波前优化和波前引导准分子激光角膜切削对比

传统的准分子激光角膜切削术经过多年临床实践证实能获得较好的视力，然而传统疗法行角膜球面切削会将一般的扁平角膜变成更扁圆的轮廓，并导致球面像差。角膜非球面性的改变引起球面像差的增加，并影响夜视力和对比敏感度等视觉质量。波前优化旨在用基于总体均数的调整措施保留眼球先前的视觉像差，并优化角膜的非球面性，从而建立一个基于理想模型的个体化调整措施。波前引导测量眼球像差并行个体化切削治疗可达到更好的视觉效果。就波前优化和波前引导疗法对于球面像差的矫正效果进行综述。     

Factors affecting corneal hysteresis in normal eyes

BACKGROUND: To evaluate factors affecting corneal hysteresis (CH) in normal eyes. METHODS: We examined 86 normal eyes of 43 healthy volunteers (age, 39.1 +/- 14.5 years (mean +/- standard deviation); range, 19 to 68 years; gender, 26 men, 60 women; manifest refraction, -2.25 +/- 2.89 diopters (D); range, -9.13 to 3.88 D). We quantitatively assessed the value of CH using an Ocular Response Analyzertrade mark (Reichert Ophthalmic Instruments). We carried out this measurement three times, and the average value was used for statistical analysis. Multiple regression analysis was used to assess the relevant factors of the CH. RESULTS: The mean CH was 10.2 +/- 1.3 mmHg. Explanatory variables relevant to the CH were, in order of magnitude of influence, the central corneal thickness (CCT) (partial regression coefficient B = 0.022, p < 0.0001), and the intraocular pressure (IOP) (B = -0.119, p = 0.04). No significant correlation was seen with other clinical factors such as age, gender, manifest refraction, or mean keratometric readings. CONCLUSIONS: Eyes with thinner CCT and eyes with higher IOP are more predisposed to have lower CH. Refractive surgeons should, from a biomechanical viewpoint, take not only CCT but also IOP into consideration before performing keratorefractive surgery.     

Q值优化角膜地形图引导的准分子激光原位角膜磨镶术临床研究

目的 观察Astrapro个性化软件Q程序引导准分子激光原位角膜磨镶术(Laserinsitukeratomileusis,LASIK)的临床效果,评价该软件应用于手术的安全性和有效性.方法 对2007年3～6月行LASIK手术的患者92例(184只眼)随机分为两组.标准化92只眼为Ⅰ组,应用传统模式;个性化92只眼为Ⅱ组,以Astrapro2.2Q程序引导.记录术前及术后3个月的数据,以术后最佳矫正视力、角膜切削深度、激光切削时间为手术安全性指标;以术后裸眼视力与术前最佳矫正视力之比、手术前后Q值的变化、术后实际光学区(OZ)大小、术后对比敏感度的恢复作为手术有效性指标.结果 两组术后裸眼视力与术前最佳矫正视力之比无统计学差异(P>0.05);两组切削深度、激光切削时间无统计学差异(P>0.05);个性化组手术前后Q值的变化较标准手术组小(P<0.001);个性化组术后实际光学区较标准手术组大(P<0.001);两组术后1个月各个空间频率的平均对比敏感度均低于术前,3个月时个性化组对比敏感度全部恢复,标准手术组尚未恢复.结论 Astrapr02.2个性化软件Q治疗程序引导的LASIK手术具有良好的临床效果和安全性.术后角膜地形图提示:角膜前表面形态虽未达到预设的目标Q值-0.26,但较标准化手术更接近术前Q值,更有效地维持了术前横椭圆非球面形态(Prolate).     

糖尿病视网膜病变激光光凝对角膜内皮的影响

目的 观察糖尿病视网膜病变患者行全视网膜光凝对角膜内皮细胞的影响.方法 用角膜内皮细胞显微镜对532 nm激光行糖尿病视网膜病变全视网膜光凝的患眼进行角膜内皮细胞的观察.结果 532 nm激光全视网膜光凝后14 d及21 d中央部位及周边6点处角膜内皮细胞的各项检测指标的改变均无统计学意义（P＞0.05）.结论 532 nm激光行糖尿病视网膜病变全视网膜光凝对角膜内皮细胞造成的损伤没有统计学意义.     

术前配戴软性角膜接触镜对LASIK术后高阶像差的影响

目的探讨术前配戴软性角膜接触镜对波前引导和传统准分子激光原位角膜磨镶术(LASIK)术后高阶像差的影响。方法采用前瞻性随机双盲比较性研究,将拟行LASIK的青壮年近视患者48名(96眼),其中,术前配戴软性角膜接触镜者26名(52眼),随机分为波前引导组和传统组,分别检查术前、术后不同时间的视力、对比敏感度和高阶像差,并比较术前戴角膜接触镜组(contactlens,C组)与未戴组(non-contactlens,N组)术后高阶像差变化。结果无论是传统组还是波前引导组术后不同时间的裸眼视力(UCVA)、最佳矫正视力(BSCVA)、安全指数、有效指数和对比敏感度增加倍率等方面C组与N组均无显著差异(P>0.05)。传统组和波前引导组术后总高阶像差和各高阶像差RMS值(RMSh和RMS3～6值)均较术前增加,平均增加约1倍。传统组中术后RMSh和RMS3～6值增加倍率和下降比例C组与N组无显著差异,术后6个月时RMSh值增加倍率分别为1.28倍、1.17倍。引导组中术后RMSh、RMS3～5值增加倍率C组均明显高于N组(P<0.05),术后6个月时RMSh值增加倍率分别为1.58倍、0.77倍(P<0.05),N组术后不同时间RMSh、RMS3～5值下降比例均高于C组。术后6个月时,RMSh值下降比例C组与N组分别为9.1%和22.7%。结论术前配戴软性角膜接触镜影响波前引导LASIK对高阶像差的矫正,而对传统LASIK术后高阶像差影响不明显。术前配戴软性角膜接触镜者行波前引导LASIK应慎重。     

Corneal ectasia after photorefractive keratectomy

Background Corneal ectasia after photorefractive keratectomy (PRK) has only been occasionally reported, and its incidence has not been assessed. Methods In a retrospective, non-comparative case series, incidence of corneal ectasia was evaluated in a personal consecutive 6453-case series of myopic PRK with a minimum follow-up of 18 months. Features and prognosis were evaluated in all patients with ectasia after PRK (in both personal and referred cases). Results Ectasia was detected in three eyes of two patients (patients 1 and 2) 3 years and 1 year after PRK performed elsewhere. In addition, in the personal PRK series, two eyes of two patients (patients 3 and 4) developed corneal ectasia 5 months after surgery (incidence: 0.03%). Pre-operatively, forme fruste keratoconus was present in patients 1, 3 and 4; keratoconus in the fellow eye in patient 2; pachymetry <500 micron in patients 2 and 3. In patient 1, rigid contact lenses were prescribed, and in patient 2 deep anterior lamellar keratoplasty was needed; in patients 3 and 4, low induced astigmatism resulted, requiring driving spectacles in patient 3. Conclusions PRK induced corneal ectasia in predisposed eyes, even after low myopic ablations. Forme fruste keratoconus and keratoconus in the fellow eye were the main pre-operative findings. Prognosis varies according to severity. The author has no financial or proprietary interest in any product or technique mentioned. The author has full control of all primary data, and agrees to allow Graefes Archive for Clinical and Experimental Ophthalmology to review the data upon request.     

Inhibition of corneal angiogenesis by ascorbic acid in the rat model

Purpose To evaluate the effect of topically administered ascorbic acid on experimentally induced corneal neovascularization in the rat model. Materials and methods Corneal chemical cauterization of 72 eyes in Long-Evans male rats was performed using silver nitrate/potassium nitrate sticks. Nine groups of eight eyes were used to evaluate eight concentrations of ascorbic acid with one group of eight eyes serving as a control. Topical instillation of 100 mg/ml non-pH-neutralized ascorbic acid was performed in one group while the remaining seven groups were evaluated using pH-neutralized ascorbic acid in concentrations of 100 mg/ml, 50 mg/ml, 10 mg/ml, 5 mg/ml, 1 mg/ml, 500 μg/ml, and 250 μg/ml. Results The percentage of corneal neovascularization and burn stimulus score was determined for all the eyes. The means of percent of corneal neovascularization in ascorbic acid 100 mg/ml (non-neutralized), 100 mg/ml, 50 mg/ml, 10 mg/ml, 5 mg/ml, 1 mg/ml, 500 μg/ml, 250 μg/ml, and control group were 17.50 ± 12.80 (p = 0.001), 17.00 ± 19.30 (p = 0.001), 15.25 ± 13.26 (p = 0.001), 17.62 ± 11.89 (p = 0.001), 28.87 ± 23.08 (p = 0.001), 29.62 ± 16.91 (p = 0.001), 60.12 ± 8.50 (p = 0.04), 65.62 ± 2.26 (p = 0.185), and 68.25 ± 4.06, respectively (Tables 1 and 2). All animals had a burn score of 2+ or higher (Table 1). Conclusion Ascorbic acid applied in a topical solution appears to inhibit corneal neovascularization in the rat model of inflammatory neovascularization in concentrations in a dose-dependent manner. The optimal dose-effect relation was in our model found in concentrations between 1 mg and 500 μg/ml. At concentrations below 500 μg/ml there was no statistically significant inhibition in the degree of corneal neovascularization compared to control. None of the authors has any proprietary interest in any technique or product described herein.     

角膜波面像差引导准分子激光原位角膜磨镶术(ORK-W)治疗近视临床研究

目的前瞻性研究角膜波面像差引导准分子激光原位角膜磨镶术(ORK-W)治疗近视临床效果。方法将球镜-8.00D以下,柱镜0.00D-3.00D的近视患者随机分成2组,实验组36例72眼行角膜波面像差引导准分子激光个体化切削(ORK-W),对照组30例(60只眼)行常规LASIK。观察术后1m裸眼视力、残余屈光度,角膜波面像差中的慧差、球差及总像差均方根RMS增加值,对比敏感度的改变,满意度等指标。结果术后裸眼视力、残余屈光度和满意度两组比较差异无统计学意义(P>0.05);但实验组角膜波面像差(慧差、球差、均方根RMS)的增加均较对照组明显小,两组差异有统计学意义(P<0.05),对比敏感度的改善较对照组也明显的好,两组差异有显著统计学意义(P<0.01)。结论角膜波面像差引导准分子激光个体化切削(ORK-W)可以减少术后角膜波面像差的增加,尤其减少慧差增加效果更明显,明显改善视觉质量。     

准分子激光原位角膜磨镶术双面切削法治疗高度近视远期疗效

目的 探讨准分子激光原位角膜磨镶术（LASIK）矫正高度近视角膜厚度不足时的治疗方法。方法 制作以角膜鼻侧或颞侧为蒂部的角膜瓣,角膜瓣翻转后将20%拟矫正手术量切削在角膜瓣基质面,80%手术量切削于角膜基质床。随访24～30月共28眼。结果 术后末次随访裸眼视力≥1.0共23眼（82.1%）,≥0.8共26眼（92.8%）。术后角膜地形图无明显的偏心及散光形成,未见明显角膜瓣并发症。结论 LASIK角膜瓣翻转后激光切削为高度近视角膜厚度不足的患者提供了一种完全矫正方法。手术操作的要点是要保证切削区中心的重合,并注意缩短手术时间以保护角膜上皮。     

角膜内皮移植术

角膜内皮移植是一种新的治疗角膜内皮病变的手术方法,主要是采用健康的角膜内皮片替代病变内皮层.该方法因为几乎不改变患者的角膜曲率和屈光状态,损伤小,视力恢复快,近年来在临床上逐渐被推广应用,取得较好愈后效果.该方法是角膜移植手术不断精细化和向屈光性手术转化的具体体现.角膜内皮移植术后良好的屈光效果和可能的低排斥率,使其有望成为角膜内皮病变治疗的重要方式.但是,目前内皮移植手术仍然需要完善,改进植入方法以减少脱片率和内皮细胞损失率,利用飞秒激光等进一步提高屈光效果,以及观察术后免疫排斥率是今后眼科学者的研究重点.