角膜胶原交联治疗进展期圆锥角膜的临床观察

目的 探讨紫外线A (UV-A)-核黄素角膜胶原交联(CXL)治疗进展期圆锥角膜的安全性和有效性.方法 回顾性系列病例研究.13例(22只眼)进展期圆锥角膜,表面麻醉下去除角膜中央8mm范围内上皮,0.1％核黄素溶液(20％右旋糖酐作为溶剂)每3 min滴1次,时间30 min,然后使用370 nm UV-A照射30 min,能量为3.0 mW/cm2.平均观察(15.23 ±3.39)个月,术前和术后1、3、6及12个月复查,检查指标包括视力、角膜地形图、角膜活体激光共焦显微镜和角膜内皮计数等.对手术前后裸眼视力、矫正视力、眼压、角膜厚度、角膜内皮计数、Kmax和平均散光差异的比较采用配对t检验.结果 术后12个月裸眼视力和最佳矫正视力分别较术前提高0.115±0.158(t=3.418,P=0.0026)和0.114±0.218(t=2.441,P=0.0236)(LogMAR视力表).术后12个月Kmax值和散光分别较术前降低(1.893±3.713)D(t=2.391,P=0.0262)和(0.117±1.488) D(t=0.370,P=0.715).角膜厚度术后1个月时减少(27.5±26.8)μm(t=4.812,P=0.000),其后角膜厚度逐渐增加,术后12个月时角膜厚度与术前相比无统计学意义(t=0.147,P =0.885).术后角膜内皮、眼压、晶状体和眼底无明显变化.结论 CXL可以阻止进展期圆锥角膜病变发展,在1年的随访期内可观察到视力和角膜地形图的指标的改善,CXL将是治疗进展期圆锥角膜一个安全有效的方法.     

角膜胶原交联术治疗圆锥角膜的疗效和安全性研究

目的：研究角膜胶原交联术治疗圆锥角膜的疗效和安全性。

方法：对2015-04/2018-08在泰国朱拉隆功国王纪念医院行角膜胶原交联术的圆锥角膜患者病历进行回顾性分析。评估术前和术后1a的视力、屈光度、角膜地形图、高阶像差(HOA)、地形图参数和角膜密度。根据患者年龄是否小于24和30岁、基线角膜最大曲率(Kmax)是否小于55 D、基线最佳矫正视力(BCVA)是否小于0.3 LogMAR分组评估年龄、基线Kmax和BCVA对手术疗效的影响。分析术前Kmax、Kmean、平均等效球镜度数(MRSE)、视力、角膜最薄点厚度值、Kmax的变化以及相关参数的变化与角膜密度测量值变化之间的关系。P<0.05具有统计学意义。

结果：共155例患者185眼纳入研究,其中119例男性,36例女性。根据Amsler-Krumeich进行分类,1期和2期占优势(分别为37.84%和35.14%)。术后1a,平均裸眼视力(UCVA)提高0.1 LogMAR(P<0.05)。与基线BCVA较好组(术前BCVA<0.3 LogMAR)相比,基线BCVA较差组(术前BCVA≥0.3 LogMAR)术后BCVA改善大于0.2 LogMAR的眼数较多(78.26% vs 21.74%,P<0.05)。平均Kmax比基线下降2.36 D(P<0.05)。术前Kmax≥55 D的患眼术后Kmax下降超过2.0 D的眼数占比73%。距角膜顶点6 mm处角膜HOA下降0.40(P<0.05)。术后1mo～1a,0～6 mm区角膜密度测量值持续增加。术后1a,角膜密度的增加与最薄点厚度的减少呈线性相关。表面变异指数、高度非对称性指数、圆锥角膜指数、高度轴偏心指数在术后1a时下降(P<0.05)。术后1a,手术成功率为90.24%。术后1wk、1、3、6mo、1a角膜混浊发生率分别为11.35%、30.27%、15.67%、10.27%、2.16%。无角膜水肿发生,但有1例无菌性角膜炎患者。

结论：角膜胶原交联术可有效治疗圆锥角膜,使角膜变平、重塑,提高视力、HOA和角膜形态指数,晚期圆锥角膜Kmax也明显降低。     

保留上皮角膜胶原交联术治疗青少年圆锥角膜的疗效分析

背景 圆锥角膜是一种角膜进行性膨隆和变薄的疾病,常于青少年时期发病,伴随不同程度的视觉质量下降.角膜胶原交联术(CXL)是利用维生素B2和紫外线A(UVA)之间的光氧化反应来增加角膜硬度,延缓甚至阻止圆锥角膜膨隆的进展. 目的 评估保留上皮CXL治疗青少年圆锥角膜的安全性和有效性. 方法 纳入2010年2月至2013年3月于温州医科大学附属眼视光医院拟行保留上皮CXL的原发性圆锥角膜患者9例10眼,年龄13 ～ 17岁,平均(15±1)岁.术中使用质量分数0.1％丁卡因滴眼液作为促渗剂点眼,再使用质量分数0.5％核黄素液点眼至前房饱和状态,最后使用强度为3 mW/cm2的紫外线A照射30 min.术后7d、1个月、3个月、6个月及12个月测量远距裸眼视力(UDVA)、远距矫正视力(CDVA)、球镜度、柱镜度、等效球镜度(SE)、角膜前表面最大角膜曲率值(Kmax)、角膜前后表面高度值、角膜最薄点厚度.术后7d测量角膜内皮细胞密度(ECD).记录术后角膜上皮愈合时间. 结果 保留上皮CXL术后角膜上皮平均愈合时间为(1.4±0.8)d.术后12个月时,平均UDVA、CDVA分别从术前的1.02±0.16和0.34±0.20改善至0.77±0.18和0.25±0.15,平均球镜度和SE分别从(-7.15±3.00)D和(-9.26±3.23)D改善为(-5.28±2.05)D和(-7.05±2.08)D,平均Kmax从(64.1±11.9)D降低至(61.8±10.4)D,差异均有统计学意义(t=4.251、3.750、-2.515、-2.597、2.304,均P＜0.05).术前与术后12个月平均柱镜度、角膜最薄点厚度比较差异均无统计学意义(t=-1.331、0.328,均P＞0.05).术前与术后7 d ECD的比较差异无统计学意义(t=1.205,P＞0.05).有2眼分别在术后3个月和术后6个月开始出现持续的角膜基质混浊. 结论 保留上皮CXL能够安全、有效地延缓或阻止青少年圆锥角膜的进展.     

核黄素/紫外线A诱导的角膜交联术治疗 薄角膜圆锥角膜术后3年疗效

目的：评估核黄素/紫外线A胶原角膜交联术（CXL）治疗薄角膜圆锥角膜患者术后的长期疗效。方法： 前瞻性研究。收集2015年1-7月因圆锥角膜于山东大学附属省立医院眼科行CXL治疗的患者19例（32 眼），其中男12例（21眼），女7例（11眼）。以角膜基质厚度400 µm为分界线，将圆锥角膜患者分为薄 角膜组和厚角膜组。薄角膜组使用低渗性核黄素溶液进行角膜交联术治疗，厚角膜组使用等渗核 黄素溶液进行CXL治疗，术后随访3年，观察角膜最大K（Kmax）值、裸眼视力（UCVA）、最佳矫正 视力（BCVA）、最薄处角膜厚度（TCT）、眼压及角膜内皮细胞计数（ECD）等参数变化。采用重复测 量方差分析、t检验、Wilcoxon符号秩和检验、Mann-Whitney U检验进行数据处理。结果：薄、厚角 膜组术后Kmax值随时间延长均持续降低（F=24.364，P<0.001；F=10.427，P=0.001）；薄角膜组术前， 术后1、2、3年Kmax值分别为（60.51±6.11）D、（57.43±6.82）D、（56.13±6.85）D、（54.97±6.66）D， 术后各时间点与术前相比差异均有统计学意义（t=3.670，P=0.002；t=4.637，P<0.001；t=5.816，P< 0.001）；厚角膜组术前，术后1、2、3年Kmax值分别为（54.56±6.27）D、（53.25±6.42）D、（52.32± 6.47）D、（51.58±6.70）D，术后各时间点与术前相比差异均有统计学意义（t=2.266，P=0.040； t=3.302，P=0.005；t=3.769，P=0.002）；术前薄角膜组Kmax值高于厚角膜组（t=2.714，P=0.011），术 后1、2、3年2组间Kmax值差异无统计学意义。术后3年，薄角膜组UCVA、BCVA、TCT与术前 相比差异有统计学意义（Z=-2.716，P=0.007；Z=-3.063，P=0.002；t=4.468，P<0.001），厚角膜组 UCVA、BCVA、TCT与术前相比差异有统计学意义（t=3.572，P=0.003；Z=-2.956，P=0.003；Z= -3.410，P=0.001）。2组眼压、ECD与术前相比差异均无统计学意义。薄、厚角膜组术前组间及术后 3年组间UCVA、BCVA、眼压、ECD比较差异均无统计学意义；术前、术后3年组间TCT差异有统计 学意义（Z=-4.816，P=0.001；Z=-4.024，P<0.001）。结论：CXL可以安全有效地控制薄角膜圆锥角膜 患者病情进展，提高视力。     

离子导入辅助角膜交联治疗青少年圆锥角膜

目的：评估离子导入辅助的跨上皮角膜交联治疗青少年圆锥角膜的安全性和有效性。方法：搜集12例(年龄12~18岁,平均15.8±2.08岁)进展期圆锥角膜患者,共15眼,采用0.1%核黄素蒸馏水溶液,离子导入(1 mA电流)辅助跨上皮给药5min,紫外线A(370 nm,3 mW/cm2)照射30min。记录术前、术后3mo和1a的裸眼视力、最佳矫正视力、K1、K2、最大K值、平均K值、角膜散光度数、角膜内皮细胞密度、眼内压、最薄角膜厚度、角膜顶点厚度。角膜参数应用角膜地形图评估,角膜内皮细胞密度应用非接触角膜内皮镜检查。结果：角膜交联1a后,裸眼视力、最佳矫正视力、K1、K2、最大K值、平均K值、角膜散光度数、角膜内皮细胞密度和眼内压均无显著变化。最薄角膜厚度从468.08±33.40μm下降到447.46±40.20μm (t=4.379,P=0.001),差异有统计学意义。角膜顶点厚度从476.07±35.96μm下降到454.60±49.32μm(t=4.270,P=0.001),差异有统计学意义。结论：采用0.1%核黄素蒸馏水溶液的离子导入辅助的角膜交联治疗青少年圆锥角膜是安全、有效的,1 a内能够阻止病情恶化,但是长期效果有待于进一步观察。     

圆锥角膜深板层角膜移植术后高度散光的角膜楔形切除术

目的 分析圆锥角膜深板层角膜移植术后高度散光行角膜楔形切除的临床疗效.方法 回顾性分析了圆锥角膜深板层角膜移植术后继发较高度散光的6例(6眼),采用对称或不对称的受体角膜植床组织楔形切除的方法治疗.随访内容为:裸眼视力、电脑验光结果、最佳矫正视力、角膜地形图结果.结果 术后3年,矫正视力由术前的0.62±0.16,增加到0.73 ±0.16(P＞0.05).K散光由术前的(8.37±2.91)D,减低到(2.86±2.06)D(P ＜0.01).所有病例均能接受佩戴框架眼镜.结论 角膜楔形切除是矫正圆锥角膜深板层角膜移植术后高度散光的有效方法.     

跨上皮快速角膜胶原交联术治疗进展期圆锥角膜

目的:研究跨上皮快速角膜胶原交联术(CXL)治疗进展期圆锥角膜的临床效果和安全性。方法:前瞻性自身前后对照研究。收集自2016-08/2019-11在我院进行跨上皮快速CXL的进展期圆锥角膜患者37例47眼,分析患者术前,术后1、3、6、12mo的裸眼视力(UCVA)和最佳矫正视力(BCVA)、屈光状态、角膜透明度、角膜前表面最大K值(Kmax)、角膜最薄点厚度、角膜内皮细胞计数、眼压。结果:术后1、3、6、12mo患者UCVA较术前提高,但总体比较无差异(F=1.372,P=0.261)。患者术后1、3、6、12mo的BCVA均较术前提高,总体比较有差异(F=3.308,P=0.019),进一步比较发现术后3、6、12mo的BCVA与术前比较有差异(P=0.04、0.01、0.007)。患者术后1、3、6、12mo的球镜度数、柱镜度数、Kmax、角膜最薄点厚度与术前总体比较无差异(F=0.293、1.378、2.448、1.970,P=0.881、0.258、0.061、0.116)。术后1mo患者角膜内皮细胞计数与术前比较无差异(t=1.156,P=0.25)。患者术后各时间点眼压与术前比较无差异(F=1.221,P=0.321)。术后7眼出现角膜Haze(1级~2级),术后3~6mo有5眼Haze消退,角膜恢复透明,1眼遗留角膜云翳,1眼角膜中央基质线状混浊,但均未对视力造成影响。结论:跨上皮快速CXL可以显著提高圆锥角膜患者BCVA,稳定患者屈光状态、角膜形态和厚度,阻止或延缓圆锥角膜进展,使患者获得更好的视功能,同时手术时间短,术后并发症少,具有较好的安全性。     

角膜交联手术前后圆锥角膜患者眼压和角膜生物力学参数的变化及其相关性

目的　探讨角膜交联手术前后圆锥角膜患者眼压和角膜生物力学参数的变化和相关性。方法　选取2017年11月至2018年10月在我院眼屈光中心就诊并确诊为进展期圆锥角膜患者68例(79眼),所有患者均行快速跨上皮角膜交联手术进行治疗。所有患者均行常规眼科检查,采用三维眼前节分析系统Pentacame(德国Oculus公司)检查患者角膜形态,非接触式眼压计（日本Topocon公司）测量患者非接触式眼压（NCT）,角膜生物力学眼压分析仪Corvis ST（德国Oculus公司）测量患者非矫正眼压（IOPnct ）、生物力学矫正眼压（bIOP）及角膜生物力学参数。结果　角膜交联手术后3个月、6个月和1年患者的角膜中央厚度分别为（443.92±28.33）μm、（448.22±34.65）μm、（449.21±32.34）μm,与术前角膜中央厚度［（449.17±32.60）μm］相比,差异无统计学意义( F=0.370,P=0.87)。角膜交联手术后3个月、6个月和1年患者的角膜前表面曲率分别为（49.41±4.28）D、（48.54±2.57）D、 （48.77±2.29）D,术前角膜前表面曲率为（49.54±4.67）D,术后6个月和1年较术前明显下降,差异均有统计学意义(均为P<0.05）。角膜交联手术后6个月和1年患者NCT分别为（10.73±2.91）mmHg（1 kPa=7.5 mmHg）、（11.13±2.50）mmHg,明显高于术前［（8.30±2.96）mmHg］,差异均有统计学意义（均为P<0.05）。术后3个月和1年患者IOPnct分别为（13.64±2.40）mmHg、（13.94±2.01）mmHg,均高于术前［（11.47±2.12） mmHg］,差异均有统计学意义（均为P<0.05）。术后6个月和1年患者角膜第一次压平长度低于术前,第二次压平速率大于术前,差异均有统计学意义（均为P<0.05）。NCT和IOPnct与角膜中央厚度均具有明显的正相关性（均为P<0.05）,与第一次压平长度、最大变形幅度和顶点距离均具有明显的负相关性（均为P<0.05）。结论　角膜交联手术会导致患者NCT测量值增高,角膜生物力学眼压分析仪Corvis ST可以排除角膜生物力学参数对圆锥角膜患者眼压测量的影响。     

进展期圆锥角膜去上皮快速角膜交联后早期角膜生物力学的变化

目的 评价去上皮快速角膜交联治疗进展期圆锥角膜的临床疗效及对早期角膜生物力学的影响。方法 前瞻性自身对照研究。对2018年3月到2019年3月进展期圆锥角膜患者18例(29只眼),进行去上皮快速角膜交联治疗。分别在治疗前(基线)和治疗后1、3、6个月采用Corvis ST和Pentacam测量角膜生物力学指标和角膜地形图等。主要观察指标包括第1次压平角膜硬度参数(SP-A1)、角膜最薄点厚度、角膜最大曲率(Kmax)、屈光状态和角膜内皮计数等。对治疗前后的指标进行配对t检验和独立样本t检验。结果 共治疗患者18例(29只眼),平均年龄为(20.33±5.91)岁。术前SP-A1为65.04±15.59,术后1、3、6个月的SP-A1分别为62.44±12.87、69.95±14.89、73.71±15.50,术后1个月SPA1较术前有所下降,但与术前比较差异无统计学意义(P> 0.05);术后6个月较术前明显升高(P <0.05)。68.9%的患者术后6个月时SP-A1改善,与无改善组相比术前Kmax和术前SPA1存在差异(P <0.05)。结论 去上皮快速角膜交联治...     

核黄素角膜胶原交联治疗早期轻中度圆锥角膜的研究

目的：核黄素角膜胶原交联早期治疗轻度至中度圆锥角膜的预后。

方法：三级眼科诊疗中心的前瞻性研究。共38例47眼轻至中度圆锥角膜接受核黄素角膜胶原交联治疗的患者纳入本研究。术前数据包括参与眼数,视力,眼压,角膜厚度与角膜地形图。术后数据包括最佳矫正视力,眼压,角膜厚度,角膜地形图和术后并发症。

结果：研究包含年龄16～30岁的患者38例47眼。平均术前视力为0.58±0.40 logMAR,术后随访2a显著提高(0.40±0.27logMAR)(P=0.005)。平均术前角膜曲率为50.5±4.6 D,术后显著降低。随访2a平均角膜曲率为48.2±4.1 D(P=0.011)。术后随访2a眼压(15.1±3.0mmHg)较术前(12.9±2.5 mmHg)显著增加(P=0.035)。术前角膜厚度467.9±38.8 μm,术后随访2a(465.0±39.3 μm)明显降低。所有患者均无并发症出现。

结论：早期使用核黄素角膜胶原交联治疗轻至中度圆锥角膜可获得长期的良好视力,而不必等其发展为进展期。     

5-year follow-up of combined non-topography guided photorefractive keratectomy and corneal collagen cross linking for keratoconus

AIM: To evaluate the visual outcomes of simultaneous non-topography guided photorefractive keratectomy (PRK) and corneal collagen cross-linking (CXL) in eyes with keratoconus 5y after the procedure. METHODS: Prospective, interventional, non-randomized, and non-controlled case series design was used. Sixty eyes of 30 patients (16 males and 14 females; age: 21-41y) with mild, non-progressive (stages 1-2) keratoconus were enrolled. Refraction, uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) , flat and steep keratometry readings, and adverse events were evaluated preoperatively and postoperatively. Data were collected preoperatively and postoperatively at 3mo, 1, 2, 3, 4, and 5y follow-up visits after combined non-topography-guided PRK with CXL was performed. All patients had at least 5y of follow-up. RESULTS: All study parameters showed a statistically significant improvement at 5y over baseline values. The mean follow-up time was 68.20±4.71mo (range: 60-106mo). Patients showed a significant improvement in UDVA from 1.24±0.79 logMAR prior to combined non-TG-PRK+CXL to 0.06±0.15 logMAR postoperatively at the time of their last follow-up visit. CDVA significantly increased from 0.06±0.19 logMAR preoperatively to 0.03±0.12 logMAR postoperatively. A significant decrease in the mean spherical equivalent (SE) refraction was observed from -2.28±1.8 to -0.79±0.93 diopters (D) (P<0.05), and the manifest sphere decreased from -1.62±1.23 to -0.27±0.21 D (P=0.001). The manifest cylinder significantly decreased from -1.73±0.86 to -0.29±0.34 D postoperatively (P=0.001). The mean steep keratometry was 45.13±1.32 vs 47.28±2.12 D preoperatively (P<0.05), and the preoperative mean steepest keratometry (Kmax) 48.6±3.1 was reduced significantly to 46.8±2.9 postoperatively (P<0.05). CONCLUSION: Combined non-TG-PRK with 15min CXL is an effective and safe option for correcting mild refractive error and improving visual acuity in patients with mild stable keratoconus.     

【In Press】 Five-year follow-up of combined non-topography guided photorefractive keratectomy and corneal collagen cross linking for keratoconus

AIM: To evaluate the visual outcomes of simultaneous non-topography guided photorefractive keratectomy (PRK) and corneal collagen cross-linking (CXL) in eyes with keratoconus 5 y after the procedure. METHODS: Prospective, interventional, non-randomized, and non-controlled case series design was used. Sixty eyes of 30 patients (16 males and 14 females; age: 21-41y) with mild, non-progressive (stages 1-2) keratoconus were enrolled. Refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuities, flat and steep keratometry (K) readings, and adverse events were evaluated preoperatively and postoperatively. Data were collected preoperatively and postoperatively at 3-months, 1-, 2-, 3-, 4-, and 5-year follow-up visits after combined non-topography-guided PRK with CXL was performed. All patients had at least 5y of follow-up. RESULTS: All study parameters showed a statistically significant improvement at 5y over baseline values. The mean follow-up time was 68.20±4.71mo (range: 60-106mo). Patients showed a significant improvement in UDVA from 1.24±0.00 logMAR prior to combined non-TG-PRK+CXL to 0.06±0.00 logMAR postoperatively at the time of their last follow-up visit. CDVA significantly increased from 0.06±0.00 logMAR preoperatively to 0.03±0.00 logMAR postoperatively. A significant decrease in the mean spherical equivalent (SE) refraction was observed from -2.28±1.8 to -0.79±0.93 diopters (D) (P<0.05), and the mean cylinder decreased from -1.628±0.76 (preoperative) to -0.25±0 (postoperative) (P=0.001). The mean keratometry was 45.13±0.00 vs 47.28±0.00 D preoperatively (P<0.05), and the manifest astigmatism significantly decreased from -1.63±0.76 to -0.25±0 (P=0.001). CONCLUSION: Combined non-topography-guided PRK with 15min is an effective and safe option for correcting mild refractive error and improving visual acuity in patients with mild stable keratoconus.     

非角膜地形图引导PRK联合角膜胶原交联术治疗圆锥角膜

目的：评估非角膜地形图引导圆锥角膜患者行光折变角膜切除术(PRK)和角膜胶原交联术(CXL)的视力、屈光度和临床疗效。

方法：术后1mo, 3mo, 6mo and 12mo对34例患者未矫正视力(UDVA)和矫正距离视力(CDVA),平、陡角膜测量读数以及并发症进行评估。

结果：共34例患者平均年龄为23.3±4.0岁。UDVA和CDVA显著提高,且术后1a恢复平稳。通过超过1a的定期随访,T检验显示术前术后值有显著不同(P<0.05)包括视力,球面和柱面变化。Fourier术后图像分析显示轴向位移垂直于术前轴。

结论：非角膜地形图引导PRK联合CXL对于治疗圆锥角膜是一种安全有效的手术选择,能够提高UDVA,CDVA和屈光状态。术后3mo达到稳定状态,与非角膜地形图引导PRK相比,地形图引导的唯一优势可能是通过Fourier术后分析,在某些患者中,球镜和柱镜轴位漂移。     

A novel analysis of Scheimpflug total corneal refractive power following corneal cross-linking in mild to moderate keratoconus

AIM: To detect an earlier improvement in mild to moderate keratoconus following corneal cross-linking (CXL) with total corneal refractive power (TCRP) using ray tracing method. METHODS: A total of 40 eyes of 30 consecutive patients who underwent CXL for progressive keratoconus were retrospectively enrolled. The following keratometric parameters provided by Pentacam HR, including maximum keratometry (Kmax), steepest keratometry (Ksteep), 3 mm zonal TCRP centered over corneal apex (TCRPapex,zone 3 mm), zonal mean keratometry and TCRP centered over corneal cone (Kmcone,zone and TCRPcone,zone 1, 2, 3 mm) were evaluated preoperatively and 1, 3, 6, and 12mo postoperatively. Groups 1 and 2 were defined based on Kmax at postoperative 1mo as improved (the initial improvement group) or worsen (the initial deterioration group) compared to the preoperative level. RESULTS: In the overall group, only keratometric parameters based on ray tracing method displayed significant improvement early at 3mo postoperatively, in which TCRPcone,zone 1 mm and 2 mm exhibited the largest flattening (0.57 D and 0.53 D, respectively). In Group 1, only Kmax, Kmcone,zone 2 mm and TCRPcone,zone 2 mm showed significant improvement initially at 1mo postoperatively, in which Kmax exhibited the largest improvement (1.05 D), followed by TCRPcone,zone 2 mm (0.82 D). In Group 2, only keratometric parameters based on ray tracing method and Kmcone,zone 3 mm showed slight but not significant improvement early at 3mo, in which TCRPcone,zone 3 mm displayed the most improvement (0.19 D), followed by TCRPcone,zone 2 mm (0.15 D). CONCLUSION: The findings indicate that a 2 mm zonal TCRP centered over Kmax could earlier detect keratometric improvement by CXL compared to other commonly used parameters in mild to moderate keratoconic eyes.     

Visual rehabilitation in low-moderate keratoconus:intracorneal ring segment implantation followed by same-day topography-guided photorefractive keratectomy and collagen cross linking

AIM:To present the results of same-day topography-guided photorefractive keratectomy (TG-PRK) and corneal collagen crosslinking (CXL) after previous intrastromal corneal ring segment (ISCR) implantation for keratoconus.METHODS:An experimental clinical study on twenty-one eyes of 19 patients aged 27.1±6.6y (range 19-43y), with low to moderate keratoconus who were selected to undergo customized TG-PRK immediately followed by same-day CXL, 9mo after ISCR implantation in a university ophthalmology clinic. Refraction, uncorrected distance visual acuities (UDVA) and corrected distance visual acuities (CDVA), keratometry (K) values, central corneal thickness (CCT) and coma were assessed 3mo after TG-PRK and CXL.RESULTS:After TG-PRK/CXL:the mean UDVA (logMAR) improved significantly from 0.66±0.41 to 0.20±0.25 (P<0.05); Kflat value decreased from:48.44±3.66 D to 43.71±1.95 D; Ksteep value decreased from 45.61±2.40 D to 41.56±2.05 D; Kaverage also decreased from 47.00±2.66 D to 42.42±2.07 D (P<0.05 for all). The mean sphere and cylinder decreased significantly post-surgery from, -3.10±2.99 D to -0.11±0.93 D and from -3.68±1.53 to -1.11±0.75 D respectively, while the CDVA, CCT and coma showed no significant changes. Compared to post-ISCR, significant reductions (P<0.05 or all) in all K values, sphere and cylinder were observed after TG-PRK/CXL.CONCLUSION:Same-day combined topography-guided PRK and corneal crosslinking following placement of ISCR is a safe and potentially effective option in treating low-moderate keratoconus. It significantly improves all visual acuity, reduced keratometry, sphere and astigmatism, but causes no change in central corneal thickness and coma.     

Topography versus non-topography-guided photorefractive keratectomy with corneal cross-linking variations in keratoconus

AIM: To compare the visual results of non-topography-guided and topography-guided photorefractive keratectomy (PRK) applying sequential and simultaneous corneal cross-linking (CXL) treatment for keratoconus. METHODS: Interventional and comparative prospective study. Sixty-nine eyes (36 patients) suffering from keratoconus (stages 1 Amsler-Krumeich classification) were divided into four groups: sequential topography-guided photorefractive keratectomy with CXL, simultaneous topography-guided photorefractive keratectomy with CXL, simultaneous non-topography guided photorefractive keratectomy with CXL, and sequential non-topography guided photorefractive keratectomy with CXL. The main outcome measures were pre- and postoperative uncorrected distance visual acuity (UDVA), best corrected distance visual acuity (CDVA), manifest refraction, contrast sensitivity, and keratometry. RESULTS: All analyzed visual, contrast sensitivity, and refractive parameters showed a significant improvement in the four groups (all P<0.05). A noticeable improvement was seen in keratometry in all the groups, and a remarkable difference was observed between topography-guided groups in comparison to non-topography-guided groups (P<0.05). Interestingly, the improvement in all parameters showed a degree of stability to the end of the follow-up. CONCLUSION: The treatment priorities in all four groups are safety, efficacy, and predictability in the correction of the sphero-cylindrical errors in mild and moderate keratoconus. No significant differences among groups in the recorded objective outcomes were found.     

Predictors for treatment outcomes after corneal crosslinking for keratoconus: a validation study

Previous research suggested that baseline corrected distance visual acuity (CDVA) and maximum keratometry (Kmax) are the predictors for effectiveness of corneal crosslinking (CXL) for keratoconus. The aim of this study was to validate the previously determined predictors in a new treatment cohort. A prospective cohort of 112 eyes in 90 consecutive patients was used to validate the results of 102 eyes in 79 patients from our previous prospective cohort. All patients were treated using epithelium-off corneal CXL in a tertiary hospital setting. Primary outcomes were changes in CDVA (LogMAR) and Kmax between baseline and 1-year post-treatment. Predictive factors for both outcomes were determined using univariable and multivariable analyses. Lower pretreatment CDVA was found to be the sole independent factor predicting an improvement in CDVA 1 year after CXL (β coefficient: ?0.476, P < 0.01). Kmax flattening is more likely to take place in eyes with preoperative central cones (β coefficient: 0.655, P < 0.01). These results are consistent with our initial research and indicate high reproducibility in the new cohort. The previously postulated prediction model for postoperative CDVA showed limited predictive value in the validation cohort (R ² = 0.15). The clinical implication of these results is that patients with lower pretreatment visual acuity are more likely to benefit from CXL (with respect to visual acuity), and patients with more central cones will benefit more in terms of cone flattening. Furthermore, those results can be used to guide customization of the crosslinking treatment.     

Contralateral eye study of refractive, topographic and aberrometric outcomes after femtosecond assisted MyoRing implantation and DALK for management of keratoconus

AIM: To evaluate the efficacy of femtosecond laser assisted MyoRing intrastromal corneal implant and deep anterior lamellar keratoplasty (DALK) for management of moderate to advanced keratoconus regarding the degree of changes in visual acuity, refraction, corneal asphericity and aberrations. METHODS: A prospective non comparative interventional case study was conducted in Ophthalmology Department, Ain Shams University Hospital in the period from January 2015 to February 2017. The study included 30 eyes of moderate to advanced keratoconus. MyoRing was implanted in one eye (Group I) and DALK operation was performed in the contralateral eye of the same patient (Group II). Preoperative and 6mo post-operative uncorrected visual acuity (UCVA), corrected distance visual acuity (CDVA), spherical equivalent (SE), corneal and refractive astigmatisms, keratometry and Q-value using topography images were acquired. Quality of vision was assessed in all eyes including total corneal, anterior corneal high order aberrations analysis at 5 mm pupil size and the Strehl ratio of point spread function (PSF) as an objective measure of glare. RESULTS: Mean postoperative UCVA, CDVA, SE, refractive astigmatism, keratometry readings and asphericity were statistically improved compared to preoperative parameters in both groups (P<0.05). Significant reduction of all corneal aberrations following both techniques (P<0.05) was achieved except mean trefoil and mean PSF in Group I (P>0.05). Postoperative corneal aberrations were significantly lower in Group II compared to Group I. A statistically significant negative correlation was found in Group I between the mean change in CDVA (logMAR) and the mean preoperative and mean postoperative total corneal aberrations root mean square (RMS; r=-0.78, P=0.04). Also a statistically significant negative correlation was found between mean preoperative coma RMS and mean post PSF (r=-0.86, P=0.01). In Group II, there was a statistically significant positive correlation between mean change in CDVA (logMAR) and mean change in Kmax (r=0.87, P=0.01) and between mean change in refractive cylinder and mean postoperative PSF (r=0.76, P=0.05). CONCLUSION: Femtosecond laser assisted MyoRing and DALK are effective in improving visual acuities, refraction, corneal asphericity and aberrations. MyoRing reduced spherical error more than the corneal cylinder. Post operative homogenous corneal surface and good image quality were achieved following both techniques compared to the preoperative state. However, DALK results in better image quality and lower corneal aberrations.