A HISTOPATHOLOGIC IMMUNOHISTOCHEMICAL AND ULTRASTRUCTURAL STUDY OF RABBIT CORNEA AFTER EXCIMER LASER PHOTOREFRACTIVE KERATECTOMY

Objective To evaluate the corneal healing of non-epuality diopter response histopathologically, immunohistochemically and ultrastructurally after excimer laser photorefractive keratectomy(PRK) with SVS APEX PLUS(Summit Technology Inc. USA) excimer laser, and the effects of corticosteroid on the healing. Methods PRK on 6 white rabbits(12 eyes) was performed on right eye or the rabbit for an attampted correction or -4.00 diopter and on left eye for an attempted correction of -8.00 diopter. The rabbits were divided into 2 groups randomly and each group included 6 eyes: Group FLM (3 rabbits, 6 eyes) and group CM (3 rabbits, 6 eyes). Fluoromethalone was given to group FLM,and chloromycetin to group CM. On 10d, 30d and 100d,the eyes of one rabbit in each group were enucleated randomly. Half of each cornea was prepared for electron microscope observation (SEM and TEM) and the rest embedded in OCT compound for immunohistochemical study to examine Ⅲ-C and FN. Results All eyes were reepithelialized within 3d after PRK. Subepithelial corneal haze was observed on 15d,which was dominant on 30 or 60d. On 100d postoperatively,corneal hazes of 11 eyes were grades 0 or 0.5,only 1 eye(the left eye or group CM) was denser haze (grade 1). On 3d postoperatively, one or two layers of corneal epithelial cell covered the ablation zone. On 30d after PRK,the epithelial cells showed hyperplastic changes. The cells were larger and increased from normal 5 or 6 layers to 7 or 8 layers of cells on l00d after PRK,epithelium was clear with more bright epithelium. Mi- croplicae and microvilli were less than before. The expression of Ⅲ-C and FN in group CM was significantly more evi- dent than that in group FLM. Conclusion The study show that despite recovery of a continuous and smooth epithelial layer and nearly normal corneal tissues on 100d after PRK,abnormalities of both epithelium and superficial stroma can be detected in the area of ablation. The ablation depth of stroma can influence the appearance of corneal haze af- ter PRK. The microplicae and microvilli of rabbit cornea epithelium become less after PRK,which can be one of cause leading to ocular dry sensation in some patients.

CLINICAL ANALYSIS OF EXCIMER LASER PHOTOREFRACTIVE KERATECTOMY FOR TREATMENT OF MYOPIA AND MYOPIC ASTIGMATISM

To evaluate the efficacy and accuracy of photorefractive keratectomy (PRK) for myopia and myopic astigmatism .SVS APEX excimer laser with a wave length of 193 nm(Sumit Technology Inc. Waltham, Mass, USA) was applied. 316 myopic eyes of 168 patients were treated with PRK between September, 1996 and October, 1997, and 260 eyes (84%) of 150 patients were followed for more than three months, including male 68(116 eyes, 401%) and female 82(144 eyes, 599%). The preoperative spherical equivalent refractive errors ranged from -125D to -1000 (mean -467163D), and astigmatism ranged from 0 to -200D (means -033045D). We divided the patients into two groups according to the referaction: group A (from -125D to -590D) and group B(from -600 to -1000D). The number of eyes in the two groups were 220 and 40 respectively. In group A, on the 10th day, 689% has the uncorrected visual acuity (UCVA) equal to or one line better or lower than the preoperative best corrected visual acuity (BCVA). In 1,3,6 and 12 months, 90 %, 96%, 95% and 94% had the UCVA equal to or one line better or lower than the preoperative BCVA respectively. In group B, on the 10 th day, in 1,3,6 and 12 months, UCVA equal to or one line better or lower than the preoperative BCVA occurred in 359%, 83%, 87%, 86%, and 84% of the cases respectively. Most of the haze showed 051 grades except 3 eyes with the haze of 2 grade in 3 or 6 months and it changed to 1 and 05 grade respectively within one year. In 10 days and 1,3,6,12 months postoperatively, the corneal haze was noted in 329%, 848%, 628%,90% and 28% of the treated eyes respectively. We found that 193 nm excimer laser PRK was a predictable, safe, stable, and effective refractive surgery for correcting myopia up to -1000D in Chinese patients, and the effect was better in myopia lower than -600D.

Clinical outcomes of transepithelial photorefractive keratectomy versus femtosecond laser assisted keratomileusis for correction of high myopia in South Egyptian population

AIM: To evaluate the safety and efficacy of transepithelial photorefractive keratectomy(t-PRK) with adjuvant mitomycin C(MMC) versus femtosecond laser assisted keratomileusis(Femto-LASIK) in correction of high myopia.METHODS: Prospective randomized comparative study including 156 eyes of 156 patients with high myopia and a spherical equivalent refraction(SER) <-6.00 D. They were divided randomly into two groups: Group A included 72 eyes treated with t-PRK with adjuvant MMC and Group B included 84 eyes treated with Femto-LASIK. Visual acuity, SER, corneal topography, pachymetry and keratometry were assessed for 12 mo postoperatively.RESULTS: The preoperative mean SER was-8.86±1.81 and-9.25±1.70 D in t-PRK MMC group and Femto-LASIK respectively(P=0.99) which improved to-0.65±0.43 D and-0.69±0.50 D at 12 mo follow up. Mean SER remained stable during the 12 mo of follow-up, with no statistically significant difference between the two groups(P=0.64). In t-PRK MMC group, only six eyes needed retreatment after six months of follow up. And two eyes showed haze(one reversible haze grade 2, while the other had dense irreversible haze grade 4).CONCLUSION: t-PRK MMC provides safe and satisfactory visual outcomes and acceptable risk as Femto-LASIK in patients with high myopia.

Long term results of no- alcohol laser epithelial keratomileusis and photorefractive keratectomy for myopia

AIM: To evaluate the long term clinical results of mechanical no-alcohol-assisted laser epithelial keratomileusis(LASEK) versus standard photorefractive keratectomy(PRK) for low-moderate myopia.METHODS: Twenty-five eyes treated with LASEK and twenty-five eyes treated with PRK were evaluated with a mean follow-up duration of 60 mo. Mechanical separation of the epithelium was performed with blunt spatula and without application of alcohol. Laser ablation was performed with the MEL-70 excimer laser. All patients were examined daily until epithelial closure; at 1, 3, 6,and 12 mo, and every year subsequently. Main outcome measures were uncorrected distance visual acuity(UDVA), corrected distance visual acuity(CDVA),manifest refraction, haze, efficacy and safety indexes.RESULTS: Twenty-one eyes and 22 eyes completed follow-up of 60 mo in LASEK and PRK group respectively. Manifest refraction at 60 mo follow-up was-0.01 and 0.26 in LASEK and PRK group respectively. In the LASEK group mean UDVA and mean CDVA after60 mo were 20/22 and 20/20 respectively(P 】0.01). In the PRK group mean UDVA and mean CDVA at 60 mo follow-up were 20/20 and 20/20 after 60mo(P 】0.01). The efficacy indexes were 0.87 and 0.95, and the safety indexes were1.25 and 1.4 respectively for LASEK group and PRK group.CONCLUSION: Both standard PRK and no-alcohol LASEK offer safe and effective correction of low-moderate myopia in the long term without any statistically significant difference between the two groups.

Comparison of Postoperative Pain Following Laser-assisted Subepithelial Keratectomy and Transepithelial Photorefractive Keratectomy:a Prospective,Random Paired Bilateral Eye Study

Purpose:To compare postoperative pain following laser-assisted subepithelial keratectomy(LASEK) and transepithelial photorefractive keratectomy(T-PRK, two-step surgery) and alleviate postoperative subjective pain.Methods:.Thirty patients(60 eyes) with myopia or myopic astigmatism were consecutively recruited into this prospective,randomized paired study..Patients underwent LASEK in one eye,and T-PRK in the other. The degree of pain was rated on a scale of 0-10 on postoperative days 1,2 and 3..Uncorrected visual acuity(UCVA) and subepithelial corneal haze were assessed at postoperative 1 and 3 months.Results:.The pain was relieved on the 4th postoperative day in all patients,.healing of corneal epithelium was observed at4-5 days after surgery and contact lenses were removed promptly.At postoperative 1 day,.the mean subjective pain score in the LASEK group was 3.2±1.88 and 4.43±1.61 in TPRK group(P=0.008).No significant difference was found between two groups on postoperative 2 and 3 days. At postoperative 3 months, the percentage of UCVA ≥0.8 in the LASEK group was 100% and 96.7% in the T-PRK group.(P =0.24),93.3% of patients in the LASEK with UCVA ≥1.0 and 90%in the T-PRK group(P=0.64). In the LASEK group, the value of corneal haze was 0.26 ±0.21 and 0.27 ±0.25 in the T-PRK group(P=0.877).Conclusion:.Good visual acuity was obtained in both groups at postoperative 3 months. Compared with those in the T-PRKgroup, patients undergoing had less discomfort in the LASEK group, which may be associated with corneal epithelial activity. The changing curve of subjective pain in the T-PRK group was relatively flat and stable at postoperative 3 days.

EXCIMER LASER PHOTOREFRACTIVE KERATECTOMY FOR MYOPIA IN CHINA A REPORT OF 750 EYES WITH A 6-MONTH FOLLOW-UP

A total of 750 six-month follow-up records of myopia treated with excimer laser photorefractive keratectomy (PRK) were analyzed. By 6 months, in group 1 (up to-6.00D, 587 eyes), uncorrected visual acuity was improved to 20 / 20 or better in 86.7% of treated eyes and 95.4% fell into the range of refraction of±1.00D. In group 2 (-6.25D to -11.00D, 163 eyes), 74.5% of treated eyes had uncorrected visual acuity of 20 / 20 or better and 89.4% of the eyes were within ±1.00D. The designed predictability of the two groups was the same (P>0.1). The refractive stability from 3 to 6 months between the two groups was not statistically different, and no severe complications were observed in these two groups. The excimer laser PRK for correcting myopia up to -11.00D appears to be effective, predictable, stable and safe in this study. The ideal outcome may result from the precise ablation quality of excimer laser, its computerized surgical manipulation and an appropriate postoperative management including detection of refractive indices by conical topography and modulation by steroid.

Comparison of laser epithelial keratomileusis and photorefractive keratectomy for the correction of myopia： a meta-analysis

Background It is unclear whether a laser epithelial keratomileusis （LASEK） has any significant advantage over a photorefractive keratectomy （PRK） for correcting myopia. We undertook this meta-analysis of randomized controlled trials to examine possible differences in efficacy, accuracy, safety and side-effects between two methods, LASEK and PRK, for correcting myopia. Methods A systematic literature retrieval was conducted in the PubMed, EMBASE, Chinese Bio-medicine Database, and Cochrane Controlled Trials Register to identify potentially relevant randomized controlled trials. The statistical analysis was performed using a RevMan 4.2 software. The results included efficacy outcomes （proportion of eyes with uncorrected visual acuity （UCVA）〉 20/20 at 1 month and 12 months post-treatment）, accuracy outcomes （proportion of eyes within ±0.50 diopters （D） of target refraction at 1 month and 12 months post-treatment）, safety outcomes （loss of 〉2 lines of best spectacle-corrected visual acuity （BSCVA） at 〉 6 months post-treatment）, mean pain scores on day 1 post-treatment, and mean corneal haze scores at 6 and 12 months post-treatment. Results Seven articles describing a total of 604 eyes with myopia from 0 to -9.0 D were identified in this meta-analysis. The combined results showed that the efficacy and accuracy outcomes between the two groups at 1 month and 12 months post-treatment were comparable. No patient lost 〉 2 lines of BSCVA at 〉 6 months post-treatment in four relevant trials. Compared with PRK, LASEK did not relieve discomfort on day 1 post-treatment or reduce corneal haze intensity at 6 and 12 months post-treatment. Conclusions According to the available data, LASEK does not appear to have any advantage over PRK for correcting myopia from 0 to -9.0 D. This meta-analysis focuses mainly on the comparison of the early, mid-term and mid-long term results of the two methods. Additional studies to compare the long-term （〉one year） results should be considered.

Corneal topographic analysis after excimer photorefractive keratectomy

Objective To evaluate the corneal surface changes and visual quality after excimer photorefractive keratectomy (PRK) for myopia. Methods Corneal topographic analysis was performed on 23 patients (38 eyes) with myopia after PRK at the 1 , 3 , 6 month postoperative follow up visits. Results The corneal sphericity was changed after excimer PRK. As time went on, the mean surface regularity index (SRI) and the surface asymmetry index (SAI) decreased gradually, and the corneal surface became more smooth; mean simulated keratoscope readings (SimK) showed a gradual restoration. At the 6 month postoperative examination, corneal topography showed four main patterns of ablation: round or oblong (50%), collar button (23.68%), semicircular (18.42%) and central island (7.9%). Patterns of ablation were correlated with visual acuity. Conclusion The quantitative analysis of coneal topography is essential for evaluating corneal surface changes after PRK and helpful in the surgical design of PRK and in predicting the refractive outcome with greater precision.

LASEK和TransPRK及FS-LASIK术后角膜屈光力及视觉质量比较

目的:比较准分子激光上皮下角膜磨镶术(LASEK)、经上皮准分子激光角膜切削术(TransPRK)、飞秒激光制瓣的准分子激光原位角膜磨镶术(FS-LASIK)三种角膜屈光手术术后角膜屈光力及视觉质量。方法:回顾性研究。选取2021-01/2022-12在我院择期行角膜屈光手术的232例464眼患者作为研究对象,根据患者选择手术方式不同分为LASEK组70例140眼、TransPRK组76例152眼、FS-LASIK组86例172眼。比较三组患者术前,术后1、3 mo时裸眼视力(UCVA)、视觉质量、生物力学稳定性、泪膜破裂时间(BUT)、泪液分泌试验(SⅠt)及生活质量变化情况。结果:术后1、3 mo三组患者裸眼视力较术前均改善,全角膜总高阶像差、球差、水平彗差、垂直彗差均升高,生物学稳定性均降低(均P<0.05)。术后3 mo, TransPRK组、LASEK组生物学稳定性均高于FS-LASIK组(均P<0.05),TransPRK组生活质量评分较LASEK组及FS-LASIK组高(P<0.05)。手术前后三组患者BUT、SⅠt比较均无差异(均P>0.05)。结论:LASEK、TransPRK、FS-LASIK三种角膜屈光手术治疗屈光不正疗效确切,在改善裸眼视力和提高视觉质量方面结果相似,但TransPRK、LASEK较FS-LASIK具有更稳定的生物力学性能,且TransPRK组在改善患者生活质量方面具有更好的效果。

Trans-PRK联合预防性快速CXL矫正薄角膜或角膜形态欠规则屈光不正的疗效及安全性

目的评估经上皮准分子激光屈光性角膜切削术(Trans-PRK)联合预防性快速角膜交联术(CXL)矫正薄角膜或角膜形态欠规则(除外圆锥角膜)屈光不正的疗效及安全性。方法采用系列病例观察研究方法,纳入2017年8月至2018年7月于包头朝聚眼科医院诊断为薄角膜或角膜形态欠规则并行Trans-PRK联合预防性CXL手术的近视患者55例55眼,所有患者均取右眼数据进行分析。术前、术后1周及术后1、3、6、12个月采用国际标准视力表检测术眼裸眼远视力(UDVA);采用电脑验光和综合验光检测屈光度。术前及术后3、6、12个月采用Pentacam眼前节分析仪检查角膜形态;术前及术后1、3、6、12个月采用非接触式眼压计测量眼压。记录术后并发症发生情况。结果术前、术后1周及术后1、3、6和12个月术眼UDVA(LogMAR视力)分别为0.52(0.55,0.78)、0.22(0.12,0.17)、0.10(0.04,0.07)、0.00(-0.04,-0.16)、-0.08(-0.05,-0.03)、-0.08(-0.06,-0.04),总体比较差异有统计学意义(Z=249.44,P<0.001),其中术后各时间点UDVA均较术前提高,术后3、6和12个月术眼UDVA较术后1周和1个月明显改善,差异均有统计学意义(均P<0.001)。术眼术后各时间点球镜度较术前均明显下降,术后1、3、6和12个月术眼球镜度低于术后1周,术后12个月术眼球镜度低于术后3和6个月,差异均有统计学意义(均P<0.001)。术后1、3、6和12个月术眼柱镜度低于术前和术后1周,差异均有统计学意义(均P<0.05)。术眼术后等效球镜度随时间延长逐渐下降,趋于正视状态;术后各时间点术眼等效球镜度低于术前,术后1、3、6和12个月术眼等效球镜度低于术后1周,术后12个月低于术后3和6个月,差异均有统计学意义(均P<0.001)。术后3、6及12个月术眼角膜K1值、K2值均明显低于术前,差异均有统计学意义(均P<0.001),术后3个月角膜K1值、K2值趋于稳定。术后3、6、12个月术眼眼压均显著低于术前,术后6和12个月术眼眼压低于术后1和3个月,差异均有统计学意义(均P<0.001)。术后1周1眼出现0.5级角膜上皮下雾状混浊,于术后1个月角膜自行恢复透明。结论Trans-PRK联合预防性快速CXL手术矫治合并薄角膜或角膜形态欠规则的(除外圆锥角膜)屈光不正眼具有良好的有效性、稳定性及安全性。

Correlation between Post-LASIK Starburst Symptom and Ocular Wavefront Aberrations

Monochromatic aberrations in post laser in-situ keratomileusis （LASIK） eyes are measured. The data are categorized into reference group and starburst group according to the visual symptoms. Statistic analysis has been made to find the correlation between the ocular wavefront aberrations and the starburst symptom. The rms aberrations of the 3rd and 4th orders for the starburst group are significantly larger than those for the reference group. The starburst symptom shows a strong correlation with vertical coma, total coma, spherical aberrations. For 3-mm pupil size and 5.8-mm pupil size, the modulation transfer function （MTF） of the starburst group are lower than those of the reference group, but their visual acuities are close. MTF and PSF analyses are made for two groups, and the results are consistent with the statistical analysis, which means the difference between the two groups is mainly due to the third- and fourth-order Zernike aberrations.

准分子激光屈光性角膜切削术矫治近视术后角膜上皮的重塑及相关因素分析

背景准分子激光角膜屈光手术矫治近视后角膜上皮会发生重塑效应，主要表现为上皮厚度的变化，目前关于单一步骤的经角膜上皮的准分子激光屈光性角膜切削术（TransPRK）后角膜上皮厚度变化的研究鲜见报道。目的探讨TransPRK矫治近视术后角膜光学区内不同区域上皮厚度的变化及其相关影响因素。方法采用回顾性研究设计，收集2014年8月至2015年6月在济南市明水眼科医院行TransPRK手术的近视及近视散光患者43例43眼，术前等效球镜度为一1．25- -6．25D。分别于术前及术后1周、1个月、3个月及6个月应用频域眼前节光相干断层扫描仪（OCT）对患者角膜0～2、2～5及5～6mm范围内的上皮厚度进行测量，研究术后不同时间角膜上皮厚度的变化规律并分析其与屈光度、切削深度、光学区大小以及角膜非球面性变化（Q值）等因素的相关性。结果术前及术后1周、1个月、3个月及6个月角膜中央上皮厚度分别为（52．37±3．42）、（53．97±4．33）、（51．03±4．11）、（55．14±5．46）和（56．68±5．09）p,m，术后3个月与6个月角膜上皮厚度与术前比较差异均有统计学意义（均P〈0．05）。术后6个月，角膜0～2、2～5及5～6mm范围内角膜上皮厚度较术前分别增厚（3．69±4．23）、（5．19±3．88）和（6．23±3．91）txm，与术前比较差异均有统计学意义（均P〈0．01）；角膜上皮厚度与屈光度和Q值变化量均呈正相关，与光学区大小呈负相关（均P〈0．05）；2-5mm区和5～6mm区上皮厚度变化与切削深度均呈正相关（r=0．380、0．383，均P〈O．05），而中央区角膜上皮厚度与切削深度无相关性（P〉0．05）。结论TransPRK术后角膜光学区内上皮增厚的分布呈“负透镜式”的变化，越接近光学区周边增厚越显著，上皮厚度变化量受屈光度、切削区大小及切削深度的影响，且这种不均匀增厚会影响角膜的非球面特性，可能会在一定程度上掩藏个性化手术应该达到的效果。

激光角膜切削术后皮质类固醇性高眼压

为防止准分子激光角膜切削术后近视度数回退，术后局部滴强地松龙６个月。经对皮质类固醇性高眼压和青光眼进行了分析结果表明，１６２８只术眼皮质类固醇性高眼压（≥２．９３３ｋＰａ）术后１个月和３个月的发生率分别为９．８９％和１５．０５％，３月高眼压的发生率高于１月高眼压的发生率，差异有显著性；男性患者激素升压反应比女性患者明显，１个月时分别为１６．６４％和５．５４％；３个月时分别为１８．０５％和１３．１２％；高眼压的发生与原屈光状态（≤－２．９０Ｄ和≥－３．００Ｄ）无关。皮质类固醇性青光眼５例（０．３０％）。同时对准分子激光角膜切削术后皮质类固醇性高眼压的防治进行了讨论。

TransPRK与Epi-LASIK术后角膜上皮重塑的对比研究

目的:对比观察TransPRK与Epi-LASIK手术治疗近视术后角膜不同区域上皮厚度的变化。方法:前瞻性对照研究。选择行表层切削手术的近视及近视散光患者76例76眼,其中纳入TransP RK组43例43眼,Epi-LASIK组33例33眼,术前等效球镜度-1.25^-6.00D。分别于术前及术后1、3、6mo应用傅立叶域眼前节OCT对患者角膜0~2、2~5、5~6mm的角膜上皮厚度进行测量,研究两组患者术后不同时间角膜上皮厚度的变化规律。结果:两组患者术后3mo与6mo角膜各区域上皮厚度均较术前增厚,且差异有统计学意义(P<0.05)。TransPRK组上皮厚度的增厚表现为越接近光学区周边增厚越显著的特点(F3mo=-2.687,P=0.027;F6mo=-2.908,P=0.000),Epi-LASIK组各区域之间增厚的差异比较无统计学意义(F=1.365,P=0.237)。两组患者仅在光学区周边5~6mm上皮厚度变化的差异比较有统计学意义(P<0.05)。结论:TransP RK与Epi-LASIK两种表层手术后角膜上皮均发生重塑效应,表现为上皮厚度的增厚;TransPRK术后角膜上皮增厚在光学区周边较Epi-LASIK手术显著,且符合越接近周边增厚越显著的特点,可能与其愈合反应有关。

PRK与LASIK治疗单纯性近视术后散光的分析

目的 探讨PRK与LASIK治疗单纯性近视术后产生散光的原因及变化规律。方法 对屈光度 -1 2 5D～ -8 0 0D的单纯性近视 3 85眼分别行PRK( 2 0 1眼 )及LASIK( 184眼 )手术 ,随访 1年。结果 PRK与LASIK术后散光度逐渐减小或消失。术后各时期平均散光度PRK组均大于LASIK组 ,1周、1、3月有显著性差异 (P <0 0 1) ,6、12月无显著性差异 (P >0 0 5 )。结论 PRK术后产生散光主要与角膜的损伤修复反应有关 ,而LASIK主要与手术并发症有关。

TransPRK与Epi-LASIK矫治薄角膜近视眼的临床疗效比较

背景单一步骤的经角膜上皮的准分子激光屈光性角膜切削术（TransPRK）是一种新型的表层切削术，术后角膜上皮愈合快，术眼刺激性小，但关于TransPRK术后临床效果的动态性观察、角膜生物力学性能以及角膜后表面形态等的变化研究鲜见报道。目的评价TransPRK矫治薄角膜近视眼的手术效果及安全性，并与机械法准分子激光角膜上皮瓣下磨镶术（Epi-LASIK）进行比较。方法采用前瞻性非随机对照研究设计，收集2013年6-12月在济南市明水眼科医院拟行表层准分子激光手术的近视及近视散光患者93例93眼，均纳入右眼进行分析。术眼术前角膜厚度为460～500μm，其中TransPRK组46眼，Epi-LASIK组47眼，分别于术前及术后1周、1个月、3个月和6个月记录并比较2个组术眼的裸眼视力（UCVA）、屈光度、角膜上皮下雾状混浊（haze）程度、角膜生物力学参数、角膜后表面高度及Q值、角膜像差。结果TransPRK组术后不同时间点视力和屈光度变化的眼数分布与Epi-LASIK组的差异均无统计学意义（均P〉0．05）。术后6个月，TransPRK组UCVA≥1．0者占93．9％，屈光度在±1．00D以内者占90．9％，具有良好的安全性和稳定性。术后1个月haze最明显，TransPRK组有15眼出现haze，占32．6％，Epi-LASIK组有8眼出现haze，占17．4％，均在0．5级以下。TransPRK组haze的发生率略高于Epi-LASIK组，2个组间差异无统计学意义（X^2=2．841，P=0．092）。2个组间角膜滞后量（CH）值和角膜阻力因子（CRF）值的总体差异均无统计学意义（CH：F分组=0．000，P=0．999；CRF：F分组=0．110，P=0．741），但2个组术眼术后CH值和CRF值均明显下降，不同时间点的总体比较差异均有统计学意义（CH：F时间=103．658，P=0．000；CRF：F时间=132．008，P=0．000），其中术后不同时间点CH值和CRF值均较术前明显降低，差异均有统计学意义（均P〈0．01），而术后各时间点间的相互比较差异均无统计学意义（均P〉0．05）。2个组间术后各时间点角膜后表面高度较术前均轻微后移，与术前值比较差异有统计学意义（F时间=12．868，P=0．001），但组间比较差异无统计学意义（F分组=1．923，P=0．169）。2个组手术前后不同时间点术眼角膜后表面Q值总体比较差异均无统计学意义（F分组=0．191，P=0．663；F时间=1．783，P=0．185）。2个组术眼术后各时间点角膜高阶像差均方根（RMS）值与球差值均较术前明显增加，差异均有统计学意义（均P〈0．01），但组间总体比较差异均无统计学意义（角膜RMS：F分组=0．299，P=0．586；角膜球差：F分组=1．290，P=0．259）。结论TransPRK矫正薄角膜的近视眼术后视力和屈光稳定性较好，与Epi—LASIK比较无明显差异；术后早期角膜生物力学性能降低，但随着术后时间的延长逐步恢复；术后角膜后表面高度有轻微后移的现象，但并未影响后表面整体的非球面形态。

准分子激光屈光性角膜切削术治疗轻、中度近视眼

目的：评价准分子激光屈光性角膜切削术（ＰＲＫ）治疗轻、中度近视眼的临床效果。方法：对在我院接受ＰＲＫ治疗的８１只轻、中度近视及近视散光眼的术后半年随访结果进行统计分析。结果：术前近视度（等值球镜）范围为－１．００～－６．００Ｄ，其中轻度近视占１６．０％，中度近视占８４．０％，单纯近视占５６．８％，复性近视散光占４３．２％。术后半年裸眼视力≥１．０者占７４．１％，≥０．８者占８８．９％，≥０．５者占９２．６％。剩余屈光度≤±０．５Ｄ者占８４．０％，≤－１．０Ｄ者占９５．１％。剩余屈光度的均数及标准差为－（０．３３±０．３８）Ｄ。角膜上皮下混浊情况：０级占６０．５％，１／２＋占３５．８％，＋占３．７％。无角膜感染、角膜疤痕、复发性角膜糜烂、过矫及不规则散光等并发症发生。结论：ＰＲＫ治疗轻、中度近视眼预测性及稳定性好、安全有效。远期效果有待继续随访。

LASEK、PRK和LASIK治疗中低度近视的比较

目的对比分析准分子激光上皮下角膜磨镶术(LASEK)、碰光性角膜切削术(PRK)、激光原位角膜磨镶术(LASIK)治疗中低度近视临床疗效。方法LASEK组58例(112眼)随访3-9月,PRK、LASIK组各120眼随访1a以上,观察分析术后疼痛症状,裸眼视力及角膜混浊情况。结果术后1d出现疼痛症状:LASEK组:81眼(72.3％),PRK组120 眼(100.0％),LASIK组13眼(10.8％);术后3d裸眼视力≥0.8:LASEK组24眼(21.4％),PRK组27眼(22.5％),LASIK组113 眼(94.2％);术后3月存在角膜Haze:LASEK组31眼(27.6％)、PRK组94眼(78.3％),LASIK组0眼。结论LASEK后疼痛症状、角膜Haze明显减轻,疗效优于PRK;LASEK与LASIK相比没有角膜瓣相关并发症,早期视力恢复较慢。

准分子激光原位角膜磨镶术治疗近视并发症

目的 分析准分子激光原位角膜磨镶术 (LASIK)治疗近视的并发症 ,探讨其发生的原因、预防和处理措施。方法 72 3例 ( 1390只眼 )近视患者 ( - 1 5 0～ - 2 2 0 0D)行LASIK术后随访 12个月 ,观察其术中、术后并发症。结果 术中角膜瓣形成不全 5只眼 ( 0 36 % ) ,角膜瓣过薄 4只眼( 0 2 9% ) ,角膜瓣游离 6只眼 ( 0 4 3% ) ,角膜瓣层间异物残留 12只眼 ( 0 86 % ) ,屈光回退 >1 0D者 2 0只眼 ( 1 4 4 % ) ,激素性高眼压 16只眼 ( 1 15 % ) ,眩光和夜驶困难 2 4只眼( 1 73% )。结论 LASIK治疗近视安全、有效 ,但仍存在一定的并发症 ,必须引起重视 。

准分子激光角膜原位磨镶术治疗近视的手术预测性分析

目的 探讨准分子激光角膜原位磨镶术 (Lasik)对不同屈光度近视的治疗效果及手术预测性。方法 应用Co herent公司的SchwindKeratomF型准分子激光机和SCMD公司的可调式气动微型角膜刀治疗近视眼 ,术后 1周、1个月、3个月、6个月定期复查视力、裂隙灯、角膜地形图及屈光度。将随访 6个月以上资料完整的 146例 2 83只眼根据术前屈光度分为 3组。比较 3组术后的屈光度及角膜偏中心切削的情况。结果 术后 6个月 ,Ⅰ、Ⅱ、Ⅲ组屈光度在±1 0 0以内者分别占 91 2 %、83 9%、6 1 4% ,差异有显著性。偏中心切削的发生率随着术前屈光度的增加而增加 ,但差异无显著性。结论 准分子激光角膜原位磨镶术治疗近视效果确切、可靠 。