: To evaluate the efficacy, predictability, and safety of custom laser in situ keratomileusis (LASIK) using the Visx wavefront platform CustomVue for the treatment of myopia and myopic astigmatism. SETTING: Stanford University Eye Laser Center, Stanford, California, USA. METHODS: This retrospective analysis was of the initial 140 eyes of 78 patients treated consecutively with LASIK for myopia using the Visx Star S4 excimer laser. Primary outcome variables, including uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and complications, were evaluated at 1 week and 1 and 3 months. Vector analysis was performed on eyes that received astigmatic correction. RESULTS: Mean preoperative spherical equivalent (SE) was reduced from -3.89 diopters +/- 1.48 (SD) to an SE of -0.21 +/- 0.36 D at 1 month and -0.28 +/- 0.36 D at 3 months (P < .001). At 1 and 3 months, UCVA was 20/20 or better in 84.3% and 87.9%, respectively. Eighty-six percent of eyes at 1 month and 81.4% of eyes at 3 months were within +/-0.5 D of emmetropia. No eyes lost more than 2 lines of BSCVA. Vector analysis yielded an index of success of 0.39, indicating a 61% success rate in achieving the astigmatic surgical correction at 3 months. The preoperative root-mean-square value of 0.28 +/- 0.08 microm increased slightly to 0.33 +/- 0.11 microm at 1 month and 0.34 +/- 0.11 microm at 3 months. CONCLUSION: Wavefront-guided LASIK using the Visx CustomVue system was effective, predictable, and safe for correction of low to moderate myopic refractive error.     

Surgical outcomes of photorefractive keratectomy and laser in situ keratomileusis by inexperienced surgeons

PURPOSE: To investigate the results of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) procedures performed by novice ophthalmologists and compare the results with those of experienced refractive surgeons. SETTING: Doheny Eye Institute, University of Southern California, Los Angeles, and Department of Ophthalmology, University of California, Irvine, California, USA. METHODS: In this retrospective case series, data were examined from the first PRK procedures by 33 consecutive ophthalmologists and the first LASIK procedures by 19 consecutive ophthalmologists. Preoperative and postoperative uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA), as well as intraoperative and early postoperative complications, were recorded. RESULTS: In the PRK group, 33.3% of eyes achieved a UCVA of 20/20 and 87.8%, 20/40 or better; 54.5% were within +/-0.5 diopter (D) of emmetropia and 87.8%, within +/-1.0 D. Two eyes with a preoperative spherical equivalent of greater than -11.0 D lost 2 lines of BSCVA. If eyes with low myopia (相似文献   

飞秒激光小切口微透镜取出术并发症分析

目的:回顾分析本院飞秒激光小切口透镜取出术(small incision lenticule extraction,SMILE)患者临床资料,探讨术中及术后出现的并发症及如何有效预防与处理. 方法:对2015-01/12本院实施的799眼SMILE手术进行统计, 回顾性分析其术中术后出现的各类并发症. 结果:选取患者中798眼均顺利完成手术,术后视力恢复好,仅1眼术中扫描出现严重黑斑,改行飞秒激光LASIK,手术过程中5例5眼(0.6%)患者发生失吸,11例17眼(2.1%)患者发生了不透明气泡层(OBL),术后BCVA无下降.术后的角膜上皮下雾状混浊及弥漫性板层角膜炎(DLK)的发生率低,分别为0.3%和0.4%,未出现其他严重的并发症,角膜愈合良好.仅6例9眼(1.1%)于6mo后复查出现不同程度的屈光回退,其余患者SMILE术后3mo均获得1.0以上UCVA,达到术前BCVA.结论:SMILE手术具有较好的安全性, 预防并及时正确处理各类并发症是术后获得良好视力的关键.     

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.