Corneal flap thickness with the Moria M2 single-use head 90 microkeratome

PURPOSE: To analyse the accuracy of corneal flap thickness created in laser-assisted in situ keratomileusis (LASIK) using the Moria Model 2 (M2) single-use head 90 microkeratome. METHODS: The corneal thickness of 300 (266 myopic and 34 hyperopic) eyes of 150 patients was measured by ultrasonic pachymetry preoperationally and intraoperationally after flap cut. The Moria M2 single-use head 90, intended to create a flap with a thickness of 120 microm, was used in all eyes. The right eye was always operated first and the left eye second, using the same blade. RESULTS: Mean corneal flap thickness was 115.4 microm (standard deviation [SD] 12.5) in the two eyes, 115.7 microm (SD 12.4, range 73-147 microm) in right eyes and 115.1 microm (SD 12.6, range 74-144 microm) in left eyes. Mean horizontal flap diameter was 9.1 mm (SD 0.2) and mean hinge length 4.1 mm (SD 0.1). There were no free flaps, incomplete flaps or flaps with buttonholes in the study. Occasional iron particles were observed in three (1.0%) eyes. CONCLUSIONS: As with most microkeratomes, the single-use head 90 microkeratome cut thinner flaps than were intended. The range of the cuts was relatively wide. However, thin flaps did not increase the rate of flap-related complications. The difference between the first and second eyes was not significant.     

Bilateral comparison of corneal flap dimensions with the Moria M2 reusable head and single use head microkeratomes

PURPOSE: To compare the Moria (Antony, France) M2 automated microkeratome with the head 130 to a new disposable single use head to evaluate complications, accuracy, and safety of the procedure. METHODS: Ninety-eight eyes of 49 consecutive patients were operated with the Moria M2 microkeratome. One eye was operated with the metallic head 130 and the other with a plastic single use head, both designed to create a 160-microm flap. Intraoperative flap dimensions were correlated to preoperative parameters and evaluated 1 month postoperatively. RESULTS: With the head 130, mean thickness was 153.3 microm (standard deviation [SD] 13.3, range: 102 to 179 microm). When using a single use head, mean thickness was 148.0 microm (SD 9.8, range: 120 to 170 microm). Occasional iron particles were observed in one eye with both head types. No true epithelial ingrowth was detected in any of the eyes, but epithelial dots at the wound edge occurred in one eye, when using the head 130, but not in the eyes operated with a single use head. CONCLUSIONS: On average, both head types created thinner flaps than attempted. Single use heads produced thinner flaps than the head 130. Accuracy in flap thickness in terms of standard deviation was significantly better in single use heads than in the head 130. Single use heads also had fewer microkeratome-related complications. In clinical practice, the single use head was easier to use because no assembly was required. Plastic single use heads also worked more smoothly than the metallic head 130.     

Very high-frequency digital ultrasound measurement of the LASIK flap thickness profile using the IntraLase femtosecond laser and M2 and Carriazo-Pendular microkeratomes

PURPOSE: To evaluate the corneal aberrometric outcomes and corneal flap thickness profile after LASIK using three different devices for lamellar keratotomy: Moria M2 microkeratome, SCHWIND Carriazo-Pendular microkeratome, and IntraLase femtosecond laser. METHODS: Sixty-six myopic eyes of 33 patients who underwent LASIK with the SCHWIND ESIRIS excimer laser were enrolled in this study. Lamellar keratotomy was performed using three different devices that were assigned randomly to each patient: the Moria M2 microkeratome, SCHWIND Carriazo-Pendular microkeratome, and IntraLase femtosecond laser. The intended flap depth was 110 microm in all cases. Flap thickness profile, corneal aberrations, contrast sensitivity, and refractive outcomes were evaluated. RESULTS: Mean central flap thickness was 117.50 +/- 7.80, 118.08 +/- 8.34, and 115.95 +/- 6.22 microm for the M2, Carriazo-Pendular, and IntraLase systems, respectively. No significant differences were found among the groups. Nasal thicknesses were significantly larger for the M2 flaps compared to IntraLase (P < .05) and Carriazo-Pendular flaps (P = .046 only at 3-mm position). Temporal thicknesses were larger for the M2 flaps, although only differences between M2 and Carriazo-Pendular flaps reached statistical significance. Larger superior and inferior thicknesses were also observed for M2 flaps, although no statistically significant differences were found. Regarding corneal aberrometry, no statistically significant differences were observed in coma-like (P = .138) and spherical-like root-mean-square (P = .300). CONCLUSIONS: The M2, Carriazo-Pendular, and IntraLase systems create flaps of predictable thickness during lamellar keratotomy in LASIK. Additionally, the Carriazo-Pendular and IntraLase devices create flaps with a planar profile.     

两种不同制瓣方式对LASIK术角膜瓣厚度的影响

目的:比较Ziemer LDV飞秒激光与Moria M2机械板层刀不同制瓣方式对LASIK术角膜瓣厚度的影响。 方法：选取近视患者100例200眼（近视度数-2.00~-12.00D,散光度数0.00 ~ -3.50D）,分别应用Ziemer LDV飞秒激光（设定角膜瓣切削厚度110μm）与Moria M2 （110刀头）微型角膜刀制作角膜瓣,各50例 100眼。术后1wk,应用眼前节RTVue FD-OCT 测量,每个角膜上 0°,45°,90°,135°四条子午线所在截面上中心点、距离中心1,2,3mm特定7个点（共计28个点）的角膜瓣厚度测量,并作分析比较。 结果:角膜瓣中央点厚度:Ziemer LDV飞秒激光组108.69±11.75μm,Moria M2 微型角膜刀组130.75±13.36μm,所有观测点（共28点）两组间有明显统计学差异（P<0.01）。角膜中心点厚度与预计值差值比较:Ziemer LDV飞秒激光组 9.70±6.84μm,Moria M2 微型角膜刀组 21.63±11.79μm。Ziemer LDV飞秒激光组预计值差值明显低于Moria M2 微型角膜刀组（t=17.493,P＜0.01）。Ziemer LDV飞秒激光组与Moria M2微型角膜刀组同一截面中各点角膜瓣厚度值差异有统计学差异（P<0.01）。 结论:角膜瓣制作方式相比,在角膜瓣的精确性、可预测性等方面 Ziemer LDV飞秒激光优于Moria M2 微型角膜刀。Ziemer LDV组与Moria M2 机械板层刀组都未表现角膜瓣厚度的均匀性。     

Corneal flap thickness in laser in situ keratomileusis using the Moria M2 microkeratome

PURPOSE: To determine the predictability of flap thickness in laser in situ keratomileusis (LASIK) using the Moria M2 microkeratome and identify factors that may be related to variations in flap thickness. SETTING: Laser Vision Correction Center, Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida, USA. METHODS: Charts of 208 patients having same-day bilateral LASIK using the Moria M2 microkeratome were reviewed. Intraoperative pachymetry was performed routinely. The right eye was always treated first. The same suction ring, stop, microkeratome head (110 microm or 130 microm), and blade were used in fellow eyes. Subtraction pachymetry was used to calculate flap thickness. Other collected data included age, keratometry, corneal diameter, and preoperative spherical equivalent (SE). RESULTS: With the 110 microm head and slow translation velocity in both eyes, the mean flap thickness was 151.6 microm +/- 24.0 (SD) and 148.5 +/- 24.3 microm in the right and left eyes, respectively. With the 110 microm head and fast translation velocity in both eyes, the mean thickness was 136.2 +/- 25.5 microm and 132.8 +/- 23.5 microm, respectively. With the 130 microm head and fast translation velocity, the mean flap thickness was 145.8 +/- 25.4 microm and 139.9 +/- 25.5 microm, respectively. Flaps were thinner with fast translation velocity, the 110 microm head, and presumably duller blades used in the left eyes. There was a weak but statistically significant inverse correlation between flap thickness and age and between flap thickness and SE. A stronger correlation was found in flap thickness between right and left eyes. CONCLUSIONS: Flap thickness with the Moria M2 microkeratome was variable. Fast translation velocity, a used (presumably duller) blade, and the 110 microm head produced thinner flaps. Given the potential variation in flap thickness (SD 23.5 to 25.5 microm), intraoperative pachymetry might be an adjunctive measure to prevent residual stromal beds that are thinner than planned, especially in patients with high myopia and/or thin corneas.     

Moria M290一次性微型板层角膜刀制作角膜瓣的临床研究

目的：探讨Moria M290一次性微型板层角膜刀制作角膜瓣的可预测性及其影响因素。方法共入选104例（208只眼）拟行准分子激光原位角膜磨镶术（LASIK）患者参加此研究。术中使用Moria M290一次性微型板层角膜刀制作角膜瓣,所有患者均使用全新刀头,先右眼制瓣,然后左眼制瓣。制瓣前及制瓣后均使用超声角膜测厚仪测量术眼中央角膜厚度,同时测量角膜瓣直径及蒂长。结果平均角膜瓣厚度为（113．26±12．12）μm,其中右眼平均角膜瓣厚度为（121．42±12．08）μm,左眼平均角膜瓣厚度为（107．24±12．24）μm,两者比较有显著统计学差异（P ＜0．01）。右眼平均角膜瓣直径（9．46±0．15）mm,平均蒂长（5．16±0．25）mm;左眼平均角膜瓣直径（9．39±0．19）mm,平均蒂长（5．09±0．24）mm,两者比较均无显著性差异（P ＝0．08和P ＝0．95）。角膜瓣厚度与患者年龄,术前屈光度,术前角膜曲率及角膜直径均无明显相关性（分别P ＝0．56,P ＝0．50,P ＝0．19,P ＝0.42）,与术前中央角膜厚度呈正相关性（r ＝0．448,P ＜0．01）。结论 Moria M290一次性微型板层角膜刀制作角膜瓣预测性良好,角膜瓣厚度与术前中央角膜厚度呈正相关性。     

眼前节OCT测量法对FS200飞秒激光和Moria 90刀头行薄瓣LASIK中角膜瓣形态比较

背景 薄瓣准分子激光角膜原位磨镶术(LASIK)是角膜屈光手术的主流方法,越来越多的薄瓣LASIK应用飞秒激光制作角膜瓣,傅里叶眼前节OCT角膜瓣厚度及形态的测量为角膜瓣和角膜基质层厚度的控制提供了依据,但应用眼前节OCT测量法对FS200飞秒激光和Moria 90刀头行薄瓣LASIK中角膜瓣形态进行比较的研究较少. 目的 利用傅里叶频域OCT测量法比较应用Wavelight FS200飞秒激光和传统微型角膜刀Moria 90刀头制作的角膜瓣形态及其厚度,评价两种方法制作角膜瓣的特点. 方法 选取2011年12月至2012年6月在南京同仁医院眼科行FS200飞秒激光辅助LASIK和Moria 90刀头行LASIK的患者各30例30眼,于术后1个月应用傅里叶频域OCT(OPTOVUE RTVue-100)测量和比较两种方法所制的中央角膜瓣厚度以及角膜0°和90°径线所在截面上特定10个点的角膜瓣厚度. 结果 FS200飞秒激光制瓣组术眼中央角膜瓣厚度值为(112±3)μm,全角膜瓣平均厚度值为(112±3) μm,分别低于Moria 90刀头制瓣组的(121±7) μm及(128±11) μm,差异均有统计学意义(P=0.031、0.030),FS200飞秒激光制瓣组角膜瓣厚度的变异范围也明显小于Moria 90刀头制瓣组.FS200飞秒激光制作的角膜瓣形态规整、均一,形状近似规则的平面,其中央、旁中央、周边厚度的差异无统计学意义(P=0.320).Moria 90刀头制作的角膜瓣中间薄,周边厚,近似弯月形透镜,其中央、旁中央、周边区角膜瓣厚度的差异有统计学意义(P=0.038).FS200飞秒激光制瓣组各测量点角膜瓣厚度与预期角膜瓣厚度(110 μm)的平均差为(3±4)μm,而Moria 90刀头制瓣组为(17±10) μm,两组间差异有统计学意义(P=0.009).结论 傅里叶眼前节OCT测量表明,Wavelight FS200飞秒激光制作角膜瓣精确度高,可控性强,稳定性好,且操作更安全,是薄瓣LASIK的首选.傅里叶眼前节OCT是评价LASIK术后角膜瓣形态和厚度的有用工具.     

Assessment of keratocyte activation following LASIK with flap creation using the IntraLase FS60 laser

PURPOSE: To assess the response of corneal keratocytes to the IntraLase FS60 femtosecond laser using attenuated steroids. METHODS: Thirty patients (30 eyes) who underwent LASIK with the IntraLase FS60 were assessed by clinical examination and confocal microscopy 3 months postoperatively. Postoperative steroid regimen was Econopred Plus (Alcon Laboratories Inc) every hour for 1 day and four times daily for 7 days. RESULTS: No cornea had clinically significant flap interface haze. Two corneas had trace haze at the interface detected by slit-lamp examination; both showed significant keratocyte activation by confocal microscopy. Overall, some degree of keratocyte activation was detected at the flap interface in 10 of 30 eyes. The measured interface reflectivity was 328.8 +/- 85.0 confocal backscatter units (CBU) in eyes with activated keratocytes and 88.9 +/- 74.5 CBU for the remaining 19 eyes (P < .001). CONCLUSIONS: With attenuated steroids, keratocyte activation was found in a significant number of eyes, although interface haze was subclinical. A higher steroid dosage might therefore be indicated.     

Corneal flap thickness with the Moria M2™ microkeratome and Med‐Logics calibrated LASIK blades

Purpose: This study aimed to compare and study potential factors that affect the accuracy of corneal flap thickness created in laser‐assisted in situ keratomileusis (LASIK) using the Moria model 2 (M2?) head 130 microkeratome with the Med‐Logics calibrated LASIK blades Minus 20 (ML –20) and Minus 30 (ML –30). Methods: Corneal thickness in 200 (164 myopic and 36 hyperopic) eyes (100 patients) was measured by ultrasonic pachymetry preoperatively and intraoperatively after flap cutting. A total of 100 eyes were treated with the ML –20 and 100 with the ML –30. The right eye was operated before the left eye in each patient, using the same blade. In an additional group of 40 eyes, the left eye was operated first. Results: Mean corneal flap thickness using the ML –20 blade for an intended flap thickness of 140 μm was 129.1 μm (standard deviation [SD] 15.6, range 104–165 μm) in right eyes and 111.5 μm (SD 14.5, range 78–144 μm) in left eyes. Mean corneal flap thickness using the ML –30 blade for an intended flap thickness of 130 μm was 127.1 μm (SD 16.6, range 90–168 μm) in right eyes and 109.9 μm (SD 16.8, range 72–149 μm) in left eyes. Conclusions: Both microkeratome blade types cut thinner flaps than were intended. There was substantial variation in flap thickness. The first flap to be cut with a particular blade was considerably thicker than the second flap cut with the same blade. Based on these data, we recommend the use of disposable single‐use microkeratomes rather than these ML blades.     

两种显微角膜板层刀制作角膜瓣厚度的对比分析

目的:对Hansatome自动旋转式显微角膜刀及AmadeusⅡ自动平推式显微角膜刀制作准分子激光原位角膜磨镶术(LASIK)角膜瓣厚度进行对比分析。方法:对来我院行LASIK的患者50例100眼,随机分成两组,一组用Hansatome显微角膜刀160μm刀头制作角膜瓣,另一组用AmadeusⅡ显微角膜刀140μm刀头制作角膜瓣。对所有患者进行术前中央角膜厚度测量及术中角膜基质床厚度测量,从而计算角膜瓣厚度。所有的患者均先行右眼手术再行左眼。对两组患者实际切削的角膜瓣厚度进行对比,同时对两种显微角膜板层刀制作角膜瓣厚度左右眼之间进行对比分析。结果:Hansatome组实际角膜瓣厚度67～158(平均98.70±18.04)μm;AmadeusⅡ组实际角膜瓣厚度69～171(平均110.60±16.47)μm,两种角膜刀制作角膜瓣厚度差异有统计学意义(P=0.001)。Hansatome组右眼104.40±18.78μm,左眼93.00±15.61μm,两眼角膜瓣厚度差异有统计学意义(P=0.01);AmadeusⅡ组右眼115.12±18.74μm,左眼105.20±12.29μm,P=0.024,患者左眼角膜瓣均比右眼要薄,差异有统计学意义。结论:在LASIK术中角膜板层刀制作的角膜瓣厚度与预计值有一定的偏差,术中测量角膜瓣厚度有重要的参考价值。     

飞秒激光制作的角膜瓣形态及其厚度的相关影响因素

目的探讨应用飞秒激光制作的角膜瓣的形态及其厚度的相关影响因素。设计前瞻性病例系列。研究对象北京同仁医院的36例（72眼）应用IntraLa。seFS60飞秒激光制作角膜瓣后行LASIK手术患者。方法术前所有患者均进行常规检查并记录相关资料,包括角膜曲率、角膜厚度、角膜直径等。术后1个月应用VisanteOCT测量角膜上0°、45°、90°和135°四条经线所在截面上特定5个点的角膜瓣厚度,中央角膜瓣厚度与术前角膜曲率等参数进行线性相关分析。主要指标不同测量点的角膜瓣厚度值及相关系数。结果术后1个月,每个角膜上20个测量点对应的角膜瓣厚度均值分散在预计值110μm周围,其中20个对应测量点中最大最小标准差变异分别为9μm和5μm。实际角膜瓣厚度与预计值差值≤5μm的测量点占到全部测量点的55．07％。中心、旁中心、周边区域角膜瓣厚度分别为（110．72±3．76）μm、（110．99±3．52）μm和（110．00±3．62）μm;4条经线所在截面角膜瓣厚度分别为（109．80±4．02）μm、（110．82±3．98）μm、（110．78±4．01）μm和（110．79±3．54）μm;右眼、左眼中央区角膜瓣厚度分别为（110．47＋4．29）μm和（110．97±3．16）μm（P均〉0．05）。术后中央角膜瓣厚度与术前患者角膜曲率、角膜厚度、角膜直径、年龄均无显著相关性（P均〉0．05）。结论应用IntraLaseFS60飞秒激光制作的LASIK角膜瓣形态均一规整,受术前个体差异及环境因素影响小。     

Comparison of flap thickness reproducibility using microkeratomes with a second motor for advancement

PURPOSE: To compare flap thickness and reproducibility of four different types of microkeratomes during LASIK. DESIGN: Retrospective, nonrandomized, comparative case series. PARTICIPANTS: Four hundred ninety consecutive eyes underwent LASIK and were evaluated by measuring the central flap thickness by subtractive pachymetry. METHODS: All flaps were created using the Bausch & Lomb (Miami, FL) Hansatome 180 head, the Alcon (Fort Worth, TX) Summit Krumeich Barraquer Microkeratome 160 head, the Moria (Antony, France) Carriazo Barraquer (CB) 130 head, or the Moria M2 110 head. RESULTS: The flap thickness measurements differed according to the microkeratome used and were 131+/-28 microm in 41 eyes (8.4%) with the Bausch & Lomb Hansatome 180 head, 162+/-21 microm in 127 eyes (25.9%) with the Alcon Summit Krumeich Barraquer Microkeratome (SKBM) 160 head, 157+/-40 microm in 65 eyes (13.3%) with the Moria CB 130 head, and 134+/-23 microm in 257 eyes (52.4%) with the Moria M2 110 head. The central flap thickness with the SKBM and Moria M2 was statistically significantly more reproducible than with the Moria CB (P< 0.0005). There is no correlation between flap thickness reproducibility and age, corneal thickness, or corneal keratometric values. However, considering all the microkeratomes, female gender had statistically significantly more variability than male gender (P<0.02). CONCLUSIONS: Based on these results, the greatest predictability of flap thickness was seen with the SKBM and Moria M2 microkeratomes, which both use a second motor for advancement. The greatest variability, noted with the Moria CB, was likely due to the manual translation feature and places further importance on the safety of the second motor and automation when performing LASIK.     

Comparison of corneal flap thickness between primary and fellow eyes using three microkeratomes

PURPOSE: To compare corneal flap thickness created in laser in situ keratomileusis (LASIK) in primary (right) and fellow (left) eyes (same blade for both eyes) using three microkeratomes. METHODS: The corneal thickness of 132 eyes (66 patients) was measured preoperatively and intraoperatively after flap creation. Corneal flap thickness was calculated by subtracting stromal bed thickness from total corneal thickness. Three microkeratomes were used: Nidek MK-2000, Bausch and Lomb Surgical Hansatome, and the Chiron Automated Corneal Shaper (ACS). Each patient had both corneas cut by one microkeratome and one blade at the same session. RESULTS: Mean corneal flap thickness created in primary eyes was 128.30 +/- 12.57 microm (range 105 to 147 microm) for the ACS (160-microm plate and 8.5-mm ring) and 122.96 +/- 13.30 microm (range 86 to 140 microm) for fellow eyes; Hansatome (160-microm plate and 8.5-mm ring): 141.16 +/- 20.11 microm (range 101 to 169 microm) in primary eyes and 120.95 +/- 26.95 microm (range 107 to 151 microm) in fellow eyes; Nidek (130-microm plate and 8.5-mm ring): 127.25 +/- 4.12 microm (range 116 to 134 microm) in primary eyes and 127.54 +/- 3.7 microm (range 119 to 134 microm) in fellow eyes. The corneal flap in the ACS and Hansatome microkeratomes was always thicker in the primary than the fellow eye, using the same blade for both eyes. No significant difference was found using the Nidek microkeratome. CONCLUSION: Corneal flap thickness tended to be thinner in fellow eyes than in primary eyes for the ACS and Hanstome microkeratomes. The Nidek microkeratome results were closer to specified corneal flap thickness than the ACS and Hanstome microkeratomes.     

Incidence of diffuse lamellar keratitis after laser in situ keratomileusis associated with the IntraLase 15 kHz femtosecond laser and Moria M2 microkeratome

PURPOSE: To analyze the incidence of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK) performed with an IntraLase 15 kHz femtosecond laser (IntraLase, Corp.) or a Moria M2 mechanical microkeratome (Moria SA). SETTING: Vissum Madrid, Madrid, Spain. METHODS: This retrospective study compared the incidence of DLK in consecutive LASIK procedures performed with the IntraLase 15 kHz femtosecond laser (study group) or the Moria M2 microkeratome (control group). Two surgeons performed both types of surgeries (femtosecond laser and microkeratome) using the same excimer laser (Technolas 217, Bausch & Lomb). During the first week postoperatively, topical dexamethasone drops were applied 8 times daily in the femtosecond group and 4 times daily in the mechanical microkeratome group. RESULTS: A total of 2000 consecutive eyes were analyzed (1000 eyes in each group). Diffuse lamellar keratitis stage 2 developed in 1 patient in each group; DLK stage 3 developed in 4 patients in the study group and in no patient in the control group (P = .03). CONCLUSION: Despite more intense postoperative steroid treatment, DLK seemed to occur more frequently after LASIK performed with the IntraLase 15 kHz femtosecond laser than after LASIK performed with the Moria M2 microkeratome.     

Reproducibility of corneal flap thickness in LASIK.

BACKGROUND: The purpose of the microkeratome in laser assisted in situ keratomileusis (LASIK) is to create a corneal flap of desired thickness, thus exposing the stroma. The accuracy and repeatability of intended flap thickness with the current microkeratome system has not been documented. The purpose of this study was to determine the precision and consistency of creating a corneal flap thickness of 160 microns with the Moria LSK-One microkeratome (distributed by Microtech, Inc., Doylestown, PA). PATIENTS AND METHODS: The records of 93 eyes from 67 patients who underwent LASIK were reviewed. The central corneal thickness was measured at baseline. The microkeratome using a "130" footplate was used to create an intended flap 160 microns thick, and the corneal thickness was then remeasured. RESULTS: The mean flap thickness for both eyes combined was 159 microns (S.D. = 28). There was no significant correlation between pre-flap corneal thickness or average K and the corneal flap thickness. CONCLUSION: This study provides evidence that the Moria LSK-One microkeratome creates reproducible LASIK flaps consistently near the intended 160 microns corneal flap thickness. This knowledge enables the surgeon to make a corneal flap with great confidence in the thickness of the excision. In addition, this study provides a clinical, in vivo model for testing corneal flap thickness.     

LASIK flap characteristics using the Moria M2 microkeratome with the 90-microm single use head

PURPOSE: To evaluate the accuracy and consistency of corneal flap thickness, horizontal diameter, and hinge size with the Moria M2 90-microm single use head. METHODS: Fifty-two myopic patients (104 eyes), mean age 32.6 years, underwent bilateral LASIK with a superior hinged flap using the Moria M2 microkeratome (90-microm single use head). Prospective evaluation included flap thickness (subtraction method), diameter, hinge size, interface particles, intraoperative complications, and visual recovery. RESULTS: The mean preoperative spherical equivalent refraction was -5.72 +/- 2.59 diopters (D) (range: -2.88 to -10.75 D) and -5.84 +/- 2.73 D (range: -3.13 to -9.38 D) for right and left eyes, respectively. The mean preoperative central corneal thickness was 548 +/- 24 microm and 547 +/- 25 microm for right and left eyes, respectively. The mean preoperative steepest K was 44.12 +/- 1.28 D and 44.41 +/- 1.27 D for right and left eyes, respectively. Corneal diameter (white-to-white) was 12 +/- 0.4 mm and 11.9 +/- 0.4 mm for right and left eyes, respectively. The mean postoperative flap thickness was 109 +/- 18 microm (range: 67 to 152 microm) and 103 +/- 15 microm (range: 65 to 151 microm) for right and left eyes, respectively. The mean postoperative flap diameter was 9.4 +/- 0.3 mm (expected mean according to the nomogram given by the company was 9.5 mm). The mean postoperative hinge chord was 4.4 +/- 0.4 mm (expected mean 4.2 mm). No interface particles were detected on slit-lamp examination. CONCLUSIONS: The Moria M2 90-microm single use head is safe with reasonable predictability for LASIK flap creation.     

Diffuse lamellar keratitis after laser in situ keratomileusis with the Moria LSK-One and Carriazo-Barraquer microkeratomes

PURPOSE: To assess risk factors for and incidence of diffuse lamellar keratitis (DLK) and to investigate whether microkeratome design is associated with the incidence of DLK. SETTING: The Laser Eye Consultants of Boston, Boston and Waltham, Massachusetts, USA. METHODS: In a retrospective nonrandomized comparative study, 1122 consecutive primary laser in situ keratomileusis (LASIK) treatments (584 patients) were analyzed to determine the incidence of DLK using 2 different microkeratome designs (Moria LSK-One [LSK] and Moria Carriazo-Barraquer [C-B]). The incidence of DLK was as determined by clinical signs. RESULTS: The overall incidence of DLK was 2.23%. The incidence in the LSK and C-B groups was 1.09% and 4.38%, respectively, with a statistically significant difference in incidence between the 2 groups (P<.01). Epithelial irregularities increased the risk for DLK. There was no significant statistical difference in sex, age, operating room location, type of laser, or time of day the surgery was performed between the 2 groups or between eyes that had DLK and eyes without DLK. The incidence of DLK using the C-B microkeratome fell significantly after May 2000, when new cleaning methods for this device were introduced. CONCLUSIONS: Different microkeratomes and how they are maintained may influence the incidence of DLK. Diffuse lamellar keratitis is more common after LASIK in a setting of epithelial irregularities, whether or not an actual epithelial defect is created.     

Corneal flap measurements in laser in situ keratomileusis using the Moria M2 automated microkeratome

PURPOSE: To evaluate accuracy and predictability and factors that influence the dimensions of the laser in situ keratomileusis (LASIK) corneal flap created with the Moria M2 automated microkeratome (Moria SA, Antony, France). METHODS: The flap thickness of 454 eyes of 243 consecutive patients was measured using subtraction ultrasonic pachymetry during LASIK with the Moria M2 microkeratome head 130 designed to create a 160-microm-thick flap. Flap dimensions were evaluated and measurements were correlated with preoperative parameters. A stepwise regression analysis was used to determine the factors that influenced actual flap thickness. RESULTS: The preoperative spherical equivalent refraction of the 454 eyes ranged from -12.125 diopters (D) to +6.25 D. Patient age ranged from 18 to 57 years (mean age: 31.3 +/- 8.8 years). Mean preoperative keratometric power K1 was 44.31 +/- 1.59 D and K2 was 43.32 +/- 1.54 D. Mean preoperative central comeal thickness was 552.4 +/- 32.5 microm (range: 466 to 665 microm). With an attempted thickness of 160 microm, the Moria M2 flap thickness ranged from 77 to 209 microm (mean: 153.3 +/- 19.0 microm). Mean horizontal flap diameter was 9.2 +/- 0.2 mm and mean hinge length 4.6 +/- 0.3 mm. Increasing flap thickness was found to correlate with increasing preoperative comeal thickness, younger patient age, and flatter preoperative keratometric power K1. CONCLUSIONS: Although the standard deviation of the flap thickness was relatively small, remarkable individual variation was noted. Therefore, the intraoperative calculation of the remaining stromal bed is recommended. Furthermore, the consideration of central corneal thickness, patient age, and preoperative keratometry are helpful parameters to avoid too deep ablation.     

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.