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.     

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.     

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.     

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.     

LASEK and photorefractive keratectomy for myopia: clinical and confocal microscopy comparison

PURPOSE: To compare postoperative visual acuity and corneal morphology after laser epithelial keratomileusis (LASEK) versus photorefractive keratectomy (PRK) in the correction of low to moderate myopia. METHODS: In a double-blind, randomized clinical trial, 50 myopic patients (mean: -4.5 +/- 1.35 diopters) were randomized to receive LASEK in one eye and PRK in the fellow eye. No mitomycin C eye drops were used in this study. Patients were observed daily for 4 days, then at 1 month and every 3 months up to 1 year. Uncorrected and best-corrected visual acuity (UCVA and BSCVA), manifest refraction, corneal epithelium healing time, postoperative pain, and corneal haze were evaluated. Corneal wound healing was quantified with corneal confocal microscopy. RESULTS: Refractive error, UCVA, and BSCVA were not statistically different between eyes treated with LASEK and PRK. Corneal epithelium healing time was 2.52 +/- 0.99 days in the eyes treated with PRK and 2.29 +/- 0.52 days in the eyes treated with LASEK (P=.22). The postoperative pain score was 2.17 +/- 0.87 in the eyes treated with PRK and 2.62 +/- 0.60 (P=.02) in the eyes treated with LASEK. Corneal confocal microscopy showed fewer stromal activated keratocytes and less extracellular matrix deposition in the eyes treated with LASEK than in the eyes treated with PRK at 1 month postoperatively (P=.003). CONCLUSIONS: LASEK is an effective and safe procedure for low to moderate myopia, but it seems more painful until full corneal reepithelization. In the early postoperative period, the corneal wound healing process is significantly less intense in eyes treated with LASEK than in eyes treated with PRK. The role of LASEK in corneal wound healing modulation remains controversial.     

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.     

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。     

Prospective study of photorefractive keratectomy for hyperopia using an axicon lens and erodible mask

PURPOSE: To evaluate prospectively the long-term safety, efficacy, and visual performance following photorefractive keratectomy (PRK) for hyperopia using an erodible mask and axicon lens system. METHODS: Eighteen eyes of 9 patients with a mean preoperative spherical equivalent refraction of +2.26 +/- 0.82 D (range, +1.13 to +4.00 D) underwent PRK with the Summit Apex Plus excimer laser following manual scraping of the epithelium. Eyes were prospectively evaluated 1, 3, 6, 9, 12, 18, and 24 months following the procedure. Primary outcome variables included cycloplegic refraction and uncorrected visual acuity (UCVA). Visual performance was determined by contrast sensitivity measurements under scotopic (21 lux) and photopic (324 lux) conditions and best spectacle-corrected visual acuity (BSCVA) under scotopic, photopic, and glare conditions. RESULTS: For 18 eyes, 98.2% of the mean preoperative spherical equivalent refraction was corrected to +0.04 +/- 0.87 D (range, -1.38 to +2.00 D) at 24 months after PRK. Twelve eyes (67%) were within +/-0.50 D of attempted correction and 15 eyes (83%) were within +/-1.00 D. Stability within +/-0.50 D was achieved after 6 months. Two eyes (11%) experienced almost complete regression of the refractive effect. There was no statistically significant decrease in contrast sensitivity under scotopic or photopic conditions. (P > .05). Best spectacle-corrected visual acuity showed progressive improvement in the early postoperative period. By 24 months, 0 eyes (0%) lost 2 or more lines of BSCVA under scotopic and photopic conditions and 1 eye (5.5%) lost 2 or more lines under glare conditions. Fourteen eyes (78%) had grade 1 to 3 anterior stromal haze at 24 months which was characteristically mid-peripheral and did not adversely affect visual performance. CONCLUSION: Photorefractive keratectomy with the the Summit Apex Plus excimer laser for low to moderate hyperopia resulted in an effective reduction of hyperopia without compromising long-term visual performance. Stability and recovery of distance uncorrected and best spectacle-corrected visual acuity took approximately 6 months.     

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.     

Photorefractive keratectomy with 0.02% mitomycin C for treatment of residual refractive errors after LASIK

PURPOSE: To evaluate the efficacy and safety of prophylactic mitomycin C (MMC) during photorefractive keratectomy (PRK) over LASIK flaps for the treatment of residual refractive errors following LASIK. METHODS: In this single center, retrospective clinical study, 30 eyes of 33 patients (mean age 37.2 years) who had MMC (0.02%, 30 to 120 seconds) during PRK for the treatment of residual refractive errors following myopic LASIK were evaluated. The retreatment procedures were performed with a VISX S4 laser with iris registration. All patients underwent slit-lamp microscopy, manifest and cycloplegic refraction, corneal topography, pachymetry, pupillometry, and wavefront analysis pre- and postoperatively. All patients underwent follow-up at 1 day, 1 week, and 1, 3, and 6 months and thereafter as required. RESULTS: Mean time between LASIK and PRK retreatment was 67.3 months (range: 7 to 113 months). No intra- or postoperative complications occurred during primary LASIK or PRK retreatment. Mean spherical equivalent refraction of attempted correction with PRK was -0.94 diopters (D) (range: -2.38 to +0.75 D). At mean 7.1-month follow-up, the average uncorrected visual acuity (UCVA) improved from 20/50 (range: 20/30 to 20/200) to 20/28 (range: 20/15 to 20/70). Twenty-seven of 30 eyes showed improvement in UCVA. Two eyes had subjective improvement of glare symptoms (and objective improvement in higher order aberrations), and one eye lost one line of best spectacle-corrected visual acuity due to unrelated corneal abrasion in the postoperative period. None of the eyes in the cohort developed postoperative haze. CONCLUSIONS: Photorefractive keratectomy with prophylactic MMC (0.02%) is a safe and effective option for treating myopic regression following LASIK. A single intraoperative application of 0.02% MMC for as few as 30 seconds was effective in preventing postoperative haze formation.     

Photorefractive keratectomy with mitomycin C versus LASIK in custom surgeries for myopia: a bilateral prospective randomized clinical trial

PURPOSE: To compare photorefractive keratectomy (PRK) with prophylactic use of mitomycin C (MMC) and LASIK in custom surgeries for myopic astigmatism. METHODS: Eighty-eight eyes of 44 patients with a minimum estimated ablation depth of 50 microm were randomized to receive PRK with MMC 0.002% for 1 minute in one eye and LASIK in the fellow eye. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), cycloplegic refraction, slit-lamp microscopy, contrast sensitivity, specular microscopy, aberrometry, and a subjective questionnaire were evaluated. Forty-two patients completed 6-month follow-up. RESULTS: Mean spherical equivalent refraction error before surgery and mean ablation depth were -3.99+/-1.20 diopters (D) and 73.09+/-14.55 microm in LASIK eyes, and -3.85+/-1.12 D and 70.7+/-14.07 microm in PRK with MMC eyes, respectively. Uncorrected visual acuity was significantly better in PRK with MMC eyes 3 months (P=.04) and 6 months (P=.01) after surgery. Best spectacle-corrected visual acuity and spherical equivalent refraction did not differ significantly in the groups during follow-up (P>.05). Significant haze was not observed in any PRK with MMC eye. Mean higher order aberration was lower in PRK with MMC eyes postoperatively compared with LASIK eyes (P=.01). Better contrast sensitivity was observed in PRK with MMC eyes than LASIK eyes (P<.05). The endothelial cell count did not differ significantly between groups (P=.65). In terms of visual satisfaction, PRK with MMC eyes were better rated. CONCLUSIONS: Photorefractive keratectomy with MMC appears to be more effective than LASIK in custom surgery for moderate myopia. During 6-month follow-up, no toxic effects of MMC were evident. Long-term follow-up is necessary to attest its safety.     

One-year outcomes of a bilateral randomized prospective clinical trial comparing laser subepithelial keratomileusis and photorefractive keratectomy

PURPOSE: To compare laser subepithelial keratomileusis (LASEK) and photorefractive keratectomy (PRK) in different eyes of the same patients in terms of visual acuity, refractive error, and complications over 1 year. METHODS: This prospective, randomized, double-masked study comprised 30 active-duty military personnel with myopia who underwent LASEK in one eye and PRK in the other eye. RESULTS: Twenty-eight patients' results were available for 1-year follow-up. The primary outcome measures were visual acuity and refractive error. The mean visual acuity for the LASEK group was 1.56 and 1.67 for the PRK group (z = -0.18, P = .15). The mean spherical equivalent refraction for the LASEK group was -0.007 D and +0.124 D for the PRK group (t = 0.982, P = .40). No significant differences were noted in visual acuity or refractive error in the eyes that had LASEK versus the eyes that had PRK. CONCLUSIONS: After 1-year follow-up, LASEK and PRK show similar levels of visual acuity and refractive error.     

PRK+MMC与LASEK治疗高度近视效果比较

目的比较PRK术中预防性使用丝裂霉素C（MMC）治疗高度近视和LASEK治疗高度近视的疗效.方法将高度近视（-6.0～-10.0D）随机分为PRK＋MMC组40例（80眼）和LASEK组38例（76眼）.另以早年PRK手术屈光状态与之相似的40例（80眼）作为对照.PRK＋MMC组在PRK术中使用0.02%MMC,LASEK组采用常规LASEK,评价术后角膜上皮下雾状浑浊（haze）,屈光回退、视力及角膜内皮细胞改变等情况.结果PRK＋MMC组未出现2级或2级以上haze,无术后矫正视力下降者,术后欠矫小于-0.5D者70眼;LASEK组有6眼出现2级及2级以上haze,有6眼出现术后矫正视力下降,术后欠矫小于-0.5D者56眼.两组的差异有显著性.使用MMC未见明显毒副作用.结论PRK术中预防性使用MMC,在术后减少haze、防止屈光回退、改善视力方面较LASEK为优.     

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.     

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.     

Long-term outcomes of photorefractive keratectomy and laser-assisted subepithelial keratectomy in children

PURPOSE: To assess the long-term refractive, visual acuity, binocular vision, and quality-of-life outcomes of photorefractive keratectomy (PRK) and laser-assisted subepithelial keratectomy (LASEK) in children. SETTING: Non-hospital surgical facility with follow-up in a hospital clinical setting. METHODS: In this retrospective review, 56 eyes of 39 patients had PRK or LASEK under general anesthesia. Patients were examined preoperatively and postoperatively at 2 and 6 months and 1 year and then annually for a minimum of 3.5 years. Recorded variables included demographics, refractive error, best corrected visual acuity (BCVA), stereopsis, corneal haze, and quality of life. RESULTS: The mean age at surgery was 6.5 years (range 1.0 to 17.4 years). At the final postoperative examination (mean 5.15 years), the mean spherical equivalent was -1.73 diopters (D) in all patients, -3.20 D in PRK patients, and -1.37 D in LASEK patients. Refraction and corneal clarity were stable over the long term in all eyes. In 28 eyes that were measurable preoperatively, visual acuity improved by a mean of 1.6 lines (range 0 to 7 lines). Seven patients (18%) had measurable stereopsis before surgery and 19 (49%), after PRK or LASEK. No patient had reduced BCVA or loss of binocular fusion postoperatively. On a quality-of-life questionnaire, no family recorded negative opinions of the procedure or negative social or functional outcomes postoperatively. CONCLUSION: Photorefractive keratectomy and LASEK were effective and stable surgical alternative treatments in children with refractive errors who were unable to tolerate or who failed conventional methods of treatment.     

Results of photorefractive keratectomy for hyperopia using the VISX star excimer laser system

PURPOSE: To evaluate safety, efficacy, and predictability of photorefractive keratectomy (PRK) for hyperopic astigmatism of +1.75 to 00 D manifest refractive sphere and up to -2.50 D manifest refractive astigmatism using the VISX Star excimer laser system, version 2.5 software. METHODS: Treatment was performed on 32 eyes of 21 patients. Eighteen of 21 patients were 45 years of age or older. Manifest and cycloplegic refraction together with Pelli-Robson contrast sensitivity assessment was performed prior to surgery and 1, 3, 6, 12, and 24 months after treatment. RESULTS: Twenty-seven of 32 surgical procedures were reviewed 1 year after treatment (84%). Corneal epithelial healing was complete between day 4 and 10. Twelve months after treatment, 25 of 27 eyes (93%) achieved 20/40 or better uncorrected visual acuity and 19 eyes (70%) achieved 20/20. No patient lost two or more lines of Snellen visual acuity assessed 6 months and later after treatment. The mean spherical equivalent refraction was reduced from +2.90 at baseline to +0.10 D at 1 year and +0.40 D at 2 years; 65% of eyes had a refraction within +/- 0.50 D. Four patients had further treatment by laser in situ keratomileusis for undercorrection in three eyes and overcorrection in one eye. Pelli-Robson contrast acuity was significantly reduced 12 months after treatment from a mean 1.72 before to 1.66 after PRK (P = .02, t-test). CONCLUSIONS: PRK for hyperopia using the VISX Star excimer laser system was effective in the treatment of hyperopic astigmatism. Although no patient lost two or more lines of high contrast best spectacle-corrected Snellen visual acuity 1 year after treatment, there was a significant decrease in Pelli-Robson contrast acuity.     

Effectiveness of laser-assisted subepithelial keratectomy to treat residual refractive errors after laser in situ keratomileusis

PURPOSE: To evaluate the effectiveness of laser-assisted subepithelial keratectomy (LASEK) to treat residual refractive errors after laser in situ keratomileusis (LASIK). SETTINGS: Isik Eye Clinic, Ankara, Turkey. METHODS: This retrospective study included 24 eyes of 15 patients who had retreatment by LASEK for residual refractive errors after myopic LASIK. All patients had examinations that included slitlamp biomicroscopy, subjective and cycloplegic refractions, uncorrected visual acuity (UCVA), best corrected visual acuity, corneal topography, and pachymetry preoperatively and postoperatively. Postoperative examinations were performed at 1 week and 1, 3, and 6 months. RESULTS: The patient cohort comprised 9 men and 6 women. The median spherical equivalent (SE) of attempted correction for retreatment with LASEK was -1.25 diopters (D). The median follow-up after LASEK was 11.5 months (range 6 to 16 months). At the end of the follow-up, the median SE of the refractive error was -0.38 D. The median UCVA increased from 20/45 before LASEK to 20/25 at the last follow-up visit, which was statistically significant (P<.001). After LASEK, significant postoperative haze developed in 5 eyes. In all 5 eyes, the estimated ablation depth was more than 40 mum and the SE of attempted correction was -2.00 D or greater. CONCLUSIONS: Laser-assisted subepithelial keratectomy retreatment in eyes with myopic regression after LASIK resulted in a significant improvement in UCVA that was comparable to the improvement after flap lifting. An SE of attempted correction greater than -2.00 D was associated with a significant rate of haze.     

Clinical results of excimer laser photorefractive keratectomy for high myopic anisometropia in children: four-year follow-up

PURPOSE: To evaluate the visual and refractive results of multizonal photorefractive keratectomy (PRK) for high myopic anisometropia and contact-lens intolerance in children. SETTING: Department of Ophthalmology, Masaryk University Hospital, Brno, Czech Republic. METHODS: Twenty-one patients aged 7 to 15 years with high myopic anisometropia had multizonal PRK in the more myopic eye and were retrospectively analyzed. The scanning-slit Nidek EC-5000 excimer laser was used. Postoperatively, patients were reviewed at 1 and 3 days, 1 week, and 1, 3, 6, 12, 18, 24, 36, and 48 months. The examination included cycloplegic refraction, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), biomicroscopy, grading of postoperative haze, corneal topography, pachymetry, intraocular pressure, biometry, orthoptic status, binocular vision (BV), and fundus evaluation. The safety, efficacy, predictability, and stability of the procedure were evaluated. Long-term binocular vision outcome was analyzed. All patients completed a 4-year follow-up. RESULTS: The mean preoperative spherical equivalent (SE) refraction was 8.93 diopters (D) +/- 1.39 (SD) (range -6.75 to -11.75 D) and the mean postoperative SE, -1.66 +/- 0.68 D (range -0.50 to -2.75 D) (P <.05). The mean preoperative UCVA of 0.034 +/- 0.016 increased to 0.35 +/- 0.15 (P <.05) postoperatively. The mean preoperative BSCVA was 0.53 +/- 0.19 and changed to 0.64 +/- 0.16 postoperatively. The safety index was 1.21. No eye lost a line of BSCVA; 9 eyes gained 1 line, and 5 eyes gained 2 lines. The efficacy index was 0.66. The postoperative uncorrected and best spectacle-corrected BV were the same or improved. No eye had +3 haze. There were no significant complications. CONCLUSIONS: Photorefractive keratectomy was safe and effective in correcting high myopic anisometropia in children who were contact-lens intolerant. It provided good visual results and preserved or improved BV over the 4-year follow-up.