准分子激光屈光性角膜切削术治疗高度近视探讨

目的探讨准分子激光角膜切削术(PRK)治疗高度近视的效果.方法应用VISX20/20B型准分子激光仪,采用多光区切削法治疗-15D以上超高度近视.术后随访19～38月,并对结果进行分析.结果术前最佳矫正视力0.69±0.19,术后裸眼视力0.61±0.11.术后3月左右角膜上皮下混浊(haze)明显,1年后最轻,该组haze平均(0.53±0.17)级,屈光度回退平均(3.15±1.56)D.结论对于角膜较薄,不适于准分子激光原位角膜磨削术(LASIK)的超高度近视患者,PRK的多光区切削方式仍不失为一种安全、有效且稳定性较好的方法.     

激光屈光性角膜切削术联合丝裂霉素C矫治近视的临床观察

目的评价准分子激光屈光性角膜切削术（PRK）术中预防性使用丝裂霉素C（MMC）矫治角膜较薄的近视的作用。方法角膜较薄的近视（-2．00D--0．00D）128例（243眼）采用PRK＋MMC治疗。术后随访6个月。结果128例（243眼）均未出现2级或2级以上角膜上皮下雾状浑浊（haze）,术后1周裸眼视力≥0．8者206眼（84．77％）,术后6个月裸眼视力≥0．8者216眼（88．89％）,术后6个月裸眼视力达到或超过术前最佳矫正视力233眼（95．88％）。术后6个月与术后1周屈光状态相比无回退。使用MMC未见明显毒副作用。结论角膜较薄的近视治疗采用PRK＋MMC,在术后减少haze、预防屈光回退及改善视力方面安全有效。     

准分子激光角膜切削术随访十年结果分析

目的评价准分子激光角膜切削术（PRK）远期疗效。方法收集在我院施行PRK手术随访10年近视156例（308眼）。根据术前屈光度（等值球镜）分为A、B两组，A组屈光度-1．50D～-6．00D者224眼，B组-6．12D--10．00D者84眼。术后随访视力、屈光度、眼前段及眼底表现，眼压、角膜地形图等。6个月后每年复查1次，以1、5、10年检查情况为准。结果PRK术后随访10年，裸眼视力达预期矫正视力A组为91．96％、B组为76．19％，屈光度±0．75D正视范围内比率A组为90．18％，B组为75．00％。近视屈光回退-1．00D以上在5年和10年时A组为7．14％和6．70％，B组为22．62％和23．81％，屈光回退率相比，相同时间两组间P〈0．01，同一组5年和10年相比P〉0．05。随时间延长haze逐渐吸收，无角膜感染、角膜扩张及变性样角膜病变等发生。结论PRK矫正近视远期效果稳定，预测性、安全性好，中低度近视优于高度近视。随时间延长haze逐渐吸收，回退的屈光度稳定。     

LASIK矫治PRK术后屈光度欠矫及回退

目的　探讨准分子激光原位角膜磨镶术(LASIK)用于矫治屈光性角膜切削术(PRK)后欠矫及屈光度回退的效果。方法　2 6例(4 9眼)因PRK术后屈光度欠矫及回退再行LASIK矫治。49眼PRK术前的屈光度为-5 . 5 0D～-10 . 0 0D ,平均(-6 2 5±1 .5 0 )D ,PRK术后欠矫及回退的度数为-2. 2 5D～-5 . 75D ,平均(-3 0±1. 12 )D。观察LASIK矫治术后裸眼视力、屈光度、最佳矫正视力及并发症。术后随访6月以上。结果　裸眼视力≥0 .5者42眼(85. 71% ) ,其中≥1 .0者2 3眼(4 6 .94% )。实际屈光矫正度在预测矫正度的±0. 75以内者为43眼(87 .76% ) ,1眼发生角膜瓣下上皮植入。结论　PRK术后屈光欠矫及回退而残留的近视度数可以用LASIK手术矫治,且疗效好、安全性高,但远期效果尚需进一步观察。     

准分子激光角膜上皮瓣下磨镶术和准分子激光屈光性角膜切削术后角膜上皮下雾状浑浊的对比观察

目的探讨准分子激光角膜上皮瓣下磨镶术（LASEK）手术和准分子激光屈光性角膜切削术（PRK）手术后角膜上皮下雾状浑浊（haze）的发生率。方法分别对120例（240眼）左右眼分别行LASEK和PRK手术,观察12个月,计算出低中度近视组（等于或低于-6.00D）和高度近视组（-6.00D以上）haze的发生率。结果低中度近视组和高度近视组LASEK手术后1,3,6,12个月haze的发生率均低于PRK手术后1,3,6,12个月haze的发生率,其中低中度近视组和高度近视组LASEK手术后1,3个月1级haze的发生率和PRK手术后1、3个月1级haze的发生率比较差异均有统计学意义（P〈0.05）,低中度近视组LASEK手术后12个月1级haze的发生率和PRK手术后12个月1级haze的发生率比较差异有统计学意义（P〈0.05）。结论 LASEK手术后haze形成情况显著好于PRK手术。     

准分子激光角膜瓣背面磨镶术治疗LASIK术后屈光欠矫和回退

目的 探讨准分子激光角膜瓣背面磨镶术(LASUK)治疗准分子激光原位角膜磨镶术(LASIK)术后屈光欠矫和回退的疗效.方法 对LASIK后屈光欠矫和回退的14例(24眼)施行LASUK,观察术后视力、屈光度、角膜后表面及haze情况.结果 术后3个月视力和屈光度趋于稳定,术后无角膜浑浊,无继发性圆锥角膜.术后6个月,裸眼视力≥0.6和≥1.0者分别为24眼(100.00%)和18眼(75.00%).屈光度介于±1.00D者22眼(91.67%),19眼屈光度介于±0.50D之间,最佳矫正视力无下降者.结论 LASUK治疗LASIK术后屈光欠矫是安伞有效的.     

准分子激光原位角膜磨镶术治疗多种角膜屈光性手术后屈光回退

目的　探讨准分子激光原位角膜磨镶术 (laser in situ keratomileusis,L asik)对临床常见角膜屈光性手术 L asik、准分子激光屈光性角膜切削术 (photorefractive keratectomy,PRK)、放射性角膜切开术 (radial kerato-tomy,RK)后屈光回退的矫治效果。方法　自 1998年 1月～ 2 0 0 1年 10月 ,对 34例 (6 4只眼 )角膜屈光矫治术后屈光回退 >- 1.5 D患者进行 L asik手术再矫治 ,其中 RK术后 9例 (18只眼 ) ,PRK术后 9例 (17只眼 ) ,L asik术后16例 (2 9只眼 )。术前检查、手术步骤及术后用药同临床 L asik手术 ,术后随访 6个月～ 30个月 ,观察视力及屈光变化等。结果　 2 1只曾行 L asik术眼掀开原角膜瓣 ,其他 4 3只眼制作角膜瓣 ,过程顺利 ,全部术眼术后 3～ 6个月裸眼视力由术前 0 .0 2～ 0 .2提高至 0 .5～ 1.2。 5 7只眼 (89.1% )达到或超过术前最佳矫正视力。其平均屈光度由术前(- 5 .11± 1.97) D降至术后 (- 0 .16± 0 .5 6 ) D。无严重并发症发生。结论　 L asik手术矫治 RK、PRK、L asik术后屈光回退安全有效 ,但需深入研究和严格掌握适应证。     

准分子激光上皮下角膜磨镶术治疗中高度近视的效果分析

目的探讨准分子激光上皮下角膜磨镶术（LASEK）治疗中高度近视的疗效。方法40例（79眼）行LASEK,屈光度-3．50D～-15．00D,平均-8．50D;随访6个月,观察早期眼部症状、视力、眼压、屈光状态、雾状角膜浑浊（haze）程度及屈光回退等情况。结果LASEK术后早期眼部刺激症状较重;术后角膜上皮愈合时间为3～7d,平均为5d;术后2周裸眼视力（UCVA）〉0．5者71眼（89．87％）,术后6个月UCVA等于或优于术前最佳矫正视力（BCVA）者74眼（93．67％）;术后6个月发生（haze）：0级76眼（96．20％）;0．5级2眼（2．53％）;2级1眼（1．27％）;无1级及2级以上haze。结论LASEK治疗中高度近视有一定的疗效,但手术后早期跟部刺激症状重,视力恢复慢,haze和屈光回退有待观察与研究。     

准分子激光屈光性角膜切削术后屈光回退的多因素分析

目的：探讨准分子激光屈光性角膜切削术后屈光回退的主要因素。方法：采用VISX20／20型准分子激光仪对121例214眼近视患者行准分子激光角膜切削术,术后随访2年。分二组进行比较,Ⅰ组为低中度近视（－1．00D－－6．00D）124眼,Ⅱ组为高度近视（－6．25D－－16．00D）90眼。结果：术后2年低中度近视回退率9．7％,高度近视回退率27．8％（P＜0．005）,高度近视中高龄组较低龄组回退率高（P＜0．005）,较严重的角膜上皮下雾状混浊与回退伴行。结论：准分子激光角膜切削术后屈光回退的主要因素有预期矫正屈光度,角膜Haze及年龄。     

准分子激光屈光性角膜切削术治疗近视的临床分析

目的：评价准分子激光屈光性角膜切削术（PRK）治疗不同程度近视的疗效。方法：应用SchwindKeratomF准分子激光机对1995眼不同程度近视（－0．75～15．50D）行PRK治疗。按屈光度分三组：组Ⅰ≤－6．00D,873眼;组Ⅱ－6.25D—－10．00D,774眼;组Ⅲ＞－10．00D,348眼。术后12个月,对三组术后的视力、屈光度及Haze进行随访比较。结果：术后12个月Ⅰ、Ⅱ、Ⅲ组裸眼视力≥0．5者分别为986%,94．2％和60.04％;≥1.0者分别为85．5％,71.3％和25.9％;屈光度在±1．00D以内分别为90．5％,68．8％和29．3％。角膜雾状混浊（Haze）≥2级者分别为0.8％,11．5％和13．7％。结论：PRK治疗中低度近视疗效较好,对高度和超高度近视由于术后Haze和屈光度回退发生率增高,疗效受到明显影响,有待进一步完善手术方法和术后用药等问题。     

Haze after laser in situ keratomileusis in eyes with previous photorefractive keratectomy.

In cases with previous photorefractive keratectomy (PRK), there is a risk of developing severe haze after laser in situ keratomileusis (LASIK). We report 3 patients (4 eyes) who developed severe haze after LASIK treatment for residual myopia following PRK. Both PRK and LASIK procedures were performed using the VISX 20/20 excimer laser. We report the grade of haze, amount of regression, and visual acuity after the patients were treated with topical steroids. In 2 eyes, the uncorrected visual acuity was 1.0 after 1 year with grade I haze. In the other 2 eyes, there was a residual refractive error, and the best spectacle-corrected visual acuity was 0.7 with grade II haze.     

Comparison of two procedures: photorefractive keratectomy versus laser in situ keratomileusis for low to moderate myopia

PURPOSE: A prospective study was conducted to compare the effectiveness, safety, and stability of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) for correction of low to moderate myopia. METHODS: Forty-five patients with a manifest refraction (PRK, -4.54 +/- 0.80; LASIK, -4.82 +/- 1.10) from -1.50 to -6.00 diopters (D) were treated and followed-up for 6 months. In each case, 1 eye received PRK and the other LASIK. The first eye treated, and the surgical method used in the first eye, were randomized. Uncorrected and corrected visual acuity, manifest refraction, corneal haze, and topographic analysis of ablation decentration were examined. RESULTS: The uncorrected visual acuity was 20/20 or better in 35 PRK eyes (77.8%) and 28 LASIK eyes (62.2%) at 6 months (P =.107). At 6 months, 28 eyes (62.2%) that received PRK showed a spherical equivalent of within +/-0.5 D as compared with 24 eyes (53.4%) that received LASIK (P =.393). The amount of ablation decentration was 0.37 +/- 0.25 mm in PRK eyes and 0.49 +/- 0.38 mm in LASIK eyes at 3 months (P =.36). CONCLUSIONS: In our study, PRK and LASIK were found to be similarly effective and predictive of correction in low to moderate myopia. PRK has the advantage of less ablation decentration and is safer than LASIK, so we recommend PRK for eyes with low to moderate myopia.     

Photorefractive keratectomy retreatment after LASIK

PURPOSE: To study the results of late photorefractive keratectomy (PRK) in corneas originally subjected to LASIK. METHODS: Seven eyes of seven patients who had LASIK for myopia were retreated with PRK at least 2 years after LASIK. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, and haze were evaluated before and after LASIK and after retreatment by PRK. RESULTS: Photorefractive keratectomy retreatment improved BSCVA in six (86%) of seven eyes, and one (14%) eye showed no changes. None of the eyes lost lines of BSCVA. Five of seven eyes developed mild haze, which disappeared before the last postoperative follow-up. CONCLUSIONS: Photorefractive keratectomy retreatment performed at least 2 years after LASIK can improve visual acuity. We hypothesize that LASIK-induced corneal nerve damage disturbs corneal wound healing by increasing the tendency for development of haze.     

Laser in situ keratomileusis for residual myopia after photorefractive keratectomy

PURPOSE: To evaluate the efficacy and safety of laser in situ keratomileusis (LASIK) for myopic regression and undercorrection after photorefractive keratectomy (PRK). SETTING: The Eye Institute, Sydney, Australia. METHODS: Fifty eyes of 32 patients were treated by LASIK for residual myopia following primary PRK. The mean spherical equivalent refraction (SEQ) was -2.92 diopters (D) +/- 1.57 (SD) (range -0.75 to -7.88 D). The mean refractive cylinder was 0.96 +/- 0.74 D (range 0 to 3.50 D). For analysis, the eyes were divided into 2 groups: those with 0 or low corneal haze (Group 1) and those with severe corneal haze (Group 2). In Group 1, the SEQ was -1.99 +/- 0.79 D (range -0.75 to -3.75 D) and in Group 2, -3.77 +/- 1.62 D (range -0.75 to -7.90 D). The procedure was performed using the Chiron Automated Corneal Shaper and the Summit Apex Plus laser. The mean interval between PRK and LASIK was 25 months (range 9 to 59 months). The following parameters were studied before and after LASIK retreatment: SEQ, mean refractive cylinder, uncorrected visual acuity (UCVA), and best corrected visual acuity (BCVA). Complications after LASIK retreatment were evaluated. RESULTS: Six months after LASIK, the mean SEQ in all eyes was -0.65 +/- 0.86 D (range +1.50 to -3.35 D); 70.0% of eyes were within +/-1.00 D of emmetropia and the UCVA was 6/12 or better in 72.5%. The mean SEQ in Group 1 was -0.22 +/- 0.55 D (range -0.88 to -1.50 D) and in Group 2, -0.97+/- 0.92 D (range 0.12 to -3.25 D); the UCVA was 6/12 or better in 94.0% of eyes in Group 1 and in 56.0% in Group 2. No statistically significant between-group difference was found in lines of Snellen acuity lost or gained at 6 months. No eye lost more than 1 line of BCVA. CONCLUSIONS: Laser in situ keratomileusis appears to be a safe, effective, and predictable procedure for treating eyes with 0 or low haze with residual myopia after PRK. It is less predictable in eyes with severe haze.     

Intacs after laser in situ keratomileusis and photorefractive keratectomy

PURPOSE: To evaluate the efficacy of intrastromal corneal ring segments (Intacs, Addition Technology) for the correction of residual myopia after laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). METHODS: In this prospective noncomparative case series, Intacs were implanted in 5 eyes (4 patients) that developed myopic regression after LASIK or PRK. Intacs were implanted a minimum of 11 months after the laser procedure. The technique was identical to the standard procedure for myopic unoperated eyes. The Intacs thickness was based on the amount of residual myopia. RESULTS: Postoperative results revealed a reduction in the residual myopia and the mean K-reading. No eye lost best corrected Snellen visual acuity. No intraoperative or postoperative complications occurred. CONCLUSIONS: Implantation of Intacs in eyes with myopic regression after LASIK and PRK resulted in a good refractive outcome and an improvement in uncorrected visual acuity.     

Laser in situ keratomileusis enhancement after photorefractive keratectomy

OBJECTIVE: To describe the safety, effectiveness, and predictability of laser in situ keratomileusis (LASIK) for correcting residual myopia after primary photorefractive keratectomy (PRK). DESIGN: A retrospective, noncomparative case series. PARTICIPANTS AND INTERVENTION: Thirty-six consecutive eyes of 30 patients underwent LASIK after primary PRK. A Multiscan Schwind excimer laser was used for LASIK enhancement. MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity, refraction, videokeratography, and complications were determined before and after LASIK retreatment. Follow-up was at least 12 months. RESULTS: Before LASIK, 11.11% of eyes showed a UCVA of 20/40 or better. This increased to 94.44% 12 months after LASIK. A UCVA of 20/25 or better was achieved in 0% before and in 72.22% after retreatment. Refraction +/-0.5 diopters (spherical equivalent) represented 0% of eyes before and 77.78% of eyes after enhancement. Before LASIK, two eyes had significant haze. Haze remained in these two eyes and appeared in another eye. CONCLUSIONS: Laser in situ keratomileusis proved to be safe and effective for treating residual myopia after PRK. Care must be taken when considering LASIK retreatment in patients with significant haze after primary PRK.     

Laser in situ keratomileusis for treatment of residual myopia after photorefractive keratectomy

PURPOSE: To evaluate the results of laser in situ keratomileusis after photorefractive keratectomy. METHODS: Eighty eyes of 80 patients with residual myopia after photorefractive keratectomy were reoperated with laser in situ keratomileusis. The study was retrospective. Laser in situ keratomileusis was performed using the automated corneal shaper microkeratome and Chiron Technolas 217-C d1 excimer laser. Data measured after laser in situ keratomileusis included uncorrected visual acuity, best-corrected visual acuity, refraction, haze, pachymetry, and keratometry. The follow-up was at least 12 +/- 1.6 months (range, 12 to 15 months). RESULTS: After laser in situ keratomileusis the mean spherical equivalent was -0.24 diopters +/- 0.78. (range, -3 to +1.5) at 12 months, and the mean uncorrected visual acuity was 0.76 diopters +/- 0.24 (range, 0.1 to 1). Sixty-five eyes (81.3%) had various degrees of haze after laser in situ keratomileusis. One eye (1.2%) lost 2 lines of best-corrected visual acuity. CONCLUSIONS: Laser in situ keratomileusis enhancement may be a good alternative to correct residual myopia and astigmatism after primary photorefractive keratectomy. Corneal haze is a common problem in these eyes, and the treatment after laser in situ keratomileusis enhancement should be the same as the treatment after primary photorefractive keratectomy.     

Comparison of laser in situ keratomileusis and photorefractive keratectomy for the correction of myopia of -6.00 diopters or less. Melbourne Excimer Laser Group

PURPOSE: To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) compared to photorefractive keratectomy (PRK) for the correction of low or moderate myopia (-0.50 to -6.00 D) at 6 months after surgery. METHODS: The study population comprised a non-randomized consecutive series of 622 eyes of 392 patients who were treated with the Nidek EC-5000 excimer laser. LASIK was performed using the ACS Chiron microkeratome on 314 eyes and surface PRK on 308 eyes. All patients were treated using a standard protocol, then assessed at 1, 3, and 6 months postoperatively. RESULTS: Forty-four percent of the LASIK group and 67% of the PRK group attended their 6-month examination. Eighty percent of patients (111 eyes) after LASIK and 65% (136 eyes) after PRK had an uncorrected visual acuity of 20/20 or better. Spherical equivalent refraction was within +/-0.50 D of intended refraction in 78% (109 eyes) for LASIK and 82% (170 eyes) for PRK. Loss of two more lines of best spectacle-corrected visual acuity at 6 months occurred in 1.4% (2 eyes) of the LASIK group and 1.0% (2 eyes) of the PRK group. CONCLUSION: At 1 month follow-up, the percentage of eyes that achieved 20/20 uncorrected visual acuity was greater in the LASIK group than in the PRK group. At 6 months, visual and refractive outcomes of LASIK and PRK were similar. Although flap related complications occurred only after LASIK, the overall risk of loss of best spectacle-corrected visual acuity was not significantly greater than for PRK.     

Wavefront-guided treatment for previous laser in situ keratomileusis and photorefractive keratectomy: case reports

PURPOSE: To describe the off-label use of the Alcon LADARVision System for CustomCornea (LADARWave and LADARVision4000) in two patients, one for retreatment after laser in situ keratomileusis (LASIK) and one for retreatment after photorefractive keratectomy (PRK). METHODS AND RESULTS: Both patients were unhappy with the quality of their vision after initial refractive surgery. The first patient initially had LASIK to correct -4.75 D of myopia in each eye, and then had retreatment with CustomCornea. Before retreatment, manifest refraction was OD 0.50 -0.50 x 180 degrees (20/25 uncorrected) and OS -0.50 -0.75 x 180 degrees (20/40 uncorrected). Two months after retreatment with CustomCornea, his uncorrected visual acuity OD was 20/15, and 1 month after retreatment in his left eye, uncorrected visual acuity was 20/15. The second patient had PRK OD, with a postoperative uncorrected visual acuity of 20/25 and cycloplegic refraction of +1.00 -0.75 x 84 degrees. After CustomCornea retreatment, his 3.5-month postoperative uncorrected visual acuity was 20/15 and manifest refraction was +0.50 -0.50 x 180 degrees. CONCLUSION: The Alcon LADARVision System for CustomCornea was used effectively to retreat both a myopic LASIK and myopic PRK patient, primarily for subjective quality of night vision complaints.     

Clear lens extraction with intraocular lens followed by photorefractive keratectomy or laser in situ keratomileusis

OBJECTIVE: To study photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) after clear lens extraction (CLE) with intraocular lens (IOL) implantation for hyperopia or astigmatism. DESIGN: Retrospective, noncomparative interventional case series. PARTICIPANTS: Sixty-five eyes (55 subjects) had CLE with posterior chamber IOL implants for hyperopia up to 12.25 diopters (D); 31 eyes were retreated with PRK, and 34 eyes were retreated with LASIK for residual ametropias. INTERVENTION: For PRK and LASIK, the refractive surgery was performed with the slit-scanning excimer laser Nidek EC-5000, Nidek Co., Tokyo, Japan. MAIN OUTCOME MEASURES: Manifest refraction, best-spectacle and uncorrected Snellen visual acuity, haze, and halos were evaluated before surgery and at 1, 3, 6, and 12 months postoperative. RESULTS: Forty-seven eyes were evaluated at the 12-month postoperative examination: 96% of these eyes had spherical equivalents (SE) within +/-2 D of emmetropia, 79% of eyes had SE within +/-1 D of emmetropia and 51% of eyes had SE within +/-0.50 D of emmetropia. Eighty-five percent of the eyes at 12 months postoperative had uncorrected visual acuity of 20/40 or better, and 46% of eyes had uncorrected visual acuity of 20/20 or better. Eighty-seven percent of the eyes at 12 months postoperative had uncorrected visual acuity within 1 Snellen line of their initial best spectacle-corrected visual acuity (BSCVA) before all treatment. No eye lost 2 Snellen lines of BSCVA at 3, 6, or 12 months after PRK or after LASIK. CONCLUSIONS: IOL implantation for CLE, although an invasive technique, resulted in better refractive outcomes without laser-related clinical complications after PRK or LASIK adjustment.