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。     

角膜基質環植入術治療低度近視8例

目的 评价角膜内基质环矫正低度近视的短期疗效。方法 对2001年7月～2002年3月在我院治疗的8例(15只眼)低度近视患者,分别在角膜缘植入0.25mm、0.30mm、0.35mm的角膜基质环。手术後行裂隙灯检查角膜,比较手术前後视力、角膜曲率的变化。结果 术中和术后无严重并发症。术後随访3～13(平均6.75±6.22)个月、有12只眼术後视力≥0.8(75％)。手术1周後视力和角膜曲率基本稳定。结论 经短期临床观察,ICRs能够安全有效地治疗低度近视。手术操作简单、时间短     

圆锥角膜基质环植入手术前后人工晶状体度数的比较

目的:评估圆锥角膜基质环(keraring 355°)(ICRS)植入术前术后3mo人工晶状体(IOL)度数的计算和生物学特征.方法:队列研究.收集18例(19眼)圆锥角膜接受角膜基质环植入术患者术前及术后3mo数据.分析裸眼视力(UCVA), 最佳矫正视力(BCVA),屈光度,人工晶体度数计算公式,眼轴长度(AL)和角膜曲率.结果:患者平均年龄为29.58±0.6y.裸眼视力由0.84(0.35) LogMAR 显著提高到0.43 (0.31) LogMAR (P<0.001).3mo后,最佳矫正视力和眼轴长度无明显变化.球镜度数,柱镜度数和等效球镜(SE)均显著提高 (P<0.001).另一方面,角膜曲率1(K1)和角膜曲率2(K2)显著下降.3mo后, SRK/II (P<0.001), Hoffer Q (P<0.001) and Holladay I (P<0.001)发生显著变化.结论:角膜基质环植入术后,视力,屈光率和角膜曲率均有所提高,此外,人工晶状体计算公式度数明显改变.然而,角膜基质环植入术过程没有过度干预眼轴长,但降低角膜曲率值使得人工晶状体度数计算更加精确,所有公式得出同一晶状体度数.     

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。     

圆锥角膜的治疗进展

本文通过对圆锥角膜治疗方法的综述,为临床医生选择合适的治疗方法做出参考。通过数据库对“圆锥角膜”“隐形眼镜”“角膜胶原交联”“Intacs(角膜环)”“角膜成形术”“基因治疗”“不规则散光”等关键词进行搜索,并根据相关文献对圆锥角膜的治疗方法进行综述。眼镜和隐形眼镜可用于圆锥角膜早期,而疾病晚期时可采用前弹力层移植术、穿透性角膜成形术(PK)和深层前板层角膜成形术(DALK)、传导性角膜成形术和基因治疗。此外,角膜胶原交联可以阻止圆锥角膜进展,角膜基质环植入术(ICRS)通过使变形角膜变平,减少屈光不正以达到治疗目的。总得来说,眼科诊断技术和治疗方法的发展可以减缓圆锥角膜进展,从而减少晚期角膜圆锥患者对角膜移植的需要。选择恰当的圆锥角膜治疗方案可以帮助患者改善视力和预防失明。     

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。     

圆锥角膜治疗进展

圆锥角膜是一种以角膜扩张为特征,病因不明的双侧进行性角膜病变。角膜接触镜是轻中度圆锥角膜最常用的矫正方法。角膜表层镜片术、深板层角膜移植术、角膜基质环植入术、角膜交联疗法及穿透性角膜移植术是临床上常用的手术治疗方法。     

圆锥角膜的诊断与治疗

圆锥角膜是一种双侧非炎性角膜扩张性疾病,其特征主要为中央和旁中央区角膜基质变薄和呈圆锥形突起。早期圆锥角膜的诊断标准并未完全统一。现今用于诊断圆锥角膜的仪器主要有Orbscan角膜地形图、Pentacam眼前节测量分析仪、共焦显微镜、眼反应分析仪等,手术治疗方法主要有角膜移植术、基质环植入术、交联疗法等。本文综述近年来用于圆锥角膜诊断的常用仪器的优缺点及手术治疗方法,为临床上选择更适宜的检测仪器和治疗方法提供依据。     

角膜基质环植入术的研究进展

角膜基质环(intrastromal corneal ring，ICR)植入术，是一种矫正低、中度近视的角膜屈光手术。它与PRK，LASIK不同，不需切削角膜中央光学区组织，手术后患者不会出现任何异物感。而且具有可预测性、安全性、稳定性及可逆性和可调换性的优点。     

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。     

Intraocular pressure measurement in patients with instrastromal corneal ring segments.

PURPOSE: To study the measurement of intraocular pressure after implantation of Intacs (ICRS) intrastromal corneal ring segment, a device that is positioned circumferentially in the peripheral corneal stroma to correct myopia. The device changes the corneal curvature by shortening arc length. Since the ring segments are made of polymethylmethacrylate, this may cause localized changes in corneal elasticity so intraocular pressure measurement may be affected. METHODS: We measured the intraocular pressure of 12 eyes in which the ICRS had been in place longer than 6 months. We used Goldmann applanation and Tono-Pen tonometers over the central corneal and the paracentral corneal areas. We also measured the intraocular pressure with the Tono-Pen applanated directly over the intrastromal corneal ring segments. RESULTS: The resulting intraocular pressure measurements were similar for the Tono-Pen tonometer readings over the central cornea, paracentral cornea, and the Goldmann applanation tonometer readings over the central cornea (P < .01). Our measurements using the Goldmann applanation tonometer on the paracentral corneal area showed artificially elevated intraocular pressure in the 40 to 60 mmHg range. We were not able to obtain consistent results when we measured the intraocular pressure using the Tono-Pen on the corneal area directly overlying the intrastromal corneal ring segment implants. CONCLUSION: Consistent intraocular pressure measurements on eyes with the ICRS can be obtained with the Goldmann applanation tonometer over the central corneal area or with the Tono-Pen tonometer over the central or paracentral corneal areas.     

Photorefractive keratectomy after intrastromal corneal ring segment explantation

PURPOSE: To describe a case of photorefractive keratectomy after removal of intrastromal corneal ring segments from the cornea. METHODS: During United States Food and Drug Administration Phase III Trials for intrastromal corneal ring segments (ICRS), the implanted segments were removed from the cornea of the right eye of a patient because of dissatisfaction with glare, halos, and fluctuating vision. Ten months after ICRS explantation, the-patient underwent a photorefractive keratectomy procedure to the same eye. RESULTS: One month after removal of the ICRS, the patient's manifest refraction was within +/- 0.50 diopters of his original manifest refraction. Photorefractive keratectomy was planned to the same eye 6 months later. At the first attempt, the epithelium could not be removed with the laser and scrape technique, and residual epithelium was noted at the vertical meridian (12 o'clock) corneal incision site, which had been used for ICRS surgery and explant; therefore, the procedure was aborted. At the second attempt, with a mechanical epithelial brush (AMOILS Epithelial Scrubber; Innova, Inc, Toronto, Canada), the epithelium was removed with ease. After this, photorefractive keratectomy was done without difficulty or complication. At his most recent 8-month postphotorefractive keratectomy examination, the patient had an uncorrected visual acuity of RE: 20/16, with a manifest refraction of -0.75 to 0.75 x 170 degrees, a faint haze at the site of the stromal channel, and a small scar at the incision site on slit-lamp examination. CONCLUSIONS: Intrastromal corneal ring segments can be readily removed from the cornea, if required. In this case, the refraction returned to its preoperative state soon after the explant procedure and remained stable over time. Photorefractive keratectomy was performed as a secondary refractive surgical procedure after the removal of ICRS without difficulty or complication. However, removal of the epithelium is probably best accomplished with the use of an epithelial brush, considering the changes in the epithelial adherence in a postsurgical cornea. Further studies are required to establish the safety and efficacy of secondary refractive surgical procedures after ICRS explantation.     

Spontaneous breakage of intracorneal ring segments (ICRS) 8 years after implantation

We present a case of spontaneous in situ breakage of intracorneal ring segments (ICRSs) 8?years after their implantation in a patient with keratoconus. The patient presented to our clinic with a red and painful right eye that had not improved despite topical steroids and antibiotics. The decision was made to explant the broken ICRSs from the cornea and send them for laboratory analyses, by which manufacturer defects were excluded. It is noteworthy that corneal curvature re-steepening was observed 4?months after ICRS removal despite the performance of crosslinking (CXL) 1?year prior to ICRS implantation.     

Topographic predicted corneal acuity with intrastromal corneal ring segments.

PURPOSE: To evaluate predicted optical quality of the central anterior corneal surface before and after the intrastromal corneal ring segment (ICRS) refractive procedure using a clinical videokeratoscope and software index developed for that purpose. METHODS: Predicted corneal acuity, a topographically derived index provided with the EyeSys System 2000 videokeratscope, representing potential optical quality of the cornea, was assessed preoperatively and at postoperative month 3 in 94 eyes that received an ICRS to treat -1.00 to -6.00 D of myopia. Predicted corneal acuity was calculated by determining the difference between a measured cornea and its best-fit ellipses for reflected ring circumferences within the central 3 mm diameter zone. RESULTS: Preoperative predicted corneal acuity was 20/10 in 92 of 94 eyes (98%). At month 3 after the ICRS procedure, 48 (51%) of moderately myopic eyes were corrected to 20/20 or better, 96% (90 eyes) were corrected to 20/40 or better, and 98% of eyes (92 eyes) had a predicted corneal acuity of 20/10. For the eyes with a predicted corneal acuity of 20/10, spectacle-corrected visual acuity was normally distributed between 20/10 and 20/25. CONCLUSION: Predicted corneal acuity did not change significantly from baseline in eyes with an ICRS. This suggests that topographic irregularities in the central 3 mm of the cornea detectable by predicted corneal acuity software were not induced in the central cornea with the ICRS.     

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.     

Aspergillus fumigatus keratitis following intracorneal ring segment implantation

ABSTRACT: BACKGROUND: Fungal keratitis has been rarely reported following intracorneal ring segment (ICRS) inmplantation. This paper aims to report a case of fungal keratitis with aspergillus fumigatus following ICRS implantation for correction of keratoconus. METHODS: A retrospective chart review was done. Data including demographics, clinical history and presentation, microbiological analysis as well as clinical management were recorded. RESULTS: A 34 year old male presented with pain, photophobia, redness and decreased vision in his right eye ten days after ICRS implantation for correction of keratoconus. Slit-lamp examination showed chemosis, ciliary injection, corneal abcess with ill defined edges and hypopyon. Microbiological analysis and culture of the corneal scrapes were positive for aspergillus fumigatus. The patient did not respond to medical treatment and ended up with corneal transplantation. CONCLUSION: Although rare, fungal keratitis is a serious vision threatening complication that can complicate intrastromal ring implantation. Prompt and aggressive treatment is essential to prevent irreversible reduction of vision.     

Intrastromal corneal ring segments for management of keratoconus

Keratoconus is a progressive corneal ectasia, which can be managed both by conservative measures like glasses or contact lenses in non-progressive cases or surgical procedures like collagen crosslinking (CXL) with or without adjuvant measures like intrastromal corneal rings segments (ICRS) or topography guided ablation. Various kinds of ICRS are available to the surgeon, but it is most essential to be able to plan the implantation of the ring to optimize outcomes.

Aims:

The aim of this study is to evaluate the visual outcome and progression in patients of keratoconus implanted with ICRS.

Materials and Methods:

Two different types of ICRS-Intacs (Addition Technology) and Kerarings (Mediphacos Inc.) were implanted in 2 different cohorts of patients and were followed-up to evaluate the outcome of the procedure. All patients underwent a complete ocular examination including best spectacle corrected visual acuity, slit lamp examination fundus examination, corneal topography and pachymetry. The ICRS implantation is done with CXL to stop the progression of the disease. Improvement in uncorrected visual acuity (UCVA), best spectacle corrected visual acuity and topographic changes were analyzed.

Results:

A significant improvement in keratometry and vision was seen in both groups.

Conclusion:

ICRS have been found to reduce corneal irregularity and flatten keratometry with improvement in UCVA and best corrected visual acuity.     

Experimental imaging of intracorneal ring segments with optical coherence tomography

PURPOSE: To investigate the imaging of corneal structures with optical coherence tomography (OCT) after implantation of intracorneal ring segments (ICRS). METHODS: In an experimental study with six porcine eyes, qualitative and quantitative imaging with corneal OCT using a wavelength of 1310 nm after implantation of ICRS was performed. The optical results were compared with light microscopy of the histological sections. RESULTS: In corneal OCT, the ICRS revealed marked hyporeflective intrastromal areas, which correlated well with macroscopic and microscopic findings. Corneal OCT enabled precise images of the incision depth for the implantation of ICRS, and the exact intrastromal segment position. CONCLUSIONS: Noncontact slit lamp-adapted corneal optical coherence tomography could be employed to clinically monitor corneal changes after implantation of ICRS, evaluate the depth of the segments to correlate refractive changes, and quantify the stromal wound healing response.     

Confocal microscopy after implantation of intrastromal corneal ring segments

OBJECTIVE: Confocal in vivo real-time microscopy was used to study the corneal morphologic features in eyes after Intrastromal Corneal Ring Segments (ICRS; now called KeraVision INTACS, KeraVision, Inc., Fremont, CA) implantation. DESIGN: Noncomparative, interventional case series. PARTICIPANTS: The authors performed confocal real-time microscopy on a total of 21 eyes from 11 patients. Seventeen eyes from 10 patients (five female, five male; mean age 32.3 years; range 22-42 years) underwent uncomplicated ICRS surgery to correct myopia and were examined after surgery (average 8.6 months; range 2-15 months). Three patients had the ICRS implanted into only one eye, and those eyes were compared with the untreated fellow eyes. One eye of another patient was examined 1 and 6 months after ICRS removal. INTERVENTION: Flying slit-confocal microscopy was performed with water immersion objectives in the corneal center and near the nasal or temporal ICRS. Corneal optical sections were recorded in real time without further digital processing and were reviewed frame by frame. MAIN OUTCOME MEASURES: Video frames selected from all corneal layers were evaluated qualitatively and quantitatively. RESULTS: In the central cornea, we found normal morphologic features at all layers. In peripheral sections, epithelial cells with highly reflective nuclei in the basal cell layer were observed in six of 17 eyes (35%) implanted with ICRS. We found an intact corneal nerve plexus and undisturbed corneal endothelium immediately underneath the ICRS. Around the ICRS, moderate fibrosis was seen. In one eye, linear structures in bamboo-like orientation were detected after ICRS removal in the last keratocyte layer underneath the collapsed tunnel. CONCLUSIONS: Whereas the central corneal zone appears unchanged, the corneal stroma adjacent to the ICRS displays a slight, but distinct, activation of wound healing. Epithelial cells with highly reflective nuclei in this region may be an indicator for an increased biologic stress caused by the device.     

Clinical outcomes of management of posterior capsule rupture with air bubble techniques

AIM: To evaluate the clinical outcomes after implantation of a new intrastromal corneal ring segment associated with photorefractive keratectomy (PRK) to correct high myopia (ICRS HM) in patients with thin corneas. METHODS: We evaluated 42 eyes of 23 patients that had ICRS HM implantation followed by PRK. The mean age of patients was 29.1±7.12y (range 18 to 40 years old). Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), keratometry, spherical equivalent, pachymetry, and aberrometry were compared using ANOVA with repeated measurements assessed preoperatively and at last follow-up visit after the procedures. The refractive predictability and simulated/real corneal ablation were also assessed. RESULTS: The mean follow-up time after PRK was 6.8±1.6mo. The mean preoperative UCVA improved from 20/800 preoperative to 20/100 after ICRS and 20/35 after PRK. The mean preoperative BCVA was 20/25 (range from 20/40 to 20/20) and remained unchanged after ICRS HM implantation. Following the PRK the mean BCVA was 20/25 (range from 20/40 to 20/20). The mean spherical equivalent decreased from -7.25±1.12 (range -5.00 to -9.00) preoperatively to -3.32±1.0 (range -2.00 to -5.00) postoperatively (P<0.001) after ICRS HM, ICRS implantation and decreased from -2.44±1.51 preoperatively to 0.32±0.45 (range -0.625 to 0.875) postoperatively (P<0.001) after PRK. The change in BCVA and topographic astigmatism was statistically significant (P<0.0001). CONCLUSION: ICRS HM associated with PRK can be a tissue saving procedure and an alternative surgical option for correction of moderate to high myopia.