Laser in situ keratomileusis using the Nidek EC-5000 or the Alcon LADARVision 4000 systems

PURPOSE: To compare the refractive results of eyes with low to moderate myopia that underwent laser in situ keratomileusis with either the Nidek EC-5000 or the Alcon LADARVision 4000 excimer laser systems. METHODS: We performed a retrospective review of 114 LASIK procedures with either the Nidek EC-5000 (54 eyes) or the Alcon LADARVision 4000 (60 eyes) excimer laser systems. Preoperative refractive errors were similar and both populations were treated during the same time period. Data analyzed included uncorrected visual acuity (UCVA), spherical magnitude, spherical equivalent refraction, astigmatism power, astigmatism axis, and vector astigmatism change. RESULTS: Results at 6 months were analyzed. Spherical correction change was a mean -3.95 D for Nidek treated eyes and a mean -4.53 D for LADARVision treated eyes (P = .20). Mean spherical equivalent refraction change was -3.70 D for Nidek eyes and -4.20 D for LADARVision eyes (P = .23). Mean change in UCVA (LogMAR) was 1.05 for Nidek eyes and 0.99 for LADARVision eyes (P = .40). Mean astigmatism magnitude change was 0.71 D for Nidek eyes and 0.77 D for LADARVision eyes (P = .63). Mean vector-corrected astigmatism change was 0.93 D for Nidek eyes and 1.00 D for LADARVision eyes (P = .63). Mean vector-corrected astigmatism axis for Nidek eyes was 3.08 D and for LADARVision eyes 6.58 D (P = .70). CONCLUSION: There was no significant difference in refractive results in eyes treated with the Alcon LADARVision 4000 or the Nidek EC-5000 excimer laser systems. Inherent differences between the two laser systems are highlighted.     

Photorefractive keratectomy versus laser in situ keratomileusis: a control-matched study

OBJECTIVE: Photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) outcomes were compared at 1, 3, 6, and 12 months after surgery. DESIGN: Retrospective, nonrandomized, comparative study. PARTICIPANTS: One hundred seven LASIK-treated eyes (58 patients) and 107 PRK-treated eyes (91 patients) having myopia between -1 and -9.50 diopters (D). All LASIK-treated eyes were analyzed retrospectively and matched with PRK-treated eyes having sphere within +/-0.25 D, +/-1 D of cylinder, and +/-7 years of age. INTERVENTION: For PRK and LASIK, the refractive surgery was performed with the slit-scanning excimer laser Nidek EC-5000, (Nidek Co. Tokyo, Japan) MAIN OUTCOME MEASURES: Manifest refraction, best-spectacle and uncorrected Snellen visual acuity, haze, halos, and keratometry were evaluated before surgery and up to 12 months after surgery. RESULTS: Seventy percent of eyes were evaluated at the 12-month postoperative exam. Of these eyes, 83% of LASIK cases and 86% of PRK cases had uncorrected visual acuities of 20/20 or better. Refractions within +/-0.5 D represented 78% of the LASIK eyes and 83% of the PRK eyes at that follow-up. Patients who underwent LASIK reported halos twice as often as patients who underwent PRK using a subjective scale. The odds ratio of high halos for LASIK versus PRK was 3.50 (95% confidence interval, 1.89-6.46; P<0.0001). At 1 month after surgery, 64% of the LASIK eyes were within +/-0.50 D compared with 77% of the PRK eyes. No eye lost 2 Snellen lines of best corrected visual acuity at 6 or 12 months after surgery. Ten PRK eyes (9.3%) and three LASIK eyes (2.8%) were retreated. CONCLUSIONS: PRK and LASIK achieved equal refractive outcomes at all postoperative follow-ups, but LASIK patients were twice as likely to experience halos.     

Clear lens extraction with intraocular lens followed by photorefractive keratectomy or laser in situ keratomileusis

OBJECTIVE: To study photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) after clear lens extraction (CLE) with intraocular lens (IOL) implantation for hyperopia or astigmatism. DESIGN: Retrospective, noncomparative interventional case series. PARTICIPANTS: Sixty-five eyes (55 subjects) had CLE with posterior chamber IOL implants for hyperopia up to 12.25 diopters (D); 31 eyes were retreated with PRK, and 34 eyes were retreated with LASIK for residual ametropias. INTERVENTION: For PRK and LASIK, the refractive surgery was performed with the slit-scanning excimer laser Nidek EC-5000, Nidek Co., Tokyo, Japan. MAIN OUTCOME MEASURES: Manifest refraction, best-spectacle and uncorrected Snellen visual acuity, haze, and halos were evaluated before surgery and at 1, 3, 6, and 12 months postoperative. RESULTS: Forty-seven eyes were evaluated at the 12-month postoperative examination: 96% of these eyes had spherical equivalents (SE) within +/-2 D of emmetropia, 79% of eyes had SE within +/-1 D of emmetropia and 51% of eyes had SE within +/-0.50 D of emmetropia. Eighty-five percent of the eyes at 12 months postoperative had uncorrected visual acuity of 20/40 or better, and 46% of eyes had uncorrected visual acuity of 20/20 or better. Eighty-seven percent of the eyes at 12 months postoperative had uncorrected visual acuity within 1 Snellen line of their initial best spectacle-corrected visual acuity (BSCVA) before all treatment. No eye lost 2 Snellen lines of BSCVA at 3, 6, or 12 months after PRK or after LASIK. CONCLUSIONS: IOL implantation for CLE, although an invasive technique, resulted in better refractive outcomes without laser-related clinical complications after PRK or LASIK adjustment.     

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

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

Laser in situ keratomileusis improves visual acuity in some adult eyes with amblyopia

PURPOSE: To report the results of laser in situ keratomileusis (LASIK) in a series of adult patients with amblyopia. METHODS: A retrospective noncomparative review was performed on patients with amblyopia who underwent LASIK for correction of ametropia, using the Summit Krumeich Barraquer microkeratome and the Nidek EC-5000 excimer laser. Data were collected on uncorrected visual acuity, best spectacle-corrected visual acuity, manifest refraction, anterior segment evaluation, intraocular pressure, corneal topography, and dilated fundus examination (preoperative and postoperatively on day 1, months 2 and 6). RESULTS: Eight eyes of seven patients were included, with a mean patient age of 30 +/- 10 years (range 21 to 49 yr). Mean preoperative spherical equivalent refraction was -4.70 D (range -12.62 to +4.71 D) and the best spectacle-corrected visual acuity varied from 20/32 to 20/80. At 2 months after LASIK, mean spherical equivalent refraction was -0.37 +/- 0.60 D (range -1.37 to + 0.60 D), uncorrected visual acuity ranged between 20/20 to 20/30, and a mean gain of 3 Snellen lines (range 2 to 4 lines) was observed. All patients reported significant subjective improvement in their perception of vision. The visual acuity and subjective improvement were maintained throughout 6 months postoperatively. CONCLUSIONS: LASIK with the Nidek EC-5000 laser for correction of ametropia in adult amblyopic eyes provided encouraging results for visual acuity improvement beyond correction of the refractive error.     

Outcomes after laser in situ keratomileusis retreatment in high myopes

PURPOSE: To evaluate the refractive and visual performance after laser in situ keratomileusis (LASIK) retreatment. METHODS: A retrospective study was performed on 33 eyes of 23 patients who underwent LASIK (Bausch & Lomb Technolas 217C) retreatment for residual myopia with or without astigmatism. Parameters evaluated were uncorrected and best spectacle-corrected visual acuity, spherical equivalent refraction, contrast sensitivity, glare acuity, and pachymetry, preoperatively and at 1, 3, and 6 months postoperatively. RESULTS: The mean spherical equivalent refraction before primary LASIK was -9.89 +/- 4.00 D and before retreatment was -2.85 +/- 2.17 D. Although contrast sensitivity and glare acuity decreased significantly after primary LASIK (P<.05), no significant change in these parameters was observed after retreatment. Smaller ablation zones were associated with decreased contrast sensitivity and glare acuity after primary LASIK as well as following retreatment. Contrast sensitivity and glare acuity following primary LASIK were significantly better in eyes with ablation zones > or = 5 mm than those with < 5 mm (P<.05). Eyes in which the ablation zone was the same as that for primary LASIK had significantly better contrast sensitivity than those with different ablation zones (increased or decreased) during retreatment. Attempted refractive correction during primary LASIK and retreatment had a significant negative correlation with contrast sensitivity and glare acuity following primary LASIK as well as retreatment. CONCLUSION: The ablation zones following primary LASIK and retreatment should be > or = 5.00 mm and remain unchanged to improve visual performance.     

Comparison of laser in situ keratomileusis and photorefractive keratectomy for the correction of myopia of -6.00 diopters or less. Melbourne Excimer Laser Group

PURPOSE: To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) compared to photorefractive keratectomy (PRK) for the correction of low or moderate myopia (-0.50 to -6.00 D) at 6 months after surgery. METHODS: The study population comprised a non-randomized consecutive series of 622 eyes of 392 patients who were treated with the Nidek EC-5000 excimer laser. LASIK was performed using the ACS Chiron microkeratome on 314 eyes and surface PRK on 308 eyes. All patients were treated using a standard protocol, then assessed at 1, 3, and 6 months postoperatively. RESULTS: Forty-four percent of the LASIK group and 67% of the PRK group attended their 6-month examination. Eighty percent of patients (111 eyes) after LASIK and 65% (136 eyes) after PRK had an uncorrected visual acuity of 20/20 or better. Spherical equivalent refraction was within +/-0.50 D of intended refraction in 78% (109 eyes) for LASIK and 82% (170 eyes) for PRK. Loss of two more lines of best spectacle-corrected visual acuity at 6 months occurred in 1.4% (2 eyes) of the LASIK group and 1.0% (2 eyes) of the PRK group. CONCLUSION: At 1 month follow-up, the percentage of eyes that achieved 20/20 uncorrected visual acuity was greater in the LASIK group than in the PRK group. At 6 months, visual and refractive outcomes of LASIK and PRK were similar. Although flap related complications occurred only after LASIK, the overall risk of loss of best spectacle-corrected visual acuity was not significantly greater than for PRK.     

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.     

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.     

Laser in situ keratomileusis for hyperopia and hyperopic astigmatism with the Nidek EC-5000 Excimer laser.

PURPOSE: We evaluated the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) for hyperopia and hyperopic astigmatism. METHODS: A retrospective study was performed for 92 eyes of 62 consecutive patients to evaluate uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA) and manifest refraction before and 3 and 6 months after LASIK (Moria LSK-ONE microkeratome, Nidek EC-5000 excimer laser). Eyes were divided into groups: Group 1 (low hyperopia) for spherical correction of +1.00 to +3.00 D (22 eyes), Group 2 (low hyperopic astigmatism) for toric correction with spherical equivalent refraction of +1.00 to +3.00 D (18 eyes), Group 3 (moderate hyperopia) for spherical correction of +3.25 to +6.00 D (10 eyes), and Group 4 (moderate hyperopic astigmatism) for toric correction with spherical equivalent refraction between +3.25 and +6.00 D (18 eyes). RESULTS: At 3 and 6 months after LASIK, 68 eyes (73.9%) were available for follow-up examination. Percentage of eyes with a spherical equivalent refraction within +/-0.50 D of emmetropia for Group 1 was 54.5% (12 eyes); Group 2, 50% (9 eyes); Group 3, 40% (4 eyes), and Group 4, 38.8% (7 eyes). UCVA > or =20/20 in Group 1 was 14% and in Groups 2, 3, and 4, 0%. One eye (5.5%) lost two lines of BSCVA. CONCLUSION: LASIK with the Moria LSK-ONE microkeratome and the Nidek EC-5000 excimer laser reduced low and moderate hyperopia and was within +/-0.50 D of target outcome in approximately 50% of eyes. Undercorrection was evident in all groups. The procedure was safe.     

Hyperopic laser in situ keratomileusis with the Nidek EC-5000 excimer laser

OBJECTIVE: To evaluate the efficacy, safety, and predictability of hyperopic laser in situ keratomileusis (H-LASIK) using modified software. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: The first 72 consecutive eyes of 44 patients with up to +5.00 diopters (D) hyperopia. INTERVENTION: Hyperopic LASIK using the Automatic Corneal Shaper (ACS; Chiron Vision, Claremont, CA) and the Nidek EC-5000 excimer laser (Nidek, Tokyo, Japan). MAIN OUTCOME MEASURES: Uncorrected visual acuity, manifest spherical equivalent (MSE), best-corrected visual acuity (BCVA), and complications were studied. RESULTS: At 6 months, in the low hyperopia group (<3.00 D), mean MSE was +0.30 +/- 0.71 D, with 88.9% eyes within 1 D of emmetropia compared with +1.09 +/- 0.92 D and 51.8% within 1 D of emmetropia in the moderate hyperopia group (> or =3.00 D; P = 0.003). Uncorrected visual acuity was 20/40 or better in 43 of 45 eyes (95.6%) and in 21 of 27 (77.8%) eyes in the low and moderate hyperopia groups, respectively. Only one eye (1.4%) from the moderate hyperopia group lost two lines of BCVA. Eighteen eyes (25%) required retreatment to correct residual hyperopia, 9 eyes (20.0%) in the low hyperopia group and 9 eyes (33.3%) in the moderate hyperopia group. Retreatments resulted in an MSE of +0.02 +/- 0.45 D and +0.04 +/- 0.73 D in the low and moderate hyperopia groups, respectively. No flap-related complications were seen. CONCLUSIONS: Hyperopic LASIK with the ACS and the Nidek EC-5000 excimer laser using our modified software is a safe, effective, and predictable procedure for low hyperopia. Results are satisfactory up to moderate hyperopia. Significant regression can occur for low and moderate hyperopia. Retreatment can be performed safely and effectively to improve the visual and refractive results.     

Laser in situ keratomileusus for mixed and simple myopic astigmatism with the Nidek EC-5000 Laser

PURPOSE: To evaluate the visual and refractive results of laser in situ keratomileusis (LASIK) for mixed and simple myopic astigmatism using bitoric ablation. METHODS: A retrospective study was performed in 65 eyes of 38 consecutive patients to evaluate uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA) and cyclopegic and manifest refraction, before and 3 and 6 months after LASIK (Moria LSK-ONE microkeratome, Nidek EC-5000 excimer laser). RESULTS: At 3 and 6 months after LASIK, 40 eyes of 24 patients (64.5%) were available for follow-up examination. Mean age was 25.9 +/- 6.6 years (range 18 to 43 yr). Mean preoperative manifest spherical equivalent refraction was -1.40 +/- 0.80 D (range -3.80 to +0.50 D) mean preoperative cylinder was -3.30 +/- 1.30 D (range -1.00 to -6.00 D). At 6 months follow-up, mean manifest spherical equivalent refraction was +0.30 +/- 0.46 D (range -0.38 to +1.88 D), mean cylinder was -0.73 +/- 0.61 D (range -2.25 to 0 D). There was a 77.8% decrease in astigmatism magnitude. According to vector analysis, mean achieved vector magnitude was 80% of intended. Fifty percent (20 eyes) had a cylinder within +/- 0.50 D of emmetropia. Twenty-three eyes (57.5%) had a spherical component within +/- 0.50 D. Eighty-five percent (34 eyes) had postoperative UCVA of 20/40 or better. Ten percent (four eyes) lost two lines of Snellen BSCVA, whereas 35% (14 eyes) gained one or more lines. CONCLUSIONS: Bitoric LASIK with the Moria LSK-ONE microkeratome and Nidek EC-5000 excimer laser was effective and safe for the reduction of cylinder in mixed and simple myopic astigmatism. Moderate undercorrection of the cylinder was evident.     

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.     

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.     

准分子激光原位角膜磨镶技术分步多区切削治疗高度近视的疗效分析

目的:探讨准分子激光原位角膜磨镶技术(laser in situker-atomileusis,LASIK)治疗高度近视的疗效。方法:应用日本Nidek EC5000Ⅱ准分子激光仪,采用多步分区切削法治疗高度近视。按屈光度分为两组,I组:-6.00～-9.00D,128眼;II组:-9.00～-14.00D,147眼。术后随访1a,并对结果进行分析。结果:两组患者术后1a裸眼视力≥0.6者占89.6%,≥1.0者占55.6%(其中I组≥0.6者占95.1%,Ⅱ组≥0.6者占88.9%)。术后最佳矫正视力大于术前者占38.1%,小于术前者占6.0%,94.0%术后最佳矫正视力不变或上升。术后1a实际矫正度在预测矫正度±1.00D内者占81.3%,±2.00D内者占90.2%。激素性高眼压占0.04%。结论:准分子激光原位角膜磨镶技术多步分区切削法治疗高度近视伴薄角膜及超高度近视是一种安全、有效,且稳定性较好的方法,能有效预防屈光回退的发生,同时可以减少术后眩光和暗视力下降等现象。     

准分子激光原位角膜磨镶术治疗超高度近视远期疗效分析

目的探讨准分子激光原位角膜磨镶术(LASIK)治疗超高度(等效球镜度数>-10.00 D)近视的远期效果和安全性.方法对99例(173只眼)超高度近视行LASIK矫正,术前屈光度数-10.00～-23.50 D,平均(-13.7±3.6)D(等效球镜),其中-15.00 D以上41只眼.常规行裂隙灯显微镜、三面镜眼底检查、OrbscanⅡ眼前段分析系统、眼压、A超、角膜测厚、电脑验光、散瞳检影、主观验光等检查.术后随访18个月以上.结果术后18个月时裸眼视力≥0.5者148只眼(85.6%),最佳矫正视力高于或等于术前最佳矫正视力者147只眼(84.4%),未见术后最佳矫正视力较术前最佳矫正视力低于2行以上的眼;屈光度数稳定在±1.00 D以下者109只眼(63.0%),术前屈光度数在-14.75 D以下和-15.00 D以上达到±1.00 D内者的百分数分别为73.5%(97只眼/132只眼)和29.3%(12只眼/41只眼).术后角膜后表面前移,术后3个月时后表面顶点距理想球面的距离为(0.069±0.031)mm,18个月为(0.065±0.025)mm,均大于术前的(0.029±0.010)mm;角膜微皱褶2只眼,诉暗视力下降眩光6例(10只眼).结论 LASIK矫正超高度近视有效安全,同时在选择手术适应证方面应谨慎从之.对于屈光度数太高而角膜厚度偏薄者行LASIK应慎重,可考虑其他方法矫正如晶状体屈光手术或联合手术.(中华眼科杂志,2004,40816-818)     

Large optical ablation zone using the VISX S2 smoothscan excimer laser

PURPOSE: To prospectively evaluate the safety and efficacy of the new large-zone (6.5 mm) photoablation technology using the VISX S2 Smoothscan excimer laser. SETTING: University-based hospital, Stanford, California, USA. METHODS: Forty-two eyes of 21 patients with a mean preoperative spherical equivalent (SE) of-5.55 diopters (D)+/- 2.24 (SD) (range-2.13 to-10.75 D) had laser in situ keratomileusis (LASIK) using the VISX Smoothscan S2 excimer laser for simple myopia or compound myopic astigmatism. A 6.5 mm optical zone was used in all eyes. Patients were prospectively followed 1 day and 1 and 3 months postoperatively. RESULTS: At 3 months, the mean SE was reduced 94% to-0. 31+/- 0.55 D. Ninety-one percent of eyes had an uncorrected visual acuity of 20/40 or better. Eighty-eight percent were within+/-1.00 D of attempted correction and 84%, within +/-0.50 D. Stability within+/-0.50 D occurred after the first postoperative month. Vector analysis of eyes that had toric ablations demonstrated a difference vector within+/-1.00 D in 100% of eyes. The mean angle of error was-0.04+/- 6.37 degrees. Visually significant steep central islands associated with loss of best spectacle-corrected visual acuity was observed in 7.5% of eyes at 1 month. No eyes experienced significant glare or halos. CONCLUSIONS: The new large-zone (6.5 mm) photoablation technology with the VISX S2 Smoothscan resulted in effective reduction of simple myopia and compound myopic astigmatism. However, with the 6.5 mm zone, there may be an increased risk of developing symptomatic steep central islands in the early post-LASIK period compared with the standard 6.0 mm treatment zone.     

Visual performance after interface haemorrhage during laser in situ keratomileusis

AIM: To study the visual performance in eyes with interface haemorrhage during laser assisted in situ keratomileusis (LASIK). METHODS: Case records of 20 patients, who had bleeding from the limbal vessels in one eye during LASIK (group 1) and uncomplicated surgery in the fellow eye (group 2) were studied. The parameters evaluated were uncorrected visual acuity (UCVA) best corrected visual acuity (BCVA), spherical equivalent of refraction (SEQ), contrast sensitivity, and glare acuity preoperatively and at 1, 3, and 6 months postoperatively. RESULTS: The mean preoperative SEQ in group 1 and 2 eyes was -5.79 (2.3) D and -5.27 (1.68) D, respectively. The mean decimal UCVA at 6 months after LASIK in group 1 and 2 eyes were 0.6 (0.2) and 1.0 respectively (p<0.001). The mean decimal BCVA at 1 week after LASIK in group 1 and 2 eyes were 0.89 (0.04) and 1.0 respectively (p<0.05). However, all eyes had a BCVA of 6/6 at 1, 3, and 6 months after LASIK. The mean contrast sensitivity values preoperatively in group 1 and 2 eyes were 161.3 (8.7) and 172 (68.2) respectively. There was a significant decrease in group 1 at 6 months (102 (60.5) (p<0.01)) compared to group 2. The decimal glare acuity preoperatively in group 1 and 2 eyes was 0.95 (0.11) and 0.89 (0.12), respectively. It decreased significantly in group 1 (0.7) (0.1 (p<0.01)) compared to group 2 at the 6 month follow up. CONCLUSION: Occurrence of intraoperative interface haemorrhage may affect the visual performance following LASIK surgery.     

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.     

Laser-assisted subepithelial keratectomy for low to high myopia and astigmatism

PURPOSE: To evaluate the safety and efficacy of laser-assisted subepithelial keratectomy (LASEK) for the treatment of low to high myopia and astigmatism. SETTING: Solo private practice, Mountain View, California, USA. METHODS: Laser-assisted subepithelial keratectomy was performed in 146 eyes of 83 consecutive patients with myopia or myopic astigmatism using a VISX Star S2 excimer laser (72 eyes) or a Nidek EC-5000 excimer laser (74 eyes). The mean preoperative myopic spherical equivalent was -5.32 diopters (D) (range -1.25 to -14.38 D). Data were collected prospectively with a follow-up of 1 to 12 months. Outcome measurements included uncorrected visual acuity (UCVA), manifest refraction, best spectacle-corrected visual acuity (BSCVA), corneal haze, and complications. RESULTS: After 6 and 12 months, no eye lost 2 or more lines of BSCVA. After 6 months, the UCVA was 20/20 in 57% of eyes and 20/40 or better in 96%. After 12 months, it was 20/20 in 56% of eyes and 20/40 or better in 96%. No eye developed corneal haze that affected visual acuity. There were no serious or vision-threatening complications. CONCLUSIONS: Laser-assisted subepithelial keratectomy was safe and effective in treating a wide range of myopia and astigmatism. The potential advantages of LASEK over laser in situ keratomileusis (LASIK) include the elimination of stromal flap complications and greater choice in patient selection. The disadvantages include varying degrees of pain for 2 days and blurry vision for several days postoperatively.