Stromal lenticule addition keratoplasty with corneal crosslinking for corneal ectasia secondary to FS-LASIK:a case series

●AIM:To explore the clinical efficacy and safety of stromal lenticule addition keratoplasty(SLAK)with corneal crosslinking(CXL)on patients with corneal ectasia secondary to femtosecond laser-assisted in situ keratomileusis(FS-LASIK).●METHODS:A series of 5 patients undertaking SLAK with CXL for the treatment of corneal ectasia secondary to FS-LASIK were followed for 4-9mo.The lenticules were collected from patients undertaking small incision lenticule extraction(SMILE)for the correction of myopia.Adding a stromal lenticule was aimed at improving the corneal thickness for the safe application of crosslinking and compensating for the thin cornea to improve its mechanical strength.●RESULTS:All surgeries were conducted successfully with no significant complications.Their best corrected visual acuity(BCVA)ranged from 0.05 to 0.8-2 before surgery.The pre-operational total corneal thickness ranged from 345-404μm and maximum keratometry(Kmax)ranged from 50.8 to 86.3.After the combination surgery,both the corneal keratometry(range 55.9 to 92.8)and total corneal thickness(range 413-482μm)significantly increased.Four out of 5 patients had improvement of corneal biomechanical parameters(reflected by stiffness parameter A1 in Corvis ST).However,3 patients showed decreased BCVA after surgery due to the development of irregular astigmatism and transient haze.Despite the onset of corneal edema right after SLAK,the corneal topography and thickness generally stabilized after 3mo.●CONCLUSION:SLAK with CXL is a potentially beneficial and safe therapy for advanced corneal ectasia.Future work needs to address the poor predictability of corneal refractometry and compare the outcomes of different surgical modes.

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 followup was 16.81±10.8 mo.The CDVA（logM AR） 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.

Post photorefractive keratectomy corneal ectasia

Dear Editor,We write to describe two cases of corneal ectasia occurred after photorefractive keratectomy.Due to the wide diffusion of refractive surgery,many ophthalmologists attempted to identify the risk factors and prevention methods to avoid such severe complication of this technique.

Comment on “Post photorefractive keratectomy corneal ectasia”

Citation：O’Brart D.Comment on＂Post photorefractive keratectomy corneal ectasia＂.Int J Ophthalmol 2018;11（4）：705-708Dear Editor,It is with interest that I read this paper[1]of two patients with ectasia after photorefractive keratectomy（PRK）,

Anterior Segment Optical Coherence Tomography Indices and Their Value in Diagnosing Corneal Ectasia

Purpose: To determine the diagnostic value of the anterior segment optical coherence tomography (AS-OCT) indices in differentiating normal from ectatic corneas. Material and Methods: Two groups of patients—with corneal ectasia and normal controls were compared. Each group consists of 80 eyes of 43 age and sex-matched patients. All of them underwent corneal topography with OCULUS Keratograph 5M and corneal pachymetry with AS-OCT with RTVue-100. The indices generated by the AS-OCT pachymetric scans were analyzed. Results: There was a statistically significant difference for all the examined indices between the two groups with p values <0.001 and a confidence interval of 95%. The minimal corneal thickness (Min) was the best performing index according to the ROC analysis with an area under the curve of 0.976 and a combination of sensitivity and specificity of 0.925 and 0.911 respectively, and a “cut-off” value of 484 microns, followed by the indices of focal thinning—Min-Med and Min-Max with an area under the curve of 0.973 and 0.971 and sensitivity/specificity of 0.938/0.962 and 0.938/0.937 respectively. The rest of the examined parameters had an area under the curve in the range between 0.950 for the central corneal thickness and 0.814 for the outer superior segment. Conclusion: The anterior segment OCT indices showed excellent capability in differentiating ectatic from normal corneas.

Changes in posterior corneal elevation after small incision lenticule extraction for different myopic diopters

●AIM:To study the changes and effect factors of posterior corneal surface after small incision lenticule extraction(SMILE)with different myopic diopters.●METHODS:Ninety eyes of 90 patients who underwent SMILE were included in this retrospective study.Patients were allocated into three groups based on the preoperative spherical equivalent(SE):low myopia(SE≥-3.00 D),moderate myopia(-3.00 D>SE>-6.00 D)and high myopia(SE≤-6.00 D).Posterior corneal surfaces were measured by a Scheimpflug camera preoperatively and different postoperative times(1wk,1,3,6mo,and 1y).Posterior mean elevation(PME)at 25 predetermined points of 3 concentric circles(2-,4-,and 6-mm diameter)above the best fit sphere was analyzed.●RESULTS:All surgeries were completed uneventfully and no ectasia was found through the observation.The difference of myopia group was significant at the 2-mm ring at 1 and 3mo postoperatively(1mo:P=0.017;3mo:P=0.018).The effect of time onΔPME was statistically significant(2-mm ring:P=0.001;4-mm ring:P<0.001;6-mm ring:P<0.001).The effect of different corneal locations onΔPME was significant except 1wk postoperatively(1mo:P=0.000;3mo:P=0.000;6mo:P=0.001;1y:P=0.001).Posterior corneal stability was linearly correlated with SE,central corneal thickness,ablation depth,residual bed thickness,percent ablation depth and percent stromal bed thickness.●CONCLUSION:The posterior corneal surface changes dynamically after SMILE.No protrusion is observed on the posterior corneal surface in patients with different degrees of myopia within one year after surgery.SMILE has good stability,accuracy,safety and predictability.

Long term efficacy and stability of corneal collagen cross linking for post-LASIK ectasia: an average of 80mo follow-up

This study was designed to evaluate efficacy and stability of corneal collagen crosslinking(CXL) in halting the progression of post-laser in situ keratomileusis(LASIK) ectasia and provide long-term follow-up results with an average of 80 mo. Patients with post-LASIK ectasia were treated with CXL between December 2007 and January 2012. Main outcome measures were uncorrected distance visual acuities(UDVA) and corrected distance visual acuities(CDVA), minimum and maximum keratometry(K) values, spherical and cylindrical refraction, and corneal thickness. The study evaluated 17 eyes for 13 patients(8 men, 5 women) with mean age of 31y(range 23 to 39) and mean follow-up of 80.7±15(range 57 to 102)mo. UDVA and CDVA improved from logMAR 0.53±0.36(20/63) to 0.49±0.4(20/50)(P=0.43) and from 0.18±0.17(20/28) to 0.16±0.16(20/27)(P=0.55) respectively. In 15 eyes UDVA and in 13 eyes CDVA either remained stable or improved ≥1 Snellen lines(88.2%) and(76.5%) respectively. Although statistically insignificant, spherical and cylindrical refraction decreased post-CXL from-1.26±2.87 to-0.38±2.32 diopters(D)(P=0.054) and from-3.80±2.47 to-3.04±2.18 D(P=0.13) respectively. Kmax significantly decreased from 44.23±3.76 to 42.85±3.08 D(P=0.013) and Kmin decreased from 41.07±3.61 to 40.00±2.65 D(P=0.057). Corneal thickness decreased from 470±42 to 460±41 μm, but was statistically non-significant(P=0.063). Therefore, CXL is effective in halting and partially reversing the progression of postLASIK ectasia on the long-term(mean follow-up of more than 80mo), thus highlighting the stability and maintained effect of CXL for such cases.

Accelerated versus standard corneal cross linking in the treatment of ectasia post refractive surgery and penetrating keratoplasty: a medium term randomized trial

AIM: To compare the clinical outcomes of the standard corneal cross linking(CXL) and the accelerated CXL in patients with progressive corneal ectasia post refractive surgery and penetrating keratoplasty.METHODS: Totally 120 eyes of 83 patients scheduled to receive either standard CXL(3 m W/cm^2 for a period of 30 min) or accelerated CXL(18 m W/cm2 for a period of 5 min). The main outcomes for comparison were the change in: maximum-K reading(K-max), manifest refractive spherical equivalent(SE), central corneal thickness(CCT), and the best corrected distance visual acuity(CDVA).RESULTS: One hundred and eleven eyes completed the study. The main outcome measurement was the K-max reading. Both group showed significant improvement in the value postoperatively at 6 and 12 mo. The mean change in the standard group was 1.21±0.11 D and in the accelerated group was 0.90±0.05 D at the end of 12 mo postoperatively, with no statistically significant difference between the 2 groups. Similarly, CDVA improved significantly from their preoperative value in the standard group by 2.98±0.11 letters, and in the accelerated group by 2.20±0.06 letters, with no statistically significant difference between the two groups. Both of the SE, and CCT showed no statistically significant difference at the end of follow up period in each group.CONCLUSION: Both standard CXL and accelerated CXL are safe and effective treatment in halting ectasia after corneal refractive surgery. The accelerated CXL results are comparable to the standard CXL with short time exposure of the cornea to ultraviolet irradiation, leading to reduced operation time, reduced operative ocular discomfort, and corneal haze.

Comparative 2-year outcomes of conventional and accelerated corneal collagen crosslinking in progressive keratoconus

AIM:To compare the safety and efficacy of conventional versus accelerated(9 mW/cm^2)corneal collagen crosslinking(CXL)in progressive keratoconus at the 2-year follow-up.METHODS:In this prospective study,consecutive progressive keratoconus patients were randomized to receive either conventional CXL(CCXL)or accelerated CXL(ACXL;using hydroxypropyl methylcellulose-assisted riboflavin imbibition for 10 min at 9 mW/cm^2).Visual,refractive,keratometric,topographic,and aberrometric outcomes and stromal demarcation line depth(DLD)measurements were compared at the end of a 2-year follow-up.RESULTS:Thirty-two eyes from 32 patients in the CCXL and 27 eyes from 27 patients in the ACXL groups completed 2-year follow-up.At 2y post-CXL,both uncorrected and corrected visual acuities improved significantly in both groups.The improvements in keratometric readings,flattening rate(flattening of the maximum keratometry more than 1 D),3 topographic indices,and vertical coma were significantly better in the CCXL group compared to the ACXL group(P<0.05).The DLD as measured by anterior segment optical coherence tomography or in vivo confocal microscopy was better detectable and significantly deeper in the CCXL group compared to the ACXL group.The deeper DLD was found to be significantly correlated with improvements in the mean keratometry measurements.Progression was noted in 11.1%of eyes in the ACXL group,whereas progression was not observed in any patient eye in the CCXL group.CONCLUSION:In this prospective randomized study,ACXL is less effective in halting the progression of keratoconus at a 2-year follow-up compared to CCXL.

屈光手术联合预防性角膜胶原交联矫正屈光不正的疗效及安全性研究进展

角膜屈光手术是一种安全、有效的屈光不正矫正方式。尽管因术后角膜组织完整性改变,导致角膜生物力学稳定性下降,但术后角膜结构绝大多数是安全的。如果术前存在危险因素,如屈光度数高、角膜薄、角膜地形图形态欠规则、散光度数高、双眼对称性差、过敏体质、有揉眼习惯等,术后有可能发生屈光回退和角膜膨隆。角膜胶原交联术可增强角膜生物力学,有效阻止角膜膨隆、圆锥角膜或其他扩张性疾病的发生和发展。近年来,国内外一些研究者相继尝试一种新型的屈光手术设计,即角膜屈光手术联合预防性角膜胶原交联术,以期改善屈光术后角膜的生物力学稳定性,进而潜在预防角膜扩张和屈光回退。多项研究已经观察到联合手术具有良好的视力和屈光预后,尤其是对于术前评估角膜存在相对扩张风险的患者。本文将主要从有效性、安全性、可预测性、稳定性及并发症5个方面综述该联合手术矫治屈光不正的疗效及安全性。

Effect of intracorneal ring segment implantation on corneal asphericity

AIM： To evaluate the visual, refractive and corneal asphericity changes after intrastromal corneal ring segment（ICRS） implantation for visual rehabilitation of keratoconus.METHODS： A total of 42 eyes of 32 patients were included. After creation of intrastromal tunnels of 5.01±0.03 mm inner diameter, 5.71±0.03 mm outer diameter and at 384.21±34.12 μm depth, 1 or 2 ICRS of 150-300 μm thickness and 90°-210° arc length were implanted. Changes in uncorrected distance visual acuity（UDVA）, corrected distance visual acuity（CDVA）, refractive errors, mean simulated keratometry readings SimK_（avg）, anterior and posterior corneal asphericity values（Q_（ant） and Q_（post）, respectively） measured with Scheimpflug topography were evaluated retrospectively. RESULTS： There was a significant improvement in UDVA and CDVA, along with a significant decrease in refractive spherical equivalent（SE）, cylinder and SimK_（avg） postoperatively（P〈0.001 for all）. Mean Qant increased from-1.06±0.48 to-0.57±0.58 postoperatively（P〈0.001）. Change in mean Qpost was insignificant（P=0.92）. Postoperative changes in UDVA and CDVA were not correlated with the postoperative changes in SE and cylinder（P〉0.05 for all）; but were correlated with the preoperative SimK_（avg） and Q_（ant） values（P〈0.001 for all）. CONCLUSION： ICRS implantation seems to approximate the anterior corneal asphericity of ＂advanced prolate＂ shape to ＂optimal prolate＂ shape and an ＂ideal Q value＂ of-0.46; which may have a role in improved UDVA and CDVA postoperatively, besides decreased refractive cylinder values.

去上皮快速角膜胶原交联术对近视眼角膜屈光术后角膜扩张的疗效评估

目的探讨去上皮快速角膜胶原交联术(CXL)治疗近视角膜屈光手术后角膜扩张的有效性及安全性。方法采用系列病例观察研究方法,纳入2016年1月至2018年12月于陆军军医大学第一附属医院眼科确诊的近视角膜屈光手术后角膜扩张的患者12例22眼,患者均行去上皮快速CXL。分别于术前及术后1周、1个月、3个月、6个月、12个月,检测受试者裸眼视力(UCVA)、最佳矫正视力(BCVA);采用Topcon全自动综合验光仪测量球镜度、柱镜度、等效球镜度;采用Sirius眼前节分析仪测量角膜前表面最大曲率(Kmax)、前表面平均曲率(Km)、后表面Km、前表面对称指数(SIf)、角膜后表面对称指数(SIb)、最薄点角膜厚度(TCT)、总像差、总高阶像差、慧差、三叶草像差、球差;采用眼前节光学相干断层扫描仪测量角膜交联分界线深度;采用非接触眼压计测量眼压;采用角膜内皮细胞密度测量仪测量角膜内皮细胞密度;采用裂隙灯显微镜观察角膜炎性反应及角膜上皮下雾状混浊(haze)情况。结果所有受试者中接受小切口角膜基质透镜取出术者2例3眼,占13.64%,准分子激光角膜厚位磨镶术者10例19眼,占86.36%。去上皮CXL术后12个月UCVA(LogMAR)、BCVA(LogMAR)、柱镜度及等效球镜度分别为0.45±0.31、0.12±0.15、(-2.11±1.67)D和(-3.12±2.31)D,明显优于术前的0.61±0.42、0.24±0.23、(-2.83±2.39)D、(-3.60±2.66)D,差异均有统计学意义(t=4.054、4.956、-3.728、-2.742,均P<0.05)。术后12个月角膜前表面Kmax、前表面Km、SIf分别为(48.37±5.80)、(41.49±3.04)、(5.36±4.07)D,明显低于术前的(49.61±5.97)、(41.66±2.97)、(5.85±4.18)D,差异均有统计学意义(t=5.949、2.278、2.719,均P<0.05)。术前与术后12个月球镜度、后表面Km、SIb、TCT、总像差、总高阶像差、慧差、三叶草像差、球差、眼压、角膜内皮细胞密度比较,差异均无统计学意义(均P>0.05)。术后1个月4例8眼出现0.5~2级haze,经过醋酸泼尼松龙滴眼液点眼冲击治疗后,术后3个月复查haze均减退或消失,未出现UCVA及BCVA下降。术后1个月6例11眼在角膜基质平均深度(285.40±51.61)μm处查见明显角膜交联分界线。结论去上皮快速CXL能显著提高近视屈光术后角膜扩张患者术后视力,减少角膜散光,降低角膜曲率,有效阻止角膜扩张进展,具有良好的有效性及安全性。

近视眼患者LASIK和LASEK术后角膜后表面变化的比较研究

目的探讨近视眼LASIK及LASEK术后角膜后表面变化的差异及意义。方法随机选取近视眼准分子激光患者72例143眼,根据患者接受手术方式的不同分成LASIK组(简称IK组)和LASEK组(简称EK组),根据术后剩余角膜基质床厚度/术前角膜厚度(residual corneal stroma thickness/cornea thickness,RCST/CT)的不同将IK组患者分为IK-I组(RCST/CT<55%;15例30眼)、IK-II组(55%≤RCST/CT<60%;17例34眼)和IK-III组(RCST/CT≥60%;19例38眼),EK组(21例41眼)RCST/CT均≥60%。分别于术前、术后1个月、3个月和6个月应用Oculyzer眼前节分析系统检测角膜后表面高度差异(difference posterior elevation,Diff)值的变化。结果 IK组与EK组术后角膜后表面均向前膨隆。IK-I组术后1个月时Diff值为34.15±24.73,3个月、6个月时分别为28.15±24.82和29.19±23.54,术后1个月与3个月、6个月相比差异均有统计学意义(均为P<0.05),3个月和6个月比较差异无统计学意义(P>0.05)。IK-II组和K-III组术后各时间点角膜后表面Diff值分别为22.59±11.00、22.63±14.08、22.36±14.96和18.72±10.37、18.72±11.93、17.22±10.47,组内比较差异均无统计学意义(均为P>0.05)。术后不同时间点IK-I组和IK-III组比较角膜后表面Diff的差异均有统计学意义(均为P<0.05),IK-I组和IK-II组、IK-II组和IK-III组间比较差异均无统计学意义(均为P>0.05)。EK组术后1个月、3个月和6个月时角膜后表面Diff值分别为14.41±10.44,13.73±10.41和14.72±12.31,同术前相比差异均有统计学意义(均为P<0.05),但术后各时间点间比较差异均无统计学意义(均为P>0.05)。术后不同时间点IK-III组和EK组Diff值的变化差异均无统计学意义(均为P>0.05)。结论 LASIK及LASEK术后角膜后表面均有膨隆,术后RCST/CT越大,对角膜后表面膨隆的影响越小。RCST/CT可以作为临床评估准分子激光角膜屈光手术安全性的重要指标。

近视LASIK术后角膜膨隆的研究进展

角膜膨隆是近视LASIK术后少见而严重的并发症之一。它严重损害视功能,是对公众健康的潜在危胁。本文从近视LASIK术后角膜膨隆的一般概况、发病的危险因素、病理变化、发病机制、临床特征及诊断、处理等方面总结了近年来对其研究现状及进展。

角膜屈光手术后继发性圆锥角膜的RGP矫正疗效观察

目的评价硬性透气性角膜接触镜(rigid permeability contact lenses,RGP)矫正角膜屈光手术后圆锥角膜的疗效。方法选择笔者医院收治的11例(21眼)角膜屈光手术后圆锥角膜患者配戴RGP,观察1年后角膜前后表明曲率,RGP和普通软性角膜接触镜的角膜地形图改变。结果配戴RGP1年后角膜前表面最平平均曲率值和后表面曲率值没有明显变化。RGP矫正1年后角膜前表面的最陡平均曲率明显下降,角膜地形图SRI,SAI,散光减少,PVA提高。对照组佩戴普通软性角膜接触镜1年后角膜地形图无明显改善。结论经1年的随访观察,RGP对角膜屈光手术后的圆锥角膜能明显改善患者的角膜前表面最陡平均曲率,角膜后表面和角膜前表面最平平均曲率保持稳定。是目前矫正角膜屈光手术后圆锥角膜的有效方法。

兔眼准分子激光近视角膜切削术后角膜膨出的研究

目的:探讨兔眼在准分子激光近视角膜切削术（Excimer laser in-situ he。tomileusis,LASIK）手术后在不同的眼压下角膜膨出的程度。方法:26兔52眼随机分为对照组、LASIK手术组,单盲法,术前、术后测量角膜厚度和角膜地形图后,再将两组随机交叉分为正常眼压组、低度高眼压组、高度高眼压组,并观察1个月,用角膜地形图对实验前后的角膜形态进行分析,并应用统计学方法将手术切削量和眼压两个因素对角膜扩张的影响做双因素方差分析。结果:LASIK手术的角膜切削量、术后高眼压以及两者的交互效应对角膜抵抗力都有显著影响。较大的切削量和术后持续高眼压后的兔眼角膜地形图经分析符合圆锥角膜模式,并出现前、后弹力膜断裂的形态学改变。结论:角膜较大的切削量和术后持续的高眼压是导致兔眼LASIK术后发生圆锥角膜的重要原因。

角膜屈光手术后圆锥角膜的临床分析

目的 :研究角膜屈光手术后出现的圆锥角膜的特性 ,探讨圆锥角膜发生的可能机制 ,为临床提供有价值的建议 ,并评价硬性透氧性角膜接触镜 (RGP)在术后圆锥角膜中的治疗作用。方法 :对角膜屈光手术后出现角膜膨出的 11例 18眼患者做常规裂隙灯检查、主客观验光、角膜曲率测定、角膜厚度检测和角膜地形图检查 ,并根据角膜曲率特征选择试戴镜片 ,以荧光素图判断配适情况 ,选择镜片 ,并作片上验光。结果 :11例 18眼患者 ,术前屈光度 :球镜平均为 (-8.6 9± - 0 .94 )DS ,柱镜度数平均为 (- 1.2 8± - 0 .5 4 )DC。其中 14眼出现圆锥角膜为LASIK术后 ,2眼为PRK后 ,2眼为RK术后。表现圆锥角膜特征的时间在术后 2～ 12个月 ,平均为 (7.4 1± 3.95 )个月。圆锥的位置 :角膜正中 9眼 ,角膜正中上方 1眼 ,颞下方 1眼 ,外围 1眼 ,正下方 4眼 ,水平蝴蝶型 2眼。RGP镜片配适满意的达 90 % ,可以接受的为10 % ;患者戴镜后的矫正视力 0 .1～ 1.0D ,平均为 (0 .72± 0 .2 3)D。结论 :角膜屈光手术后圆锥角膜往往出现在高度数近收稿日期 :2 0 0 3 -0 5 -0 3 ;修回日期 :2 0 0 3 -10 -3 0作者简介 :瞿小妹 (1965 -) ,女 ,上海人 ,医学博士 ,副主任医师 ,研究方向 :眼视光学。E -mail:quxiaomei2 0 0 2 @hotmail.

准分子激光原位角膜磨镶术后角膜后表面高度研究

目的观察准分子激光原位角膜磨镶术(LASIK)术后角膜后表面高度的改变,探讨角膜后表面膨隆与剩余角膜基质床厚度(RBT),以及与激光切削所占角膜厚度比例(AP/TCT)的关系。方法回顾分析LASIK157例(157眼),根据RBT分组:组1为79眼,RBT≥350μm;组2为52眼,300μm≤RBT<350μm;组3为26眼,250μm≤RBT<300μm。根据AP/TCT分组:组A为44眼,AP/TCT≤10%;组B为84眼,10%<AP/TCT≤20%;组C为29眼,AP/TCT>20%。术前、术后1周、术后1个月、术后3个月、术后6个月应用OrbscanII行角膜地形图检查,分析比较各组各个不同时间点的角膜后表面膨隆程度。结果角膜后表面高度各组术后1周、术后1个月、术后3个月、术后6个月与术前比较,差异均有统计学意义(P均<0.05);术后同一时间点,组1、组2、组3组间及组A、组B、组C组间角膜后表面高度差异值(PED)两两比较差异有统计学意义(P均<0.05)。术后6个月PED值与RBT呈线性负相关(r=-0.77,P=0.00);与AP/TCT呈线性正相关(r=0.90,P=0.00),且与AP/TCT相关性更好。结论 LASIK术后角膜后表面均有不同程度的膨隆,并与RBT和AP/TCT相关;RBT不应为LASIK术后评价角膜后表面膨隆风险的唯一指标,AP/TCT是重要补充指标。

Keratoconus therapeutics advances

Keratoconus is a progressive, usually bilateral disease of the cornea that significantly diminishes visual acuity, secondary to a progressive corneal deformity which is characterized by corneal thinning, variable degrees of irregular astigmatism and specific abnormal topographic patterns. Normally it initiates during puberty and is progressive until the third or fourth decade of life, when normally the progression rate is diminished or waned. There are multiple scales to clinically classify keratoconus. One of the most commonly used is Amsler-Krumeich and recently with the development of morphometric and aberrometric techniques, additional scales have been created that allow keratoconus to be classified according to its severity. Despite certain etiology of keratoconus remains unknown, current treatment options are available in patients with ectatic corneas and they vary depending on the severity of the disease and they include spectacles, contact lenses, intrastromal rings, keratoplasty both penetrant or lamellar, cross-linking, refractive lens exchange withintraocular lens implant, phakic intraocular lenses and the combination of these alternatives. Some authors have been using excimer laser in patients with keratoconus but the safety of the procedure is controversial. Currently, the techniques for the management of keratoconus can be classified in 3 types: corneal strengthening techniques, optical optimization techniques and combined techniques.

Clinical outcomes at one year following keratoconus treatment with accelerated transepithelial cross-linking

This study evaluated the clinical outcomes in keratoconus corneas following accelerated transepithelial corneal collagen cross-linking（CXL）（Avedro KXL system,Waltham,MA,USA） over one year of follow-up.The mean depth of the demarcation line measured by optical coherence tomography（OCT） was 205.19 μm.One month after surgery,a non-statistically significant change was noted in sphere（P= 0.18） and in spherical equivalent（P= 0.17）,whereas a significant improvement was observed in corrected distance visual acuity（P=0.04）.A significant change was observed in topographic astigmatism（P= 0.03） and posterior corneal a sphericity（P= 0.04）.Accelerated transepithelial CXL may be a useful technique for the management of progressive keratoconus.