Corneal scarring and irregular astigmatism following refractive surgery in a corneal transplant

Background: Scarring may follow refractive surgery, causing irregular astigmatism and loss of visual acuity. Methods: A case report of scarring and irregular astigmatism occurring in a corneal transplant following photorefractive keratectomy and arcuate incisions is presented. Results: Following surgical excision of the scan unaided visual acuity improved from 1/60 to 6/12. Histopathology of the excised scar was obtained. Conclusions: Refractive surgery following corneal transplantation may produce scarring. The origin of the scar in the present case has not been established.     

Excimer laser surface ablation: a review of recent literature

The aim was to review the recently published literature on excimer laser surface ablation procedures, including photorefractive keratectomy (PRK), laser sub‐epithelial keratomileusis (LASEK), microkeratome‐assisted PRK (epi‐LASIK) and trans‐epithelial (laser‐assisted) PRK, to help elucidate where and how surface ablation may best fit into current refractive surgical practice. The emphasis was on publications within the last three years and included systemic reviews, meta‐analyses and randomised controlled trials. Where such evidence did not exist, selective large series cohort studies, case‐controlled studies and case series with follow‐up preferably greater than six months were examined and included. Refractive and visual outcomes are excellent and comparable to those after LASIK even in complex cases after previous corneal surgery. Indeed, surface ablation combined with corneal collagen cross‐linking may be used in selected eyes with biomechanical instability, where LASIK is contraindicated. In addition, there is evidence to suggest that there may be less induction of higher order aberrations with surface techniques. Long‐term stability and safety appear to be extremely satisfactory. The literature supports the use of modern excimer laser surface treatments, with outcomes comparable to those after LASIK and evidence of less induction of higher‐order aberrations. Follow‐up studies at 10 to 20 years indicate excellent stability and safety.     

PRK术后屈光回退和Haze的药物防治进展

就近年来准分子激光屈光性角膜切削术 (PRK )后屈光回退和角膜上皮下雾状混浊 (Haze)两大并发症的药物防治进展作一简要综述。阐述了局部应用皮质类固醇药物、非甾体抗炎药物、抗代谢药物、抗氧化剂、Caspase抑制剂、细胞因子调控、锌制剂对减弱角膜创伤愈合反应 ,阻断或减少角膜细胞凋亡的作用 ,从而预防和治疗屈光回退和Haze形成 ,提高PRK手术的稳定性和预测性。     

A 3-month comparison study of subjective and objective visual quality of small incision lenticule extraction and transepithelial photorefractive keratectomy in patients with low and moderate myopia

AIM: To compare the subjective and objective visual quality between small incision lenticule extraction (SMILE) and transepithelial photorefractive keratectomy (tPRK) in patients with low and moderate myopia. METHODS: Patients undertaking SMILE or tPRK for the correction of low and moderate myopia were consecutively recruited in this prospective cohort study with a 3-month follow-up period. Objective evaluation [visual acuity test, manifest refraction, wavefront aberrations, the total cut-off value of the total modulation transfer function (MTFcut-off), and Strehl ratio (SR)] and subjective evaluation of visual quality (quality-of-life questionnaire) were conducted before surgery and at days 1, 7, 30, and 90 after surgery. RESULTS: A total of 47 patients (94 eyes) with SMILE and 22 patients (22 eyes) with tPRK were enrolled. The uncorrected visual acuity (UCVA) was better in SMILE patients on day 7 after surgery (1.13±0.13 vs 0.99±0.17, t=4.85, P<0.001) but was comparable at days 30 and 90. At day 90, the SMILE group had a lower spherical equivalent (SE) than the tPRK group (0.04±0.31 vs 0.19±0.43, t=2.08, P=0.042). Total higher order aberrations (HOAs) were induced in both surgical types, which were more evident in the tPRK group with 3-mm pupil diameter (0.16±0.07 vs 0.11±0.05, t=4.27, P<0.001) and 5-mm pupil diameter (0.39±0.17 vs 0.36±0.11, t=2.33, P=0.022). The MTFcut-off and SR showed a trend of improvement in both SMILE and tPRK patients but were statistically better in the SMILE group with both pupil diameters. There was a significant improvement of contrast sensitivity (CS) over baseline levels at the spatial frequency of 18 cycles/degree (c/d) in the SMILE group (F=2.72, P=0.033) and at 3 c/d (F=3.03, P=0.031), 12 c/d (F=3.72, P=0.013), and 18 c/d (F=4.62, P=0.004) in the tPRK group. The subjective quality of life questionnaire showed a steady improvement in the SMILE group (F=8.31, P<0.001) but not the tPRK group. CONCLUSION: SMILE and tPRK are both safe and effective ways to correct low and moderate myopia. A generally better and quicker recovery of visual quality favors the application of SMILE in qualified patients.     

准分子激光屈光性角膜切削术后角膜的组织形态改变

目的 动态观察准分子激光屈光性角膜切削术（ＰＲＫ）后角膜修复过程中的组织形态改变。方法 ２４只兔右眼按近视－１０．００Ｄ行ＰＲＫ术。按术后即刻、２４小时、１、２周、１、３、６月及１２月８个时间点观察,每个时间点３只。裂隙灯显微镜检查各组角膜上皮修复及角膜雾状浑浊（ｈａｚｅ）情况,并取角膜行光镜及电镜观察。结果 ＰＲＫ术后早期角膜上皮易剥脱,ｈａｚｅ的发生率为１００％。ＰＲＫ术后角膜上皮增生;新合成     

10272眼准分子激光角膜切削术临床研究

目的评价准分子激光屈光性角膜手术治疗轻、中、重度近视的远期临床效果。方法对在我院接受ＰＲＫ治疗的１０２７２眼近视眼术后１月～５ａ的结果进行了统计学分析。结果术后１月视力≥５０的占９０４％,术后２ａ以上的１组（≤－６００Ｄ）、２组（－６２５～－８７５Ｄ）和３组（－９００Ｄ～－１２００Ｄ）裸眼视力分别是９２５％、７２５％、４６５％;术后３组屈光度其正视率分别是９８４％、９４８％、７８６％,没有严重并发症发生。结论ＰＲＫ治疗－１２００Ｄ以下,特别是－６００Ｄ以下的近视眼安全有效,稳定性及预测性好     

应用高透氧性角膜接触镜在准分子激光角膜切削术后的病原学分析

目的针对准分子激光屈光性角膜切削术(PRK)后所使用的绷带式高透氧性角膜接触镜的病原学进行分析。方法对接受PRK手术的50例(100只眼)患者,手术前取结膜囊分泌物进行细菌学培养。术后给予术眼配戴高透氧性绷带式角膜接触镜,术后第6~8天摘除角膜接触镜,将角膜接触镜进行细菌学检测,并同时再次取结膜囊分泌物进行细菌学培养。并将接触镜培养阳性的患者与培养阴性的患者分组对比,分析两组间矫正视力、眼压、角膜厚度等相关影响因素的差异性。结果 100片角膜接触镜中,3片(3%)细菌学检测结果呈阳性,均为表皮葡萄球菌。所有患者术前、术后结膜囊均未监测到细菌,术后均未见眼部感染表现。阳性组和阴性组间,泪液分泌量存在差异,可能与培养阳性有相关。结论 PRK术后使用的高透氧性绷带式角膜接触镜具有发生细菌污染的可能,尤其对于泪液分泌量较少的患者,其角膜接触镜发生感染机率较高。手术前后合理用药可有效控制接触镜中细菌的繁殖。     

激光角膜光学切除术后兔角膜上皮细胞凋亡的研究

目的 探讨激光角膜光学切除术后（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅ ｋｅｒａｔｅｃｔｏｍｙ,ＰＲＫ）伤口愈合过程中角膜上皮细胞凋亡情况。方法 对６只兔双眼分别行Ｐ．Ｒ,激光切削参数为一８．０Ｄ、１５６μｍ深,消隔直径５．６ｍｍ。将兔分别于ＰＲＫ后１ｍｏ、３ｍｏ处死,取下角膜进行冰冻切片,用的位标记检测法（ＴＵＮＥＬ法）分别检测角膜上皮细胞凋亡情况。结果 正常兔角膜可见上皮上皮浅层有少量细胞亡,ＰＲＫ后     

准分子激光散光性角膜切削术治疗复合性近视散光

目的 探讨准分子激光散光性角膜切削术（ｐｈｏｔｏａｓｔｉｇｍａｔｉｃ ｒｅｆｒａｃｔｉｖｅ ｋｅｒａｔｅｃｔｏｍｙ,ＰＡＲＫ）矫治复性近视散光的有效性、准确性和预测性。方法 采用Ｃｏｍｍｐａｋ－２００型准分子激光机,对３４例４６眼复性近视散光行角膜椭圆形切削,根据散光度大小分为２组;Ａ组（－１．７５～－２．７５Ｄ）,Ｂ组（－３．００～－５．２５Ｄ）,并随访０．５ａ以上,观察手术前后的视力、屈光度、     

准分子激光屈光性角膜切削术矫正放射状角膜切开术后残留近视

探讨准分子激光角膜切削术矫正放射状角膜切开术后残留近视的效果及影响因素,方法２９例３０眼ＲＫ术后８个月以上接受ＰＲＫ矫正残留近视,分为中低度近视组和高度近视组,平均随访６．４个月。结果ＰＲＫ术后第１组下降３．３０Ｄ,第２组下降５．２３Ｄ。