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.     

Laser in situ keratomileusis versus laser-assisted subepithelial keratectomy for the correction of high myopia

PURPOSE: To compare the visual and refractive outcomes of laser in situ keratomileusis (LASIK) and laser-assisted subepithelial keratectomy (LASEK) in the treatment of high myopia. SETTING: Institute of Vision Research, Department of Ophthalmology, College of Medicine, Yonsei University, and Balgeunsesang Ophthalmology Clinic, Seoul, South Korea. METHODS: Four hundred seventy eyes of 240 patients with manifest refraction spherical components greater than -6.00 diopters (D) were assigned to 2 groups: 324 eyes (167 patients) were treated with LASIK and 146 eyes (73 patients), with LASEK. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), remaining refractive error, corneal haze, and complications were followed in both groups for 12 months. RESULTS: At 12 months, the mean spherical equivalent (SE) was within +/-0.50 D of emmetropia in 205 eyes (63.3%) in the LASIK group and 81 eyes (55.5%) in the LASEK group and within +/-1.00 D in 261 eyes (80.6%) and 104 eyes (71.2%), respectively. The UCVA was 20/25 or better in 269 LASIK eyes (83.0%) and 111 LASEK eyes (76.0%). There was more than a 1-line loss of BSCVA in 4 LASIK eyes (1.2%) and 21 LASEK eyes (14.3%). The between-group differences in SE, magnitude of cylinder, UCVA, and haze were statistically significant (P<.05). CONCLUSIONS: Both LASIK and LASEK were safe and effectively treated eyes with high myopia. Laser in situ keratomileusis provided superior results in visual predictability and corneal opacity.     

Laser in situ keratomileusis versus surface ablation: visual outcomes and complications

PURPOSE: To compare the visual outcomes and complications of laser in situ keratomileusis (LASIK) with those of surface treatment by laser-assisted subepithelial keratectomy (LASEK), photorefractive keratectomy with mechanical epithelial removal (M-PRK), and transepithelial photorefractive keratectomy (T-PRK). SETTING: Tertiary care eye center. METHODS: This retrospective review comprised all cases of LASIK, LASEK, M-PRK, and T-PRK performed at King Khaled Eye Specialist Hospital between July 1, 2004, and June 30, 2005. Separate statistical analyses were performed for eyes with low to moderate myopia (spherical equivalent [SE] less than -6.00 diopters [D]) and high myopia (SE -6.00 to -11.25 D). RESULTS: Of 696 eyes that met the inclusion criteria, 464 had LASIK, 104 had LASEK, 69 had M-PRK, and 59 had T-PRK. Eyes with low to moderate myopia had a statistically significantly smaller mean difference between logMAR final postoperative uncorrected visual acuity (UCVA) and preoperative best spectacle-corrected visual acuity (BSCVA) after T-PRK and M-PRK than after LASIK or LASEK. A higher percentage of eyes with high myopia had a final UCVA within +/-2 lines of the preoperative BSCVA with T-PRK than with LASIK, LASEK, or M-PRK. There were more major non-flap-related complications after LASEK than after LASIK, M-PRK, or T-PRK. CONCLUSIONS: In eyes with low to moderate myopia, T-PRK and M-PRK provided slightly better visual outcomes than LASIK or LASEK. In eyes with high myopia, T-PRK provided better visual outcomes than LASIK, LASEK, and M-PRK. Laser in situ keratomileusis was associated with the most major postoperative complications.     

非球面切削LASEK治疗薄角膜高度近视的临床疗效研究

目的 探讨角膜波前像差引导联合Q值优化的最优个性化角膜屈光矫正程序(ORK-CAM)引导的非球面切削准分子激光上皮下角膜磨镶术(LASEK)治疗角膜薄的高度近视临床疗效.方法 运用角膜波前像差引导联合Q值优化的ORK-CAM及小光斑高速飞点激光扫描系统对49例76只眼角膜薄的高度近视患者行LASEK.术后2周,1月,3及6月检查裸眼视力、验光、Haze等级.术后半年时复查角膜地形图、波前像差、视觉对比敏感度并进行满意度调查.结果 术前平均最佳眼镜矫正视力(BSCVA)为1.10+0.12,术后6月BUCVA(BUCVA)为1.12+0.17.术后平均模拟角膜记读数(SimK)等效值、慧差、球差、总体像差分别增加了-13.5%、93.87%、172.22%、23.81%、43.28%,较术前差异有统计学意义.角膜地形图形态有92.11%为同心圆型,视觉质量满意度为95.92%.结论 角膜波前像差引导的LASEK治疗角膜薄的高度近视,术后3个月以后平均视力稳定,且好于术前BCVA.术后6月时平均总波前像差增加百分比较小,球差增加较少,较好的保持了角膜的的非球面性.术后患者出现眩光、夜视力差的机率较低,具有较好的临床疗效.     

Laser-assisted subepithelial keratectomy for myopia: two-year follow-up

PURPOSE: To assess and compare the clinical results (efficacy, safety, stability, and postoperative pain or discomfort) of laser-assisted subepithelial keratectomy (LASEK) and conventional photorefractive keratectomy (PRK) for the correction of low to moderate myopia. SETTING: Department of Ophthalmology, Masaryk University Hospital, Brno, Czech Republic. METHODS: A prospective comparative study was performed in 184 eyes of 92 patients who had surface excimer ablation for the correction of myopia. The preoperative mean spherical equivalent (MSE) was -4.65 diopters (D) +/- 3.14 (SD) (range -1.75 to -7.50 D). In each patient, LASEK was performed in 1 eye and PRK in the fellow eye by the same surgeon. The first eye treated and the surgical method used in the first eye were randomized. Both procedures were performed with the Nidek EC-5000 excimer laser using the same parameters and nomogram. The postoperative pain level, visual recovery, complications (haze), uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and refractive outcome were evaluated and compared. All eyes completed a 24-month follow-up. RESULTS: The postoperative MSE was -0.18 +/- 0.53 D in the PRK eyes and -0.33 +/- 0.46 D in the LASEK eyes. At 1 week, the mean UCVA was 0.64 +/- 0.21 and 0.87 +/- 0.23, respectively. No LASEK eye lost a line of BSCVA. There were no statistically significant differences between PRK and LASEK eyes in the safety and efficacy indices at 2 years. The mean pain level was significantly lower on days 1 to 3 in the LASEK eyes (P <.05). The mean corneal haze level was lower in the LASEK eyes (0.21) than in the PRK eyes (0.43) (P <.05). Seventy-nine patients preferred LASEK to PRK. CONCLUSIONS: Laser-assisted subepithelial keratectomy provided significantly quicker visual recovery, eliminated post-PRK pain, and reduced the haze level in eyes with low to moderate myopia compared with conventional PRK. It provided good visual and refractive outcomes. There were no serious complications.     

Analysis of the efficacy, predictability, and safety of LASEK for myopia and myopic astigmatism using the Technolas 217 excimer laser

PURPOSE: To evaluate the efficacy, predictability, and safety of laser-assisted subepithelial keratectomy (LASEK) for the treatment of myopia and myopic astigmatism. SETTING: Stanford University Eye Laser Center, Stanford, California, USA. METHODS: This retrospective analysis comprised 102 eyes that had LASEK for myopia using the Bausch & Lomb Technolas 217 excimer laser. Primary outcome variables including uncorrected visual acuity (UCVA), best spectacle- corrected visual acuity (BSCVA), manifest refraction, and complications were evaluated at 3, 6, and 12 months. Vector analysis was performed on eyes that received astigmatic correction. RESULTS: The mean spherical equivalent was -7.03 diopters (D) +/- 2.61 (SD) preoperatively, +0.19 +/- 0.64 D at 3 months, +0.23 +/- 0.82 D at 6 months, and +0.03 +/- 0.63 D at 12 months (P<.001). At 3, 6, and 12 months, the UCVA was 20/20 or better in 66%, 67%, and 83% of eyes, respectively, and 20/40 or better in 98%, 99%, and 100%; 74%, 70%, and 83%, respectively, were within +/-0.5 D of emmetropia, and 89%, 86%, and 97%, respectively, were within +/-1.0 D. No eye lost more than 2 lines of BSCVA. At 3, 6, and 12 months, 10.0%, 8.7%, and 0% of eyes, respectively, had trace corneal haze. Vector analysis found a success rate of approximately 78% to 80% in achieving the astigmatic surgical correction at the 3 postoperative visits. CONCLUSIONS: Laser-assisted subepithelial keratectomy was an effective, predictable, and safe procedure for the treatment of myopia and myopic astigmatism. Further studies are needed to determine the role of LASEK in the refractive surgery spectrum.     

Safety, efficacy, and stability indices of LASEK correction in moderate myopia and astigmatism

PURPOSE: To evaluate the visual outcomes and complications in low to moderate levels of myopia and astigmatism treated with laser-assisted subepithelial keratectomy (LASEK) with a focus on postoperative recovery. SETTING: Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA. METHODS: A retrospective analysis of a case series of eyes treated with LASEK from 1996 to July 2002 with a follow-up of 2 years was performed. The LASEK technique involved creating an epithelial flap with 25 to 45 seconds of exposure to 20% alcohol, ablating the corneal surface using 3 different excimer lasers and nomogram adjustment, and repositioning the flap and applying a bandage contact lens. The main outcome measures were uncorrected visual acuity (UCVA), efficacy index, manifest refraction, best spectacle-corrected visual acuity (BSCVA), safety index, retreatment rate, and complications. RESULTS: One hundred seventy-one eyes (85 right eyes and 86 left eyes) of 105 patients were studied. Preoperatively, the mean spherical equivalent was -2.99 diopters (D) +/- 1.43 (SD) (range -0.38 to -7.75 D) and the mean cylinder, -0.78 +/- 0.73 D. The UCVA ranged from 20/800 to 20/32, and the BSCVA ranged from 20/63 to 20/16; the median was 20/20. One week postoperatively, 96% of eyes had a UCVA of 20/40 or better but definitive visual recovery took more than 4 weeks in some eyes. Approximately 95% of eyes were within +/-1.0 D of emmetropia after 4 to 52 weeks; the remaining 5% did not show major deviations. At 4 to 52 weeks, only 1 eye was overcorrected by more than 1.0 D of manifest refraction. The safety index remained close to 1.0 for the follow-up after 4 weeks. The efficacy index displayed a plateau at 0.9 from 1 month to 1 year. No serious complication (including recurrent erosion syndrome) was encountered. The mean follow-up was 31 weeks, and the retreatment rate was 2.9% up to 2 years of follow-up. CONCLUSIONS: The long-term safety and effectiveness of LASEK for the correction of low to moderate myopia and astigmatism were demonstrated. The treatment effect stabilized after 4 weeks.     

Learning curve of laser-assisted subepithelial keratectomy: influence on visual and refractive results

PURPOSE: To study the effect of the learning curve of laser-assisted subepithelial keratectomy (LASEK) on the visual and refractive results. METHODS: This retrospective study comprised 56 eyes that had LASEK for myopia. The eyes were among the first 143 that had LASEK by the same surgeon with the same excimer laser and same nomogram. The 56 eyes were separated into 2 groups. Group 1 included the first 28 eyes to have LASEK by the surgeon. Group 2 comprised the last 28 eyes in the series whose refractive error could be matched with that in Group 1. The outcomes in the 2 groups were compared. RESULTS: The mean preoperative spherical refraction was -3.90 diopters (D) +/- 1.90 (SD) in Group 1 and -3.70 +/- 2.53 D in Group 2 (P = .2). There were no significant differences in preoperative cylinder or best spectacle-corrected visual acuity (BSCVA) between groups. The postoperative uncorrected visual acuity (UCVA) was significantly worse in Group 1 on 1 day and 7 days postoperatively (P = .02 and P = .03, respectively); there was no significant difference at 1 month and 3 months. The safety index (postoperative BSCVA/preoperative BSCVA) and efficacy index (postoperative UCVA/preoperative BSCVA) were better in Group 2, although the difference was not statistically significant. The spherical refraction 3 months postoperatively was +0.50 +/- 0.83 D in Group 1 and +0.10 +/- 0.27 D in Group 2 (P = .02); 75.00% of eyes and 96.42% of eyes, respectively, were within +/-0.50 D of the intended correction (P = .01). Seven percent of eyes in Group 1 and no eye in Group 2 lost 2 or more lines of BSCVA. CONCLUSIONS: Results indicate that the outcomes of LASEK depend on surgeon experience. Thus, caution is advised when interpreting LASEK results without knowing the surgeon's level of experience.     

Effect of amniotic membrane after laser-assisted subepithelial keratectomy on epithelial healing: clinical and refractive outcomes

PURPOSE: To evaluate the effect of an amniotic membrane (AM) on reepithelialization time, corneal haze, and postoperative visual and refractive outcomes after laser-assisted subepithelial keratectomy (LASEK) for myopia and myopic astigmatism. SETTING: Department of Ophthalmology, Yonsei University College of Medicine, and Balgeunsesang Ophthalmology Clinic, Seoul, Korea. METHODS: One hundred fifty-two eyes of 84 patients with myopia or myopic astigmatism were prospectively evaluated for 6 months after LASEK. An AM was placed as a strip on the inferior limbus in 94 eyes of 54 patients after LASEK; 58 eyes of 30 patients served as the control group. Postoperative epithelial healing time, uncorrected visual acuity (UCVA), best corrected visual acuity, remaining refractive error, and corneal haze were examined. RESULTS: The reepithelialization time was shorter in the AM group (2.40 days +/- 0.94 [SD]) than in the control group (3.90 +/- 0.97 days) (P<.001). At 6 months, 86 eyes (91.5%) in the AM group had a UCVA of 20/25 or better and 90 eyes (95.7%) had a UCVA of 20/40 or better; 48 eyes (82.8%) and 53 eyes (91.4%) in the control group had a UCVA of 20/25 or better and 20/40 or better, respectively. The mean spherical equivalent in the AM group was -0.48 +/- 0.54 diopter (D) and in the control group, -0.94 +/- 0.60 D (P<.001). The corneal haze was significantly less in the AM group than in the control group (P<.001). CONCLUSION: Amniotic membrane use after LASEK induced rapid epithelial healing with more favorable visual and refractive outcomes and lower corneal haze scores than conventional LASEK.     

MEL-80治疗近视的准分子激光上皮下角膜磨镶术效果评价

目的评价使用蔡司MEL-80准分子激光治疗仪施行准分子激光上皮下角膜磨镶术（1aser-assisted subepithe-lial keratomileusis，LASEK）治疗近视和近视散光的预测性、有效性、安全性和稳定性。方法回顾性分析使用MEL-80准分子激光治疗系统行LASEK治疗近视和近视散光的连续性病例76例（150眼），于术后第1天、第1、第3、第6和第12个月定期随访，检查裸眼视力，以显然主觉验光检查术后屈光状态及最佳矫正视力。结果术后第10天、第1、第3、第6和第12个月时，裸眼视力平均值分别为4．91±0．15、4．97±0．26、5．05±0．37、5．12±0、20、4．96±0．24。预测性：术前屈光度等效球镜值为（-6．25±1．25）D，术后第3、第6和第12个月分别降到（＋0．12±0．42）D、（-0．03±0．23）D、（-0．15±0．36）D，术后第3、第6和第12个月屈光度变化量在＋0．50D以内的比例分别为94．6％、96．0％、97．3％。术后第3、第6和第12个月离焦等效球镜值在±0．50D内的眼数分别为88．0％、96．0％、96．6％。有效性：术后第3个月，24．0％的眼裸眼视力（uncor-rected visual acuity,UCVA）≥5．1，94．6％的眼UCVA≥5．0，97.3％的眼UCVA≥4．9。术后第6个月，36．0％的眼UCVA≥5．1．96．0％的眼UCVA≥5．0，98．6％的眼UCVA≥4．9。术后第12个月，38．0％的眼UCVA≥5．1，98．0％的眼UCVA≥5．0，98．6％的眼UCVA≥4．9。安全性：术后第3、第6、第12个月，均无任何一眼最佳矫正视力（best spectacle corrected vision acuity，BSCVA）下降2行以上；分别有34．6％、34．6％和30．0％的眼BSCVA提高1行；16．0％、17．3％和14．6％的眼BSCVA提高2行。稳定性：术后第3、第6、第12个月显然验光值等效球镜平均值变化小于1．00D。结论使用MEL-80的LASEK治疗近视和近视散光有良好的预测性、有效性、安全性和稳定性。     

Photorefractive keratectomy for myopia with a 15 Hz repetition rate

PURPOSE: To evaluate excimer laser photorefractive keratectomy (PRK) for myopia using a repetition rate of 15 Hz instead of 10 Hz. SETTING: The Cornea and Laser Eye Institute, Teaneck, and Department of Ophthalmology, UMDNJ-New Jersey Medical School, Newark, New Jersey, USA. METHODS: Photorefractive keratectomy using a 15 Hz repetition rate was performed in 23 eyes of 14 patients by a single surgeon at 1 center. The attempted corrections ranged from -2.8 diopters (D) to -5.5 D. Preoperative and postoperative uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), predictability, corneal haze, and subjective glare/halo were evaluated over 6 months. RESULTS: At 6 months, UCVA was 20/32 or better in all eyes and at least 20/20 in 14 eyes (73.7%). Two eyes (10.5%) lost 2 or more Snellen lines of BSCVA; postoperative BSCVA was at least 20/25 in 100% of eyes and 20/20 or better in 95.0%. Fifteen eyes (78.9%) were within +/-0.5 D of attempted correction, and 19 (100%) were within +/-1.0 D. Mean spherical equivalent refraction was -4.62 D preoperatively, +0.15 D at 1 month, -0.09 D at 3 months, and -0.37 D at 6 months. At 6 months, 4 eyes (21.0%) had no corneal haze and 14 (73.7%) had trace subepithelial haze. Fifteen eyes (78.9%) had no glare/halo effect at 6 months, and 4 (21.0%) had minimal glare/halo effect. CONCLUSIONS: Clinical outcomes after excimer laser PRK for myopia using an increased repetition rate of 15 Hz were good and similar to those in studies conducted with a 10 Hz repetition rate.     

Laser-assisted subepithelial keratectomy versus photorefractive keratectomy for the correction of myopia. A prospective comparative study

PURPOSE: To compare the early postoperative visual rehabilitation after laser-assisted subepithelial keratectomy (LASEK) and photorefractive keratectomy (PRK) for the correction of myopia. SETTING: CODET Aris Vision Institute, Tijuana, Mexico. METHODS: This prospective study included 50 eyes of 25 patients with myopia who received LASEK in 1 eye and PRK in the contralateral eye. Excimer laser corneal ablation was done using the Nidek EC-5000 excimer laser. Patients were seen at 1 and 3 days, 1 week, and 1 month. Discomfort, subjective uncorrected visual acuity (UCVA), objective UCVA, best corrected visual acuity (BCVA), corneal clarity (haze), and time for corneal reepithelialization were analyzed. RESULTS: Seventy-two percent and 80% of the LASEK eyes had more discomfort at 1 day and 3 days, respectively. Eighty percent and 96% of the PRK eyes had better subjective UCVA at 1 day and 3 days, respectively. Corneas were fully reepithelialized at a mean of 3.3 days +/- 0.5 (SD) and 3.6 +/- 0.5 days in the PRK and LASEK groups, respectively. At 1 month, the UCVA was similar in both groups; no eye had lost lines of BCVA or developed haze. CONCLUSIONS: Both LASEK and PRK were effective and safe procedures in the surgical correction of myopia at the 1-month postoperative visit. Patients reported less discomfort and better visual acuity in their PRK eye during the early postoperative period. Patients should be informed that LASEK, whose acronym is similar to that of laser in situ keratomileusis, has a recovery speed that is similar to that of surface laser refractive procedures such as PRK.     

LASEK治疗中高度近视疗效分析

目的:观察准分子激光上皮瓣下角膜磨镶术(LASEK)治疗中高度近视的临床效果。方法:对46例85眼中度以上近视进行LASEK矫正,根据等效球镜度分为I组(-3.25～-6.00)D、II组(-6.25～-10.00)D、III组(-10.25～-12.9)D。观察术后裸眼视力和最佳矫正视力、显然屈光度、眼压及haze情况。术后随访6mo以上。结果:术后6mo时裸眼视力达到术前最佳矫正视力或更好者3组分别为100%,78%,75%,裸眼视力≥0.5分别为100%,96%,88%,未见最佳矫正视力较术前最佳矫正视力低于2行以上的眼;3组的屈光度稳定在±1.00D内者分别为68.4%,58.0%,43.7%;3组的平均屈光度分别为(-0.38±0.66)D、(-0.77±1.25)D、(-1.25±1.97)D。II组和III组术后发生不同程度的haze(≤2级)。结论:LASEK治疗中高度近视安全有效。haze和屈光回退是治疗高度和超高度近视主要并发症,从某种角度说,控制了haze的发生也就在很大程度上控制了术后的屈光回退的速率。     

Laser-assisted subepithelial keratectomy enhancement of residual myopia after primary myopic LASEK: six-month results in 10 eyes

PURPOSE: To determine whether residual myopia after primary laser-assisted subepithelial keratectomy (LASEK) can be corrected by repeated LASEK and whether this procedure is safe and effective. SETTING: University Eye Clinic, University of Regensburg, Regensburg, Germany. METHODS: Laser-assisted subepithelial keratectomy was performed in 10 eyes that had had primary LASEK for myopia. The initial mean spherical equivalent (SE) was -6.2 diopters (D) (range -2.5 to -8.0 D), and the residual mean SE was -1.6 D (range -1.0 to -3.0 D). The retreatment ratio was 7.6%. The exposure time of the corneal epithelium to alcohol (20% ethanol) was 30 seconds plus an additional 10 to 15 seconds in cases of strong epithelial adherence. Laser ablation was performed with a Keracor 117 excimer laser (Chiron Technolas). The follow-up after the second LASEK treatment was 6 months. RESULTS: The epithelial flap for repeated LASEK was successfully created in all 10 eyes. The postoperative course in the eyes was uneventful. Six months after LASEK enhancement, the SE refraction was within +/-0.5 D in all eyes. No eye lost more than 1 line of best corrected visual acuity, and the uncorrected visual acuity was 20/20 or better in 8 eyes. Significant haze was not observed after repeated LASEK (mean 0.35 before and 6 months after LASEK enhancement). CONCLUSIONS: Laser-assisted subepithelial keratectomy enhancement appears to be safe and effective for the correction of residual myopia after primary LASEK. Repeated epithelial flap preparation is possible without technical modifications.     

Prophylactic mitomycin C to inhibit corneal haze after photorefractive keratectomy for residual myopia following radial keratotomy

PURPOSE: To evaluate the efficacy and safety of mitomycin C (MMC) 0.02% in inhibiting haze formation after excimer laser photorefractive keratectomy (PRK) for residual myopia following radial keratotomy (RK). METHODS: A prospective, nonrandomized, noncomparative interventional case series was conducted of 22 eyes (14 patients) with residual myopia after RK performed at a single institution. All eyes were treated with PRK and a single intraoperative topical application of MMC 0.02% solution for 2 minutes using a soaked cellulose sponge placed over the ablated area. Refraction, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and slit-lamp evidence of cotneal opacity (haze) were evaluated over 12 months. RESULTS: Twelve months postoperatively, 3 eyes showed grade 1 haze, and 2 eyes showed grade 0.5 haze. Twelve months postoperatively, 2 (9%) eyes had UCVA > or = 20/20. No eye before and 17 (77%) eyes after treatment had UCVA > or = 20/40, and no eye before and 9 eyes (40.9%) after treatment had UCVA > or = 20/25. Best spectacle-corrected visual acuity was > or = 20/40 in all (100%) eyes and 21 (95%) eyes before and after treatment, respectively, and > or = 20/25 in 12 (54.5%) eyes before and after treatment. One (4.5%) eye lost 1 line of BSCVA. Mean spherical equivalent refraction achieved was -0.18 diopters (D) (range: -0.75 to +0.50 D) compared to -2.72 D (range: -1.50 to -4.00 D) before treatment. Twelve months after treatment, 19 (85.5%) eyes had a refractive outcome within +/- 0.50 D. CONCLUSIONS: A single intraoperative application of MMC 0.02% for 2 minutes appears to be effective in preventing subepithelial haze after PRK for residual myopia in patients with undercorrection or regression following RK.     

Effectiveness of laser-assisted subepithelial keratectomy without mitomycin-C for the treatment of high myopia

PURPOSE: To evaluate the effectiveness and therapeutic range of laser-assisted subepithelial keratectomy (LASEK) without mitomycin-C (MMC) to treat high myopia. SETTING: Isik Eye Clinic, Ankara, Turkey. METHODS: This study comprised 31 highly myopic eyes (19 patients) that had LASEK. Before primary LASEK treatment and 1, 3, 6, 12, and 24 months after, all patients had a complete ophthalmic examination including visual acuity, refractive outcomes, and biomicroscopy. RESULTS: The mean spherical equivalent (SE) was -9.01 diopters (D) +/- 2.66 (SD) preoperatively and -1.00 +/- 1.15 D at the end of follow-up. At 24 months, the mean SE was within +/-1.00 D of the intended correction in 23 eyes (74.19%). The median uncorrected visual acuity (UCVA) increased from 20/606 preoperatively to 20/28.6 at 24 months and the median best corrected visual acuity, from 20/25 to 20/22, respectively. Total higher-order and spherical aberrations increased significantly at the end of follow-up. All 14 eyes that had ablations greater than -8.62 D developed varying degrees of haze. Significant myopic regression (>1.00 D) leading to UCVA loss occurred in all eyes with a preoperative SE of -12.00 D or greater. CONCLUSIONS: The results of LASEK without MMC were excellent in eyes with up to -8.6 D of SE. All eyes with a preoperative SE between -8.6 and -12.0 D developed haze but had acceptable refractive and visual outcomes. Haze and myopic regression limited the success of LASEK in eyes with a preoperative SE of -12.0 D and greater.     

Photorefractive keratectomy for myopia with the Meditec MEL 70G-Scan flying spot laser

PURPOSE: To evaluate the efficacy, predictability, stability, and safety of the Meditec MEL 70G-Scan flying spot excimer laser. METHODS: One hundred thirty myopic eyes were treated with the Aesculap Meditec Mel 70G-Scan ArF flying spot excimer laser with photorefractive keratectomy (PRK). Patient groups: low myopia (Group 1) from -1.50 to -6.00 D (90 eyes), medium myopia (Group 2) from -6.10 to -9.00 D (31 eyes), high myopia (Group 3) from -9.10 to -14.00 D (9 eyes). RESULTS: At 12 months in the low myopia group, uncorrected visual acuity (UCVA) of 20/40 or better was achieved in 95.5% (86 eyes), 20/20 or better in 77.7% (70 eyes); 2.2% (two eyes) lost two or more lines of best spectacle-corrected visual acuity (BSCVA); 73.3% (66 eyes) were within +/-0.50 D of the target correction and 98.8% (89 eyes) were within +/-1.00 D. In the medium myopia group, UCVA of 20/40 or better was achieved in 74.2% (23 eyes), 20/20 or better in 25.8% (eight eyes); 3.2% (one eye) lost two lines, 61% (19 eyes) were within +/-0.50 D of desired correction and 83.8% (26 eyes) were within +/-1.00 D. In the high myopia group, UCVA of 20/40 or better was achieved in 22.2% (two eyes); 20/25 or better in 11.1% (one eye); none of the eyes achieved 20/20 UCVA; 22.2% (two eyes) lost two lines of BSCVA; 44.4% (four eyes) were within +/-0.50 D and 66.6% (six eyes) were within +/-1.00 D of the target correction. Refractive stability was achieved between 3 and 6 months. Increased intraocular pressure was detected overall in 7.69%. CONCLUSIONS: The results of predictability, safety, and efficacy in low and medium myopia with the Meditec MEL 70G-Scan flying spot excimer laser were good, but poorer predictability, regression, and a significant loss of BSCVA were observed in the high myopia group.     

Comparison between LASEK with mitomycin C and LASIK for the correction of myopia of -7.00 to -13.75 D

PURPOSE: To compare laser epithelial keratomileusis (LASEK) and LASIK for the correction of high myopia. METHODS: A prospective, single-masked study was conducted. Patients treated with LASEK to correct myopia > or = -7.00 diopters (D) (spherical equivalent manifest refraction) with a cylinder < or = -3.50 D (LASEK group) were compared to patients treated with LASIK (LASIK group) using the same excimer laser (Technolas 217C). Mitomycin C (MMC) 0.02% was applied for 1 minute in all LASEK-treated eyes. RESULTS: A total of 228 consecutive eyes were included in the study (114 in each group, matched for preoperative refraction). The mean preoperative spherical equivalent manifest refraction was -8.72 +/- 1.20 D in the LASEK group and -8.74 +/- 1.20 D in the LASIK group (range: -7.00 to -13.75 D) (P = .9). Uncorrected visual acuity (UCVA) was significantly lower in LASEK eyes 1, 7, and 30 days postoperatively (P = .0001 for each comparison). No significant differences were found at 3 months postoperatively in UCVA (P = .3), best spectacle-corrected visual acuity (BSCVA) (P = .2), or in the safety (P = .6) and efficacy (P = .8) indices. Uncorrected visual acuity was 1.0 or better in 34.2% of LASEK eyes and 44.7% of LASIK eyes. Spherical refraction was +0.25 +/- 0.6 D after LASEK and -0.06 +/- 0.5 D after LASIK (P = .0001). Sixty-eight percent of LASEK eyes and 79% of LASIK eyes were within +/- 0.50 D of intended refraction. No LASEK eye versus 7 LASIK eyes lost 2 lines of BSCVA. Eight LASEK eyes gained 2 or more lines of BSCVA versus 1 LASIK eye. CONCLUSIONS: Visual improvement after LASEK with intraoperative MMC was significantly slower than after LASIK. Visual outcomes (UCVA, BSCVA, and safety and efficacy indices) 3 months after surgery were similar with both techniques for the correction of high myopia. Ten percent more eyes after LASIK were within +/- 0.50 D of intended refraction.     

Laser in situ keratomileusis for myopia up to -11 diopters with up to -5 diopters of astigmatism with the summit autonomous LADARVision excimer laser system

OBJECTIVE: To assess the safety and effectiveness of the Summit Autonomous LADARVision active tracking narrow beam excimer laser system for laser in situ keratomileusis (LASIK) correction of myopia and astigmatism. DESIGN: A multicenter, prospective noncomparative case series. PARTICIPANTS: This cohort consisted of 177 eyes corrected for spherical myopia up to -11 diopters (D) and 170 eyes corrected for myopia up to -11 D spherical equivalent with astigmatism up to -5 D. INTERVENTION: Treatments were performed at four sites in the United States using a 6-mm optic zone for spherical myopes and a 5.5-mm optic zone with a 1-mm blend for astigmats. MAIN OUTCOME MEASURES: Visual acuity, subjective refraction, vector analysis, subject satisfaction, intraocular pressure, complications, and adverse reactions. RESULTS: Six-month follow-up was available on 157 spherical eyes and 113 astigmatic eyes. For spherical myopes, uncorrected visual acuity (UCVA) was 20/20 or better in 60.5%, 20/25 or better in 80.3%, and 20/40 or better in 93.9%. The mean spherical equivalent was -0.29 +/- 0.45 D with 75.2% +/- 0.50 D and 94.9% +/- 1.00 D of intended. A loss of two lines of best spectacle-corrected visual acuity (BSCVA) occurred in 0.6%, and no eyes lost greater than two lines of BSCVA. For astigmatic myopes, UCVA was 20/20 or better in 52.0%, 20/25 or better in 74.5%, and 20/40 or better in 94.1%. The mean spherical equivalent was -0.23 +/- 0.49 D with 75.2% +/- 0.50 D and 95.6% +/- 1.00 D of intended. A loss of two lines of BSCVA occurred in 0.9%, and no eyes lost greater than two lines of BSCVA. Vector analysis showed that 99% of the intended cylinder was corrected on average with a mean angle of error of 4.2 degrees. Refractive stability was achieved between 1 and 3 months in 97.5% of spherical eyes and 99.4% of astigmatic eyes and confirmed between 3 and 6 months in 100% of both spherical and astigmatic eyes. CONCLUSIONS: Eyes treated for myopia up to -11 D of spherical equivalent with or without astigmatism up to -5 D show early refractive stability, good UCVA outcomes, no significant loss of BSCVA, accurate correction of astigmatism, and slight undercorrection without a change from the photorefractive keratectomy algorithm and with a single treatment.     

Phototherapeutic keratectomy with mitomycin C for corneal haze following photorefractive keratectomy for myopia

PURPOSE: To evaluate the safety and efficacy of phototherapeutic keratectomy (PTK) with single application of mitomycin C for patients with severe corneal haze following photorefractive keratectomy (PRK) for high myopia. METHODS: Eight eyes of seven patients were treated with PTK and intraoperative topical application of mitomycin C (0.02%) for severe corneal haze (grade 3) following PRK for myopia. RESULTS: All patients' visual performance improved significantly. Mean preoperative visual acuity (20/200 for both UCVA and BSCVA) improved significantly to 20/33 (0.6) and 20/30 (0.7) for UCVA and BSCVA, respectively. Six eyes (85.7%) had improved UCVA to 20/40 or better and gained five or more lines of UCVA. The corneal haze score decreased from grade 3 initially (for all eyes prior to PTK and mitomycin C) to a final mean haze score of 0.3 (range 0 to 0.5). Mean final spherical equivalent refraction achieved was -1.30 +/- 1.60 D (range -3.75 to +1.25 D). One eye gained only three lines of visual acuity due to regression and residual haze. No adverse effects related to the use of mitomycin C were recorded. CONCLUSION: PTK with a single intraoperative application of mitomycin C was safe and effective in reducing corneal haze and improving visual acuity in patients with severe corneal haze following PRK.