Central flap necrosis after LASIK with microkeratome and femtosecond laser created flaps

PURPOSE: To report nine cases of severe central flap inflammation and necrosis after LASIK. METHODS: A retrospective chart review was conducted on 17,100 LASIK cases performed at two laser centers in Indiana from January 1995 through May 2005. All patients with central lamellar flap necrosis were identified. RESULTS: Severe central flap inflammation and necrosis occurred in nine eyes of eight patients. Six patients underwent flap creation with a mechanical microkeratome and two with a femtosecond laser. Of eight eyes with > 2-month follow-up, one lost at least two lines of best spectacle-corrected visual acuity and two experienced a hyperopic shift in spherical equivalent refraction. Typically, inflammation was minimal the day after surgery, peaked 5 to 10 days later, and subsided by 60 days. Six of nine cases were treated by lifting the flap and irrigating the stromal bed. In each of these cases, few or no inflammatory cells were observed in the stromal bed, the posterior flap surface was intact, and the central portion of the anterior flap had a jelly-like consistency. CONCLUSIONS: Central lamellar flap necrosis appears to differ from diffuse lamellar keratitis because the location of stromal inflammation is not in the flap interface but rather in the flap anterior stroma. Treatment with corticosteroids seemed to have little effect on outcomes. This is thought to be the first documentation of central lamellar flap necrosis following the use of a femtosecond laser.     

Moria M2双马达旋转刀角膜瓣制作的结果与分析

目的　探讨MoriaM2 双马达旋转刀制作角膜瓣的效果与技巧。方法　采用MoriaM2 双马达旋转刀为 4 0 9例 (80 6只眼 )行准分子激光原位角膜磨镶术 (LASIK)的患者制作角膜瓣。刀头选择130 ,负压 <2 5 0mmHg(1mmHg =0 133kPa) ,终止环设定在 8 0位置 ,吸力环根据角膜曲率表选择。结果　所有患眼角膜瓣均一次制作成功 ,无破碎瓣、薄瓣及未到达瓣 ,蒂大小适中 ,瓣翻转自如 ,复位容易。无卡刀、中途停顿及停停走走现象。角膜瓣边缘整齐 ,无锯齿样改变 ,角膜基质床光滑。术中出现游离瓣者 3只眼 (0 37% ) ;出现“岛屿现象” ,即角膜基质床有不规则隆起 ,呈孤立的片状或条状者 2只眼 (0 2 5 % ) ;发生走空刀现象者 3只眼 (0 37% )。结论　MoriaM2 双马达旋转刀制作角膜瓣的效果较好 ,无严重并发症。按角膜曲率选择吸力环 ,正确插入刀片及术前检查刀片可避免术中并发症。     

飞秒激光制瓣与机械板层刀制瓣的LASIK术后临床疗效的比较

目的：比较飞秒激光制瓣的LASIK(Femto-LASIK)与经典的机械板层刀制瓣的准分子激光原位角膜磨镶术两种手术方式矫治近视患者的安全性、有效性及术后视觉质量的区别。

方法：回顾性病例对照研究,选取2016-07/2017-06在襄阳市中心医院飞秒激光中心进行板层刀制瓣-LASIK(62例124眼)或Femto-LASIK(58例116眼)手术的近视患者120例240眼。测量两种不同制瓣术式中制作的角膜瓣厚度以及术后视力、屈光状态及角膜地形图参数和像差等并进行比较。

结果：所有患者角膜瓣均制作成功,并且都顺利地完成了手术,术中及术后无明显的并发症发生。术后两组间患者的裸眼视力、屈光度差异无统计学意义(P>0.05)。术中Femto-LASIK组制作的角膜瓣厚度与预设差值小于板层刀制瓣-LASIK组(t=26.67,P<0.01),且球差、彗差和总高阶像差增幅均小于板层刀制瓣-LASIK组(t=-4.16、-4.92、-22.19,均P<0.01)。板层刀制瓣-LASIK组和Femto-LASIK术后角膜表面规则指数(SRI)分别为0.31±0.09、0.25±0.04,二者比较差异有统计学意义(t=6.59,P<0.01)。

结论：飞秒激光制作角膜瓣比板层刀制瓣较为精确,并且术后角膜的像差相对较小,飞秒激光制瓣可提供相对较好的视觉质量,但是这两种制瓣方式术后患者的裸眼视力和屈光状态无明显差异。     

Comparison of LASEK,mechanical microkeratome LASIK and Femtosecond LASIK in low and moderate myopia

Purpose

We conducted a prospective study to determine the best treatment option for patients with low-to-moderate spherical myopia or myopic astigmatism who are considered equally eligible for LASEK with mitomycin-C (MMC) and LASIK with either mechanical microkeratome or femtosecond laser flap creation.

Methods

Forty-six adult patients (86 eyes) who underwent LASEK with MMC (16 patients, 31 eyes), and mechanical microkeratome LASIK (13 patients, 23 eyes) or Femtosecond LASIK (17 patients, 32 eyes) were assessed for clinical outcomes 1, 3 and 6 months post-operatively.

Results

Six months after surgery, all eyes in all three groups were within 1 D of the intended refractive change. UCVA 20/20 or better was achieved in 96% of eyes undergoing LASEK with MMC 88% of eyes in the mechanical microkeratome LASIK and 72% of eyes in the Femtosecond LASIK group at 6 months. Mean spherical equivalent was −0.12 ± 0.22 D, −0.09 ± 0.28 D and −0.25 ± 0.28 D in the three groups, respectively (p = 0.077). Patients in the LASEK with MMC group had less high order aberrations at 3 and 6 months compared to the two LASIK groups. None of the three procedures were associated with early- or late-onset complications or loss of 2 or more lines after surgery.

Conclusions

After an initially slower visual improvement, LASEK with MMC, and to lesser extent, LASIK with mechanical microkeratome, produced better visual acuity and less corneal aberrations compared to Femtosecond LASIK at 3 and 6 months after surgery. These observations deserve further investigation in a randomized controlled trial.     

准分子激光原位角膜磨镶术中不同的微型角膜刀对术后散光的影响

目的 研究准分子激光原位角膜磨镶术（LASIK）中不同的微型角膜刀对术后散光的影响。方法158人（24眼）随机分为H230型微型角膜刀组80人（124眼）和HT230型微型角膜刀组78人（124眼）。所有患者均随访6个月,并对其术前、术后1,3,6个月的散光及其轴的绝对改变和矢量改变进行分析。结果LASIK术后1,3,6个月,散光的绝对值,H230型组分别为0.23D±0.38 D,0.15±0.37D和0.13 D±0.38 D,而 HT230型组分别为0.18D±0.41,0.14 D±0.43D和0.12D±0.42D;散光的矢量值,H230型组分别为0.53D±0.28 D,0.46 D±0.30 D和0.46 D±0.30D,而HT230型组分别为0.46 D±0.33 D,0.50 D ±0.37 D和0.41±0.35D。手术所致散光矢量的改变（包括轴的改变）,除术后3个月时两组间无显著性差异,余均具有显著性差异（术后1个月时,P=0.04;3个月时,P=0.06;6个月时,P=0.02）。结论H230型比HT230型微型角膜刀更易引起较大的散光轴改变,而HT230型比H230型微型角膜刀所致的术后散光改变更趋向于逆规性散光。     

Reproducibility of LASIK flap thickness using the Hansatome microkeratome

PURPOSE: To evaluate the actual versus the expected thickness of laser in situ keratomileusis (LASIK) flaps and to determine the factors that affect flap thickness. SETTING: Centre For Sight, Queen Victoria Hospital, East Grinstead, United Kingdom. METHODS: A retrospective analysis of LASIK procedures in 757 consecutive eyes was done. The surgery was performed by a single surgeon using 2 Hansatome microkeratomes (Bausch & Lomb) with 160 microm and 180 microm heads. Patient age, preoperative manifest refraction, automated keratometry, preoperative central pachymetry, and intraoperative stromal pachymetry were evaluated to determine whether they influenced the actual flap thickness. RESULTS: Bilateral LASIK was performed in 343 patients (686 eyes). The 160 microm head was used in 641 eyes (84.6%) (Group 1) and the 180 microm head, in 116 eyes (15.4%) (Group 2). The mean preoperative manifest refraction spherical equivalent (SE) was -3.9 diopters (D) +/- 4.5 (SD) (range +7.4 to -25.0 D) in Group 1 and -4.4 +/- 3.7 D (range +7.1 to -12.9 D) in Group 2. The mean preoperative keratometry reading was 43.6 +/- 1.8 D (range 36.0 to 48.6 D) and 43.6 +/- 1.8 D (range 35.9 to 47.0 D), respectively; the mean preoperative central pachymetry was 543 +/- 35 microm (range 447 to 643 microm) and 548 +/- 31 microm (range 453 to 613 microm), respectively; and the mean flap thickness was 116.4 +/- 19.8 microm and 117.3 +/- 18.0 microm, respectively. The difference between the actual and the expected flap thickness in each group was statistically significant (P<.001). There was no significant difference in the actual flap thickness between the 2 Hansatomes. The preoperative SE and central pachymetry were the only factors that influenced the actual flap thickness (P<.05); thin flaps were more common with increasing myopia and increasing corneal thickness. CONCLUSIONS: Spherical equivalent and preoperative pachymetry were the principal factors that influenced flap thickness. Preoperative keratometry values and patient age did not influence the actual flap thickness.     

飞秒激光和微型角膜刀制瓣LASIK术后共焦显微镜检查比较

背景 飞秒激光制作准分子激光角膜原位磨镶术(LASIK)角膜瓣技术日渐成熟,术后角膜创伤愈合及神经纤维的再生成为关注热点.目的 对比分析FEMTO LDV飞秒激光及Hansatome机械角膜刀制瓣对LASIK后角膜细胞的影响.方法 采用前瞻性病例对照研究设计.纳入2010年3-7月在武警河南总队医院眼科连续收治的行LASIK的近视患者38例38眼,分为FEMTO LDV组20例20眼(采用FEMTOLDV飞秒激光制瓣)及Hansatome组18例18眼(采用Hansatome微型角膜刀制瓣),两组患者性别、年龄、术前等效球镜度等资料相匹配.分别于术前及术后1周、1个月、3个月应用共焦显微镜检测角膜中央及角膜瓣边缘的形态学变化,并比较两种制瓣方式术后角膜细胞形态学的异同.观察两组患者的术后视力、屈光度变化和裂隙灯下表现.结果 本研究中两组术眼术后1个月最佳矫正视力均≥1.0.FEMTO LDV组平均等效球镜度为(+0.21±0.48)D,Hansatome组为(-0.04±0.54)D,两组屈光度结果接近.FEMTO LDV组术后1周角膜上皮有增厚表现,但与术前比较差异无统计学意义(t=1.63,P＞0.05).FEMTO LDV组术后1周、1个月和3个月浅基质细胞密度较术前均明显减少,差异均有统计学意义(t=-27.99、-25.49、-28.87,P＜0.01).Hansatome组术后1周角膜上皮厚度为(56.73±2.47)μm,较术前值(51.16±1.11)μm明显增加,差异有统计学意义(t=9.29,P＜0.05),3个月时接近术前厚度;Hansatome组术后1周、1个月和3个月浅基质细胞密度较术前明显减少,差异均有统计学意义(t=-17.57、-14.13、-19.63,P=0.00).所有眼均可在切削面见到高反光颗粒,FEMTO LDV组术后1周、1个月和3个月切削面高反光颗粒密度均明显少于Hansatome组,差异均有统计学意义(t=-13.505、-11.900、-14.084,P＜0.01).术后1周时两组均观察到角膜细胞形态改变,切削界面后见激活的基质细胞,3个月时激活细胞减少.FEMTO LDV组术后3个月可见完整的神经纤维,而Hansatome组神经纤维短小.术后3个月,FEMTO LDV组周边角膜基质高反光,并有不规则纤维化,而Hansatome组角膜瓣边缘基质反光较弱.结论 与Hansatome机械角膜刀制瓣LASIK比较,FEMTO LDV飞秒激光制瓣LASIK术后神经纤维再生较早,角膜瓣边缘瘢痕化改变较明显,显示出较强的愈合过程.     

Accuracy of the microkeratome keratectomies in pig eyes

Keratokyphosis is a procedure of lamellar refractive corneal surgery in which corneal tissue does not have to be frozen. Corneal lamellae of 30 pig eyes were separated with either the Berlin microkeratome developed for keratokyphosis or the Barraquer microkeratome. The layer thickness was measured within the optical area at 25 measuring points 0.2-mm apart using the Universal Measuring Microscope. Corneal lamellae separated parallel to the surface by means of the Berlin microkeratome showed layer-thickness differences of 0.008 +/- 0.028 mm in the optical zone between the beginning and end of the incision. When using a convex applanation surface in the microkeratome with an optical zone of 5 mm and a vertex of 0.22, 0.2, and 0.15 mm, the vertex of the central part of the optical zone in the corneal disc attained a value of 0.114 +/- 0.018 mm instead of 0.114 mm (100%), 0.075 +/- 0.015 mm instead of 0.105 mm (72%), and 0.076 +/- 0.014 mm instead of 0.080 mm (84%) (mean +/- standard deviation [SD]). When using a concave applanation surface with the same vertex, it attained 0.076 +/- 0.020 mm (67%), 0.075 +/- 0.019 mm (72%), and 0.067 +/- 0.027 mm (84%). The measured vertex of the corneal lamellae was shifted up to 0.8 +/- 0.5 mm in the feed direction of the microkeratome, probably due to the frictional forces acting on the blade during the cutting process. After separation of the lamellae, the cut surface of the eye was measured planimetrically.(ABSTRACT TRUNCATED AT 250 WORDS)     

飞秒激光与角膜板层刀辅助 LASlK 术后早期角膜生物力学变化的比较

目的：基于角膜基质床厚度／术前角膜厚度（ residual corneal stroma thickness ／corneal thickness,RCST／CT）的不同,比较飞秒激光辅助LASIK和角膜板层刀辅助LASIK术后早期角膜生物力学的变化。
　　方法：选取190例379眼,其中飞秒激光辅助LASIK组94例187眼,角膜板层刀辅助LASIK组96例192眼。根据术后剩余RCST／CT 的不同,将飞秒激光辅助LASIK 组（ FS－IK组）和角膜板层刀辅助LASIK组（ M－IK组）各分为三组, IK－Ⅰ组（ RCST／CT＜55％）、IK－Ⅱ组（55％≤RCST／CT＜60％）和IK－Ⅲ组（ RCST／CT≥60％）。分别于术前、术后1mo和3mo应用眼反应分析仪（ reichert ocular response analyzer,ORA）检测角膜滞后量（ corneal hysteresis, CH）和角膜阻力因子（corneal resistance factor,CRF）。
　　结果：不同手术方式（ FS－IK与M－IK）比较,CH和CRF均无统计学差异（F＝0．44,F＝2．56,P＝0．51,P＝0．11）。不同的RCST／CT 比较, CH 和 CRF 均有统计学差异（ F＝103．03,128．48,P均＜0．05）。Ⅰ组CH和CRF较Ⅱ组明显减小（P＜0．05）,Ⅱ组CH和CRF较Ⅲ组明显减小（P＜0．05）,Ⅰ组CH和CRF较Ⅲ组明显减小（P＜0．05）。术前及术后不同时间比较, CH和CRF均有统计学差异（ F＝576．99,1162．06,P均＜0．05）。术后1mo和3mo,CH和CRF均较术前明显减小（ P＜0．05）,术后1 mo和术后3 mo比较,CH和CRF差异无统计学意义（ P＞0．05）。
　　结论：无论是飞秒激光辅助LASIK还是角膜板层刀辅助LASIK在术后早期角膜生物力学参数均下降,但两种手术方式对角膜生物力学的影响无差异。 LASIK术后保留角膜基质床比例越小对角膜生物力学的影响越大。     

飞秒激光与角膜板层刀辅助LASIK术后早期角膜生物力学变化的比较

目的：基于角膜基质床厚度/术前角膜厚度(residual corneal stroma thickness /corneal thickness,RCST/CT)的不同,比较飞秒激光辅助LASIK和角膜板层刀辅助LASIK术后早期角膜生物力学的变化。

方法：选取190例379眼,其中飞秒激光辅助LASIK组94例187眼,角膜板层刀辅助LASIK组96例192眼。根据术后剩余RCST/CT的不同,将飞秒激光辅助LASIK组(FS-IK组)和角膜板层刀辅助LASIK组(M-IK组)各分为三组,IK-Ⅰ组(RCST/CT<55%)、IK-Ⅱ组(55%≤RCST/CT<60%)和IK-Ⅲ组(RCST/CT≥60%)。分别于术前、术后1mo和3mo应用眼反应分析仪(reichert ocular response analyzer,ORA)检测角膜滞后量(corneal hysteresis,CH)和角膜阻力因子(corneal resistance factor,CRF)。

结果：不同手术方式(FS-IK与M-IK)比较,CH和CRF均无统计学差异(F=0.44,F=2.56,P=0.51,P=0.11)。不同的RCST/CT比较,CH和CRF均有统计学差异(F=103.03,128.48,P均<0.05)。Ⅰ组CH和CRF较Ⅱ组明显减小(P<0.05),Ⅱ组CH和CRF较Ⅲ组明显减小(P<0.05),Ⅰ组CH和CRF较Ⅲ组明显减小(P<0.05)。术前及术后不同时间比较,CH和CRF均有统计学差异(F=576.99, 1162.06,P均<0.05)。术后1mo和3mo,CH和CRF均较术前明显减小(P<0.05),术后1mo和术后3mo比较,CH和CRF差异无统计学意义(P>0.05)。

结论：无论是飞秒激光辅助LASIK还是角膜板层刀辅助LASIK在术后早期角膜生物力学参数均下降,但两种手术方式对角膜生物力学的影响无差异。LASIK术后保留角膜基质床比例越小对角膜生物力学的影响越大。     

Accuracy and precision of LASIK flap thickness using the IntraLase femtosecond laser in 1000 consecutive cases

PURPOSE: To report the safety and flap thickness predictability of LASIK using the IntraLase femtosecond laser. METHOD: A retrospective analysis of 1000 consecutive LASIK cases was performed to assess the rate of intra- and postoperative complications and loss of best spectacle-corrected visual acuity (BSCVA). A subset of 260 eyes was prospectively analyzed to assess flap thickness predictability using subtraction ultrasound on the day of surgery. RESULTS: No serious intra- or postoperative complications were noted. Three (0.3%) patients had epithelial defects that required a bandage contact lens. Four (0.4%) patients had slipped caps on day 1 that required repositioning. Two (0.2%) patients developed grade I diffuse lamellar keratitis. No patient developed epithelial ingrowth >1 mm from the flap edge, transient light sensitivity, or infection. No patient lost > or = 2 lines of BSCVA at 6 months postoperatively. With an attempted flap thickness of 105 microm with the 15-KHz laser, the mean flap thickness was 116.79 +/- 10.75 microm (range: 95 to 148 microm) (n = 119). In the 30-KHz group (n = 141), the target corneal flap thickness was 115 microm, with a mean flap thickness of 114.02 +/- 9.82 microm (range: 93 to 163 microm). Overall 87.3% of eyes were within +/- 20 microm of the intended result. Ninety-eight percent of caps created with the 30-KHz laser were within +/- 20 microm compared to 74.8% in the 15-KHz group. CONCLUSIONS: LASIK surgery with the IntraLase femtosecond laser is safe and flap thickness is predictable.     

Comparison of the femtosecond laser and mechanical microkeratome for flap cutting in LASIK

AIM: To compare refractive results, higher-order aberrations (HOAs), contrast sensitivity and dry eye after laser in situ keratomileusis (LASIK) performed with a femtosecond laser versus a mechanical microkeratome for myopia and astigmatism.METHODS: In this prospective, non-randomized study, 120 eyes with myopia received a LASIK surgery with the VisuMax femtosecond laser for flap cutting, and 120 eyes received a conventional LASIK surgery with a mechanical microkeratome. Flap thickness, visual acuity, manifest refraction, contrast sensitivity function (CSF) curves, HOAs and dry-eye were measured at 1wk; 1, 3, 6mo after surgery.RESULTS:At 6mo postoperatively, the mean central flap thickness in femtosecond laser procedure was 113.05±5.89 µm (attempted thickness 110 µm), and 148.36±21.24 µm (attempted thickness 140 µm) in mechanical microkeratome procedure. An uncorrected distance visual acuity (UDVA) of 4.9 or better was obtained in more than 98% of eyes treated by both methods, a gain in logMAR lines of corrected distance visual acuity (CDVA) occurred in more than 70% of eyes treated by both methods, and no eye lost ≥1 lines of CDVA in both groups. The difference of the mean UDVA and CDVA between two groups at any time post-surgery were not statistically significant (P＞0.05). The postoperative changes of spherical equivalent occurred markedly during the first month in both groups. The total root mean square values of HOAs and spherical aberrations in the femtosecond treated eyes were markedly less than those in the microkeratome treated eyes during 6mo visit after surgery (P＜0.01). The CSF values of the femtosecond treated eyes were also higher than those of the microkeratome treated eyes at all space frequency (P＜0.01). The mean ocular surface disease index scores in both groups were increased at 1wk, and recovered to preoperative level at 1mo after surgery. The mean tear breakup time (TBUT) of the femtosecond treated eyes were markedly longer than those of the microkeratome treated eyes at postoperative 1, 3mo (P＜0.01).CONCLUSION:Both the femtosecond laser and the mechanical microkeratome for LASIK flap cutting are safe and effective to correct myopia, with no statistically significant difference in the UDVA, CDVA during 6mo follow-up. Refractive results remained stable after 1mo post-operation for both groups. The femtosecond laser may have advantages over the microkeratome in the flap thickness predictability, fewer induced HOAs, better CSF, and longer TBUT.     

旋转式角膜板层刀在893眼LASIK中的应用

目的：评价旋转式角膜板层刀在准分子激光原位角膜磨镶术（ｅｘｃｉｍｅｒ ｌａｓｅｒ ｉｎ ｓｉｔｕ ｋｅｒａｔｏｍｉｌｅｕｓｉｓ,ＬＡＳＩＫ）中的应用效果。方法：应用Ｍｏｒｉａ旋转式角膜板层刀对４７１例（８９３眼）近视－０．７５￣－１８．０Ｄ的患者进行ＬＡＳＩＫ治疗。结果：术后１周８９３眼中有８７６眼（９８．１％）,视力达到了术前最好矫正视力,角膜瓣蒂位置;留在鼻上方有５９２眼（６６．２９％）,鼻侧     

Factors predictive of LASIK flap thickness with the Hansatome zero compression microkeratome

PURPOSE: To determine the explanatory power of preoperative variables and comeal flap thickness in laser in situ keratomileusis (LASIK) using the Hansatome zero compression microkeratome (Bausch & Lomb, Rochester, NY). METHODS: A prospective, nonrandomized, comparative interventional case study was performed on 250 eyes of 129 consecutive patients who underwent LASIK surgery using the Hansatome zero compression microkeratome. A 160-microm or 180-microm microkeratome head and an 8.5- or 9.5-mm suction ring were used in the procedures. Preoperative measurements included refraction, spherical equivalent, keratometry, intraocular pressure, corneal white-to-white, anterior chamber depth, and corneal eccentricity. Corneal thickness was measured intraoperatively using ultrasonic pachymetry before and after flap creation, and the difference was taken as flap thickness. Flap diameter was measured with a corneal gauge. Data were analyzed using simple, multiple, stepwise linear and non-linear regression analyses and two-tailed t tests. RESULTS: The mean flap thickness was 124 +/- 17 microm with the nominal 160-microm head and 142 +/- 20 microm with the nominal 180-microm head. One third (33%) of the total variation in flap thickness could be accounted for by three preoperative variables: average corneal thickness, spherical equivalent refraction, and choice of 160- or 180-microm microkeratome head. A simple correlation of 0.114 was noted between corneal eccentricity and flap thickness, but this variable did not add significant explanatory power on multiple regression analysis. Linear regression analysis allowed determination of a flap thickness nomogram with a standard error of the estimate of 16.9 microm and a 95% confidence interval of +/- 33.1. CONCLUSIONS: Comeal thickness is the most systematic predictor of corneal flap thickness using the Hansatome microkeratome. Because three preoperative variables account for only 33% of the range in flap thickness, future studies should focus on variations in blade extension and corneal biomechanical factors, which may also play an important role in determining flap thickness.     

LASIK complication: loss of electricity to the microkeratome during the forward pass

CONTEXT: A 32-year-old woman was scheduled for myopic laser in situ keratomileusis (LASIK) because of myopia and anisometropia caused by retinal detachment surgery. CASE REPORT: During surgery, a sudden malfunction of the microkeratome during the forward pass was experienced. It was not possible to reverse the blade manually along the suction ring. Moreover, disconnecting the suction from the control unit did not help at first, because the suction ring was firmly attached to the ocular surface. However, detaching the suction line from the control unit aborted the vacuum and allowed the surgeon to turn the whole microkeratome backwards, mimicking the normal blade movement. Finally, an almost normal flap was observed, and the operation was successfully completed. Afterwards, the wire to the electromotor of the microkeratome was found to be broken and subsequently replaced. CONCLUSION: This type of unforeseen microkeratome malfunction may result in serious flap or other complications.