Evolution, techniques, clinical outcomes, and pathophysiology of LASEK: review of the literature

Laser subepithelial keratomileusis (LASEK) is a relatively new laser surgical procedure that combines certain elements of both laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) to improve the risk/benefit ratio. Diluted alcohol is used to loosen the epithelial adhesion to the corneal stroma. The loosened epithelium is moved aside from the treatment zone as a hinged sheet. Laser ablation of the subepithelial stroma is performed before the epithelial sheet is returned to its original position. We reviewed the literature regarding modifications of the technique, indications, outcomes, and complications, as well as wound healing after LASEK surgery. This literature review of 1,421 LASEK-treated eyes provided many findings: 1) The long-term stable results in the absence of serious complications, such as infections, recurrent erosions, scars, or late-onset corneal haze formation in patients re-examined up to 5 years after LASEK; 2) Epithelial closure with recovery of functional vision was completed at days 4 to 7 in most cases; 3) A tendency toward overcorrection with PRK nomograms; 4) We hypothesize that this tendency may be due to the decreased wound healing response, which may lead to myopic regression in PRK; and 5) Postoperative discomfort and prolonged visual recovery until the epithelium closes remain the biggest disadvantages of LASEK compared to LASIK. LASEK surgery is especially valuable in patients with thin corneas who would not qualify for LASIK surgery. However, a potential superiority of LASEK to LASIK in wavefront guided ablations still remains speculative.     

准分子激光角膜上皮瓣下磨镶术的临床观察

目的 观察准分子激光角膜上皮瓣下磨镶术（LASEK）治疗近视眼的临床效果。方法：选择术后随访达到6个月的146例（280眼），观察术后3天、10天，1、2、3、6个月的症状、视力、屈光状态、角膜并发症情况。结果 观察Nidek EC-5000准分子激光治疗结果表明，LASEK术后症状轻微，手术稳定性、预测性及安全性优于准分子激光屈光性角膜切削术（PRK）及准分子激光原位角膜磨镶术（LASIK）。结论 LASEK手术有可能成为今后主要的屈光治疗方法。     

LASEK与LASIK治疗高度近视

目的:对比观察准分子激光上皮瓣下角膜磨削术(LASEK)与准分子激光原位角膜磨削术(LASIK)治疗高度近视的临床疗效。评估2种手术的安全性和有效性。方法:对行LASEK治疗的39例75只眼和同期行LASIK治疗的41例79只眼高度近视分别进行6个月以上的临床观察。结果:LASEK组术后1周至1个月达最佳矫正视力,术后3个月部分出现视力回退,术后6个月裸眼视力达术前矫正视力占95.83%,主要并发症有术后高眼压及Haze形成;LASIK组术后6个月裸眼视力达术前矫正视力占94.35%,主要并发症为屈光回退,角膜上皮内生或角膜瓣皱折等。结论:LASIK与LASEK均能安全、有效地矫正高度近视。     

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

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

LASEK (laser subepithelial keratomileusis)

Laser subepithelial keratomileusis (LASEK) is a relatively new refractive surgical technique that purportedly combines the advantages of laser in-situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). Like LASIK, on the one hand, it employs a "flap" and consequently has the advantages of faster visual recovery, less postoperative pain, reduced stromal haze, and faster epithelial healing than PRK. Like PRK, on the other hand, because the procedure is performed on the anterior cornea, there are virtually no flap- or interface-related complications per se. It may thus be safer for patients who are at an inherently higher risk of developing flap complications, such as those with small palpebral fissures, deep-set eyes, corneal basement membrane dystrophy, and extremely steep or flat corneas. Furthermore, it conserves precious stroma in eyes with thin corneas or high myopia, which otherwise may not qualify for LASIK. It may also be more apropos for patients whose jobs or recreational activities put them at a higher risk of corneal trauma. In a very timely fashion, for reasons discussed below, LASEK may also prove to be superior to LASIK in customized ablations.     

准分子激光原位角膜磨镶术和准分子激光上皮下磨镶术矫正高度近视的视觉质量对比研究

目的 从视觉质量的角度评价准分子激光原位角膜磨镶术（LASIK）和准分子激光上皮下磨镶术（LASEK）矫正高度近视的疗效。方法对34人（68眼）进行LASIK或LASEK手术的高度近视患者（其中LASEK19人38眼，LASIK组15人30眼）术前，术后1月和术后3月时评价视觉质量，包括术后裸眼视力（UCVA），最佳矫正视组（BCVA组），对比敏感度，眩光和波前像差。结果 LASEK组UCVA提高较LASIK组慢。LASEK和LASIK的术后IN2VA无差异。LASEK组术后的对比敏感度无下降；眩光在术后1月时下降，术后3月时恢复至术前水平。LASIK组术后1月时对比敏感度和眩光均明显下降，术后3月时对比敏感度恢复但眩光仍未恢复至术前水平。LASEK组和LASIK组术后1月和3月的高阶像差RMS均较术前大，但前者比后者小。LASEK组有一定的haze发生，但程度轻。结论 LASEK矫正高度近视能获得更好的视觉质量，关键在于如何更好的保留上皮瓣的活力。     

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

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

Recovery of uncorrected visual acuity after laser in situ keratomileusis or photorefractive keratectomy for low myopia

PURPOSE: To compare uncorrected visual acuity and refractive error in patients undergoing photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) between 1 week and 6 months after surgery. METHODS: All eyes underwent PRK or LASIK with the VisX StarS2 excimer laser. We retrospectively analyzed data from 77 random eyes of 77 patients in the PRK group and 76 eyes of 76 patients in the LASIK group. All eyes had a low myopic refractive error (spherical equivalent range, -0.88 diopters (D) to -5.13 D; mean PRK. -2.8 +/- 0.20 D: LASIK, -2.5 +/- 0.22 D). Uncorrected visual acuity and manifest refractive error were evaluated 1 week, 1 month, and 6 months after surgery. RESULTS: Each eye undergoing PRK was paired with an eye undergoing LASIK for a similar level of spherical equivalent. Mean uncorrected visual acuity after 1 week was 0.85 +/- 0.06 (20/25, logMAR 0.12 +/- 0.04) for the PRK group and 1.01 +/- 0.06 (20/20, logMAR 0.01 +/- 0.03) for the LASIK group (p < 0.001). Mean spherical equivalent after 1 week was 0.23 +/- 0.12 D for the PRK group and -0.02 +/- 0.07 D for the LASIK group (p = 0.02). Mean uncorrected visual acuity after 1 month was 1.03 +/- 0.05 (20/20, logMAR 0.02 +/- 0.03) for the PRK group and 1.05 +/- 0.05 (20/20. -0.02 +/- 0.03) for the LASIK group (p = 0.16). Mean spherical equivalent after I month was 0.19 +/- 0.10 D for the PRK group and -0.02 +/- 0.09 D for the LASIK group. This difference was statistically significant (p = 0.02), but was unlikely to be clinically significant. Mean uncorrected visual acuity after 6 months was 1.05 +/- 0.06 (20/20, logMAR -0.01 +/- 0.03) for the PRK group and 1.06 +/- 0.05 (20/20, logMAR -0.14 +/- 0.03) for the LASIK group (p = 0.41). Mean spherical equivalent after 6 months was 0.02 +/- 0.08 D for the PRK group and 0.00 +/- 0.08 D for the LASIK group (p = 0.35). CONCLUSION: Uncorrected visual acuity 1 week after surgery is significantly better in eyes undergoing LASIK than in eyes undergoing PRK. Both procedures provide functional vision by 1 week after surgery. The difference does not relate to refractive error, which was similar between the two groups, but to differences in healing of the epithelium. By 1 month after surgery, there is no difference in mean uncorrected visual acuity between eyes that undergo PRK or LASIK for low myopia.     

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.     

LASIK vs LASEK vs PRK: advantages and indications

The advent of the excimer laser as an instrument for use in reshaping the corneal stroma was a great step forward in refractive surgery. Laser energy can be delivered on the stromal surface in the photorefractive keratectomy (PRK) procedure or deeper on the corneal stroma by the means of a lamellar surgery in which a flap is created with the microkeratome in the laser in situ keratomileusis (LASIK) procedure. LASIK is currently the dominant procedure in refractive surgery. The main advantage of LASIK over PRK is related to maintaining the central corneal epithelium. This increases comfort during the early post-operative period, allows for rapid visual recovery, and reduces the wound healing response. Reduced wound healing correlates with less regression for high corrections and a lower rate of complications such as significant stromal opacity (haze). PRK, however, remains as an excellent option for mild to moderate corrections, particularly for cases associated with thin corneas, recurrent erosions, or a predisposition for trauma (Martial arts, military, etc.). Recently, a modification of PRK, laser subepithelial keratomileusis (LASEK), was introduced. In the LASEK procedure, an epithelial flap is created and replaced after the ablation. The benefits, if any, of the creation of an epithelial flap compared to traditional PRK are not fully appreciated. Advocates of LASEK suggest that there is less discomfort in the early postoperative period, faster visual recovery, and less haze compared to standard PRK for correction of similar levels of refractive error. Additional long-term clinical studies, along with laboratory research, will be crucial to validate these potential advantages of LASEK procedure.     

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.     

Prospective, randomized, paired comparison of laser epithelial keratomileusis and photorefractive keratectomy for myopia less than -6.50 diopters

PURPOSE: We compared predictability, efficacy, safety, and patient satisfaction following laser epithelial keratomileusis (LASEK) and photorefractive keratectomy (PRK) for low to moderate myopia with either the Nidek EC-5000 excimer laser or the Technolas 217C excimer laser. METHODS: Forty-two patients with spherical equivalent refraction in the range -1.00 to -6.50 D were enrolled in this prospective study, each randomized for choice and sequence of LASEK and PRK on each of their eyes. Patients were examined daily for 7 days, and at 1 and 3 months. Patient satisfaction and quality of vision were assessed using a subjective questionnaire. RESULTS: Mean baseline refraction was -3.57 +/- 1.25 D in LASEK eyes and -3.44 +/- 1.13 D in PRK eyes. Follow-up rates were 100% up to 1 month and 76% at 3 months. At 3 months, 32 (100%) of LASEK eyes and 31 (97%) of PRK eyes had uncorrected visual acuity > or = 20/40, 25 (79%) of LASEK eyes and 26 (82%) of PRK eyes had uncorrected visual acuity > or = 20/20, mean refraction was 0.08 +/- 0.53 D in LASEK eyes and 0.12 +/- 0.50 D in PRK eyes, 26 (81%) of LASEK eyes and 23 (72%) of PRK eyes had a refraction within +/- 0.50 D and 29 (91%) of LASEK eyes and 30 (94%) of PRK eyes had refraction within +/- 1.00 D. Epithelial healing time and pain in LASEK and PRK eyes were not statistically different, and patients were equally satisfied. CONCLUSION: LASEK had similar predictability, efficacy, safety, and patient satisfaction to PRK in the treatment of low to moderate myopia.     

Immediate transepithelial photorefractive keratectomy for treatment of laser in situ keratomileusis flap complications

PURPOSE: To study the role of photorefractive keratectomy (PRK) in the management of laser in situ keratomileusis (LASIK) flap complications. METHODS: A retrospective analysis was performed of seven patients (14 eyes) who had bilateral, simultaneous LASIK (single surgeon [TGA], Summit Apex Plus laser, Hansatome microkeratome in six patients [12 eyes], Automated Corneal Shaper keratome in one patient [two eyes]). One eye of each patient received PRK for a flap complication. The seven patients (four women, three men) had a mean age of 39.2 years (range, 22 to 64 yr). The uncomplicated LASIK eyes had moderate to high myopia (-2.25 to -8.75 D) and the eyes with LASIK flap complications had mild to moderate myopia (-1.50 to -5.75 D). Immediate transepithelial PRK was performed in all eyes after repositioning the defective flap. RESULTS: All seven patients had excellent visual outcome at 6 months follow-up; one patient required an enhancement (astigmatic keratotomy). Six of the seven LASIK eyes had best spectacle-corrected visual acuity of 20/20 or better and one LASIK eye had 20/25. In the transepithelial PRK eyes, six of the seven eyes had best spectacle-corrected visual acuity of 20/20 or better and one eye had 20/30. CONCLUSIONS: Immediate transepithelial PRK treatment of irregular and incomplete LASIK flaps at the time of surgery is an excellent therapeutic option to delayed surgical treatment.     

Photorefractive keratectomy for treatment of flap complications in laser in situ keratomileusis

PURPOSE: To present the results of photorefractive keratectomy (PRK) for treatment of laser in situ keratomileusis (LASIK) flap complications. METHODS: Compilation of case reports through solicitation on Kera-net, an Internet surgery discussion site. RESULTS: PRK was performed on 13 patients from 2 weeks to 6 months after LASIK flap complications. The technique used for the PRK varied. Epithelial removal was performed using no-touch phototherapeutic keratectomy (PTK) in six of the 13 patients and manual debridement in the other seven patients. A dilute solution of 20% ethanol was used to facilitate manual debridement in five of the seven patients. In two of these five patients, the epithelium was replaced as in laser-assisted subepithelial keratomileusis (LASEK). A solution of 0.02% mitomycin C was used after laser ablation to prevent haze formation in three patients. After an average 7 months of follow-up, uncorrected visual acuity was 20/20 in six patients, 20/25 in four patients, and 20/30 in two patients. The visual acuity in one patient was 20/80, purposely left undercorrected for monovision. Best spectacle-corrected visual acuity was 20/20 in 10 of 13 patients. Three patients were 20/25, losing one line of best spectacle-corrected visual acuity. On slit-lamp examination, at last follow-up appointment, stromal haze was graded from trace to none in all patients. CONCLUSIONS: Photorefractive keratectomy is a safe and effective technique for treatment of patients with LASIK flap complications.     

Laser in situ keratomileusis enhancement after photorefractive keratectomy

OBJECTIVE: To describe the safety, effectiveness, and predictability of laser in situ keratomileusis (LASIK) for correcting residual myopia after primary photorefractive keratectomy (PRK). DESIGN: A retrospective, noncomparative case series. PARTICIPANTS AND INTERVENTION: Thirty-six consecutive eyes of 30 patients underwent LASIK after primary PRK. A Multiscan Schwind excimer laser was used for LASIK enhancement. MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity, refraction, videokeratography, and complications were determined before and after LASIK retreatment. Follow-up was at least 12 months. RESULTS: Before LASIK, 11.11% of eyes showed a UCVA of 20/40 or better. This increased to 94.44% 12 months after LASIK. A UCVA of 20/25 or better was achieved in 0% before and in 72.22% after retreatment. Refraction +/-0.5 diopters (spherical equivalent) represented 0% of eyes before and 77.78% of eyes after enhancement. Before LASIK, two eyes had significant haze. Haze remained in these two eyes and appeared in another eye. CONCLUSIONS: Laser in situ keratomileusis proved to be safe and effective for treating residual myopia after PRK. Care must be taken when considering LASIK retreatment in patients with significant haze after primary PRK.     

Haze after laser in situ keratomileusis in eyes with previous photorefractive keratectomy.

In cases with previous photorefractive keratectomy (PRK), there is a risk of developing severe haze after laser in situ keratomileusis (LASIK). We report 3 patients (4 eyes) who developed severe haze after LASIK treatment for residual myopia following PRK. Both PRK and LASIK procedures were performed using the VISX 20/20 excimer laser. We report the grade of haze, amount of regression, and visual acuity after the patients were treated with topical steroids. In 2 eyes, the uncorrected visual acuity was 1.0 after 1 year with grade I haze. In the other 2 eyes, there was a residual refractive error, and the best spectacle-corrected visual acuity was 0.7 with grade II haze.     

Customized ablation algorithm for the treatment of steep central islands after refractive laser surgery

Steep central island (SCI) formation after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) represents a major drawback in the visual rehabilitation of patients after refractive laser surgery. Because of the small size of SCIs, current ablation algorithms are unable to properly calculate an ablation pattern for customized retreatment. We present the use of a new ablation algorithm for the treatment of SCIs that occurred after PRK or LASIK surgery. This algorithm uses a smaller zone of approximation and takes into account the spherical shift induced by removal of the SCI. In all 3 eyes treated, best spectacle-corrected visual acuity increased to 20/16 and remained stable at the 1- and 3-month follow-up, with disappearance of the SCI in corneal topography. This new treatment algorithm may be of benefit to patients experiencing visual side effects due to SCI formation after PRK or LASIK surgery.     

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。     

激光角膜上皮瓣下磨镶术和激光原位角膜磨镶术治疗中高度近视的对比研究

目的比较激光角膜瓣下磨镶术(LASEK)和激光原位角膜磨镶术(LASIK)治疗中高度近视的临床效果. 方法中高度近视患者198例(394只眼).其中LASEK手术治疗93例(184只眼), LASIK手术治疗105例(210只眼). 结果术后1天,LASIK 组28 %裸眼视力达到1.0,LASEK组无1例裸眼视力达到1.0.术后1周、1、3、6月裸眼视力大于或等于1.0者,两组比较差异无显著性 (P=0.36,P=0.58,P=0.44,P=0.64).角膜地形图分析平均角膜中央屈光力与周边屈光力的差异,LASEK组(0.69)明显小于LASIK组(2.62).结论 LASEK手术矫正中高度近视均有良好的治疗效果,是一种安全、有效、预测性好的屈光手术.     

PRK for epithelial ingrowth in buttonhole after LASIK

PURPOSE: To evaluate the efficacy of photorefractive keratectomy (PRK) in progressive central epithelial ingrowth after buttonholes after laser in situ keratomileusis (LASIK). METHODS: Two eyes of two patients with progressive central epithelial ingrowth and fibrosis in flap buttonholes after LASIK underwent PRK 6 months following primary surgery. RESULTS: Epithelial ingrowth was treated successfully in both eyes. The uncorrected visual acuities were 20/20, and there was no evidence of recurrent epithelial ingrowth after 6 months. CONCLUSIONS: Photorefractive keratectomy is a useful modality in the treatment of central epithelial ingrowth in buttonholes following LASIK. As a single-step surgery, it offers both therapeutic and optical advantages by simultaneously clearing the corneal opacity and correcting the refractive error in selected cases.