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.

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 vision-threatening complications of phakic intraocular lens implantation for high myopia

AIMTo report the long-term vision-threatening complications in patients who underwent phakic intraocular lens (pIOLs) implantation for high myopia.

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.

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.

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.

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.

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.

接触镜在圆锥角膜中的临床应用及并发症研究进展

圆锥角膜是一种不断进展的致盲性眼病,其特征是角膜变薄和突起,伴有不规则散光和视力下降。早期圆锥角膜的不规则散光可通过框架眼镜矫正,对于中重度圆锥角膜的不规则散光,框架眼镜不再适用,接触镜成为患者矫正视力的最佳选择。接触镜种类繁多,在接触镜的选择上难以抉择,如长时间试戴镜片会增加患者的不适,影响整体感受,也大大增加了医生的工作量。因此,本文对接触镜的分类、接触镜在不同圆锥角膜类型中的应用、接触镜配戴中的并发症及其未来展望等方面予以汇总和讨论,以期了解接触镜在圆锥角膜中的临床应用与管理,有助于进一步发挥接触镜在圆锥角膜中的应用价值。

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。

深板层角膜移植与穿透性角膜移植治疗基质角膜营养不良预后的比较

背景:基质角膜营养不良的传统手术治疗方式为穿透性角膜移植,近年来越来越多的医生开始考虑使用深板层角膜移植治疗基质角膜营养不良。目前国内对比穿透性角膜移植和深板层角膜移植治疗基质角膜营养不良的研究少有报道。目的:比较深板层角膜移植和穿透性角膜移植治疗基质角膜营养不良的疗效。方法:选择2000年1月至2018年1月北部战区总医院收治的基质角膜营养不良患者57例(57眼),男18例,女39例,平均年龄(52.9±20.0)岁,按照手术治疗方式分为深板层角膜移植组(n=21)、穿性角膜移植组(n=36),术后随访观察最佳矫正视力、角膜内皮细胞密度、角膜植片透明度、术中及术后并发症、原病复发情况。结果与结论:①两组患者术后1,3,6,12个月的视力均高于术前(P<0.05),两组间术后不同时间点的视力比较差异无显著性意义(P>0.05);随着术后时间的延长,两组患者角膜内皮细胞密度逐渐降低,穿透性角膜移植组患者术后6,12个月的角膜内皮细胞密度年丢失率均高于深板层角膜移植组(P<0.05);两组患者术后12个月的角膜植片透明率比较差异无显著性意义(P>0.05);②深板层角膜移植组有6例出现并发症,穿透性角膜移植组有14例出现并发症,57例患者术后12个月内均无复发,两组患者术后5年的复发率比较差异无显著性意义(P>0.05),穿透性角膜移植组和深板层角膜移植组术后5年的移植物存活率分别为83%和86%,组间比较差异无显著性意义(P>0.05);③结果表明,基质角膜营养不良的治疗可考虑使用深板层角膜移植替代一部分穿透性角膜移植。

翼状胬肉切除与角膜缘干细胞移植联合治疗对翼状胬肉患者角膜散光及视力的影响

目的:探究翼状胬肉切除联合角膜缘干细胞移植对翼状胬肉患者的影响。方法:选取2020年3月—2023年3月镇江市第四人民医院收治的100例翼状胬肉患者作为研究对象,按随机数表法分为两组,各50例。对照组行翼状胬肉切除治疗,观察组在对照组基础上加用角膜缘干细胞移植治疗。比较两组临床疗效、拆线时间、角膜上皮修复时间、视力恢复情况、泪膜功能及并发症发生情况。结果:观察组治疗总有效率高于对照组,拆线时间、角膜上皮修复时间早于对照组,并发症总发生率低于对照组,差异有统计学意义(P<0.05)。术后3个月,观察组最佳矫正视力(BCVA)、角膜水平曲度、角膜垂直曲度高于对照组,角膜散光度低于对照组,泪膜破裂时间(BUT)、泪液分泌试验(SⅠT)长于对照组,差异有统计学意义(P<0.05)。结论:翼状胬肉切除联合角膜缘干细胞移植可修复翼状胬肉患者角膜上皮,改善视力,有利于泪膜功能的提升,且并发症少。

2.2 mm角膜微切口白内障超声乳化术治疗老年白内障的临床效果

目的探究2.2 mm角膜微切口白内障超声乳化术治疗老年白内障的效果及对角膜内皮功能、并发症发生率的影响。方法以2020年3月至2022年3月期间收治的113例老年白内障患者为研究对象,均行白内障超声乳化术治疗,根据切口大小将患者分为2.2 mm组(55例)及常规组(58例)。比较两组手术相关指标及手术前后视力恢复情况,对患者手术前后角膜切口内外口处厚度、角膜内皮细胞功能、角膜生理指标及泪膜功能进行分析评估,并统计患者术后一过性高眼压、角膜水肿的并发症发生率。结果2.2 mm组术后7 d裸眼远视力、最佳矫正视力(BCVA)的LogMAR值及角膜散光值小于常规组,差异有统计学意义(P<0.05);2.2 mm组术后1 d、7 d切口外口处角膜厚度及术后1 d的切口内口处厚度小于常规组,差异有统计学意义(P<0.05);2.2 mm组术后7 d的角膜内皮细胞(CECs)密度及六角形细胞比例大于常规组,CECs变异系数小于常规组,差异有统计学意义(P<0.05);2.2 mm组术后7 d的角膜阻力因数(CRF)大于常规组,Goldmann相关眼压(IOPg)及角膜补偿眼压(IOPcc)高于常规组,差异有统计学意义(P<0.05);2.2 mm组术后7 d的泪膜破裂时间(BUT)长于常规组,基础泪液分泌试验(ST-Ⅱ)值小于常规组,差异有统计学意义(P<0.05);2.2 mm组并发症发生率为1.82%(一过性高眼压1例),常规组并发症发生率为3.39%(一过性高眼压1例、角膜水肿1例),两组并发症发生率对比差异无统计学意义(P>0.05)。结论2.2 mm角膜微切口白内障超声乳化术治疗老年白内障,可有效提高患者术后视力,促进角膜切口愈合,并能改善角膜内皮细胞功能及泪膜功能。

FEMTOLDVFS-LASIK角膜瓣发生并发症的原因及处理办法

目的分析FEMTO LDV飞秒激光辅助制作角膜瓣的准分子激光原位角膜磨镶术(FS-LASIK)角膜瓣相关并发症的发生原因,并探讨其处理方法。方法回顾性病例研究。选取2012年7月至2022年6月于医院接受FS-LASIK的10600例(20480眼)近视散光患者,术中均使用FEMTO LDV飞秒激光辅助制作角膜瓣,观察角膜瓣的制作情况。结果本研究共出现角膜瓣相关并发症5566眼(27.18%),其中术中并发症5516眼,占99.1%,术后并发症50眼,占0.9%。术中并发症:直径超小瓣2眼(0.10‰),游离瓣9眼(0.44‰),不全瓣、碎瓣、纽扣瓣15眼(0.73‰),角膜瓣掀开困难94眼(4.59‰),角膜基质床线状条纹96眼(4.69‰),角膜基质床颗粒状107眼(5.22‰),角膜基质微小气泡15眼(0.73‰),前房气泡13眼(0.63‰),角膜上皮脱落12眼(0.59‰),术中负压丢失2眼(0.10‰),角膜瓣蒂位置反向3眼(0.15‰),眼底出血1眼(0.05‰),角膜瓣边缘出血2078眼(10.15%),球结膜下出血1043眼(5.09%),角膜瓣偏中心2039眼(9.96%)。术后并发症:角膜瓣皱褶50眼(2.44‰)。结论FEMTO LDV飞秒激光辅助制作角膜瓣虽有并发症发生,但均不影响手术效果,全面了解设备的性能,合理设计切削参数,提高医生的操作技巧才能制作完美的角膜瓣。

小切口非超声乳化术治疗硬核白内障患者的效果

目的:观察小切口非超声乳化术治疗硬核白内障患者的效果。方法:选取2020年11月至2023年5月该院收治的70例硬核白内障患者进行前瞻性研究,按照随机数字表法将其分为研究组和对照组各35例。对照组采用传统超声乳化术治疗,研究组采用小切口非超声乳化术治疗。比较两组临床疗效,手术前后临床指标(裸眼视力、眼压)水平、角膜功能指标(角膜内皮细胞密度、中央角膜厚度、泪膜破裂时间)水平、炎性指标[基质金属蛋白酶-9(MMP-9)、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)]水平,以及并发症发生率。结果:研究组治疗总有效率为94.29%(33/35),高于对照组的77.14%(27/35),差异有统计学意义(P<0.05);术后1个月,研究组裸眼视力水平高于对照组,眼压水平低于对照组,差异均有统计学意义(P<0.05);术后1个月,研究组角膜内皮细胞密度、中央角膜厚度均高于对照组,泪膜破裂时间长于对照组,差异有统计学意义(P<0.05);术后7 d,研究组IL-1β、MMP-9、TNF-α水平均低于对照组,差异有统计学意义(P<0.05);两组并发症发生率比较,差异无统计学意义(P>0.05)。结论:小切口非超声乳化术治疗硬核白内障患者可提高治疗总有效率,改善临床指标和角膜功能指标水平,降低炎性指标水平,效果优于传统超声乳化术治疗。

Phaco drill与小切口非超声乳化白内障摘除术治疗硬核白内障患者的效果

目的:探讨Phaco drill与小切口非超声乳化白内障摘除术治疗硬核白内障患者的效果。方法:回顾性选取2020年10月—2022年4月麻城市中医医院收治的60例硬核白内障患者。根据不同手术治疗方法将其分为Phaco组(n=25)和小切口组(n=35)。小切口组给予小切口非超声乳化白内障摘除术,Phaco组给予Phaco drill。比较两组术前、术后1个月眼睛恢复情况,术前,术后3 d、术后1个月及术后3个月角膜散光度,并发症。结果:术后1个月,Phaco组最佳矫正视力(best corrected visual acuity,BCVA)、眼压(intraocular pressure,IOP)、角膜内皮细胞(corneal endothelial cell,CEC)密度均高于小切口组,差异有统计学意义(P<0.05),两组中央角膜厚度(central corneal thickness,CCT)比较,差异无统计学意义(P>0.05)。重复测量方差分析显示,角膜散光度组间、时间、交互比较,差异有统计学意义(P<0.001)。术后3 d、术后1个月,Phaco组角膜散光度均低于小切口组,差异有统计学意义(P<0.05)。Phaco组术后并发症发生率低于小切口组,差异有统计学意义(P<0.05)。结论:Phaco drill治疗硬核白内障可促进患者恢复,近期对角膜散光度的影响较小,对角膜内皮损伤较小,且术后并发症发生率低。

自体角膜缘干细胞移植术对翼状胬肉患者临床疗效及并发症的影响

目的探究自体角膜缘干细胞移植术治疗翼状胬肉患者的临床效果。方法选择2018年5月至2022年12月在虞城县第二人民医院治疗的82例翼状胬肉患者,应用随机数表法将其分为对照组(翼状胬肉切除术)及观察组(翼状胬肉切除术联合自体角膜缘干细胞移植术)各41例,对比两组临床指标、治疗有效率、视觉质量、泪膜功能、角膜屈光状态、并发症、复发率。结果观察组角膜上皮修复时间、术后拆线时间、视力改善时间均短于对照组,差异均有统计学意义(P<0.05)。观察组治疗有效率高于对照组,差异具有统计学意义(P<0.05)。观察组角膜散光度(CAD)、调制传递函数截止频率(MTFcutoff)、斯特列尔比(SR)、泪膜动态客观散射指数(TF-OSI)均优于对照组,差异均有统计学意义(P<0.05)。观察组泪膜破裂时间(BUT)长于对照组,泪液分泌试验(SIT)大于对照组,角膜荧光素染色(FL)评分均低于对照组,差异均有统计学意义(P<0.05)。观察组裸眼视力(UCVA)、角膜水平曲度、角膜垂直曲度均优于对照组,差异均有统计学意义(P<0.05)。对照组并发症、复发率均高于观察组,差异均有统计学意义(P<0.05)。结论对翼状胬肉患者进行翼状胬肉切除术治疗基础上联合自体角膜缘干细胞移植术,疗效显著,可提升患者视觉质量,改善患者泪膜功能、角膜屈光状态,降低并发症发生率,促进患者康复。

预装式疏水性丙烯酸酯类人工晶体和同轴微切口对年龄相关性白内障疗效分析

目的探讨与分析预装式疏水性丙烯酸酯类人工晶体和同轴微切口对年龄相关性白内障的疗效影响。方法选择2020年8月—2023年5月在蓝田华阳眼科医院诊治的80例年龄相关性白内障患者作为研究对象,根据随机数表法将其分为对照组和研究组,每组40例。所有手术均由同一位医师完成,都采用预装式疏水性丙烯酸酯类人工晶体植入,研究组行2.2 mm同轴透明角膜隧道微切口,对照组行3.0 mm透明角膜隧道切口,比较两组的最佳矫正、并发症发生情况、角膜散光度与前房深度变化情况。结果研究组术后1周与术后1个月的最佳矫正视力都高于对照组,差异有统计学意义(P<0.05);两组术后1个月的最高矫正视力与术后1周相比都升高,差异有统计学意义(P<0.05)。研究组术后1个月的角膜水肿、眼内炎、晶体混浊、囊膜破损等并发症发生率显著低于对照组,差异有统计学意义(P<0.05)。研究组术后1周与术后1个月的角膜散光度都低于对照组,差异有统计学意义(P<0.05);两组术后1个月的角膜散光度与术后1周相比都降低,差异有统计学意义(P<0.05)。研究组术后1周与术后1个月的前房深度都高于对照组,差异有统计学意义(P<0.05);研究组与对照组术后1个月与术后1周的前房深度比较,差异无统计学意义(P>0.05)。结论预装式疏水性丙烯酸酯类人工晶体联合同轴微切口在年龄相关性白内障患者的应用并不会影响患者的前房深度,能减少角膜散光度,提高患者的术后视力,减少并发症的发生。

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.