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.     

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。     

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。     

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

     

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.     

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。     

用Pentacam系统研究LASIK术后角膜后表面高度及曲率变化

目的应用Pentacam眼前节分析系统研究准分子激光原位角膜磨镶术(LASIK)术后角膜后表面高度及曲率的变化,探讨准分子激光手术对角膜后表面高度及曲率变化的影响因素。方法对200例(398只眼)施行LASIK的完整患者资料进行回顾性分析,分别于术前及术后3个月应用Pentacam系统对患者的角膜后表面高度及曲率进行检查并分析。结果角膜后表面高度变化在轻度近视组、中度近视组及高度近视组各组间比较差异具有统计学意义(P<0.05);后表面曲率变化在轻度近视组与中度近视组、高度近视组间比较差异均具有统计学意义(P<0.05),而中度近视组、高度近视组间比较差异无统计学意义(P>0.05)。角膜后表面高度及曲率变化在角膜床厚度250～280μm组与281～320μm组间、250～280μm组与>320μm组间比较差异具有统计学意义,在281～320μm组与>320μm组间比较差异无统计学意义(P>0.05)。结论 LASIK术后角膜后表面向前突,后表面高度增加,曲率负值增加,术前等效球镜越小、角膜床厚度越厚,角膜后表面高度及曲率变化越小。     

准分子激光原位角膜磨镶术后眼压和角膜厚度的研究

目的 探讨准分子激光原位角膜磨镶术（ｅｘｃｉｍｅｒ ｌａｓｅｒ ｉｎ ｓｉｔｕ ｋｅｒａｔｏｍｉｌｅｕｓｉｓ,ＬＡＳＩＫ）后眼压、角膜厚度的变化及其关系。方法 对接受ＬＡＳＩＫ的１５６例２２１只近视眼患者手术前后的屈光度、角膜厚度及眼压（非接触式和Ｇｏｌｄｍａｎｎ压平眼压）情况进行观察。结果 ＬＡＳＩＫ术后实际角膜厚度大于预计角膜厚度,屈光度数越高差别越明显,术后屈光度回退也越多。术后３个月角膜厚     

Laser-assisted In Situ Keratomileusis for Correction of Astigmatism and Increasing Contact Lens Tolerance after Penetrating Keratoplasty

Purpose

To determine effectiveness of laser-assisted in situ keratomileusis (LASIK) in the treatment of astigmatism following penetrating keratoplasty (PK).

Methods

We performed a retrospective review of medical records of patients who underwent LASIK following PK and had over 1 year of follow-up data.

Results

Twenty-six patients (26 pairs of eyes) underwent LASIK following PK. Mean age of the patients at the time of LASIK was 40.7 years (range, 26 to 72 years). Following LASIK, the mean cylinder was reduced by 2.4 diopters and mean reduction of cylinder after LASIK was 65.4% from the preoperative values at the last follow-up visit. Uncorrected visual acuity became 20 / 50 or better in 69.2% of the eyes after LASIK. Best-corrected visual acuity became 20 / 50 or better in 73.1% of the eyes after LASIK. All of them were intolerable to contact lenses before LASIK. After LASIK, 6 pairs (23.1%) did not need to use contact lenses and 18 pairs (69.2%) were tolerable to using contact lenses or spectacles. There were no significant endothelial cell density changes 12 months after LASIK (p = 0.239).

Conclusions

LASIK is effective in the treatment of astigmatism following PK and increases contact lens and spectacle tolerance.