[In Press] Systematic review and Meta-analysis comparing modified cross-linking and standard cross-linking for progressive keratoconus

AIM: To compare the effectiveness and safety between modified cross-linking (MC) and standard cross-linking (SC) in mild or moderate progressive keratoconus. METHODS: Eligible studies were retrieved from four electronic databases, including CENTRAL, Clinical Trials gov, PUBMED and OVID MEDLINE. We set post-surgical maximum K value (Kmax) as the primary outcome. In addition, uncorrected and corrected distant visual acuity (UDVA and UDVA), spherical equivalent (SE), endothelial cell density (ECD), central cornea thickness (CCT) and depth of demarcation line (DDL) were Meta-analyzed as secondary outcomes. Mean differences for these outcomes were pooled through either a random-effect model or fixed-effect model according to data heterogeneity. RESULTS: Twenty-four comparative studies either on accelerated cross-linking (AC) compared with SC or on trans-epithelial cross-linking (TC) compared with SC were included and pooled for analysis. The results indicated that MC was significantly inferior to SC at delaying Kmax deterioration [AC vs SC 0.49 (95% CI: 0.04-0.94, I2=75%, P=0.03); TC vs SC 1.15 (95% CI: 0.54-1.75, I2=50%, P=0.0002)]. SE decreased significantly for SC when compared to AC [0.62 (95% CI: 0.38-0.86, I2=22%, P<0.00001)]. DDL of SC was more significantly deeper than that of TC [-133.49 (95% CI: -145.94--121.04, I2=33%, P<0.00001)]. Other outcomes demonstrated comparable results between MC and SC. CONCLUSION: SC is more favorable at halting the progression of keratoconus, but visual acuity improvement showed comparable results between MCs and SC.     

快速角膜胶原交联治疗进展期圆锥角膜的临床研究

目的:探讨紫外光照射仪快速跨上皮胶原交联治疗进展期圆锥角膜的临床效果.方法:收集2014-12/2017-02在我院确诊为进展期圆锥角膜患者52例102眼的临床资料(角膜最大曲率值Kmax<60.0D,角膜厚度≥400μm),进行回顾性分析和随访,所有患者手术前后常规行裸眼和最佳矫正视力、眼压、裂隙灯显微镜、角膜地形图、光学相干断层扫描(optical coherence tomography,OCT)、角膜内皮镜、眼前节彩照等检查.结果:原发性圆锥角膜患者52例102眼中,男36例70眼,女16例32眼,平均年龄19.5±4.6岁.所有患者术前最佳矫正视力(LogMAR视力表)平均为0.84±0.89,术后最佳矫正视力平均为0.69±0.72,两者比较差异无统计学意义(P=0.398).所有患者术前裸眼视力(LogMAR视力表)平均为1.02±0.62,术后裸眼视力平均为0.85±0.59,两者比较差异无统计学意义(P=0.154).所有患者术前眼压平均为12.95±4.40mmHg,术后眼压平均为11.92±3.66mmHg,两者比较差异无统计学意义(P=0.272).角膜内皮镜检查结果提示,手术前后内皮细胞密度和形态无改变(P=0.552).角膜地形图检查结果提示,所有患者术后Kmax平均值为50.83±3.48D,较术前Kmax(平均值为52.05±3.63 D)降低,且两者比较差异有统计学意义(P=0.017),所有患者术后角膜平均曲率值(AveK)为47.74±2.51D,较术前AveK平均值(48.73±4.33D)降低,且两者比较差异有统计学意义(P=0.041).术后所有患者采用前节OCT随访角膜胶原交联深度,平均交联深度位于192±23.6μm.角膜厚度值术后与术前比较,差异无统计学意义(P=0.816),无1例患者术后出现严重的手术相关并发症.结论:快速角膜胶原交联治疗进展期圆锥角膜患者术后角膜K值有下降的趋势,且随访期间情况稳定.同时对角膜内皮和眼内结构没有损伤,无严重手术相关并发症,该治疗方法是一种性价比较高的治疗方式.     

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.     

离子导入辅助跨上皮角膜胶原交联治疗进展期圆锥角膜2a随访分析

目的：报道离子导入辅助跨上皮角膜胶原交联(iontophoresis-assited transepithelial corneal collagen cross-linking, I-CXL)治疗进展期圆锥角膜的2a 观察结果。
　　方法：选取进展期圆锥角膜患者24例34眼,应用1g/ L 核黄素蒸馏水溶液,离子导入(1mA 电流)辅助跨上皮给药5min 后,紫外线 A(370nm,3mW/ cm2)照射30min。观察术前和术后2a 最佳矫正视力(best corrected distance visual acuity, BCVA)、角膜散光度数、K1、K2、Kmean、Kmax、眼压、角膜内皮细胞密度、角膜顶点厚度、角膜最薄厚度变化。
　　结果：术后2a,BCVA(LogMAR)从0.32依0.25提高到0.25依0.19,差异具有统计学意义(t =2.849,P =0.015),K1从47.12依4.33下降到46.06依4.77,差异具有统计学意义(t =2.652,P =0.015), K2从51.36依5.59下降到50.40依6.16,差异具有统计学意义(t =2.121,P =0.047),Kmean从49.12依4.76下降到48.10依5.25,差异具有统计学意义(t =2.663,P=0.015),Kmax 从57.57依8.30下降到55.91依8.14,差异具有统计学意义(t =2.398,P =0.026),角膜顶点厚度从476.90依38.71下降到454.43依40.86μm ( t =2.853,P=0.010),角膜最薄厚度从464.38依39.92下降到433.86依50.78μm,差异具有统计学意义( t =3.485,P =0.002)。角膜散光度数、眼压和角膜内皮细胞密度无明显变化。
　　结论：I-CXL 治疗进展期圆锥角膜安全、有效,2a 内能够阻止进展期圆锥角膜病情恶化,但长期效果仍需进一步观察。     

保留上皮角膜胶原交联术治疗青少年圆锥角膜的疗效分析

背景 圆锥角膜是一种角膜进行性膨隆和变薄的疾病,常于青少年时期发病,伴随不同程度的视觉质量下降.角膜胶原交联术(CXL)是利用维生素B2和紫外线A(UVA)之间的光氧化反应来增加角膜硬度,延缓甚至阻止圆锥角膜膨隆的进展. 目的 评估保留上皮CXL治疗青少年圆锥角膜的安全性和有效性. 方法 纳入2010年2月至2013年3月于温州医科大学附属眼视光医院拟行保留上皮CXL的原发性圆锥角膜患者9例10眼,年龄13 ～ 17岁,平均(15±1)岁.术中使用质量分数0.1％丁卡因滴眼液作为促渗剂点眼,再使用质量分数0.5％核黄素液点眼至前房饱和状态,最后使用强度为3 mW/cm2的紫外线A照射30 min.术后7d、1个月、3个月、6个月及12个月测量远距裸眼视力(UDVA)、远距矫正视力(CDVA)、球镜度、柱镜度、等效球镜度(SE)、角膜前表面最大角膜曲率值(Kmax)、角膜前后表面高度值、角膜最薄点厚度.术后7d测量角膜内皮细胞密度(ECD).记录术后角膜上皮愈合时间. 结果 保留上皮CXL术后角膜上皮平均愈合时间为(1.4±0.8)d.术后12个月时,平均UDVA、CDVA分别从术前的1.02±0.16和0.34±0.20改善至0.77±0.18和0.25±0.15,平均球镜度和SE分别从(-7.15±3.00)D和(-9.26±3.23)D改善为(-5.28±2.05)D和(-7.05±2.08)D,平均Kmax从(64.1±11.9)D降低至(61.8±10.4)D,差异均有统计学意义(t=4.251、3.750、-2.515、-2.597、2.304,均P＜0.05).术前与术后12个月平均柱镜度、角膜最薄点厚度比较差异均无统计学意义(t=-1.331、0.328,均P＞0.05).术前与术后7 d ECD的比较差异无统计学意义(t=1.205,P＞0.05).有2眼分别在术后3个月和术后6个月开始出现持续的角膜基质混浊. 结论 保留上皮CXL能够安全、有效地延缓或阻止青少年圆锥角膜的进展.     

Topography versus non-topography-guided photorefractive keratectomy with corneal cross-linking variations in keratoconus

AIM: To compare the visual results of non-topography-guided and topography-guided photorefractive keratectomy (PRK) applying sequential and simultaneous corneal cross-linking (CXL) treatment for keratoconus. METHODS: Interventional and comparative prospective study. Sixty-nine eyes (36 patients) suffering from keratoconus (stages 1 Amsler-Krumeich classification) were divided into four groups: sequential topography-guided photorefractive keratectomy with CXL, simultaneous topography-guided photorefractive keratectomy with CXL, simultaneous non-topography guided photorefractive keratectomy with CXL, and sequential non-topography guided photorefractive keratectomy with CXL. The main outcome measures were pre- and postoperative uncorrected distance visual acuity (UDVA), best corrected distance visual acuity (CDVA), manifest refraction, contrast sensitivity, and keratometry. RESULTS: All analyzed visual, contrast sensitivity, and refractive parameters showed a significant improvement in the four groups (all P<0.05). A noticeable improvement was seen in keratometry in all the groups, and a remarkable difference was observed between topography-guided groups in comparison to non-topography-guided groups (P<0.05). Interestingly, the improvement in all parameters showed a degree of stability to the end of the follow-up. CONCLUSION: The treatment priorities in all four groups are safety, efficacy, and predictability in the correction of the sphero-cylindrical errors in mild and moderate keratoconus. No significant differences among groups in the recorded objective outcomes were found.     

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.     

【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.     

离子导入辅助角膜交联治疗青少年圆锥角膜

目的：评估离子导入辅助的跨上皮角膜交联治疗青少年圆锥角膜的安全性和有效性。方法：搜集12例(年龄12~18岁,平均15.8±2.08岁)进展期圆锥角膜患者,共15眼,采用0.1%核黄素蒸馏水溶液,离子导入(1 mA电流)辅助跨上皮给药5min,紫外线A(370 nm,3 mW/cm2)照射30min。记录术前、术后3mo和1a的裸眼视力、最佳矫正视力、K1、K2、最大K值、平均K值、角膜散光度数、角膜内皮细胞密度、眼内压、最薄角膜厚度、角膜顶点厚度。角膜参数应用角膜地形图评估,角膜内皮细胞密度应用非接触角膜内皮镜检查。结果：角膜交联1a后,裸眼视力、最佳矫正视力、K1、K2、最大K值、平均K值、角膜散光度数、角膜内皮细胞密度和眼内压均无显著变化。最薄角膜厚度从468.08±33.40μm下降到447.46±40.20μm (t=4.379,P=0.001),差异有统计学意义。角膜顶点厚度从476.07±35.96μm下降到454.60±49.32μm(t=4.270,P=0.001),差异有统计学意义。结论：采用0.1%核黄素蒸馏水溶液的离子导入辅助的角膜交联治疗青少年圆锥角膜是安全、有效的,1 a内能够阻止病情恶化,但是长期效果有待于进一步观察。     

Investigation of the efficiency of intrastromal ring segments with cross-linking using different sequence and timing for keratoconus

AIM:To evaluate and compare the efficacy and stability of intrastromal corneal ring segment (ICRs) implantation with cross-linking (CXL) using different sequence and timing.METHODS:In this single retrospective study, 86 keratoconic eyes subjected the ICRs implantation. We analyzed only 41 eyes that had complete follow-ups. They were divided into three groups:ICRs implantation was applied only (group normal), ICRs first followed by CXL immediately (group CXL-S), CXL first followed by ICRs long after (group CXL-B). The visual acuity, refractive results, keratometry were compared preoperatively and 1y postoperatively. Their differences among the three groups were also analyzed.RESULTS:Group normal comprised 25 eyes, group CXL-S 8 eyes, and group CXL-B 8 eyes. There were improvements in the mean uncorrected distance visual acuity (UDVA) and the mean corrected distance visual acuity (CDVA) compared preoperatively and 1y postoperatively {UDVA:0.31 (P=0.030) logarithmic minimum angle of resolution [logMAR] group normal, 0.4 (P=0.020) group CXL-S, 0.45 (P=0.001) group CXL-B; CDVA:0.21 logMAR (P=0.013) group normal, 0.30 (P=0.036) group CXL-S; 0.26 (P=0.000) group CXL-B}. The refractive and topographic outcomes also showed improvements. In terms of comparisons among the three groups, all the P values were above 0.05, showing no significant difference. But only group CXL-B had improvement in UDVA and CDVA for all the patients.CONCLUSION:With safety and good visual outcomes, ICRs implantation is a viable alternative for keratoconus. No significant difference was found among these three groups.     

角膜胶原交联术治疗青少年圆锥角膜的临床效果

目的探讨核黄素/紫外线A（UVA）诱导的去上皮角膜胶原交联术（CXL）用于青少年圆锥角膜患者的安全性和有效性。方法回顾性自身前后对照研究。选择山东大学附属省立医院2013年10月至2015年10月收治的青少年原发性圆锥角膜患者19例（30眼）,予去上皮核黄素/UVA诱导的CXL治疗,术后随访1年,观察术前与术后第3、6、12个月时的裸眼视力（UCVA）、最佳矫正视力（BCVA）、角膜Kmax值、最薄点角膜厚度（TCT）、角膜内皮细胞计数（ECD）等参数变化。采用单组重复测量的方差分析分析术后各时间点与术前各指标的变化情况。结果术前UCVA（LogMAR）为0.78±0.33,术后第3、6、12个月时分别为0.77±0.34、0.72±0.33、0.67±0.31,术后第12个月UCVA与术前比较差异有统计学意义（P＜0.001）;术前BCVA（LogMAR）为0.42±0.33,术后第3、6、12个月时分别为0.31±0.27、0.29±0.23、0.23±0.20,术后第6、12个月与术前比较差异均有统计学意义（P＜0.05）;术前及术后各时间点Kmax分别为（62.1±11.3）D、（61.6±9.9）D、（60.4±9.9）D、（59.9±9.5）D,术后第6、12个月与术前比较差异均有统计学意义（P＜0.05）;TCT由术前的（446±41）μm降低到术后第12个月的（430±39）μm（P＜0.001）,术后第3、6、12个月时的ECD与术前比较差异均无统计学意义。术中及术后无并发症发生。结论核黄素/UVA诱导的去上皮CXL可以有效提高青少年圆锥角膜患者视力,降低角膜K值且安全性高。     

A novel analysis of Scheimpflug total corneal refractive power following corneal cross-linking in mild to moderate keratoconus

AIM: To detect an earlier improvement in mild to moderate keratoconus following corneal cross-linking (CXL) with total corneal refractive power (TCRP) using ray tracing method. METHODS: A total of 40 eyes of 30 consecutive patients who underwent CXL for progressive keratoconus were retrospectively enrolled. The following keratometric parameters provided by Pentacam HR, including maximum keratometry (Kmax), steepest keratometry (Ksteep), 3 mm zonal TCRP centered over corneal apex (TCRPapex,zone 3 mm), zonal mean keratometry and TCRP centered over corneal cone (Kmcone,zone and TCRPcone,zone 1, 2, 3 mm) were evaluated preoperatively and 1, 3, 6, and 12mo postoperatively. Groups 1 and 2 were defined based on Kmax at postoperative 1mo as improved (the initial improvement group) or worsen (the initial deterioration group) compared to the preoperative level. RESULTS: In the overall group, only keratometric parameters based on ray tracing method displayed significant improvement early at 3mo postoperatively, in which TCRPcone,zone 1 mm and 2 mm exhibited the largest flattening (0.57 D and 0.53 D, respectively). In Group 1, only Kmax, Kmcone,zone 2 mm and TCRPcone,zone 2 mm showed significant improvement initially at 1mo postoperatively, in which Kmax exhibited the largest improvement (1.05 D), followed by TCRPcone,zone 2 mm (0.82 D). In Group 2, only keratometric parameters based on ray tracing method and Kmcone,zone 3 mm showed slight but not significant improvement early at 3mo, in which TCRPcone,zone 3 mm displayed the most improvement (0.19 D), followed by TCRPcone,zone 2 mm (0.15 D). CONCLUSION: The findings indicate that a 2 mm zonal TCRP centered over Kmax could earlier detect keratometric improvement by CXL compared to other commonly used parameters in mild to moderate keratoconic eyes.     

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.     

Clinical and microstructural changes with different iontophoresis-assisted corneal cross-linking methods for keratoconus

AIM: To compare the clinical and microstructural changes induced by different transepithelial iontophoresis-assisted corneal cross-linking (I-CXL) methods for keratoconus. METHODS: A total of 42 eyes of 42 patients with progressive keratoconus were divided into two groups. Group A received I-CXL for 5min, while group B received I-CXL for 10min. Visual acuity, optical coherence tomography (OCT), specular microscopy and confocal microscopy were evaluated preoperatively and at 1, 3, 6, and 12mo postoperatively. RESULTS: Twelve months after the operation, uncorrected visual acuity (UCVA) and corrected distance visual acuity (CDVA) were improved in both groups, with a better outcome in the I-CXL 10min group (P=0.025, 0.021, respectively). Kmax values decreased by 0.94±3.00 D in the I-CXL 10min group (P=0.033) but increased by 1.87±3.29 D in the I-CXL 5min group (P=0.012). OCT scans showed that the demarcation line was most visible and substantially deeper in the I-CXL 10min group. Confocal microscopy showed greater anterior stromal keratocyte decreases in the I-CXL 10min group than in the I-CXL 5min group at 3 and 6mo postoperatively (P<0.001); however, anterior stromal keratocytes and subbasal nerve density were not significantly different between the two groups at 12mo postoperatively. CONCLUSION: I-CXL for 10min more effectively halts the progression of keratoconus than I-CXL for 5min after 12mo of follow-up. However, long-term studies are needed to evaluate the efficacy and safety of I-CXL.     

跨上皮快速角膜胶原交联术治疗进展期圆锥角膜

目的:研究跨上皮快速角膜胶原交联术(CXL)治疗进展期圆锥角膜的临床效果和安全性。方法:前瞻性自身前后对照研究。收集自2016-08/2019-11在我院进行跨上皮快速CXL的进展期圆锥角膜患者37例47眼,分析患者术前,术后1、3、6、12mo的裸眼视力(UCVA)和最佳矫正视力(BCVA)、屈光状态、角膜透明度、角膜前表面最大K值(Kmax)、角膜最薄点厚度、角膜内皮细胞计数、眼压。结果:术后1、3、6、12mo患者UCVA较术前提高,但总体比较无差异(F=1.372,P=0.261)。患者术后1、3、6、12mo的BCVA均较术前提高,总体比较有差异(F=3.308,P=0.019),进一步比较发现术后3、6、12mo的BCVA与术前比较有差异(P=0.04、0.01、0.007)。患者术后1、3、6、12mo的球镜度数、柱镜度数、Kmax、角膜最薄点厚度与术前总体比较无差异(F=0.293、1.378、2.448、1.970,P=0.881、0.258、0.061、0.116)。术后1mo患者角膜内皮细胞计数与术前比较无差异(t=1.156,P=0.25)。患者术后各时间点眼压与术前比较无差异(F=1.221,P=0.321)。术后7眼出现角膜Haze(1级~2级),术后3~6mo有5眼Haze消退,角膜恢复透明,1眼遗留角膜云翳,1眼角膜中央基质线状混浊,但均未对视力造成影响。结论:跨上皮快速CXL可以显著提高圆锥角膜患者BCVA,稳定患者屈光状态、角膜形态和厚度,阻止或延缓圆锥角膜进展,使患者获得更好的视功能,同时手术时间短,术后并发症少,具有较好的安全性。     

准分子激光治疗性角膜切削术联合角膜胶原交联术治疗原发性圆锥角膜

目的：评估准分子激光治疗性角膜切削术（PTK）联合角膜胶原交联术（CXL）治疗原发性圆锥角膜的临床效果。方法：前瞻性自身对照临床研究。2014年9-10月期间在温州医科大学附属眼视光医院接受PTK联合CXL治疗的进展期圆锥角膜患者11例（11眼）,评估比较术前与术后12个月裸眼视力（UCVA）、最佳矫正视力（BCVA）、屈光状态、角膜形态、角膜最薄点厚度和角膜内皮细胞密度的差异。手术前后数据的比较采用配对t检验。结果：术后12个月时,UCVA较术前有所提高（t=3.692,P=0.008）,球镜度、等效球镜度（SE）、角膜前表面最大曲率值较术前均有所改善（t=-1.397,P=0.039;t=-2.363,P=0.040;t=2.941,P=0.007）,角膜最薄点厚度较术前降低（t=3.839,P=0.003）,内皮细胞计数无明显变化（t=-1.615,P=0.172）。结论：PTK联合CXL治疗进展中的原发性圆锥角膜是安全和有效的。     

Trans-epithelial accelerated corneal cross-linking for keratoconus in children

The aim of the study is to evaluate the safety and efficacy of trans-epithelial accelerated corneal cross-linking (TE-ACXL) in children with progressive keratoconus. Retrospective, case-series of 23 eyes of 14 children who underwent TE-ACXL. Evaluations were performed at baseline and 1, 3, 6, 12 and 18mo postoperatively. Mean follow-up time of 23.82±3.15mo and mean age was 13.7±1.4y (range 11 to 16y). Mean preoperative uncorrected distance visual acuity changed from 0.92±0.45 logMAR (20/160) to 0.71±0.40 logMAR (20/100) (P=0.001). Mean keratometry (Km) changed from 53.87± 6.03 to 53.00±5.81 (P=0.001). Pachymetry did not have significant changes at last follow-up (P=0.30). The mean preoperative sphere was -5.58±2.48 and -4.89±4.66 D (P=0.11) at last follow-up; refractive cylinder from -5.58±2.48 to -5.02±2.23 (P=0.046). In conclusion, tomographic and refractive stability are shown in over 91% of eyes with pediatric progressive keratoconus who underwent TE-ACXL.     

Subclinical inflammatory response after accelerated corneal cross-linking

Background: To evaluate the inlfammatory response after accelerated collagen cross-linking (CXL) in eyes with keratoconus. Methods: Consecutive eyes with keratoconus undergoing CXL surgery were included in this non-randomized interventional study. Aqueous lfare was measured pre- and post-operatively with a laser lfare photometer at 1 week, 1, 3 and 6 months after CXL. Results: Sixty eyes of 60 patients were entered into the study. Before CXL, the mean lfare value was 4.5 photons per millisecond (ph/ms). The lfare values observed at week 1 (7.1 ph/ms; P=0.008), month 1 (6.5 ph/ms; P=0.04), month 3 (6.7 ph/ms; P=0.004) and month 6 (6.7 ph/ms; P=0.004) were signiifcantly higher compared to baseline. Flare values were not signiifcantly different from week 1 up to 6 months after CXL (P=0.930). No statistically significant correlation was detected between the amount of inlfammation and keratometric indices. Conclusions: Accelerated CXL in patients with keratoconus may cause a subclinical inflammatory response which is evident as slight but rather long-lasting rise of aqueous lfare.     

去上皮快速角膜胶原交联术治疗进展期圆锥角膜

目的：研究去上皮快速角膜胶原交联术(CXL)治疗进展期圆锥角膜的疗效。

方法：回顾性研究。收集2020-04/2021-12就诊于宁夏回族自治区人民医院 宁夏眼科医院行去上皮快速CXL的进展期圆锥角膜患者32例43眼。于术前及术后1、3、6mo行裂隙灯、眼压、裸眼视力、矫正视力、角膜内皮镜、眼前节分析仪Pentacam和可视化角膜生物力学Corvis ST检查,记录手术前后角膜情况、裸眼视力(UCVA)、最佳矫正视力(BCVA)、角膜内皮数、角膜最大曲率(Kmax)、角膜厚度最薄点(TCT)、前后表面K1、K2值、矫正眼内压(bIOP)、第一次压平时间(A1T)、第一次压平长度(A1L)、第一次压平速度(A1V)、第二次压平时间(A2T)、第二次压平长度(A2L)、第二次压平速度(A2V))、最大形变幅度(HCDA)、最大形变曲率半径(HCR)、最大压陷时两峰间距(HCPD)、第1次压平时角膜硬度(SP-A1))值。

结果：术前、术后6mo UCVA(LogMAR)(1.06±0.49、0.78±0.39)和BCVA(LogMAR)(0.48±0.34、0.38±0.29)比较均有差异(P<0.05),角膜内皮细胞比较无差异(2917.39±288.38 vs 2959.19±336.27cells/mm²,P=0.477)。手术前后Kmax、TCT、前表面K1、K2值、后表面K1值比较均有差异(P<0.05),且均在术后1mo升高,术后3mo后恢复至术前水平,而后表面K2值比较无差异。手术前后A1T、HCPD、SP-A1比较差异均有统计学意义(P<0.05),A1L、A1V、A2T、A2L、A2V、HCDA、HCR、bIOP比较无差异(P>0.05)

结论：去上皮快速CXL在术后6mo内能够阻止进展期圆锥角膜进展并且具有一定的安全性。     

Comparison of corneal biological parameters between transepithelial and epithelium-off corneal cross-linking in keratoconus

AIM: To evaluate the differences in corneal biological parameters between transepithelial and epithelium-off corneal cross-linking in keratoconus. METHODS: In our prospective clinical trial, 40 patients (60 eyes) with progressive keratoconus were randomized to undergo corneal cross-linking with transepithelial (TE group, n=30) or epithelium-off (EO group, n=30) keratoconus. Examinations comprised topography, corneal biomechanical analysis and specular microscopy at 6mo postoperatively. RESULTS: The keratometer values were not significantly different between the TE and EO corneal cross-linked groups in different periods (each P>0.05). The corneal thickness of the EO group was greater than that of the TE group at 1wk after the operation (each P<0.05). Regarding corneal biomechanical responses, the EO group showed a longer second applanation length than TE group (P=0.003). Regarding the corneal endothelial function, standard deviation of the endothelial cell size, and coefficient of variation in the cell area, the values of EO group were larger than those of TE group at 1wk (P=0.011, 0.026), and the percentage of hexagonal cells in EO group was lower than that in TE group at 1 and 6mo (P=0.018, 0.019). CONCLUSION: Epithelium-off corneal cross-linking may strengthen corneal biomechanics better than TE procedure can. However, the TE procedure with a lower ultraviolet-A irradiation intensity would be safer for corneal endothelial function.