Mitomycin C application after photorefractive keratectomy in high,moderate, or low myopia: Systematic review and meta-analysis

Photorefractive keratectomy (PRK) is considered a safe approach laser procedure with a clinical significance in correcting myopia results. PRK requires removing the whole superficial epithelium. The integrity of the epithelial basement membrane and the deposition of abnormal extracellular matrix can put the cornea in a probable situation for corneal haze formation. Mitomycin C (MMC) is applied after excimer laser ablation as a primary modulator for wound healing, limiting corneal haze formation. We aim to summarize the outcomes of MMC application after laser ablation. We searched Scopus, PubMed, Cochrane CENTRAL, and Web of Science till December 2020 using relevant keywords. The data were extracted and pooled as mean difference (MD) or risk ratio (RR) with a 95% confidence interval (CI), using Review Manager software (version 5.4). Our analysis demonstrated a statistically significant result for MMC application over the control group in terms of corneal haze formation postoperatively (RR = 0.29, 95% CI: [0.19, 0.45], P < 0.00001). Regarding corrected distance visual acuity (CDVA), no significant difference was observed between the MMC group and the control group (MD = 0.02; 95% CI: [-0.04, 0.07]; P = 0.56). Regarding the uncorrected distance visual acuity (UDVA), the analysis favored the MMC application with (MD -0.03, 95% CI: [-0.06, -0.00]; P = 0.05). There was no statistically significant increase in complications with MMC. In conclusion, MMC application after PRK is associated with a lower incidence of corneal haze formation with no statistically significant side effects. The long term effect can show improvement regarding UDVA favoring MMC. However, there is no significant effect of MMCs application regarding CDVA, and SE.     

Changes in Contrast Sensitivity Function and Ocular Higher Order Aberration by Conventional Myopic Photorefractive Keratectomy

Purpose

To evaluate the relation between induced changes in ocular higher order aberrations and changes in the contrast sensitivity function in patients undergoing excimer laser photorefractive keratectomy (PRK).

Methods

Myopic PRK using excimer laser was performed in 31 patients (56 eyes). The preoperative refractive error was ?6.2 ± 2.9 diopters. Before and 1 month after surgery, we measured the ocular higher order aberrations for a 4-mm pupil, and three indices of contrast sensitivity function. From the data collected, the area under the log contrast sensitivity function (AULCSF) was calculated.

Results

PRK significantly reduced AULCSF (P = 0.004), low-contrast visual acuity (P = 0.004), and letter-contrast sensitivity (P = 0.013). Coma-like (P < 0.001) and spherical-like (P < 0.001) aberrations were significantly increased by surgery. The change in AULCSF by surgery significantly correlated with the change in coma-like (r = ?0.468, P < 0.001) and spherical-like (r = ?0.291, P = 0.033) aberrations. The change in low-contrast visual acuity by PRK significantly correlated with the change in coma-like aberration (r = 0.599, P < 0.007), but not with change in spherical-like aberrations (r = 0.136, P = 0.326). There were significant correlations between changes in letter-contrast sensitivity and changes in coma-like (r = ?0.450, P < 0.001) and spherical-like (r = ?0.255, P = 0.048) aberrations.

Conclusions

PRK significantly increases ocular higher order aberrations, which compromise contrast sensitivity function after surgery.?Jpn J Ophthalmol 2007;51:347–352 © Japanese Ophthalmological Society 2007

     

准分子激光屈光性角膜切削术后高透氧性角膜接触镜的应用

目的:探讨高透氧性角膜接触镜对准分子激光屈光性角膜切削术(photorefractive keratectomy,PRK)后眼刺激症状及角膜上皮愈合的影响。方法:共95例190眼PRK病例,术后随机选择一只眼戴软性亲水性高透氧的角膜接触镜,另一只眼配戴普通月抛型角膜接触镜。术后记录术眼自觉症状,观察角膜上皮愈合情况,检查术后6mo裸眼视力,同时进行haze评分。结果:高透氧角膜接触镜组术眼视物模糊、眼痛、畏光均轻于普通月抛型角膜接触镜组,两组比较差异有统计学意义(P<0.05)。高透氧角膜接触镜组平均角膜上皮愈合时间分别为3.11±2.12d,普通月抛型角膜接触镜组为4.02±2.21d,两组比较差异有统计学意义(P<0.05)。角膜上皮72h内愈合者高透氧角膜接触镜组占46%,普通月抛型角膜接触镜组占36%。术后第7d裸眼视力高于1.0者高透氧角膜接触镜组为60眼(63%),普通月抛型角膜接触镜组为48眼(51%)。术后6mo两组术后裸眼视力无显著性差异(P=0.35),两组haze发生率比较无显著性差异(P=0.55)。结论:PRK术后使用高透氧性角膜接触镜可以明显减轻术后患者的角膜刺激症状,减少患者的术后不适感,缩短角膜上皮的愈合时间。     

LASEK与PRK矫正近视及近视散光的疗效比较

目的 比较LASEK与PRK手术矫正不同程度近视及近视散光的有效性、安全性及稳定性。方法 70名患者(140眼)，分为中低度近视组39人(78眼)、高度近视组31人(62眼)。患者一眼行LASEK手术，对侧眼行PRK手术，术后观察术眼疼痛情况、上皮愈合时问、角膜上皮下雾状混浊(haze)、术后裸眼视力6个月。结果LASEK与PRK术后上皮愈合时间及术眼疼痛指数无明显差异；中低度近视组两种手术后裸眼视力无显著差异；高度近视组裸眼视力及角膜haze程度差异显著。结论 LASEK矫正不同程度近视均能取得较好的临床效果，术后裸眼视力及视力稳定程度优于PRK，特别表现在高度近视组。     

影响准分子激光屈光性角膜切削术后眼压的因素

目的分析影响准分子激光屈光性角膜切削术（ｅｘｃｉｍｅｒｌａｓｅｒｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ,ＰＲＫ）术后眼压的因素。方法采用非接触式眼压计（ｎｏｎｃｏｎｔａｃｔｔｏｎｏｍｅｔｒｙ,ＮＣＴ）测量眼压,对ＰＲＫ前、后随访半年以上８６例（１５０只眼）患者眼压差与角膜切削厚度、术前术后角膜曲率差之间进行多元回归分析。结果术前眼压明显高于ＰＲＫ术后１周、３及６个月的眼压,差异有非常显著性（ｔ检验,Ｐ＜０．０１）,与术后１个月时眼压比差异无显著性（Ｐ＞０．０５）。术后１个月时的眼压高于术后其他时间眼压（Ｐ＜０．０１）。ＰＲＫ后眼压降低与角膜厚度减少及角膜前表面曲率的降低有关（ｒ＝０．３６１,Ｐ＜０．０１;ｒ＝０．１８８,Ｐ＜０．０５）,建立二元回归方程如下：Ｙ＝－０．０５９－０．０３８Ｘ１＋０．００９Ｘ２。Ｙ：术前术后眼压差（ｋＰａ）,Ｘ１：术前术后角膜曲率差（Ｄ）,Ｘ２：角膜切削厚度（μｍ）。结论ＰＲＫ后ＮＣＴ测量眼压低于术前,术后眼压与氟甲脱氧泼尼松龙（ｆｌｕｏｒｏｍｅｔｈｏｌｏｎｅ）的用药次数和时间、角膜切削厚度、角膜曲率有关。     

准分子激光屈光性角膜切削术矫正散光的准确性及预测性

目的 探讨准分子激光屈光性角膜切削术（ｅｘｃｉｍｅｒ ｌａｓｅｒ ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅ ｋｅｒｅｃｔｏｍｙ,ＰＲＫ）矫正散光的准确性及预测性。方法 根据角膜地形图提供的角膜屈光力数值,用Ｈｏｌｌａｄａｙ法计算复性近视散光３０例（５３只眼）和单纯近视２３例（３３只眼）患者术前与术后６个月角膜屈光力的差值,确定实际矫正散光度及轴位,及预期矫正散光度及轴位进行对比分析。结果 复性近视散光组５３     

Transepithelial phototherapeutic keratectomy for post-traumatic recurrent corneal erosions

Purpose:To evaluate the outcomes of transepithelial phototherapeutic keratectomy (transepithelial PTK) for treatment of posttraumatic recurrent corneal erosions.Methods:Twenty-four eyes of 22 patients with posttraumatic recurrent corneal erosions who were treated with transepithelial PTK from April 2018 to July 2020 were included in this retrospective study. The rates of recurrent erosions and complications were evaluated during the follow-up after surgery. Visual acuity and refraction were recorded preoperatively and 1 year after surgery. Total corneal astigmatism, total corneal irregular astigmatism, and total corneal spherical aberrations were recorded using corneal tomography preoperatively and 1 year after surgery.Results:Mean postoperative follow-up was 13 months (range: 12–32 months). None of the patients suffered from any complications or further erosions. Uncorrected distance visual acuity, best-corrected distance visual acuity, spherical equivalent, and cylinder remained stable at 1-year postoperatively compared with the baseline (P = 0.214, P = 0.461, P = 0.084, and P = 0.879, respectively). Moreover, there was no significant difference in total corneal astigmatism, total corneal irregular astigmatism, and total corneal spherical aberrations between baseline and 1-year postoperative visit (P = 0.938, P = 0.136, and P = 0.981, respectively)Conclusion:Transepithelial PTK was an effective treatment for patients with posttraumatic recurrent corneal erosions.     

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.     

Photorefractive keratectomy in the correction of astigmatism using Schwind Amaris 750s laser

AIM:To evaluate the results of three photorefractive keratectomy (PRK) procedures in the treatment of astigmatism.METHODS:In thisretrospective comparative case series, 89 eyes of 50 patients who underwent PRK treatment for astigmatism were enrolled. The patients were divided into 3 groups based on the PRK procedure:Group 1:PRK without mitomycin-C (MMC) application, Group 2:PRK with MMC application, and Group 3:Trans-Photorefractive Keratectomy(T-PRK). The efficacy, safety, predictability, and complications of treatment were assessed at 1, 3 and 6 months after the treatment.RESULTS: At postoperative 6 months, the percentage of postoperative uncorrected visual acuity (UCVA) of 20/20 or better was 55.6% (20 eyes) in group 1, 75% (15 eyes) in group 2, and 75.8% (25 eyes) in group 3 (P=0.144).The percentage of postoperative best corrected visual acuity (BCVA) of unchanged or gained ≥1 lines was 80.6% (29 eyes) in group 1, 70% (14 eyes) in group 2, and 90.9% (30 eyes) in group 3 (P=0.151). The percentage of postoperative BCVA of lost ≥2 lines was 11.1% (4 eyes) in group 1, 20% (4 eyes) in group 2, and 6.1% (2 eyes) in group 3. The mean manifest refractivespherical equivalent (MRSE) and mean cylindrical refraction were not significantly different among the each groups (P>0.05). At postoperative 6 months, the percentage of MRSE of within ±0.50 D was 100% (36 eyes) in Group 1, 100% (20 eyes) in Group 2, and 93.9% (31 eyes) in Group 3. At the each follow-up period, there was no significant difference in number of eyes with haze and mean haze score(P>0.05).CONCLUSION:The study showed that PRK without MMC, PRK with MMC and T-PRK appears to have similar effectiveness, safety and predictability in the treatment of astigmatism. The incidence of haze was also similar between the three groups.     

[In Press] Changes in intraocular pressure and central corneal thickness during pregnancy: a systematic review and Meta-analysis

AIM: To conduct a Meta-analysis for investigating the variations in intraocular pressure (IOP) and central corneal thickness (CCT) during normal pregnancy. METHODS: We searched for clinical trials published up to November 2015 without language or region restrictions in PubMed, EMBASE, Web of Science, the Cochrane Central Register of Controlled Trials, Ovid, EBSCO, Elsevier, the Chinese Biomedicine Database, WanFang, CNKI, CQVIP and Google Scholar. Studies of the ocular changes observed in pregnant women were selected. The main outcomes were assessed by changes in IOP and CCT. RESULTS: Fifteen studies were included. In subgroup analyses, IOP was significantly decreased during the second (MD=-1.53, 95% CI [-2.19, -0.87]; P<0.00001) and third (MD=-2.91, 95% CI [-3.74, -2.08]; P<0.00001) trimesters of pregnancy. CCT was increased during the second (MD=10.12, 95% CI [2.01, 18.22]; P=0.01) trimester of pregnancy; moreover, during the third trimester of pregnancy, the CCT displayed an increasing trend, but the difference was not significant (MD=5.98, 95% CI [-1.11, 13.07]; P=0.1). CONCLUSION: A decrease in IOP was accompanied by an increase in CCT in the second and third trimesters of a normal pregnancy in women.     

Clinical outcomes of management of posterior capsule rupture with air bubble techniques

AIM: To evaluate the clinical outcomes after implantation of a new intrastromal corneal ring segment associated with photorefractive keratectomy (PRK) to correct high myopia (ICRS HM) in patients with thin corneas. METHODS: We evaluated 42 eyes of 23 patients that had ICRS HM implantation followed by PRK. The mean age of patients was 29.1±7.12y (range 18 to 40 years old). Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), keratometry, spherical equivalent, pachymetry, and aberrometry were compared using ANOVA with repeated measurements assessed preoperatively and at last follow-up visit after the procedures. The refractive predictability and simulated/real corneal ablation were also assessed. RESULTS: The mean follow-up time after PRK was 6.8±1.6mo. The mean preoperative UCVA improved from 20/800 preoperative to 20/100 after ICRS and 20/35 after PRK. The mean preoperative BCVA was 20/25 (range from 20/40 to 20/20) and remained unchanged after ICRS HM implantation. Following the PRK the mean BCVA was 20/25 (range from 20/40 to 20/20). The mean spherical equivalent decreased from -7.25±1.12 (range -5.00 to -9.00) preoperatively to -3.32±1.0 (range -2.00 to -5.00) postoperatively (P<0.001) after ICRS HM, ICRS implantation and decreased from -2.44±1.51 preoperatively to 0.32±0.45 (range -0.625 to 0.875) postoperatively (P<0.001) after PRK. The change in BCVA and topographic astigmatism was statistically significant (P<0.0001). CONCLUSION: ICRS HM associated with PRK can be a tissue saving procedure and an alternative surgical option for correction of moderate to high myopia.     

Photorefractive keratectomy in mild to moderate keratoconus: Outcomes in over 40-year-old patients

Background:Keratoconus is a contraindication for photorefractive keratectomy (PRK). In the recent decade, some efforts have been made to perform PRK in patients with keratoconus whose corneas are stable naturally or by doing corneal collagen crosslinking. These studies have suggested residual central corneal thickness (CCT) ≥450 μm.Aims:The aim was to evaluate the long-term outcomes of PRK in patients with mild to moderate keratoconus in patients older than 40 with residual CCT ≥ 400 μm.Results:A total of 38 eyes of 21 patients were studied; 20 eyes (52.6%) with a grade I and 18 eyes (47.4%) with grade II keratoconus. The mean uncorrected visual acuity, best corrected visual acuity (BCVA), spherical equivalent, cylindrical power and keratometric readings were significantly improved at the final endpoint compared to preoperation measurements (P < 0.001). Two eyes (5%) lost two lines of BCVA at the final visit. No case of ectasia occurred during the follow-up course.Conclusions:PRK did not induce keratoconus progression in patients older than 40 with a grade I/II keratoconus. Residual CCT ≥ 450 μm seems to be sufficient to prevent the ectasia.     

准分子激光屈光性角膜切削术后的再治疗

目的 评价准分子激光屈光性角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅ ｋｅｒａｔｅｃｔｏｍｙ,ＰＲＫ）术后因屈光回退,欠矫出现的残留近视及严重角膜上皮下雾状混沌（ｈａｚｅ）而再次手术治疗的疗效及安全性。方法 采用准分子激光仪对－１．００～－１６．５０Ｄ的近视眼及近视散光患者进行治疗。ＰＲＫ术后３５例（５１只眼）患者出现残留近视及严重ｈａｚｅ。结合ＰＲＫ手术及准分子激光治疗性角膜切削术（ｐｈｏｔｏｐ     

Evaluation of the efficacy of the Allegretto Wave and the Wavefront‐optimized ablation profile in non‐anterior astigmatisms

Purpose: To assess the efficacy of the Allegretto Wave and the wavefront‐optimized ablation profile (WFO) in non‐anterior astigmatism correction, in both LASIK and photorefractive keratectomy (PRK) treatments. Methods: Seventy‐four refractive surgery candidates were recruited prospectively in a non‐randomized trial. Only one eye from each candidate was randomly enrolled in the study. Of them, 40 eyes underwent LASIK treatment (LG group), while 34 eyes underwent PRK treatment (PG group). Preoperatively, the ocular residual astigmatism (ORA) was calculated for each eye, according to which each astigmatism fault was characterized as primarily anterior or non‐anterior. Twenty LG eyes and 16 PG eyes presented primarily anterior astigmatism (LG‐A and PG‐A subgroups, respectively), while 20 LG eyes and 18 PG eyes demonstrated primarily non‐anterior astigmatism (LG‐NA and PG‐NA subgroups, respectively). Postoperatively, vector analysis of astigmatism correction was conducted. The following indexes were calculated: (i) correction index (CI), (ii) difference vector (DV) and (iii) index of success (IOS). Results: Preoperatively, mean differences between manifest and topographic astigmatisms for the LG and the PG subgroups were significant (p:0.006 and p < 0.001, respectively), while postoperatively, aforementioned differences were non‐significant (p:0.18 and p:0.09, respectively). Regarding vector analysis in the LG group, mean CI, IOS and DV were 1.39 ± 1.26, 0.37 ± 1.06 and 0.30 ± 0.51, respectively. Differences in CI, IOS and DV between LG‐A and LG‐NA subgroups were non‐significant. Regarding vector analysis in the PG group, mean CI, IOS and DV were 1.22 ± 0.33, 0.47 ± 0.46 and 0.27 ± 0.25, respectively. Differences in CI, IOS and DV between PG‐A and PG‐NA subgroups were non‐significant. Conclusions: Our results suggest that the Allegretto Wave and WFO profile seem to be equally effective in both anterior and non‐anterior astigmatism correction, regardless of treatment type.     

准分子激光屈光性角膜切削术后眼压测量值的变化

目的：探讨影响准分子激光屈光性角膜切削术（laser photorefractive keratectomy,PRK)后眼压测量值变化的因素。方法：对209例（364只眼）近视患者行PRK,手术前、后采用Goldemann压平式眼压计测量患者的眼压,并测量角膜厚度和角膜曲率,进行量角膜厚度和角膜曲率,进行统计学分析。术后随访时间＞1年。结果：术后6个月和12个月术眼的眼压测量值低于术前,差异有非常显著意义（P＜0．001）,术后12个月的眼压测量值低于术后6个月,差异有非常显著意义（P＜0．001）,术后12个月的眼压测量值低于术后6个月,差异有非常显著意义（P＜0．001）。术后眼压测量值的降低与角膜厚度的减少和角膜曲率的降低均呈高度正相关（P＜0．01）,其二元回归方程为Y（手术前、后眼压差,mmHg）＝1．156＋0．022X1（手术前、后角膜厚度差,μm)＋0．052X2（手术前、后角膜曲率差,D）。结论：PRK术后眼压测量值低于术前;角膜厚度和角膜曲率是导致手术前、后眼压测量值变化的因素。     

Anterior corneal optical irregularity measured by higher-order aberrations induced by a broad beam excimer laser

Background: The aim was to analyse anterior corneal optical irregularity in patients receiving photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) with a conventional broad beam laser. Methods: Pre‐ and post‐operative anterior corneal aberrations including Zernike coefficients and root mean squares of higher‐order aberrations were measured and derived with a Placido‐ring‐based corneal topographer and wavefront software, respectively, from 768 right eyes of patients receiving either PRK or LASIK for myopia with a conventional broad beam excimer laser in National Taiwan University Hospital, Taipei, Taiwan. Multiple linear regression models selected by Mallows' Cp criteria were used to evaluate predictability of surgically induced aberrations and relevant factors. Results: Mean attempted spherical equivalent correction was ‐7.37 ± 2.33 D (range: ‐16.5 to ‐1.95). Root mean squares of higher‐order aberrations and variances of Zernike coefficients all increased significantly after surgery (p < 0.01). All post‐operative higher‐order aberrations increased with the amount of attempted myopic correction and secondary astigmatism increased with attempted cylindrical correction. LASIK surgery induced less coma and third‐order aberrations but more fifth‐ and sixth‐order aberrations than PRK, although squared partial correlation coefficients were low. Larger optic and transitional zones meant fewer higher‐order aberrations after surgery. Younger patients tended to have more surgically induced aberrations in the 3.0 mm pupil zone. Conclusions: Anterior corneal optical irregularity increased tremendously after refractive surgery by conventional broad beam lasers and correlated with greater attempted myopic correction, younger age and a smaller treatment zone. The effect of corneal flaps on post‐operative corneal irregularity differed trivially.     

准分子激光角膜切削术前后角膜地形图对比分析

应用角膜地形图仪对比分析了９０例（１７６眼）ＰＲＫ手术前后角膜表面的形态特征及其变化。结果表明,术前角膜地形图以蝴蝶结形为多（７３．３％）;术后７９．０％为圆形或钥匙孔形,半圆形和蝶形为１８．８％中央岛形占２．２％。ＰＲＫ对散光的一次最大矫正量为－１．７５Ｄ,切削中心偏位是最佳矫正视力下降,复视和屈光度回退的重要原因。提示：ＰＲＫ术后角膜地形图的检查可准确显示角膜形态的细微变化,有利于手术设计的不断完善和效果的提高。     

自体血清滴眼液对屈光性角膜切削术后角膜上皮愈合的影响

目的：研究自体血清滴眼液对屈光性角膜切削术(PRK)后角膜上皮愈合的影响。

方法：本研究共纳入20例40眼近视及近视散光患者,其中男性9例,女性11例。每例患者随机选取一眼作为研究组应用20%含自体血清的人工泪液,另一眼为对照组应用常规人工泪液。PRK 术中,40眼均于角膜表面居中放置直径8 mm的酒精储槽, 20%的酒精作用20s。术后每天观察直到角膜上皮愈合后,分别于1mo,6mo,12mo进行随访。上皮愈合时间为主要观察指标,并记录裸眼视力(UCVA),显然验光和混浊度。

结果：两组间术前小瞳检影结果无明显差异。术后1d,2d,3d,研究组平均疼痛评分均显著低于对照组(P<0.05)。术后1d,3d,研究组的平均水平和垂直上皮缺损低于对照组(P<0.05)。研究组上皮完全愈合的平均时间比对照组短约0.7d(3.15±0.366d vs 3.85±0.587d, P=0.00)。

结论：研究表明,应用自体血清滴眼液,通过加速角膜上皮愈合和减轻疼痛,从而缩短视力恢复时间,降低屈光性角膜切削术术后不适、混浊度和感染风险。     

雷帕霉素对兔眼准分子激光角膜切削术后haze的影响

目的:探究调节自噬活性对兔眼准分子激光角膜切削术(PRK)术后角膜上皮下雾状混浊(haze)的影响.方法:新西兰大白兔64只行右眼PRK手术后,根据术后局部用药不同,随机分为4组:单纯手术组、14μmol/L二甲基亚砜组(DMSO)、50μmol/L雷帕霉素组、100μmol/L雷帕霉素组,每组16只.根据分组情况,术...