基质内角膜环植入术的研究

基质内角膜环是一种新型的角膜屈光矫正装置，一种非闭合的聚甲基丙烯酸甲酯环，用于矫正近视眼。本文综介绍了基质蚋角膜环植入术的手术方法、手术效果以及与手术有关的角膜变化。     

基质内角膜环植入后角膜屈光力变化实验研究

目的：观察基质内角膜环（ICR）植入术的安全性及有效性。方法：60只兔眼随机植入不同厚度的ICR,分别于术前及术后1,3天,1,2周,1,3,6月作裂隙灯检查及角膜生物测量。结果：术后各术眼角膜屈光力均出现不同程度的降低,ICR厚度与角膜屈光力变化之间存在直线相关（Y=1.4353－32.87X）。术后角膜屈光力稳定。角膜切口愈合良好,中央角膜保持透明。结论：ICR植入术是一种安全、有效、预测性好、屈光效果稳定的角膜屈光手术。     

基质内角膜环植入术的最新研究进展

基质内角膜环植入术是一种新型的有膜屈光手术。本文综合介绍了ＩＣＲＩ对角膜非球面性的影响,生物相容性的组织学检查,屈光矫正效果和术后反应的研究,以及对圆锥角膜的治疗尝试。     

圆锥角膜基质环植入术的研究进展

角膜基质环植入术(ICRS)是一种用于治疗轻中度圆锥角膜的手术方法。ICRS是通过植入基质环,使中央角膜扁平化,弧长缩短,角膜曲率半径增大,屈光力降低,从而改善角膜前突导致的轴性近视眼与不规则散光。ICRS具有微创性、安全性、有效性、可逆性且并发症少等优点,其中长期疗效较佳。本文中笔者就ICRS的发展史、适应症、手术方法、手术疗效的影响因素、术后处理及疗效的评估等方面进行阐述。     

基质内角膜环植入术的实验研究

目的　观察基质内角膜环（ＩＣＲ） 植入术在动物实验中的安全性。方法　选择３０ 只新西兰纯种兔６０ 眼随机植入不同厚度（０１９ ～０４１ ｍ ｍ ） 的基质内角膜环,分别于术前及术后１ｄ ,１ ｗ ｋ ,１ 、３ 、６ ｍｏ 作裂隙灯检查,术前及术后１ ｗｋ ,１ ｍ ｏ 作眼压检查。结果　所有各眼的角膜切口均愈合良好,ＩＣＲ 在角膜基质中表现出良好的组织相容性,未见明显的ＩＣＲ 表面角膜上皮糜烂及ＩＣＲ 被挤出现象发生。术后所有各眼中央角膜均保持透明。术前、术后眼压比较无显著性差异。周边部的角膜浑浊及切口处的新生血管生长是常见的二个并发症。结论　ＩＣＲ 植入术是一种简单、安全的角膜屈光手术     

角膜基质环植入术治疗近视眼的临床研究进展

角膜基质环植入术是一种即将兴起新的矫正近视眼的屈光手术,其区别于当今流行的屈光手术如PK、PRK和LASIK手术的主要特点在于该手术具有不损伤角膜结构的完整性和手术操作方式的可逆性,尽管目前其仍处于临床实验阶段,但据其所取得初步临床效果,已令人感到鼓舞,为此,本就目前角膜基质环植入手术有关临床方面的研究进展加以综述。     

角膜基质环植入术治疗圆锥角膜的临床疗效

目的：评估角膜基质环植入术治疗圆锥角膜的临床疗效。

方法：这一回顾性对照干预性研究对56例87眼圆锥角膜患者进行手术后随访。所有患者完善眼科检查,评估视力。15眼使用飞秒激光制备角膜隧道。72眼使用机械的方法制备角膜隧道。

结果：所有患者术前裸眼视力1.38±0.37。术后4mo裸眼视力达到0.58±0.32。术后16mo达到0.48±0.30。

结论：角膜基质环植入术是治疗圆锥角膜的有效方法。有效的干预与理想的术后视力相关。飞秒激光角膜隧道制备和机械方法一样安全。     

准分子激光屈光性角膜切削术后兔角膜基质细胞凋亡及其防治的研究

目的：探讨准分子激光屈光性角膜切削术（photorefractive keratectomy,PRK）后凋亡机制介导的角膜创伤愈合反应对屈光度数回退和角膜雾状混浊（haze）的影响,以及局部应用锌制剂的药物效果。方法：对90只新西兰白兔行双眼PRK,将左眼作为实验眼,手术前、后分别给予A组0．1％地塞米松眼液、B组0．5％硫酸锌眼液和C组0．04％丝裂霉素眼液滴眼;右眼作为对照眼。术后定期裂隙灯下观察haze的程度,测量角膜的厚度,进行光镜和透射电镜观察,采用脱氧三磷酸尿苷缺口末端标记法行凋亡细胞检测,并进行对比性分析。结果：（1）PRK术后角膜前基质细胞出现凋亡,实验眼B组凋亡细胞最少（P＜0．01）。（2）术后角膜厚度增加,前基质细胞增多,实验眼haze和增生程度眼B组凋亡细胞最少（P＜0．01）。（3）术后角膜上皮增生,实验眼B组角膜上皮厚度最小（P＜0．01）。结论：PRK术后屈光度数回退和haze的形成是凋亡机制介导的角膜创伤愈合过程,锌制剂可阻止角膜前基质细胞凋亡,最大限度减轻反应性过度增生,有望成为临床防治haze形成和屈光度数回退的理想药物。     

Clinical outcomes after implantation of a new intrastromal corneal ring with 140-degree of arc in patients with corneal ectasia

AIM: To evaluate the clinical and tomographic outcomes after implantation of a new intrastromal corneal ring segment (ICRS) with 140-degrees of arc in eyes with corneal ectasia. METHODS: We evaluated patients with corneal ectasia implanted with Ferrara 140° ICRS from April 2010 to February 2015. Outcome measures included preoperative and postoperative corrected distance visual acuity (CDVA), keratometry simulated (K) reading, tomographic astigmatism and asphericity. All patients were evaluated using the Pentacam Scheimpflug system. RESULTS: The study evaluated 58 eyes. The mean follow-up was 16.81±10.8mo. The CDVA (logMAR) improved from 0.5±0.20 (20/60) to 0.3±0.21 (20/40) (P<0.01). The average K reduced from 49.87±7.01 to 47.34±4.90 D (P<0.01). The asphericity changed from -0.60±0.86 to -0.23±0.67 D (P<0.01). The mean preoperative tomographic astigmatism decreased from -8.0±3.45 to -4.53±2.52 D (P<0.01). CONCLUSION: The new ICRS model with 140-degrees of arc effectively improve the visual acuity and reduce the high astigmatism usually found in patients with corneal ectasia.     

Clinical outcomes after intrastromal corneal ring segments reoperation in keratoconus patients

AIM:To evaluate the clinical outcomes after Ferrara intrastromal corneal ring segments (ICRS) reoperation in patients with keratoconus.RESULTS: The mean follow-up time after the reoperation was 30.5±9.7 months. The mean UCVA improved from 20/300 to 20/80 (P=0.005); the mean BCVA improved from 20/160 to 20/50 (P=0.0002), the mean keratometry reduced from 49.33±4.19D to 46.16±3.90D (P=0.0001), the mean pachymetry at the thinnest point increased from 450±42.9mm to 469±40.8mm (P=0.0001). The asphericity increased from -0.84±0.74 to -0.35±0.81 (P=0.15) and the spherical equivalent reduced from -4.64±4.87D to -3.04±3.45D (P=0.137). The changes in the asphericity and spherical equivalent were not statistically significant.CONCLUSION: Ferrara ICRS implantation showed to be a reversible and readjustable surgical procedure for keratoconus treatment. Good outcomes can be obtained even after removal, addition, reposition or exchange of ICRS.     

Complications of intrastromal corneal ring segment implantation using a femtosecond laser for channel creation: a survey of 850 eyes with keratoconus

Acta Ophthalmol. 2011: 89: 54–57

Abstract.

Purpose: To report complications after the implantation of intrastromal corneal ring segments (Keraring; Mediphacos, Belo Horizonte, Brazil) in keratoconic eyes using a femtosecond laser (IntraLase; Advanced Medical Optics, Santa Ana, California, USA) for channel creation. Methods: Retrospective chart review of 531 patients (850 eyes) who underwent Keraring insertion using a femtosecond laser for channel creation. Intraoperative and postoperative complications were recorded. Results: Intraoperatively, there were 22 (2.7%) cases of incomplete channel formation. The rest of the intraoperative complications were galvo lag error (system malfunction) [five eyes (0.6%)], endothelial perforation [five eyes (0.6%)] and incorrect entry of the channel [two eyes (0.2%)]. Postoperatively, there were 11 (1.3%) cases of segment migration, two (0.2%) cases of corneal melting and one (0.1%) case of mild infection. The overall complication rate was 5.7% (49 cases out of 850 eyes). Conclusion: In this study, intracorneal ring segment implantation using a femtosecond laser for channel creation was related to a number of complications. The most common complications were incomplete channel creation (intraoperatively) and segment migration (postoperatively).     

Clinical effectiveness of intrastromal corneal ring segments among keratoconus patients

AIM: To evaluate the clinical effectiveness of intrastromal corneal ring segments (ICRS) among the patients suffering from keratoconus. METHODS: A retrospective and non-comparative interventional design had been utilized on the basis of postoperative follow-up among 56 keratoconus patients. Visual acuity was significantly assessed during complete ophthalmic examination of the patients. The femtosecond laser had been used to create the corneal tunnels in 15 eyes; whereas, the corneal tunnels were created in 72 eyes mechanically. RESULTS: The ranges and standard deviations had been used to obtain results. It had been revealed through ophthalmic assessment that the mean preoperative uncorrected visual acuity observed was 1.38±0.37 logarithm of Minimal Angle of Resolution. Moreover, a significant improvement was observed postoperatively in visual acuity by 0.58±0.32 during the 4th month. The improvement was also witnessed in the 16th month by 0.48±0.30. CONCLUSION: The implantation of ICRS is an efficient and effective surgical intervention for the treatment of keratoconus. Thus, identified intervention seems to be associated with appropriate visual outcomes and safety after the development of femtosecond as well as mechanical tunnels.     

Evaluation of anterior and posterior surfaces of the cornea using a dual Scheimpflug analyzer in keratoconus patients implanted with intrastromal corneal ring segments

AIM: To evaluate corneal parameters measured with a dual Scheimpflug analyzer in keratoconus patients implanted with intrastromal corneal ring segments (ICRS). METHODS: Fifty eyes of 40 keratoconus patients had Ferrara ICRS implantation from November 2010 to April 2014. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refraction, keratometry, asphericity, elevation, pachymetry, root mean square (RMS), spherical aberration and coma were studied. All patients were evaluated using a dual Scheimpflug system. RESULTS: The mean follow-up time after the procedure was 12.7mo. The mean UCVA improved from 0.82 to 0.31 (P<0.001); the mean BCVA improved from 0.42 to 0.05 (P<0.0001), the mean spherical refraction changed from -3.06±3.80 D to -0.80±2.5 D (P<0.0001) and the mean refraction astigmatism reduced from -4.51±2.08 D to -2.26±1.18 D (P<0.0001). The changes from preoperative to postoperative, in parameters of the anterior and posterior surface of the cornea, were statistically significant except the elevation posterior at the apex of the cornea and posterior asphericity. CONCLUSION: The implantation of Ferrara ICRS induces changes in both anterior and posterior surfaces of the cornea.