Surgical approaches to correct corneal astigmatism at time of cataract surgery: a mini-review

Among refractive errors,astigmatism is the most common optical aberration,where refraction changes in different meridians of the eye.It causes blurred vision at any distance and includes corneal,lenticular,and retinal astigmatism.Cataract surgery used to cause a progressive increase in the pre-exisiting corneal astigmatism because of creating a surgically induced astigmatism,for example,a large size surgery incision.The development of surgical techniques during last decades has made cataract surgery interchange to treat preoperative corneal astigmatism at time of surgery.Nowadays,three surgical approaches can be used.By placing a sutureless clear corneal incision on the steep meridian of the cornea,a preoperative corneal astigmatism less than 1.0 D can be corrected.Single or paired peripheral corneal relaxing incisions(PCRIs)provide 1.0-3.0 D corneal astigmatism correction.PCRIs are typically used for treating 1.0-1.5 D of regular corneal astigmatism,if more than 2.0 D,the risk of overcorrection and irregular astigmatism is increased.When toric intraocular lenses(IOLs)are unavailable in markets,PCRIs are still a reasonable option for patients with up to 3.0 D of pre-existing corneal astigmatism.Toric IOLs implantation can correct 1.0-4.5 D of corneal astigmatism.Several IOLs are approved to correct a high degree of corneal astigmatism with cylinder power up to 12.0 D.These approaches can be used alone or in combination.

Corneal neuromediator profiles following laser refractive surgery

Laser refractive surgery is one of the most commonly performed procedures worldwide.In laser refractive surgery,Femtosecond Laser in Situ Keratomileusis and Refractive Lenticule Extraction have emerged as promising alternatives to microkeratome Laser in Situ Keratomileusis and Photorefractive Keratectomy.Following laser refractive surgery,the corneal nerves,epithelial and stromal cells release neuromediators,including neurotrophins,neuropeptides and neurotransmitters.Notably,nerve growth factor,substance P,calcitonin gene-related peptide and various cytokines are important mediators of neurogenic inflammation and corneal nerve regeneration.Alterations in neuromediator profiles and ocular surface parameters following laser refractive surgery are attributed to the surgical techniques and the severity of tissue insult induced.In this review,we will discuss the(1)Functions of neuromediators and their physiological and clinical significance;(2)Changes in the neuromediators following various laser refractive surgeries;(3)Correlation between neuromediators,ocular surface health and corneal nerve status;and(4)Future directions,including the use of neuromediators as potential biomarkers for ocular surface health following laser refractive surgery,and as adjuncts to aid in corneal regeneration after laser refractive surgery.

Comparing corneal outcome between femtosecond laser-assisted cataract surgery and conventional phaco surgery in Fuchs’endothelial dystrophy patients:a randomized pilot study with 6mo follow up

AIM:To compare the corneal outcome in Fuchs’endothelial dystrophy(FED)patients between femtosecond laser-assisted cataract surgery(FLACS)and conventional phaco surgery(CPS).METHODS:This was a randomized controlled study comparing one eye surgery by FLACS and the contralateral eye operated by CPS(stop and chop technique)in FED patients.Central corneal thickness,corneal light backscatter,corneal densitometry,and central corneal endothelial cell count and hexagonality(noncontact endothelial cell microscope),and corrected distance visual acuity(CDVA)were assessed preoperatively and at day 1,40,and 180 postoperatively.RESULTS:Totally 31 patients(16 women)were included.At day 40 postoperatively,the mean endothelial cell loss(ECL)was 23.67%by FLACS and 17.30%by CPS(P=0.53).At day 180 postoperatively,ECL was 25.58%in FLACS and 21.32%in CPS(P=0.69).Densitometry data in all layers and all annuli from anterior layer to posterior layer in annuli 0-2,2-6,6-10 and 10-12,total densitometry with all layers and all annuli was performed.A significant difference was found in 6-10(posterior layer)at day 1 with-1.42 grayscale units(GSU;95%CI:-2.66 to-0.19,P=0.02).In 10-12(anterior layer,central layer and all layers)at day 40 were significant different with 7.7(95%CI:1.89 to 13.50,P=0.009),3.97(95%CI:0.23 to 7.71,P=0.03),4.73 GSU(95%CI:0.71 to 8.75,P=0.02),respectively.In the remaining parameters we found no difference between the two groups(P>0.05).Three CPS eyes suffered from corneal decompensation.CONCLUSION:There is no significant difference in corneal outcome between FLACS and CPS.Endothelial cell density and pentacam corneal outcome may be inadequate as outcome parameters in FED patients.

Progress of corneal collagen cross-linking combined with refractive surgery

As a photochemical reaction that can stiffen the cornea,corneal collagen cross-linking(CXL) is the only promising method of preventing the progress of keratectasia,such as keratoconus and secondary ectasia following refractive surgery. The aim of CXL is to stabilize the underlying condition,with a small chance of visual improvement. Combining CXL with refractive surgery targeting both stabilization and reshaping of the corneal tissue for visual function improvement is a good treatment option. This review aims to provide a comprehensive and unbiased summary of the published research regarding combined CXL and refractive surgery,including measures and results,to help elucidate the future direction of CXL.

Double intrastromal corneal ring segment implantation: a new approach for improved clinical outcomes in keratoconus patients

AIM:To evaluate the clinical outcomes after subsequent implantation of a new intrastromal corneal ring segment(ICRS)model followed by an additional short-arc ICRS implant in keratoconus patients.METHODS:This retrospective single-arm cohort study evaluated 25 eyes of 21 keratoconus patients implanted with the new ICRS followed by 140-arch length ICRS(140-ICRS)implantation.Uncorrected distance visual acuity(UDVA,logMAR),corrected distance visual acuity(CDVA,logMAR),sphere,astigmatism,keratometry,spherical equivalent(SE),and asphericity were compared preoperatively and postoperatively after both ICRS implantation.RESULTS:The average follow-up time after 140-ICRS implantation was 6.40±2.20mo.The mean preoperative UDVA improved from 1.27±0.14 preoperative to 0.52±0.26 after both ICRS implantation(P=0.03).The mean sphere value reduced from-5.34±2.74 preoperatively to-2.06±1.84 postoperatively(P<0.001)after the first ICRS implantation and decreased to-0.59±1.54 postoperatively(P<0.001)after 140-ICRS implantation.The mean preoperative astigmatism was-3.72±1.56 and improved to-2.82±1.08 after the first ICRS implantation,and following the 140-ICRS implantation,the mean astigmatism was-1.37±0.67(P=0.001).The SE and asphericity changes were statistically significant(P<0.001).The researchers did not find intraoperative or postoperative complications for both procedures.CONCLUSION:The combination of 2 different ICRSs can efficiently regularize the cornea,reduce the SE,and improve visual acuity in selected keratoconus patients.

Thiel-Behnke Corneal Dystrophy in a Young Man in Denmark—A Case Report

Background: This case report presents a case of bilateral Thiel-Behnke corneal dystrophy in Denmark. Thiel-Behnke is an autosomal dominant inherited epithelial-stromal TGFBI dystrophy causing visual impairment. Methods and Results: This case study presents a 24-year-old Lithuanian man, with no previous ocular history, who had experienced slowly progressive visual impairment since his childhood. He was examined at the Department of Ophthalmology at Vejle Hospital and Aarhus University Hospital, where he was diagnosed with bilateral Thiel-Behnke corneal dystrophy. Histology confirmed the diagnosis. A lamellar corneal transplantation was performed in the right eye;however, due to epithelial growth under the corneal graft, it was later decided to redo the operation. Following the operations, the patient experienced a visual improvement in best corrected visual acuity (BCVA) from 0.1 (20/25 Snellen equivalent) to 0.3 (20/40 Snellen equivalent) in his right eye. Conclusions: This case of Thiel-Behnke corneal dystrophy is to our knowledge the first reported case in Denmark.

Clinicopathological Analysis of 39 Patients with Corneal Tumors

Purpose:Corneal tumors are rarely seen in clinical practice.There is a paucity of data on the incidence of various corneal tumors,their clinical and pathological features and surgical management,especially on large patient samples.Methods:The medical records of 39 patients with corneal tumors referred to Zhongshan Ophthalmic Center,Sun Yat-sen University,China from January 1,1996 to December 31,2002 were reviewed retrospectively.Results:Of the 39 cases with corneal tumors,31 were males and 8 were females.The right eye was affected in 24 cases and the left one in 15 cases.The mean age at diagnosis was 45.7 years,ranged from 3 to 88 years.Squamous cell carcinoma was the most common tumor in the cornea(18 cases,46.15%),followed by pigmented naevus.(12 cases,30.77%),papillary epithelioma(3 cases,7.69%),melanoma(1 case,2.56%),oncosis hyperplasia(1 case,2.56%),inverting papilloma.(1 case,2.56%),primary acquired melanosis(1 case,2.56%),amyloid degeneration(1 case,2.56%),inflammatory pseudotumor(1 case,2.56%).They arose most commonly in the limbal region.All tumors were unilaterally involved.Squamous cell carcinoma of the cornea usually appears as a whitish,rough,irregular lesion or a telangiectatic,gelatinous epibulbar mass.Nevus in the cornea generally becomes clinically apparent in the first or second decade of life and the lesion may enlarge or more deeply pigmented afterwards.The corneal tumors were completely excised microsurgically in 22 cases.Six cases were treated with surgical resection combined with amniotic membrane graft.Three cases with surgical excision plus transfer of conjunctival flap.Two cases with surgical excision plus lamellar keratoplasty.Two cases with surgical excision plus cryosurgery.Two cases with orbital exenteration.One case with enuleation.One case with incision biopsy and observation.Conclusion:Squamous cell carcinoma and nevus,the most common corneal tumors,accounted for 76.92% of all cases.The therapeutic outcomes depended upon early pathologic diagnosis and early surgical management.

A recognition survey of granular corneal dystrophy type 2 genetic detection in China

AIM:To evaluate the feasibility of promoting genetic detection for granular corneal dystrophy type 2(GCD2)by a questionnaire conducted among citizens in five cities in China.METHODS:The data were collected by questionnaire,and analyzed by Chi-square test and one-tailed t test in IBM SPSS statistics.RESULTS:Based on the survey data on the awareness of GCD2 genetic detection in this study and the positive predictive analysis report of the citizens in five cities in China,the vast majority(84.2%)of respondents had never heard of it and did not know that GCD2 patients have been prohibited from performing excimer surgery that can deteriorate GCD2 patients’condition even leading to blindness.Though 3.4%of patients understood GCD2 very much,they have no idea that GCD2 could not be 100%accuracy diagnosed by the conventional inspection methods.CONCLUSION:It is feasible and necessary to use GCD2 genetic detection as an excimer preoperative examination project.In order to promote the development of detection project,a few improvements should be carried out in terms of the promoting efforts,costs,and research progress.

Laser vision correction for patients with atypical topography of cornea, LASIK vs. PRK: A review

Purpose: To search evidence and determine whether PRK (Photo Refractive Keratectomy) or LASIK (Laser in Situ Keratomileusis) produce a better outcome of laser vision correction for patients with atypical topography of cornea. Setting: Electronic search of laser vision correction related studies on Cochrane Library, Medline and PubMed. Method: The search was conducted over Cochrane Library, Embase, PubMed and Medline using the key words of refractive laser surgery, PRK, LASIK, Atypical topography, cornea ectasia and Keratoconus from 1980 to 2012. Boolean operators were used to search in electronic data bases of related studies. The combining words used here were And, OR. Result: The best corrected vision decreased for those eyes with atypical topography that were treated with either PRK or LASIK. However, in the comparison of the outcomes of vision and ectasia, PRK outperformed LASIK. Conclusion: There is possible risk of developing corneal ectasia in those patients who desire laser vision correction with atypical topographic cornea. PRK may be a safer procedure when compare to LASIK for those patients.

AB027.Varying pattern of proteases secretion in Fuchs corneal endothelial dystrophy

Background:The goal of this project was to analyze the relationship between cell morphology and proteases/proteases inhibitors(PIs)secretion profile in fuchs endothelial corneal dystrophy(FECD)corneal endothelial cells(CECs).Methods:Cell morphology was determined using a circularity index(4π×area/perimeter2)for each CECs population extracted from surgical FECD specimens(N=2)and healthy Eye bank corneas(N=3).CECs were cultured 28 days post-confluency.Supernatant was collected and analysed using Proteome Profiler Array detecting 35 proteases and 32 PIs(R&D Systems).Proteome signal was analyzed using Image Studio Lite and correlated with the population’s circularity index.Results:Calculation of circularity index reported different morphologies among FECD populations(0.59±0.18 and 0.64±0.17)and healthy populations(0.44±0.18,0.66±0.13 and 0.71±0.11).Proteome arrays revealed the presence of 10 proteases(ADAMTS1,Cathepsin A,B,D,and X/Z/P,DPPIV/CD26,MMP-2,3 and 12,uPA/Urokinase)and 10 PIs(Protease Nexin II,Cystatin B and C,EMMPRIN/CD147,Latexin,Lipocalin-1,Serpin E1,TFPI,TFPI-2,TIMP-1,2 and 4).Healthy and FECD specimens showed similar variation patterns according to morphology for secretion of ADAMTS1,MMP-3 and 12.However,opposing patterns between healthy and FECD populations were observed for Cathepsin B and D.Moreover,some proteins did not show variation according to phenotype in healthy CECs,but did in FECD CECs:Cathepsin A,Cystatin C,TFPI-2 and total TIMPs.For the other proteins,secretion did not vary according to morphology or no specific pattern was distinguishable.Conclusions:To conclude,our results suggest that cell phenotype is linked to the secretion of certain proteases/PIs in both groups.However,there seems to be differences in secretion of particular proteases and PIs between FECD and healthy specimens as morphology did not have a similar influence.These differences might initiate an imbalance between proteases and PIs explaining the irregular thickening of the Descemet membrane seen in FECD.

脉络膜脱离1例

61岁男性,因“左眼前黑影遮挡伴视力下降近2周”就诊。患者4年前、2年前和1年前分别行左眼小梁切除术,右眼穿透性角膜移植术和右眼白内障超声乳化+人工晶状体(IOL)植入术。半年前因左眼颗粒状角膜营养不良,于我院行左眼深板层角膜移植术,手术顺利,术后规律复诊。左眼角膜移植术后3个月和4个月,分别行左眼部分角膜缝线拆除,左眼白内障超声乳化+人工晶体植入术。左眼角膜移植术后半年,再次行左眼角膜缝线拆除。此次拆线术后2周至门诊复诊,主诉“左眼前黑影遮挡伴视力下降近2周”,查体如下。裸眼视力:左眼CF/10 cm;眼压:左眼5 mmHg。左眼角膜植片透明,位置良好,前房清,瞳孔圆,光反射存在,IOL明。眼底:左眼脉络膜广泛脱离,未查见裂孔及出血。B超查及脉络膜脱离回声。经扩瞳、局部及全身抗炎治疗5天后,脉络膜脱离仍未见明显好转,遂决定行左眼玻璃体切除+脉络膜脱离复位术。术中可放出大量微黄色脉络膜上腔液体,复位脉络膜,未见视网膜裂孔,术毕气体填充,术后患者脉络膜复位良好,视力逐渐提高。追问病史,患者第2次角膜拆线过程中,痛感非常明显,术中高度紧张,存在用力屏气过程。讨论体会:患者角膜拆线时的Valsava动作很有可能是该例脉络膜脱离发生的原因,要详细了解病情,做好术前沟通、加强人文关怀,术中充分麻醉,密切关注患者术中情况,做好患教工作,术后尽早随访,以便及时发现特殊并发症。

角膜屈光术后角膜上皮重塑及其影响因素

角膜上皮作为重要的屈光介质,参与了屈光术后角膜修复的过程,现有的角膜屈光术后均表现为角膜上皮重塑,过度的角膜上皮重塑影响了角膜屈光手术的矫正效果。文章一方面总结了角膜上皮重塑在屈光手术中的应用,另一方面更加全面地探究了围手术期角膜屈光术后上皮重塑的影响因素,以期提高角膜屈光手术的安全性、有效性、可预测性和稳定性。

不同类型青光眼患者手术前后角膜生物力学变化特征

目的比较不同类型青光眼患者角膜生物力学差异及其相关影响因素,探讨青光眼术后角膜生物力学的变化趋势。方法采用前瞻性病例对照研究。收集2017年1—7月天津市眼科医院收治的急性原发性闭角型青光眼(APACG)(缓解期或慢性期)患者61例61眼、慢性原发性闭角型青光眼(CPACG)患者94例94眼、原发性开角型青光眼(POAG)患者70例70眼和年龄相关性白内障(ARC)患者64例64眼。采用Corvis ST测量活体角膜的生物力学参数,分析并比较不同类型青光眼患者术前角膜生物力学参数差异以及青光眼手术后的变化,采用多重线性回归分析探讨年龄、矫正后眼压(IOPcc)、中央角膜厚度(CCT)、眼轴长度(AL)、平均角膜屈光力(K)与角膜生物力学参数的关系。结果与ARC组相比,术前CPACG组和POAG组第一压平速度(A1V)、第二压平时间(A2T)较小,差异均有统计学意义(均P<0.05);与ARC组和APACG组相比,术前CPACG组和POAG组第二压平速度(A2V)较大,差异均有统计学意义(均P<0.05)。A1V、A2T、角膜顶点改变的最大垂直距离(DA)及最大压陷时角膜表面未发生改变的两点距离(PD)与IOPcc均呈负相关(r=-0.494、-0.612、-0.652、-0.277,均P<0.05),A2V、第一压平时间(A1T)及最大压陷曲率半径(CCR)与IOPcc均呈正相关(r=0.508、0.960、0.249,均P<0.05);第一压平长度(A1L)及第二压平长度(A2L)与K均呈负相关(r=-0.323、-0.227,均P<0.05),A1V、A2T及DA与K均呈正相关(r=0.214、0.256、0.242,均P<0.05)。与术前相比,CPACG组术后1个月A1T、A2V减小,A1V、A2T、DA增大,差异均有统计学意义(均P<0.05);POAG组术后1个月A1T、A2V减小,A2T、DA增大,差异均有统计学意义(均P<0.05)。与术前相比,APACG组、ARC组术后1个月角膜生物力学指标差异无统计学意义(均P>0.05)。结论CPACG和POAG患眼角膜形变能力较差,青光眼手术后角膜形变能力逐渐恢复;APACG(缓解期或慢性期)由于眼压一过性升高,对角膜形变能力影响较小,手术前后无明显差异;角膜生物力学各参数受IOPcc和K值影响较大。

飞秒激光与常规刀片准分子激光术后角膜后表面高度早期变化的对照研究

背景 飞秒激光准分子激光角膜原位磨镶术（FS-LASIK）已广泛用于屈光不正的矫治,具有良好的安全性和可预测性,但缺乏术后角膜后表面高度动态变化的研究.了解FS-LASIK术后角膜后表面高度的动态变化对于预防医源性角膜膨隆具有重要意义. 目的 分析FS-LASIK术后早期角膜后表面高度的变化情况,并与前弹力层下准分子激光角膜磨镶术（SBK）、上皮刀辅助的准分子激光上皮瓣下角膜磨镶术（Epi-LASIK）术后情况进行比较.方法 采用前瞻性非随机对照研究设计.纳入2010年6-9月在天津市眼科医院行准分子激光角膜屈光手术的近视及近视散光患者72例144眼,分为FS-LASIK组23例46眼,SBK组28例56眼,Epi-LASIK组21例42眼.分别于术前及术后1d（Epi-LASIK组术后3d）、1周、1个月用Visante OMNI测量术眼角膜后表面水平子午线和垂直子午线上角膜顶点及距离角膜顶点1、2、3 mm共13个点的角膜后表面高度,采用重复测量的方差分析进行统计学分析. 结果 在FS-LASIK组,术前、术后1d、1周、1个月术眼角膜顶点方位角膜后表面高度分别为（2.03±0.78）、（2.26±0.96）、（2.16±0.85）和（2.06±0.89）μm；在距角膜顶点1 mm、2 mm区域,术眼的术后变化趋势与角膜顶点区域的变化相同；在距角膜顶点3 mm区域,上述4个时间点术眼的角膜后表面高度分别为（-4.64±1.68）、（-5.39±1.85）、（-4.73±1.71）和（-4.71±1.52） μm.在SBK组,术前及术后1d、1周、1个月角膜顶点区域角膜后表面高度分别为（1.44±0.63）、（1.74±0.75）、（1.66±0.69）和（1.53±0.71） μm；在距角膜顶点1 mm、2 mm区域,术眼术后角膜后表面高度变化趋势与角膜顶点区域一致；在距角膜顶点3 mm区域,上述4个时间点角膜后表面高度分别为（-5.09±1.76）、（-5.48±1.68）、（-5.27±1.81）和（-5.19±1.77）μm,术后发生了轻微后移.在Epi-LASIK组,术前,术后3d、1周、1个月在角膜顶点区角膜后表面高度分别为（2.47±0.73）、（1.55±1.43）、（1.55±1.37）和（2.37±1.06） μm,术后发生轻微后移；而在距角膜顶点1 mm、2 mm区域则与角膜顶点术后变化趋势不同,术后3d角膜后表面高度分别由术前的（1.55±0.51）μm、（-1.87±0.91）μm变为（1.92±0.91） μm、（0.24±1.35） μm,角膜发生轻微前移.在距角膜顶点3 mm区域,角膜后表面高度变化趋势与角膜顶点区相同.FS-LASIK组和SBK组术眼术后角膜后表面高度的变化较小,Epi-LASIK术后1d、1周时较术前变化较大.术后1d时,FS-LASIK相对于SBK变化较大.不同的手术方式及不同时间点角膜后表面高度的差异均无统计学意义（P＞0.05）.结论 FS-LASIK术后早期中央区和旁中央区的角膜后表面高度发生了微小的变化,但随时间的变化逐渐恢复至术前水平,与SBK、Epi-LASIK相比无明显差异.

近视眼角膜Q值的临床意义

目的:研究角膜的非球面参数Q值在不同程度近视眼中的分布情况。方法:53例106只近视眼,按照低、中、高度近视程度分为3组,用Astramax角膜分析仪测定角膜Q值并做统计学处理。结果:平均角膜Q值3组分别为-0.34±0.24,-0.21±0.24和-0.22±0.20。3组之间无统计学显著性差异(P=0.18)。结论:角膜非球面参数Q值与近视程度无关,个体间变异较大。准分子激光屈光手术中不应采用人群的角膜Q值平均值,而应当针对个体角膜的Q值进行修正,即所谓个性化治疗。

屈光性角膜手术26743例回顾

目的:总结准分子激光屈光性角膜手术的10a临床效果。方法:1993-05/2003-05包括行PRK,LASEK及LASIK的患者26743例(44580眼),应用数学模式建立数据库,进行数据统计分析。结果:男14691眼,女29889眼;年龄9～57(平均27.20)岁;左22443眼,右22137眼。术前裸眼视力0.10±0.07;矫正视力0.98±0.37,其中≥0.5者43794眼(98.23%),≥1.0者41066眼(92.11%),≥1.5者2218眼(4.98%);眼压15.76±7.25mmHg(1mmHg=0.133kPa);屈光度球镜-0.75～-18.00D(-5.65±3.24D),柱镜-0.25～-5.00D(–0.05±0.77D);角膜曲率(K)值K143.94±3.57,K242.98±3.50。筛选圆锥角膜0.99%,亚临床圆锥角膜0.93%;眼底病变及视网膜周边变性0.39%,排除系统疾病及不适宜激光手术者。术后情况裸眼视力0.98±0.34,其中≥0.5,44580眼(100%),≥1.0者44031眼(98.80%),≥1.5者4732眼(10.61%);矫正视力1.03±0.33;眼压14.87±7.06mmHg;屈光度球镜-0.001±0.06D,柱镜-0.00±0.03D;K值K138.07±9.83,K237.20±10.84。实际矫正度在预期矫正度±1.00范围内98.70%。临床、亚临床圆锥角膜及眼底病变者不手术;视网膜周边变性眼底激光1mo后可进行手术,以LASEK为主。三种手术长期效果没有统计学差异。PRK1wk内基质细胞明显减少,10d,1mo基质细胞数目增加,3mo减少。

SMILE与LASIK矫正低中度散光效果的矢量分析和比较

背景小切口角膜微透镜取出术（SMILE）术中无准分子激光虹膜跟踪技术，故矫正散光的效果存在争议，了解其矫正近视散光的效果将对临床有-定的指导意义。目的探讨SMILE与飞秒激光辅助的准分子激光角膜原位磨镶术（FS—LASIK）矫正低中度近视散光的临床效果。方法采用回顾性研究设计。纳入2013年12月至2014年7月在天津市眼科医院分别接受SMILE的患者51例95眼及同期接受FS—LASIK的低中度近视散光患者40例69眼，SMILE组与FS—LASIK组间术前球镜度、柱镜度和等效球镜度（sE）的差异均无统计学意义（均P〉0．05）。术眼于术前及术后1d、1周、1个月、3个月均检查裸眼视力（UCVA）、最佳矫正视力（BCVA），并进行显然验光、裂隙灯显微镜检查、眼压测量及角膜地形图测量。利用矢量分析法计算2种手术方式术前及术后残余散光的分布情况，并选取矫正指数（cI）、成功指数（IOS）、误差角（AofE）和变平指数（FI）等指标评价散光的矫正效果，以安全性指数、有效性指数作为评价视力恢复程度的指标，对2个组间疗效指标的差异进行比较，对术前Kappa角与各参数之间的关系进行分析。结果SMILE组术后球镜度、柱镜度和sE分别为（0．003±0．106）、（-0．063±0．126）和（-0．029±0．101）D，FS．LASIK组分别为（0．112±0．212）、（-0．091±0．142）和（0．067±0，198）D，SMILE组术后球镜度和SE均明显低于FS—LASIK组，差异均有统计学意义（Z=-4．328、-3．197，均P〈0．05）。矢量计算结果显示，SMILE组术后以顺规散光为主，而Fs．LASIK组术后则以斜轴散光为主，SMILE组术后cI和FI均明显低于FS—LASIK组，差异均有统计学意义（Z=-3．051、-3．126，均P〈0．05），SMILE组术后cI略低于1，而FS—LASIK组术后cI略高于1。SMILE组IOS和AofE小于FS—LASIK组，但差异均无统计学意义（Z=-1．557，P=0．119；Z=-1．923，P=0．054）。2个组中术眼术后的安全性指数和有效性指数差异均无统计学意义（均P〉0．05）。SMILE组安全性指数和有效性指数与术前Kappa角的偏移量均呈负相关（r=-0．258、-0．257，均P〈0．05）。结论SMILE和FS-LASIK均能有效矫正低中度近视散光，术后均能达到预期视力。SMILE手术切口的愈合反应轻于FS—LASIK，故术后残余散光轴向偏差小。SMILE术后散光呈欠矫趋势，术者可根据经验适当增加散光矫正度。

治疗性准分子激光角膜切削术及其进展

应用激光切削角膜表浅病变组织，即治疗性准分子激光角膜切削术（PTK）治疗角膜病已开展了20余年，近年来发展迅速，技术日趋完善，适应证得到拓展并且有严格的规范，安全性高。PTK已用于大泡性角膜病变、角膜的隆起性病损、角膜浅表炎症性病变、遗传性角膜营养不良性病变、翼状胬肉以及一些儿童浅表性角膜病变的治疗，PTK与其他疗法的联合应用在治疗角膜病变中也发挥着较好的治疗作用。此外PTK治疗浅表性角膜病变的安全性较好，不良反应小，可延迟或替代角膜移植术，具有较好的应用前景。就PTK在眼科临床应用中的注意事项、效果、安全性、并发症、适应证等研究进展进行综述。

准分子激光近视矫正术后角膜前表面形态变化的研究

目的:探讨准分子激光角膜屈光手术前后角膜前表面形态的改变。方法:95只近视眼分为中/低度近视组(A组,n=53)和高度近视组(B组,n=42),角膜地形图测量并记录手术前后角膜Q值并进行统计学分析。结果:所有术眼手术前后角膜Q值有显著差异(P<0.01)。术前角膜Q值两组间没有统计学差异(P>0.05),术前屈光度与角膜Q值没有相关性(P>0.05)。但术后角膜Q值在两组间有显著差异(P<0.01)。B组手术前后角膜Q值变化的绝对值大于A组(P<0.01),术后角膜Q值变化与术前屈光度的大小呈显著正相关(P<0.01)。结论:准分子激光角膜屈光手术后角膜前表面形态发生显著改变,由术前长椭圆非球面形(Prolate)变为扁椭圆非球面形(Oblate)。高度近视组手术后角膜前表面形态改变程度大于中/低近视组。

飞秒激光辅助屈光性白内障手术效果的初步观察

目的:比较飞秒激光辅助屈光性白内障手术与常规屈光性白内障手术术后视力及角膜散光的差异。方法:将老年性白内障合并角膜散光患者60例60眼,按随机自愿原则分为飞秒组及常规组。飞秒组将患者术前角膜散光陡峭轴、平坦轴轴向及屈光度数输入在线矢量计算器,得出相关切口位置、切口宽度后,利用飞秒激光做角膜松解切口、主切口及辅助切口,再按常规行白内障超声乳化+非球面多焦点人工晶状体(multifocal intraocular lenses,IOL)植入术。常规组利用角膜穿刺刀于角膜散光陡峭轴向上做角膜全层松解切口、辅助切口,然后行白内障超声乳化+非球面多焦点IOL植入术。分别于术后1d,1wk,1mo观察两组术眼的角膜散光情况及裸眼远视力(uncorrected distance visual acuity,UCDVA)、裸眼近视力(uncorrected near visual acuity,UCNVA),并进行统计分析。结果:飞秒组和常规组术后裸眼视力均较术前提高,且飞秒组远、近视力均高于常规组;而各时期角膜散光飞秒组均低于常规组。结论:飞秒激光辅助下屈光性白内障手术较传统白内障手术术后角膜散光更小、视力更好,能给患者带来更好的视觉质量。