Relationship Between Corneal Aberrations and Contrast Sensitivity After Hyperopic Laser in Situ Keratomileusis

Purpose

To evaluate the relationship between corneal aberrations and contrast sensitivity (CS) after hyperopic laser in situ keratomileusis (H-LASIK).

Methods

In 13 patients (13 eyes) who underwent H-LASIK, we measured CS and corneal topography preoperatively and at 1 year postoperatively. Photopic and scotopic CS values were measured at 3, 6, and 12 cycles/degree (cpd) using an MCT-8000 contrast tester. Corneal aberrations were determined from the data on corneal topography using CTView. The corneal high-order aberrations were defined as the sum of the third- and fourth-order aberrations in the 4-mm zone and the sum of the third- to sixth-order aberrations in the 6-mm-zone.

Results

Under scotopic conditions at 12?cpd, the changes in CS significantly correlated with changes in the corneal aberrations. Scotopic CS was significantly deteriorated by glare, but photopic CS was not significantly changed. H-LASIK induced a significant increase in corneal aberrations that positively correlated with the amount of correction, regardless of the improvement in logMAR corrected visual acuity. LogMAR corrected visual acuity did not significantly correlate with corneal aberrations. Furthermore, decentration significantly correlated with the changes in the 6-mm zone corneal aberrations.

Conclusions

In eyes after H-LASIK, the changes in scotopic CS significantly correlated with those in the corneal aberrations, which might have resulted from decentration or ablation profiles in H-LASIK and a relatively small optical zone. Further studies will be needed to validate this relationship.?Jpn J Ophthalmol 2006;50:147–152 © Japanese Ophthalmological Society 2006     

Change in Corneal Permeability to Timolol After Laser In Situ Keratomileusis and Photorefractive Keratectomy in Rabbit

Purpose To evaluate the change in corneal permeability to timolol 1 month after laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) in rabbits.Methods LASIK or PRK was performed on one eye of each of 20 rabbits. One month later, 20µl of 0.5% timolol was instilled into the 10 LASIK eyes, 10 PRK eyes, and the 20 control contralateral eyes. One hour later, 150µl of aqueous humor was collected from all eyes, and the concentration of timolol in the aqueous humor was measured by high-performance liquid chromatography. The effect of LASIK and PRK on the corneal permeability to timolol was analyzed.Results The average timolol concentrations in the aqueous humor of the ten eyes 1 month after LASIK and in the ten contralateral eyes were 1.16 ± 0.58µg/ml and 1.07 ± 0.39µg/ml (average ± SD, P = 0.678), respectively. The average timolol concentrations in the aqueous humor of the ten eyes 1 month after PRK and in the ten contralateral eyes were 1.24 ± 0.43µg/ml and 1.12 ± 0.30µg/ml (P = 0.483), respectively. The average ratio of timolol concentration in the aqueous humor of the LASIK or PRK eyes 1 month after surgery to that of the contralateral normal eyes was 1.18 ± 0.58 or 1.19 ± 0.67 (P = 0.972), respectively.Conclusions LASIK and PRK do not affect corneal permeability to timolol 1 month after surgery. Jpn J Ophthalmol 2005;49:12–14 © Japanese Ophthalmological Society 2005     

LASIK术后角膜上皮植入的发生及处理

目的探讨LASIK术后角膜上皮植入的发生、影响因素、处理方法和效果.方法回顾性分析由同一位医生所行LASIK术后随访6个月以上并有完整记录的所有病例.结果共633例病人1 240只眼,其中61眼曾行二次LASIK手术.有10人10眼(0.81%)发生角膜上皮植入.其中,1眼为二次手术后发生(1.6%);6眼有戴接触镜史;5眼术中发生瓣或上皮异常游离瓣1眼、上皮缺损2眼、上皮松解2眼;6眼术后1天时发现荧光素染色阳性(5眼)或角膜瓣皱折(1眼);9眼上皮植入发生于角膜瓣的边缘,4眼见于原上皮缺损或易脱落方向.除1眼待术外,其余9眼(5眼药物治疗,4眼手术治疗)的最终裸眼视力为0.72±0.32(0.02～1.0),最佳矫正视力为0.93二0.1(0.8～1.0),球镜为-0.31±0.97D(-2.25～1.5D),柱镜为0.61±0.50D(0～1.25D),无异物感、眩光、荧光素着染等,上皮植入消失5眼,变小1眼,静止3眼.结论术者应通过提高手术操作技能和完善各手术步骤尽可能地减少此并发症的发生.发现后恰当处理,可获得很好效果.     

神经生长因子对原位角膜激光磨镶术后角膜敏感度的影响

目的：评估原位角膜激光磨镶术后（LASIK）局部使用神经生长因子（NGF）是否在加速角膜敏感度的恢复中起作用。     

大龄近视患者准分子激光原位角膜磨镶术分析

目的　探讨大龄近视患者LASIK疗效、特点及需要加以关注的问题。方法　对 88例(16 4眼 )大龄 (年龄≥ 4 0岁 )近视患者进行LASIK治疗 ,并对术前屈光度、预矫屈光度、手术疗效等进行统计分析。结果　行LASIK治疗的大龄近视患者术前屈光度 (球镜等量 ) :轻度近视 (≤ -3D) 5眼 ,占 3% ,中度近视 (>- 3D ,≤ - 6D) 2 8眼 ,占 17% ,高度近视 (>- 6D ,≤ - 10D) 4 2眼 ,占 2 6 % ,超高度近视 (>- 10D) 89眼 ,占 5 4 %。为保证角膜的安全性 ,2 0例 (2 2 73% ) 39眼(2 3 78% )术前设计的预矫屈光度需低于术前屈光度。术后裸眼视力 0 0 6～ 1 5 ,平均 0 78± 0 39,其中裸眼视力≥ 0 5者为 6 1眼 ,占 78 2 1% ,裸眼视力≥ 1 0者 2 5眼 ,占 32 0 5 %。结论　大龄近视患者行LASIK治疗以高度、超高度近视患者为主 ,术前角膜厚度的仔细测量、预矫屈光度数的确定、激光切削直径的选择对减少眩光以及术后屈光度数回退 ,提高术后视力、改善视觉质量至关重要。     

The Impact of Learning Curve on Flap Thickness Outcome in Femtosecond Laser-assisted Laser In Situ Keratomileusis Performed with New LenSx Dual Platform

PurposeTo evaluate the effect of learning curve on flap thickness (FT) outcome in femtosecond (FS) laser-assisted laser in situ keratomileusis (LASIK) operation for myopia performed with recently introduced LenSx dual platform using curved applanation cone.MethodsSeventy eyes of 36 patients with myopia or myopic astigmatism operated with FS laser-assisted LASIK with recently introduced LenSx dual platform were evaluated in this retrospective study. Operations were divided into two groups: first 20 operations (20 eyes of 10 patients) and next 50 operations (50 eyes of 26 patients). Data on patient demographics, preoperative and postoperative keratometric and aberrometric parameters, and FT related outcome, including mean central FT, mean total FT, intra-FT range, and FT homogeneity were compared in study groups.ResultsExcept for significantly lower preoperative steepest keratometry values in the next 50 operations versus first 20 operations (p = 0.033), no significant difference was noted between study groups in terms of preoperative and postoperative parameters. When compared to first 20 operations, next 50 operations were associated with significantly higher values for mean central FT (median, 123 μm vs. 114 μm; p = 0.007) and mean total FT (median, 123 μm vs. 113 μm; p = 0.015), whereas significantly lower intra-FT range (median, 4.0 μm vs. 4.5 μm; p = 0.003).ConclusionsIn conclusion, our findings related to FS laser-assisted LASIK surgery for myopia with new LenSx dual platform using curved applanation cone revealed significant impact of learning curve on the corneal FT outcome in terms of closer FT to the intended value and lower intra-flap range.     

Interlamellar Flap Edema Due to Steroid-Induced Ocular Hypertension After Laser In Situ Keratomileusis

Background

Several recent studies have reported post-laser in situ keratomileusis (LASIK) complications related to a steroid-induced increase in intraocular pressure, including interface fluid and elevated intraocular pressure-induced interlamellar stromal keratitis.

Cases

We examined two cases of interlamellar flap edema due to steroid-induced ocular hypertension after uneventful laser in situ keratomileusis.

Observations

Oral acetazolamide and discontinuance of topical steroids were effective for treating interlamellar stromal edema in both cases.

Conclusion

A rise in intraocular pressure should be considered a cause of interlamellar stromal edema after LASIK.?Jpn J Ophthalmol 2007;51:228–230 © Japanese Ophthalmological Society 2007

     

不同浓度鼠神经生长因子对兔眼LASIK术后角膜神经修复的影响

目的：探讨不同浓度鼠神经生长因子（mNGF）对兔眼行准分子激光原位角膜磨镶术（LASIK）后角膜 神经损伤再生修复的影响。方法：实验研究。将39只LASIK术后新西兰大白兔随机划为5组：0.9% 氯化钠溶液组[7只（14眼）]、玻璃酸钠组[0.1%玻璃酸钠滴眼液,8只（16眼）]、NGF50组[50 µg/mL, 8只（16眼）]、NGF100组[100 µg/mL,8只（16眼）]与NGF200组[200 µg/ml,8只（16眼）]。利用海德堡Ⅲ 激光共聚焦显微镜分别检查LASIK术前,术后1周、1个月、2个月、3个月这5个时间点的中央角膜 上皮下神经密度（SNDs）及浅基质神经密度（SSNDs）并进行比较。使用重复测量方差分析及单因素 方差分析比较不同时间点间及5组之间神经参数的差异。结果：术前0.9%氯化钠溶液组、玻璃酸钠组、 NGF50组、NGF100组与NGF200组的中央角膜SNDs和SSNDs在组间比较差异均无统计学意义（F=1.371, P=0.252;F=0.372,P=0.828）。术后1周各组神经密度较术前均明显下降（均P<0.05）,各组间中央角 膜SNDs和SSNDs差异无统计学意义（F=1.905,P=0.119;F=0.923,P=0.455）。中央角膜SNDs,在术 后1个月NGF100组与NGF200组均大于其他3组（均P<0.05）;在术后2个月和3个月NGF200组均大于其 他4组,差异均有统计学意义（均P<0.05）。中央角膜SSNDs在术后1个月与术后2个月NGF200组均大 于其他4组（均P<0.05）;在术后3个月NGF200组大于NGF50组与2个非NGF组,NGF100组和NGF50组均 大于2个非NGF组（均P<0.05）。结论：mNGF滴眼液对兔眼LASIK术后角膜神经有促进修复作用,且 NGF浓度越高,促进修复作用越强。     

Higher Order Aberrations of the Corneal Surface after Laser Subepithelial Keratomileusis

Purpose

To evaluate the changes of higher order aberrations (HOAs) before and after laser subepithelial keratomileusis (LASEK) and to analyze the influence of tear film instability on HOAs of the corneal surface after LASEK.

Methods

In this cross-sectional study, 31 patients who underwent LASEK were divided into dry eye (16 patients, 32 eyes) and non-dry eye groups (15 patients, 30 eyes). Uncorrected distance visual acuity, spherical equivalent refraction, ablation depth, tear film parameters and Ocular Surface Disease Index (OSDI) questionnaire scores were evaluated in both groups. Total HOA root mean square (RMS), third-order coma, third-order trefoil and fourth-order spherical aberration (SA) of the corneal surface immediately and at 10 seconds after blinking were measured before and after surgery.

Results

The total HOA RMS, coma, trefoil and SA significantly increased after LASEK compared with preoperative values in both groups. In the dry eye group, total HOA RMS, coma and trefoil significantly increased except for SA at 10 seconds after blinking compared with those measured immediately after blinking. In addition, the changes of total HOA RMS, coma and trefoil were negatively correlated with tear film break-up time (R = -0.420, -0.473 and -0.439, respectively), but positively correlated with OSDI score (R = 0.433, 0.499 and 0.532, respectively). In the non-dry eye group, there were no significant differences between HOAs measured at 10 seconds after blinking and those measured immediately after blinking.

Conclusions

The HOAs including coma, trefoil and SA significantly increased after LASEK. The tear film instability in the dry eye can be associated with more deterioration of the optical quality after LASEK, due to more significant increase of total HOA RMS, coma and trefoil.     

Recovery of Corneal Nerve Morphology Following Laser in situ Keratomileusis

Morphological changes in the corneal nerves after laser in situ keratomileusis (LASIK) were investigated and the changes were compared with those observed after creation of the keratectomy flap without subsequent photoablation. After creating the hinged flap, a multizone excimer laser photoablation (myopic correction from 6.00 to 6.66 D; diameter 6 mm) was performed on 27 rabbit corneas. Seven of these 27 rabbits received an automated keratectomy without laser photoablation on the fellow eye. A histochemical acetylcholinesterase reaction was used to demonstrate the changes in the morphology of the corneal nerves 3 days, 2.5 and 5 months after the operations. In all specimens the deepest stromal nerve bundles showed normal morphology. Cut nerve trunks were found at the wound margins and at the level of the flap interphase in the stromal bed. At 3 days, both epithelial and basal epithelial/subepithelial nerves were found at the hinge of the flap but the rest of the flap showed a major loss of epithelial, basal epithelial/subepithelial and superficial stromal nerves. A few new regenerating thin nerve fibers were found to emerge from the cut stromal nerve trunks. They appeared to pass the wound margin into the flap area below the epithelium. At 2.5 and 5 months an increasing number of regenerating nerve leashes were observed to emerge from the cut stromal nerve trunks. They appeared to send anastomosing fibers among the neighboring stromal nerves. By this time the epithelial, basal epithelial/subepithelial and anterior stromal innervation had gained an almost normal nerve density and architecture. In the corneas with the flap only, the epithelial innervation was slightly better spared in the center of the flap, and the stromal changes were somewhat less prominent compared with the LASIK corneas.     

激光原位角膜磨削术在青光眼患者中的应用

激光原位角膜磨削术是否可以应用到青光眼患者是一个重要临床问题,屈光手术所造成角膜厚度和角膜曲度的改变可影响眼压的测量从而影响青光眼的诊断和治疗;在手术过程中一过性但极高的眼压可能引起视网膜神经纤维损害或视网膜中央动脉阻塞,青光眼患者或皮质类固醇敏感者屈光手术后常规应用激素类眼药水可能出现激素诱导性眼压升高。虽然如此,激光原位角膜磨削术并非青光眼手术的绝对禁忌证。本文就激光原位角膜磨削术在青光眼患者中应用的安全性以及影响作出综述。     

準分子激光兔角膜原位磨鑲術后視網膜酶組織化學和組織學研究

目的觀察兔眼準分子激光原位角膜磨鑲術(Laserin situ kratomileusis,Lasik)后視網膜糖代謝有關酶的活性及組織學變化.方法 36只兔接受不同深度的Lasik手術角膜切削,分别于手術后不同時間處死,制成冰凍切片和石蠟切片,觀察視網膜琥珀酸脱氫酶(SDH)、乳酸脱氫酶(LDH)、還原型輔酶Ⅰ(NADH)活性變化及組織學改變.結果不同切削量各手術組與對照組比較,術后不同時間各手術組比較,視網膜三種酶活性均無顯著性差异(p＞0.05).視網膜組織學觀察亦無明顯區别.結論臨床Lasik手術切削兔角膜后,視網膜SDH、LDH、NADH活性無明顯改變,組織學結構正常.     

Factors Affecting Long-term Myopic Regression after Laser In Situ Keratomileusis and Laser-assisted Subepithelial Keratectomy for Moderate Myopia

PurposeHigh myopia is known to be a risk factor for long-term regression after laser refractive surgery. There have been few studies about the correction of moderate myopias that did not need retreatment after long-term follow-up. We evaluated 10 years of change in visual acuity and refractive power in eyes with moderate myopia after laser refractive surgery.MethodsWe included patients that had undergone laser in situ keratomileusis (LASIK) or laser-assisted subepithelial keratectomy (LASEK) to correct their myopia and that had at least 10 years of follow-up. We evaluated the stability of visual acuity in terms of safety, efficacy, and refractive changes at examinations 6 months and 1, 2, 5, 7, and 10 years after surgery.ResultsThe study evaluated 62 eyes (36 eyes in LASIK patients and 26 eyes in LASEK patients). In both groups, the efficacy index tended to decrease, and it was consistently higher in the LASEK group compared to the LASIK group over the 10 years of follow-up. The safety index improved over 10 years and was always higher than 0.9 in both groups. The difference between the spherical equivalent at 6 months postoperatively and later periods was statistically significant after 5, 7, and 10 years in both groups (LASIK, p = 0.036, p = 0.003, and p < 0.001, respectively; LASEK, p = 0.006, p = 0.002, and p = 0.001, respectively). Ten years after surgery,26 eyes (66.7%) in the LASIK group and 19 eyes (73.1%) in the LASEK group had myopia greater than 1 diopter. In comparison with the thickness at 6 months postoperatively, central corneal thickness was significantly increased after 5, 7, and 10 years in both LASIK and LASEK groups (LASIK, p < 0.001, p < 0.001, and p < 0.001, respectively; LASEK, p = 0.01, p < 0.001, and p < 0.001, respectively).ConclusionsModerately myopic eyes showed progressive myopic shifting and corneal thickening after LASIK and LASEK during 10 years of follow-up. We also found that early refractive regression may indicate the long-term refractive outcome.     

Factors Affecting Myopic Regression after Laser in Situ Keratomileusis and Laser-Assisted Subepithelial Keratectomy for High Myopia

To evaluate the factors affecting the amount of myopic regression after laser refractive surgery for high myopia, we retrospectively reviewed medical records of 1591 eyes with high myopia treated by laser in situ keratomileusis or laser-assisted subepithelial keratectomy at Shandong Eye Hospital between January 2008 and December 2012. Thirty-five eyes suffering a postoperative myopic shift of manifest spherical equivalent (MSE) of 0.25 diopter (D) or greater were included in this study. The mean refractive error was ?9.34 ± 1.89 D before surgery, and the mean regression was ?1.22 ± 0.70 D. Correlation analysis and multiple regression analysis were performed to assess the factors that were associated with the refractive regression. The age displayed a negative correlation with the diopter of regression (R = ?0.404, P = .016), while the optical zone diameter had a positive correlation with it (R = 0.406, P = .016). Explanatory variables relevant to the diopter of regression were age (partial regression coefficient B = ?0.045, P = .016) and optical zone diameter (partial regression coefficient B = 0.979, P = .014). Advanced-age patients with small optical zones were more predisposed to a larger amplitude of regression after laser refractive surgery for high myopia.     

FS-LASIK手术中动态眼球旋转的相关影响因素

目的：评估飞秒激光制瓣准分子激光原位角膜磨镶术（FS-LASIK）术中动态眼球旋转（DCC）的相关影响因素。方法：回顾性系列病例研究。选取2015 年6 月至2016 年7 月在温州医科大学附属眼视光医院接受FS-LASIK手术的近视散光患者500例（1 000眼）,术中采用阿玛仕准分子激光仪进行激光切削,测量并记录手术过程中DCC值。左右眼DCC的差异比较采用配对t检验;年龄、眼别、性别、术前等效球镜度（SE）、术前球镜度、术前柱镜度、切削直径、切削时间、中央切削深度、激光腔内平 均温度及湿度等对DCC的影响采用多元线性回归进行分析。截断点的取得使用受试者工作特征曲线（ROC）分析。结果：术中测得平均DCC幅度为1.61°±0.90°,其中右眼DCC为1.50°±0.85°,左眼为1.71°±0.94°,左右眼差异有统计学意义(t=-4.85,P < 0.001）。平均DCC旋转角度范围为1.44°±0.93°,其中右眼的DCC旋转角度范围为1.32°±0.91°,左眼为1.56°±0.95°,左右眼差异有统计学意义（t=-4.87,P < 0.001）。多元线性回归分析显示切削时间（β=0.022,P < 0.001）、年龄（β=-0.026,P < 0.001）、眼别（β=-0.213,P < 0.001）、激光腔内湿度（β=-0.018,P=0.008）对DCC幅度有影响;眼别（β=-0.238,P < 0.001）、年龄（β=-0.019,P=0.001）、激光腔内湿度（β=-0.016,P=0.025）对DCC旋转角度范围有影响。结论：FS-LASIK术中,年龄、眼别、切削时间及激光腔内平均湿度会对DCC产生影响。     

准分子激光原位角膜磨镶术后早期眩光对暗视下对比敏感度的影响

目的观察准分子激光原位角膜磨镶术（laser in situ keratomileusis,LASIK）后早期眩光对暗视下对比敏感度的影响。方法采用Mesotest Ⅱb对比敏感度仪,检测72例行LASIK患者术后3个月的对比敏感度,并比较有和无眩光两种情况对暗视下对比敏感度的影响。结果无眩光时,未通过各测试等级的患者数较术前增加,但仅第4级（1：2）差异有统计学意义;有眩光时,各测试等级未通过患者数较术前明显增加,第6级（1：5）、第7级（1：2．7）、第8级（1：2）差异均有统计学意义。暗视下有眩光时,对比度降低2个等级以上的患者数明显多于无眩光时,差异有统计学意义。结论LASIK术后早期有眩光时暗视下对比敏感度明显降低。     

复性近视散光LASIK术后角膜散光的动态分析

目的　观察、分析准分子激光角膜原位磨镶术 (LaserinSituKeratomileusis,LASIK)治疗复性近视散光手术前后角膜地形图的变化规律 ,研究LASIK术对角膜各区散光度及散光轴的影响。方法　对 6 5例复性近视散光患者 (12 6眼 )行LASIK手术 ,术前、术后 1月、 3月、 6月分别行角膜地形图检查。将患者按散光程度不同分为两组 ,观察、比较两组手术前后不同时期角膜不同区的散光度及散光轴的变化规律。结果　复性近视散光患者LASIK术后角膜散光度降低以 3mm区最为明显 ,而 5mm、 7mm区表现为散光轻度增加 ,术后 3～ 6月恢复至与术前差异无显著意义 (P >0 0 5 )。角膜 3mm区散光部分欠矫与非角膜散光因素呈正相关系 :角膜 3mm区散光欠矫度 (D) =1 196×非角膜散光因素 +1 117;角膜各区之间散光轴位差异无显著意义 (P >0 0 5 ) ,术前、术后不同时期差异均无显著意义 (P >0 0 5 )。结论　复性近视散光LASIK术后角膜散光以 3mm区散光值减少明显 ,且散光高度组减少更明显 ,而 5mm、 7mm区早期散光轻度增加 ,术后 3～ 6月逐渐恢复至术前水平。角膜 3mm区散光部分欠矫与非角膜散光因素密切相关。手术前后角膜各区散光轴均保持良好的一致性。     

神经生长因子滴眼液对LASIK术后角膜瓣神经修复的影响

目的观察准分子激光原位角膜磨镶术（LASIK）术后不同时期中央角膜神经的再生情况及神经生长因子（NGF）滴眼液对神经再生的影响。方法采用随机双盲前瞻性对照研究,将35例（70眼）行LASIK的青壮年近视患者随机分为NGF组和对照组,分别检查术前、术后10d、1、3、6个月角膜知觉、泪膜破裂时间（BUT）、泪液分泌量及中央角膜神经密度并进行比较。结果术后10d、1、3、6个月角膜知觉、BUT、泪液分泌量2组间差异均无统计学意义（P〉0.05）。术后3个月内角膜神经密度2组间差异无统计学意义（P〉0.05）,术后6个月NGF组神经密度高于对照组,2组间差异有统计学意义（P〈0.05）。结论NGF滴眼液对LAISK术后角膜神经修复有促进作用。