PRK后近视回退的LASIK再矫正

为探讨准分子激光原位角膜磨镶术（ｅｘｃｉｍｅｒＬａｓｅｒｉｎｓｉｔｕｋｅｒａｔｏｍｉｌｅｕｓｉｓＬＡＳＩＫ）在准分子激光屈光性角膜切削术（ｐｈｏｔｏｒｅ－ｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙＰＲＫ）治疗中、高度近视后，屈光回退的疗效，用波长１９３ｎｍ的ＡｒＦ准分子激光对２７人（４８眼）行ＰＲＫ后屈光回退的患眼，再行ＬＡＳＩＫ，其中４眼在ＰＲＫ后１０个月施行，４４眼在ＰＲＫ后１年～１年半施行。结果：ＰＲＫ术后屈光回退为－１．７５Ｄ～１２．２５Ｄ平均为－５．４４Ｄ±３．０９Ｄ；再手术后，随访３～１０个月，４３眼的屈光度在±１．００Ｄ之内，５眼有－３．００Ｄ的欠矫。４５眼的裸眼视力达到或超过术前矫正视力，３眼低于术前矫正视力。结论：ＰＲＫ后的屈光回退可行ＬＡＳＩＫ再矫正，手术方法与第一次行ＬＡＳＩＫ完全相同，再次手术时间应在ＰＲＫ后一年以上。     

准分子激光屈光性角膜切削术与激光原位角膜磨镶术治疗中低度近视的对比

目的对准分子激光屈光性角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ，ＰＲＫ）和准分子激光原位角膜磨镶术（ｌａｓｅｒａｓｓｉｓｔｅｄｉｎｓｉｔｕｋｅｒａｔｏｍｉｌｌｅｕｓｉｓ，ＬＡＳＩＫ）治疗中、低度近视的疗效进行前瞻性对比研究。材料和方法术前屈光度为－１．２５～－６．００Ｄ的近视５６９只眼，其中１３７只眼接受ＬＡＳＩＫ手术，４３２只眼接受ＰＲＫ手术，随访６－１６个月（平均８．９±２．６个月）。在术后１周、１个月、３个月、６个月和１２个月复查。结果ＬＡＳＩＫ组术后屈光状态较ＰＲＫ稳定，回退幅度较ＰＲＫ小，术后６个月时，ＬＡＳＩＫ组和ＰＲＫ组分别有９４％和８７％屈光度在±１．００Ｄ内（ｐ＜０．０５），分别有８４％和７１％屈光度在±０．５０Ｄ以内（ｐ＜０．０１）。ＬＡＳＩＫ组术后视力恢复较ＰＲＫ快，术后１周的平均裸眼视力超过１．０，术后６个月时，ＬＡＳＩＫ和ＰＲＫ组中裸眼视力０．５或以上者分别占１００％和９４％（ｐ＜０．０１），裸眼视力１．０以上者分别占８６％和７２％（ｐ＜０．０１）。结论ＬＡＳＩＫ不仅适合治疗高度近视，也适合治疗中、低度近视。对于中、低度近视，ＬＡＳＩＫ的疗效优于ＰＲＫ。     

准分子激光屈光性角膜手术后角膜知觉的改变

目的观察和分析准分子激光屈光性角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ，ＰＲＫ）和准分子激光原位角膜磨镶术（ｌａｓｅｒｉｎ－ｓｉｔｕｋｅｒａｔｏｍｉｌｅｕｓｉｓ，ＬＡＳＩＫ）治疗近视后角膜知觉的变化。方法对２３１例（３８７只眼）近视患者施行ＰＲＫ，对４８２例（７９６只眼）施行ＬＡＳＩＫ进行治疗。对术后角膜知觉不同时期的变化进行检查、分析。结果ＰＲＫ和ＬＡＳＩＫ术后早期角膜知觉均明显下降，尤以ＰＲＫ明显。ＰＲＫ术后角膜知觉在术后６个月才能恢复，ＬＡＳＩＫ术后角膜知觉约在术后１个月即恢复。结论ＰＲＫ术后角膜知觉的恢复比ＬＡＳＩＫ慢。     

PRK与LASIK治疗PK术后残留近视的临床研究

目的 探讨准分子激光角膜切削术（ＰＲＫ）及准分子激光原位角膜磨镶术（ＬＡＳＩＫ）矫治角膜放射状切开术（ＲＫ）后残留近视的安全性、稳定性和可靠性。方法 采用美国ＣＯＭＰＡＫ－２００型准分子激光治疗仪帮ＳＣＭＤ公司的可调节器气动微型角膜刀,分别对ＲＫ后残留近视的３８眼和９眼行ＰＲＫ和ＬＡＳＩＫ术,并随访半年以上。ＰＲＫ组根据屈光状态分为３组：Ⅰ组〈－３．００Ｄ;Ⅱ组－３．００～５．７５Ｄ,Ⅲ组－６．０     

准分子激光原位角膜磨镶术后欠矫的再治疗

对２４例（３６只眼）行准分子激光原位角膜磨镶术（ｅｘｃｉｍｅｒｌａｓｅｒｉｎｓｉｔｕｋｅｒａｔｏｍｉｌｅｕｓｉｓ,ＬＡＳＩＫ）后屈光欠矫的患眼,再行原瓣下准分子激光角膜切削术。其中２只眼在ＬＡＳＩＫ术后１个月内施行,３４只眼在术后３～５个月内施行。３６只眼行ＬＡＳＩＫ前的屈光度数为：－５．００～－１７．８７Ｄ,平均－１０．７５±３．４１Ｄ,ＬＡＳＩＫ后欠矫的度数为：－１．２５～－５．５０Ｄ,平均－３．１２±１．１６Ｄ。再手术后,随诊３～６个月。２６只眼（７２．２％）的裸眼视力达到术前矫正视力,２只眼的裸眼视力较术前矫正视力增加一行,８只眼的矫正视力较术前下降一行。术后角膜瓣平整,角膜界面清晰,因此,ＬＡＳＩＫ后屈光欠矫可于术后３～６个月内于原角膜瓣下的基质层再行准分子激光角膜切削术,手术简便、安全、有效。     

角膜地形图对准分子激光屈光性角膜手术后散光变化的判断作用

目的 探讨准分子激光我性角膜手术前后角膜地形图△ＳｉｎＫ变化值在散光度数变化判断中的作用。方法 对近视度为－１．５０～－２４．００Ｄ,散光度数－０．７５～－５．５０Ｄ的患者８９例１５０眼行准分子激光屈光性角膜切削术（ＰＲＫ）或分子激光原位角膜磨削术（ＬＡＳＩＫ）,观察６个月以上,经计算机得出角膜曲率△ＳｉｎＫ变化值Ｘ与临床散光度数变化 值Ｙ的散点图及相关系数ｒ值。结果 手术前后Ｘ与Ｙ的关系：Ｙ＝１     

准分子激光原位角膜磨镶术治疗近视的并发症

目的 分析准分子原位角膜磨镶术（ｅｘｃｉｍｅｒ ｌａｓｅｒ ｉｎ ｓｉｔｕ ｋｅｒａｔｏｍｉｌｕｓｉｓ,ＬＡＳＩＫ）治疗近视的并发症,探讨其发生原因及预防措施。方法 ６６２例（１２６５只眼）近视患者（－２．００～２５．００Ｄ）按屈光度分为３组：Ａ组７２６只眼,≤－６．００Ｄ;Ｂ组２８７只眼,－６．２５～－１０．００Ｄ）;Ｃ组２５２只眼,〉－１０．００Ｄ;行ＬＡＳＩＫ后均随访１２个月,观察及分析其并     

准分子激光屈光性角膜切削术和激光原位角膜磨镶术治疗中低度近？…

目的：比较准分子激光屈光性角膜切削术（ＰＲＫ）和激光原位角膜磨镶术（ＬＡＳＩＫ）治疗中低度近视的临床效果。方法：中、低度近视４００例（７１０眼）,其中ＰＲＫ组３４３眼,平均屈光度－４．１８±１．２４Ｄ。ＬＡＳＩＫ组３６７眼,平均屈光度－４．７５±１．１０Ｄ。两组均于手术后１、３、６、１２个月复查视力、屈光度、角膜地形图及角膜上皮下基质混浊等并发症情况。结果：ＰＲＫ组欠矫〉－１．００Ｄ者９．０３％,     

准分子激光屈光性角膜手术后角膜地形图与临床屈光度变化的关系

目的：分析和探讨准分子激光屈光性角膜术后角膜地形图角膜闪表面曲率变化与临床屈光度变化的关系。方法：对近视度为－１．５０～－２．４００Ｄ的患者１７６例３２７眼行ＰＲＫ或ＬＡＳＩＫ治疗,观察６个月以上。按实矫屈光度分为二组：Ｉ组－１．５０～－６．００Ｄ有１２４眼;Ⅱ组－６．２５～－２０．００Ｄ有２０３眼;并将屈光回退患者９１眼作为Ⅱ组。经计算机得出角膜曲率变化与临床屈光度变化的散点图及相关系数ｒ值。结     

准分子激光角膜屈光手术后的对比敏感度变化

为观察准分子激光屈光性角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ，ＰＲＫ）和准分子激光原位角膜磨镶术（ｌａｓｅｒｉｎ－ｓｉｔｕｋｅｒ－ａｔｏｍｉｌｅｕｓｉｓ，ＬＡＳＩＫ）术后对比敏感度的变化，评价这两种手术后视功能的改变，对术前屈光度为－１．７５Ｄ至－７．７５Ｄ，在我院接受ＰＲＫ手术的３６只眼和接受ＬＡＳＩＫ手术的３１只眼，采用电生理方法检查手术前后远对比敏感度，用Ｆ．Ａ．Ｃ．Ｔ对比敏感度表检查近对比敏感度。所有患者术前最佳矫正视力均为１．０以上。结果：ＰＲＫ和ＬＡＳＩＫ术后几个月内远、近对比敏感度均有不同程度的降低，以中频段下降幅度最大。对比敏感度于ＰＲＫ术后１２个月、ＬＡＳＩＫ术后６个月恢复术前水平。结论：ＰＲＫ和ＬＡＳＩＫ术后均出现暂时的对比敏感度下降，ＬＡＳＩＫ术后对比敏感度恢复较ＰＲＫ快。     

Retinal detachment following excimer laser

AIMS—To report the clinical presentation, surgical management, and outcome of retinal detachment following excimer laser.
METHODS—Retrospective analysis of retinal detachments observed in 11 eyes of 10 myopic patients who had previously undergone photorefractive keratectomy (PRK) or phototherapeutic keratectomy (PTK) by excimer laser.
RESULTS—Symptoms of visual loss in two eyes were initially attributed to corneal haze. In 10 of 11 eyes visualisation of the retinal detachment and causative break was possible despite mild corneal haze and optical aberrations caused by the refractive laser procedure. Retinal reattachment was achieved in all 11 eyes though one eye required four surgical interventions.
CONCLUSION—This is the first published report to describe an association between retinal detachment and previous excimer laser treatment. The association would appear to reflect the predisposition of myopes to retinal detachment. Clinicians should be aware of potential retinal pathology in patients undergoing PRK.

     

Experimental corneal studies with the excimer laser

The excimer laser is potentially capable of achieving wide area central corneal reprofiling because of its extreme precision and limited penetration into adjacent tissues. A beam modifying system designed for this application is described. Initial clinical studies in monkeys and in ten human patients with blind eyes were performed. Long-term clinical data and interim histologic analyses are available from these studies. The results indicate that following ablation with an ultraviolet laser in both humans and primates, the ablated tissue shows a normal healing reaction resulting in a mild to moderate stromal interface haze. The effects of this healing on best corrected vision must be elucidated through additional research. Some loss of refractive effect was seen early in the healing process with apparent stabilization.     

Mitomycin C and excimer laser

Mitomycin C is an antimetabolite agent that blocks DNA and RNA replication and protein synthesis. It has been used in several ophthalmologic areas, and recently as a modulator of corneal wound healing in excimer laser surgeries. A single application of mitomycin C during surface corneal photoablative surgery seems a safe and efficient therapeutic option for eyes with corneal opacity and/or as prophylaxis in eyes with high risk for corneal opacity development. The use of this drug in photoablative surgery should be cautious until long-term safety results have been reported. The present text presents a review about corneal wound healing with the use of mitomycin C.     

Respirable particles in the excimer laser plume

PURPOSE: To determine whether respirable-size particles are present in the excimer laser plume following ablation of the corneal stroma. SETTING: Outpatient laser vision correction facility. METHODS: In this experimental study, an excimer laser was used to ablate 2 eye-bank corneas. Material from the plume was collected with filter paper that was coupled to a smoke evacuator. The filter paper was examined and photographed with an electron microscope. The particle size was measured with a computer program using digitized images of the photographs. As a control, room air was sampled using a smoke evacuator connected to a holder containing filter paper prior to the tissue ablation. RESULTS: Ninety-eight particles were measured. The mean diameter was 0.22 microm +/- 0.056 (SD). No particles were seen on the control filter paper. CONCLUSIONS: The plume created during excimer laser ablation of the cornea contained respirable-size particles. It is not known whether inhalation of these particles poses a significant health hazard. However, we recommend that a mask be worn by the surgeon and technical personnel assisting in excimer laser surgery. The plume should also be evacuated.     

Topography-controlled excimer laser photorefractive keratectomy

PURPOSE: To assess whether photorefractive keratectomy (PRK) controlled by videokeratography can successfully treat refractive errors in eyes with corneal irregularities and improve spectacle-corrected visual acuity. METHODS: In a prospective clinical study, PRK was performed in 10 eyes of 10 patients. Reason for surgery was irregular astigmatism after penetrating keratoplasty, corneal irregularity after corneal scarring, corneal astigmatism in keratoconus, and decentration after myopic and hyperopic PRK. Excimer ablation was controlled by preoperative videokeratography (Orbscan II, Orbtek) using the MEL-70 system from Aesculap Meditec. Follow-up was 6 months. RESULTS: Concerning manifest refraction, the sphere was reduced on average from +1.92 to +0.57 D, 6 months postoperatively. Cylinder changed from -1.95 D on average to -0.30 D at 6 months postoperatively. There was improvement of uncorrected visual acuity of 2 or more lines in 5 eyes and no change in 5 eyes 6 months postoperatively. Spectacle-corrected visual acuity improved in 2 eyes by 2 to 3 lines, in 9 eyes by 1 to 3 lines, and showed no change in 1 eye. CONCLUSION: Videokeratography-controlled PRK improved refractive errors in irregular corneas with improvement of spectacle-corrected visual acuity.