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.     

Comparison of laser epithelial keratomileusis and photorefractive keratectomy for low to moderate myopia

PURPOSE: To compare the effectiveness, safety, and stability of laser epithelial keratomileusis (LASEK), a modified photorefractive keratectomy (PRK) technique, with those of conventional PRK for low to moderate myopia. SETTING: Department of Ophthalmology, Yonsei University School of Medicine, Seoul, Korea. METHODS: In this prospective study, 27 patients with a manifest refraction of -3.00 to -6.50 diopters were treated and followed for 3 months. In each case, PRK was performed in 1 eye and LASEK in the other eye. The first eye treated and the surgical method used in the first eye were randomized. Postoperative pain, epithelial healing time, uncorrected visual acuity (UCVA), manifest refraction, corneal haze, and surgical preference were examined in PRK- and LASEK-treated eyes. RESULTS: During the 3 month follow-up, there were no significant between-eye differences in epithelial healing time, UCVA, or refractive error. However, LASEK-treated eyes had lower postoperative pain scores (P =.047) and corneal haze scores (1 month; P =.02) than PRK-treated eyes. Seventeen patients (63%) preferred the LASEK procedure. CONCLUSIONS: Laser epithelial keratomileusis safely and effectively treated eyes with low to moderate myopia. It reduced the incidence of significant postoperative pain and corneal haze and may prevent the flap- and interface-related problems of laser in situ keratomileusis.     

准分子激光角膜上皮瓣下磨镶术与准分子激光屈光性角膜切削术治疗近视的比较

目的　研究准分子激光角膜上皮瓣下磨镶术 (LASEK)与准分子激光屈光性角膜切削术(PRK)在治疗 - 8 0 0D以下近视的异同。方法　 4 6例近视度数在 - 1 75～ - 8 0 0D的患者在双眼同时治疗时 ,其中一只眼行PRK治疗 ,另一只眼行LASEK治疗 ,观察上皮愈合时间 ,记载疼痛程度 ,对比术后 6个月内视力、屈光状态及角膜上皮下雾状混浊 (Haze)程度。结果　LASEK组上皮愈合时间平均为 3 4 9d ,PRK组为 2 87d ,两者差异有显著意义 (P <0 0 5 ) ;平均疼痛指数LASEK组为 2 0 4 ,PRK组为 2 4 5 ,差异有显著意义 (P <0 0 5 ) ;术后 6个月内两组间视力及屈光度恢复的差异无显著意义 (P>0 0 5 ) ,并发症的发生无差异。LASEK组术后Haze程度明显低于PRK组 (P <0 0 5 )。结论　LASEK可以和PRK一样安全有效地治疗低于 - 8 0 0D的近视 ,并且与PRK相比 ,可以降低早期疼痛水平 ,减少Haze并发症的发生。     

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.     

Epithelial healing and clinical outcomes in excimer laser photorefractive surgery following three epithelial removal techniques: mechanical, alcohol, and excimer laser

PURPOSE: To evaluate epithelial healing, postoperative pain, and visual and refractive outcomes after photorefractive keratectomy (PRK) using three epithelial removal techniques. DESIGN: Prospective, nonrandomized, comparative trial. METHODS: SETTING: Department of Ophthalmology, Yonsei University College of Medicine and Balgensesang Ophthalmology Clinic, Seoul, Korea. INTERVENTIONS: For the PRK procedure, the corneal epithelium was removed in one of three ways: mechanically (conventional PRK [PRK]) in 88 eyes of 44 patients; using excimer laser (transepithelial PRK [tPRK]) in 106 eyes of 53 patients; or using 20% diluted alcohol, laser-assisted subepithelial keratomileusis (LASEK) in 106 eyes of 53 patients. MAIN OUTCOME MEASURES: Epithelial healing, postoperative pain, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and remaining refractive error. RESULTS: The mean postoperative pain scores were 4.84 +/- 1.45 for PRK, 4.71 +/- 1.62 for tPRK, and 4.63 +/- 1.52 for LASEK (P = .125). The mean epithelial healing rates were 12.3 +/- 4.6 for PRK, 15.2 +/- 4.9 for tPRK, and 18.1 +/- 5.2 mm2/day for LASEK (P < .001). The postoperative 6-month remaining mean spherical equivalents (diopters) were -0.46 +/- 1.01 for PRK, 0.18 +/- 0.91 for tPRK, and -0.82 +/- 1.18 for LASEK (P = .01). The LASEK group showed less favorable UCVA than other groups. There was no significant difference in BSCVA between the groups. CONCLUSIONS: Postoperative pain, subepithelial opacity and BSCVA were similar regardless of the epithelial removal procedure. A faster epithelial healing rate did not result in better visual or refractive outcomes. Using the same nomogram, tPRK resulted in a slight overcorrection, and LASEK resulted in a slight undercorrection.     

Photorefractive keratectomy retreatment after LASIK

PURPOSE: To study the results of late photorefractive keratectomy (PRK) in corneas originally subjected to LASIK. METHODS: Seven eyes of seven patients who had LASIK for myopia were retreated with PRK at least 2 years after LASIK. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, and haze were evaluated before and after LASIK and after retreatment by PRK. RESULTS: Photorefractive keratectomy retreatment improved BSCVA in six (86%) of seven eyes, and one (14%) eye showed no changes. None of the eyes lost lines of BSCVA. Five of seven eyes developed mild haze, which disappeared before the last postoperative follow-up. CONCLUSIONS: Photorefractive keratectomy retreatment performed at least 2 years after LASIK can improve visual acuity. We hypothesize that LASIK-induced corneal nerve damage disturbs corneal wound healing by increasing the tendency for development of haze.     

LASEK与PRK矫正近视及近视散光的疗效比较

目的 比较LASEK与PRK手术矫正不同程度近视及近视散光的有效性、安全性及稳定性。方法 70名患者(140眼)，分为中低度近视组39人(78眼)、高度近视组31人(62眼)。患者一眼行LASEK手术，对侧眼行PRK手术，术后观察术眼疼痛情况、上皮愈合时问、角膜上皮下雾状混浊(haze)、术后裸眼视力6个月。结果LASEK与PRK术后上皮愈合时间及术眼疼痛指数无明显差异；中低度近视组两种手术后裸眼视力无显著差异；高度近视组裸眼视力及角膜haze程度差异显著。结论 LASEK矫正不同程度近视均能取得较好的临床效果，术后裸眼视力及视力稳定程度优于PRK，特别表现在高度近视组。     

Photorefractive keratectomy for post-penetrating keratoplasty myopia and astigmatism

PURPOSE: To determine the safety, effectiveness, and predictability of photorefractive keratectomy (PRK) for the correction of myopia and astigmatism after penetrating keratoplasty. SETTING: Gazi University, Medical School, Department of Ophthalmology, Ankara, Turkey. METHODS: Photorefractive keratectomy was performed in 16 eyes of 16 patients with postkeratoplasty myopia and astigmatism who were unable to wear glasses due to anisometropia and were contact lens intolerant. They were examined for uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and corneal transplant integrity before and after surgery. RESULTS: The mean follow-up after PRK was 26.0 months +/- 15.7 (SD) (range 12 to 63 months). The mean preoperative spherical equivalent refraction of -4.47 +/- 1.39 diopters (D) was -3.39 +/- 1.84 D (P >.05) at the last postoperative visit and the mean preoperative cylinder of -5.62 +/- 2.88 D was -3.23 +/- 1.70 D (P <.05); refractive regression correlated with the amount of ablation performed. The BSCVA decreased in 3 eyes (18.8%), and the UCVA decreased in 2 (12.5%). Six eyes (37.5%) had grade 2 to 3 haze, which resolved spontaneously in 4 eyes within a relatively long time but caused a decrease in BSCVA in 2 (12.5%). Two of the eyes (12.5%) had a rejection episode after PRK and were successfully treated with topical steroids. CONCLUSIONS: Photorefractive keratectomy to correct postkeratoplasty myopia and astigmatism appears to be less effective and less predictable than PRK for naturally occurring myopia and astigmatism. Corneal haze and refractive regression are more prevalent, and patient satisfaction is not good.     

Laser-assisted subepithelial keratectomy and photorefractive keratectomy for the correction of hyperopia. Results of a 2-year follow-up

PURPOSE: To evaluate and compare the efficacy, safety, predictability, and stability of laser-assisted subepithelial keratectomy (LASEK) and photorefractive keratectomy (PRK) for low to moderate hyperopia with a 2-year follow-up. SETTING: Department of Ophthalmology, Masaryk University Hospital, Brno, Czech Republic. METHODS: This prospective comparative single-surgeon study included 216 eyes of 108 patients with hyperopia who received PRK in 1 eye and LASEK in the contralateral eye. The mean patient age was 38.3 years (range 25 to 58 years). The mean preoperative spherical equivalent (SE) cycloplegic refraction was +3.67 diopters (D) +/- 1.15 (SD) (range +2.00 to +5.00 D), and astigmatism was less than 1.00 D. In each patient, PRK was performed in 1 eye (Group A) and LASEK was performed in the other eye (Group B) using the Nidek EC-5000 excimer laser. Postoperative uncorrected visual acuity (UCVA), best corrected visual acuity, contrast sensitivity, manifest and cycloplegic refractions, refractive stability and predictability, postoperative pain, and corneal haze were examined and statistically analyzed. A P value less than 0.05 was considered significant. RESULTS: At 1 week, the UCVA was 20/40 or better in 58% of PRK eyes and 85% of LASEK eyes (P =.037); at 2 years, it was 20/40 or better in 81% and 91%, respectively (P =.076). At 2 years, the UCVA for near was N8 or better in 73% of PRK eyes and 89% of LASEK eyes (P =.064). No patient lost 2 or more lines of Snellen visual acuity. The safety index was 1.03 in PRK eyes and 1.08 in LASEK eyes. Refractive stability was achieved at 6 months in LASEK eyes and at 12 months in PRK eyes. The mean SE cycloplegic refraction decreased from +3.58 D (PRK eyes) and +3.76 D (LASEK eyes) at baseline to +0.74 D and +0.32 D, respectively, at 2 years; in 57% and 78% of eyes, respectively, the refraction was within +/-0.50 D of the targeted refraction. Peripheral corneal haze scores at 3 to 9 months and pain scores at 1 to 3 days were significantly lower in the LASEK group than in the PRK group. CONCLUSIONS: Laser-assisted subepithelial keratectomy for hyperopia up to +5.00 D provided good visual and refractive results. It significantly reduced postoperative pain, grade of peripheral ring-shaped corneal haze, and regression of hyperopia. Hyperopic LASEK provided quicker visual recovery and achieved better efficacy, predictability, and refractive stability than hyperopic PRK.     

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.     

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.     

Prospective, paired comparison of laser in situ keratomileusis and laser epithelial keratomileusis for myopia less than -6.00 diopters

PURPOSE: To compare visual and refractive results, contrast sensitivity, and tear stability after laser in situ keratomileusis (LASIK) in one eye and laser epithelial keratomileusis (LASEK) in the fellow eye for low myopia. METHODS: Patients diagnosed with low myopia, with a maximum difference of 1 D between their two eyes, were randomly assigned to receive LASEK on one eye and LASIK on the other eye. A total of 64 eyes of 32 patients with a mean age of 26.83 +/- 5.33 years were included in the study. Preoperative myopia ranged from -1.00 to -6.00 D. Follow-up was 6 to 12 months. Uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), Schirmer test results, tear break-up time, corneal asphericity, corneal uniformity index, predicted corneal acuity, and contrast sensitivity values were compared with preoperative values. A Wilcoxon test was used for statistical comparisons and a P-value less than .05 was considered significant. RESULTS: At 6 months after surgery, there was no statistically significant difference in UCVA, BSCVA, spherical and cylindrical refractive error, Schirmer test, or tear break-up time between groups. Contrast sensitivity values in the LASIK eyes were lower in comparison to preoperative values, but there was no change in the LASEK group. CONCLUSIONS: Based on 6-month results, LASEK for low myopia was safe and effective with predictable results, offered early refractive stability, and may be considered an alternative for LASIK.     

Photorefractive keratectomy and butterfly laser epithelial keratomileusis: a prospective, contralateral study

PURPOSE: To evaluate results of two surface excimer laser refractive surgery techniques--photorefractive keratectomy (PRK) and butterfly laser epithelial keratomileusis (butterfly LASEK). METHODS: A prospective, randomized, double-masked study of 51 patients (102 eyes) who underwent laser refractive surgery. One eye of each patient was randomized to be operated with PRK and the fellow eye with butterfly LASEK. Patients were followed for 1 year. RESULTS: No significant difference between groups for distance uncorrected visual acuity (UCVA) (P = .559) was noted. At 1 year, 98% (50 eyes) in the PRK group and 96.1% (49 eyes) in the butterfly LASEK group reached UCVA of 20/20. Predictability, efficacy, safety, and stability were not statistically significant between groups. Safety index was 1.0 for PRK and 0.996 for butterfly LASEK. One eye in the butterfly LASEK group lost one line of best-spectacle corrected visual acuity. At 12 months, 94.1% (48 eyes) and 86.3% (44 eyes) in the PRK and butterfly LASEK groups (P = .188), respectively, had a spherical equivalent refraction of +/- 0.50 diopters. Slight haze was observed in both groups. A statistical difference in haze between the groups was observed only in the first postoperative month, with higher intensity in the butterfly LASEK group (0.18 +/- 0.39) compared to the PRK group (0.08+/- 0.21) (P = .04). CONCLUSIONS: Butterfly LASEK had similar predictability, efficacy, safety, stability, and haze incidence to PRK for the treatment of low to moderate myopia. However, on the second postoperative day, PRK showed better UCVA than butterfly LASEK.     

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.     

The effect of moxifloxacin and gatifloxacin on long-term visual outcomes following photorefractive keratectomy

PURPOSE: To compare the effect of gatifloxacin and moxifloxacin on visual outcomes after photorefractive keratectomy (PRK). METHODS: Thirty-five PRK patients were treated postoperatively with gatifloxacin (Zymar) in one eye and moxifloxacin (Vigamox) in the fellow eye. Postoperative regimens were otherwise identical. In a previous study (initial phase), we evaluated epithelial healing. In this study (second phase), we compared uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest spherical equivalent (MSE), and corneal haze at 6 months postoperatively for 32 patients using the Wilcoxon signed ranks test. RESULTS: No statistically significant difference was noted between eyes treated with Zymar and Vigamox in terms of UCVA, BSCVA, MSE, or corneal haze at 6 months postoperatively. Two (6%) Vigamox-treated eyes versus 0 (0%) Zymar-treated eyes lost one line of BSCVA from preoperative examination. Median UCVA and MSE were equivalent for both groups. CONCLUSIONS: At 6 months after PRK, there was no significant difference in visual outcomes with either antibiotic.     

Laser subepithelial keratomileusis for myopia of -6 to -10 diopters with astigmatism with the MEL60 laser

PURPOSE: To evaluate the efficacy, predictability, and safety of laser subepithelial keratomileusis (LASEK) for treatment of high myopia with astigmatism. METHODS: LASEK was performed in 61 eyes of 36 consecutive patients with myopic spherical equivalent refraction of -6.00 to -10.00 D using the Aesculap-Meditec MEL60 excimer laser. Data were collected prospectively with a follow-up of 6 to 17 months. Main outcome measures recorded were UCVA, BSCVA, residual refractive error, corneal haze, and complications. RESULTS: Ninety-six percent of eyes achieved 20/40 or better UCVA at 1 month. At 12 months, 64% of eyes achieved 20/20 and 92% achieved 20/40 or better UCVA. Two eyes lost 2 lines of BSCVA at 6 or 12 months. Accuracy of correction was +/- 0.50 D from emmetropia in 82% of eyes, and +/- 1.00 D in 90% at 12 months. No eye showed more than grade 1 haze. Grade 1 haze was observed in three eyes at 12 months. One patient had mild postoperative keratitis, which was successfully treated. CONCLUSIONS: LASEK with the Aesculap-Meditec MEL60 excimer laser appeared to be safe, effective, and highly predictable in treating high myopia.     

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.     

PRK与LASEK治疗近视比较的Meta分析

目的 系统评价和比较准分子激光屈光性角膜切削术(PRK)与准分子激光角膜上皮瓣下磨镶术(LASEK)治疗近视的疗效.方法 Meta分析.按Cochrane系统评价方法,计算机检索Pubmed、EMbase、中国知网和重庆维普数据库,文献语种限制为中、英文.收集对PRK与LASEK治疗近视进行比较的随机对照试验,并按Cochrane系统评价方法选择试验、评价质量和提取有效数据,用RevMan5.0软件进行Meta分析.结果 共纳入9篇随机对照试验,884只近视眼.Meta分析结果显示,PRK和LASEK治疗近视的有效性(OR=1.08,95％CI:0.62～1.89),可预测性(OR=0.81,95％CI:0.53～1.24)以及安全性差异无统计学意义.术后角膜上皮生长完整的时间(WMD=-0.04,95％CI:-0.82～0.73)及术后眼部疼痛发生率(WMD=0.41,95 ％CI:0.00～0.82)差异均无统计学意义.与PRK相比,LASEK术后角膜上皮下混浊程度较轻(WMD=0.23,95％CI:0.13～0.33).结论 PRK和LASEK治疗近视疗效相同,但LASEK术后上皮下混浊程度较轻.     

Laser-assisted subepithelial keratectomy (LASEK) without alcohol versus photorefractive keratectomy (PRK)

PURPOSE: To evaluate epithelial healing and visual outcome after laser-assisted subepithelial keratectomy (LASEK) without alcohol de-epithelialization and to compare this technique to photorefractive keratectomy (PRK) in myopia. METHODS: In a series of 1953 patients undergoing bilateral myopic PRK, an epithelial flap could be obtained by manual de-epithelialization in the left eye of 56 patients without alcohol exposure. The right eye was treated by PRK and the left by LASEK (i.e., repositioning the viable flap after surface ablation). The two eyes were compared in terms of pain, uncorrected visual acuity (UCVA) in decimals, correction achieved, and haze. The epithelial healing pattern was assessed in the LASEK eyes. RESULTS: The flap remained viable, showing a peripheral junction, in 25 eyes (45%). Pain was higher in the PRK eye in 11/56 patients (20%), higher in the LASEK eye in 23/56 patients (41%), and the same in both eyes in 22/56 patients (39%). UCVA at one week was slightly better in the LASEK eyes (median 0.7 versus 0.6, p = 0.002 with Wilcoxon test), but was the same in PRK and LASEK eyes after 1 month (median 0.9 in both). Median haze at 6 months was 0.5 in the PRK eyes and 0 in the LASEK eyes (Wilcoxon p = 0.007). Median postoperative defocus equivalent at 9 months was 0.5 diopters in both the PRK and the LASEK eyes. CONCLUSIONS: Although our study might have selected patients with loose epithelium, LASEK performed by manual de-epithelialization in the absence of alcohol exposure is not less painful than PRK, even in case of flap survival. Visual recovery speed, as well as haze, is slightly better than in PRK, although the difference is clinically negligible.     

Topographically guided excimer laser photorefractive keratectomy to treat superficial corneal opacities

OBJECTIVE: To demonstrate the efficacy and safety of topographically guided excimer laser photorefractive keratectomy (PRK) in treating superficial corneal opacities. DESIGN: Prospective, noncomparative interventional case series. METHODS: Twenty-six eyes of 24 patients with postinfectious (n = 6), post-traumatic (n = 18), and post-PRK (n = 2) scars were treated with an excimer laser linked to a computerized videokeratography unit with a topographically supported customized ablation workstation. MAIN OUTCOME MEASURES: Manifest spectacle refraction, best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity (UCVA), change of corneal clarity, and topographic indexes of surface regularity. RESULTS: The mean follow-up period was 7.7+/-2.1 months (+/- standard deviation) (range = 6-12). Corneal clarity and corneal topography patterns improved in all eyes. Uncorrected visual acuity improved from 0.7+/-0.8 logarithm of the minimum angle of resolution (logMAR) to 0.4+/-0.5 logMAR (P = 0.008), and BSCVA improved from 0.3+/-0.6 logMAR to 0.1+/-0.6 logMAR (P<0.001). The BSCVA increased in all eyes (>/=2 lines in 76.9% of eyes and 1 line in 23.1%). The mean spherical equivalent refraction changed from -0.125+/-2.77 diopters (D) to +1.33+/-1.28 D (P = 0.019). CONCLUSIONS: The use of topographically guided PRK with the topographically supported customized ablation method resulted in significant increases of UCVA and BSCVA and improved corneal clarity in all patients. The technique seems to be safe and effective for treating various superficial corneal diseases, including postinfectious, post-traumatic, and post-PRK scars.