准分子激光LASIK和PRK治疗兔实验性远视的比较

目的:评价准分子激光原位角膜磨镶术(LASIK)和准分子激光角膜切削术(PRK)治疗高中度远视的预测性、安全性及有效性.方法:选择新西兰大白兔20只,随机分为LASIK和PRK2组,设计每组兔右眼为 5.00D,左眼为 8.00D,应用LASIK和PRK进行预期矫正度的激光切削.分别于术前、术后3,14,30,60,90,180d对术眼进行角膜地形图和裂隙灯检查和记录,同时每组随机处死1只兔子,取角膜标本进行光镜和电镜的病理学检查.结果:所有术眼均无并发症,LASIK组右眼和左眼术后180d的角膜中央曲率变化为( 4.561±0.67)D和( 8.59±0.83)D,PRK组右眼和左眼术后180d的角膜中央曲率变化为( 4.56±0.80)D和( 7.33±0.98)D.术后3～30d均有回退现象(P＜0.05),180d时已基本稳定(P＜0.05).LASIK组和PRK组比较,在 5.00D范围内的差异无显著性(P＜0.05),在 8.00D范围内的差异有显著性(P＜0.05).病理学观察显示病理损伤后LASIK与PRK的愈合过程相同.结论:LASIK与PRK治疗远视均具有安全性.LASIK对高度远视治疗的效果与可预测性优于PRK.     

LASIK correction of spherical hyperopia,hyperopic astigmatism,and mixed astigmatism with the LADARVision excimer laser system

OBJECTIVE: To assess the safety and effectiveness of the LADARVision active tracking narrow beam excimer laser system (Alcon Surgical, Orlando, FL) using laser in situ keratomileusis (LASIK) for correction of spherical hyperopia, hyperopic astigmatism, and mixed astigmatism. DESIGN: A multicenter, prospective non-randomized (self-controlled) comparative trial. PARTICIPANTS: A total of 360 eyes, including 152 spherical hyperopic, 143 hyperopic astigmatic, and 65 mixed astigmatic, were treated for up to +6.00-diopter (D) sphere with up to -6.00-D cylinder. INTERVENTION: Treatments were performed at six sites in the United States using a 6-mm optic zone with a 1.5-mm peripheral blend zone for a maximum ablation zone diameter of 9 mm. MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), manifest refraction, vector analysis, best spectacle-corrected visual acuity (BSCVA), complications and adverse reactions, subjective symptoms, and patient satisfaction. RESULTS: Six and 12 months of follow-up, respectively, were available on 143 and 117 spherical hyperopic eyes, 124 and 74 hyperopic astigmatic eyes, and 57 and 38 mixed astigmatic eyes, respectively. For spherical hyperopes at 6 and 12 months, UCVA was 20/40 or better in 93.4% and 93.9% of eyes, respectively. The manifest refraction spherical equivalent (MRSE) was within 0.50 D of intended in 65.0% and 74.1% of eyes, respectively, and within 1.00 D in 87.4% and 91.4%, respectively. Refractive stability was demonstrated in 94.2% or more of eyes between the intervals of 1 to 3 months and 3 to 6 months and in 95.3% or more of eyes to 12 months. A loss of two lines of BSCVA occurred in 3.5% and 3.4%, respectively, and no eyes lost more than two lines. For hyperopic astigmats at 6 and 12 months, UCVA was 20/40 or better in 90.9% and 93.8% of eyes, respectively. The MRSE was within 0.50 D of intended in 60.5% and 73.0% of eyes, respectively, and within 1.00 D in 88.7% and 89.2% of eyes, respectively. Refractive stability was demonstrated in 96.5% or more of eyes, respectively, between the intervals of 1 to 3 months and 3 to 6 months and 95.5% or more to 12 months. A loss of two lines of BSCVA occurred in 5.8% and 1.4% of eyes, respectively, and no eyes lost more than two lines. For mixed astigmats at 6 and 12 months, UCVA was 20/40 or better in 92.6% and 94.4% of eyes, respectively. The MRSE was within 0.50 D of intended in 64.9% and 73.7% of eyes, respectively, and within 1.00 D in 87.7% and 94.7% of eyes, respectively. Refractive stability was demonstrated in 100% of eyes between the intervals of 1 to 3 months and 3 to 6 months and in 97.0% or more to 12 months. A loss of two lines of BSCVA occurred in 1.9% and 0.0% of eyes, respectively, and no eyes lost more than two lines. CONCLUSIONS: The data support safety and effectiveness of the LASIK correction of spherical hyperopia, hyperopic astigmatism, and mixed astigmatism with the LADARVision system.     

Acute corneal necrosis after excimer laser keratectomy for hyperopia

OBJECTIVE: To describe a new, rare clinical complication after routine excimer laser photorefractive keratectomy to correct hyperopia. DESIGN: Case report with clinicopathologic correlation. MAIN OUTCOME MEASURES: Four weeks after treatment with excimer laser, a perforating keratoplasty was performed for persistent corneal opacities. The corneal button was examined using light and electron microscopy. Special immunohistochemical stains were used to detect apoptosis. RESULTS: The patient developed corneal opacities, endothelial precipitates, and a fibrinous exudate in the anterior chamber after the laser treatment. The changes did not respond to therapy directed against bacteria, fungi, and Acanthamoeba. All examinations and special stains were negative for micro-organisms. By light microscopy, an anterior zone of corneal necrosis was present with a moderate amount of acute inflammatory cells. At the interface between necrotic and viable corneal stroma, keratocytes with typical features of apoptosis were detected by immunohistochemistry and electron microscopy. CONCLUSION: This is the first full histopathologic report of a case of acute corneal necrosis with signs of apoptosis after excimer laser therapy of the cornea. Surgeons should be aware of this rare but potentially severe complication.     

准分子激光原位角膜磨镶术和钬激光热角膜成形术治疗原发性远视眼

目的　评价准分子激光原位角膜磨镶术 (LASIK)和钬激光热角膜成形术 (LTK)治疗原发性远视眼的有效性、预测性和安全性。方法　对 3 0例原发性远视眼患者 ( 1 0 0～ 8 5 0 0D) ,分别采用LASIK( 19眼 )和LTK( 11眼 )进行治疗 ,术后平均随访 12个月。结果　至术后 12个月时 ,LASIK组裸眼视力达到 0 5～ 0 9和 1 0以上者分别为 42 1%和47 4% ;LIK组裸眼视力达到 0 5～ 0 9和 1 0以上者分别为 2 7 3 %和 45 5 %。LASIK组屈光度在≤± 0 5D和 >± 0 5～± 1 0D者分别为 5 2 6%和 3 1 6% ;LIK组屈光度在≤± 0 5D和 >± 0 5～± 1 0D者分别为 45 5 %和 2 7 3 %。结论　LASIK可有效地治疗低中度远视眼且具有较好的预测性和安全性 ;LTK治疗低度远视眼简便、安全 ,但术后有屈光回退。对手术技术和激光治疗的不断改进将进一步提高预测性和稳定性。     

Results of photorefractive keratectomy for hyperopia using the VISX star excimer laser system

PURPOSE: To evaluate safety, efficacy, and predictability of photorefractive keratectomy (PRK) for hyperopic astigmatism of +1.75 to 00 D manifest refractive sphere and up to -2.50 D manifest refractive astigmatism using the VISX Star excimer laser system, version 2.5 software. METHODS: Treatment was performed on 32 eyes of 21 patients. Eighteen of 21 patients were 45 years of age or older. Manifest and cycloplegic refraction together with Pelli-Robson contrast sensitivity assessment was performed prior to surgery and 1, 3, 6, 12, and 24 months after treatment. RESULTS: Twenty-seven of 32 surgical procedures were reviewed 1 year after treatment (84%). Corneal epithelial healing was complete between day 4 and 10. Twelve months after treatment, 25 of 27 eyes (93%) achieved 20/40 or better uncorrected visual acuity and 19 eyes (70%) achieved 20/20. No patient lost two or more lines of Snellen visual acuity assessed 6 months and later after treatment. The mean spherical equivalent refraction was reduced from +2.90 at baseline to +0.10 D at 1 year and +0.40 D at 2 years; 65% of eyes had a refraction within +/- 0.50 D. Four patients had further treatment by laser in situ keratomileusis for undercorrection in three eyes and overcorrection in one eye. Pelli-Robson contrast acuity was significantly reduced 12 months after treatment from a mean 1.72 before to 1.66 after PRK (P = .02, t-test). CONCLUSIONS: PRK for hyperopia using the VISX Star excimer laser system was effective in the treatment of hyperopic astigmatism. Although no patient lost two or more lines of high contrast best spectacle-corrected Snellen visual acuity 1 year after treatment, there was a significant decrease in Pelli-Robson contrast acuity.     

Intraocular pressure after LASIK for hyperopia

PURPOSE: To determine whether hyperopic laser in situ keratomileusis (H-LASIK) affects Goldmann applanation tonometry measurements. DESIGN: Retrospective, comparative, self-controlled case series. PARTICIPANTS: One hundred eight eyes of 58 patients were enrolled in the study. METHODS: Baseline intraocular pressure (IOP) was measured by Goldmann applanation tonometry. These readings were compared with readings obtained at least 6 months after surgery. RESULTS: After H-LASIK, a decrease was observed in the measured IOP of treated eyes that could not be related to the degree of hyperopia treated or to the treatment zone diameter. A significant difference was observed between the IOP before and after surgery (P < 0.00001). CONCLUSIONS: The applanation tonometer underestimates the true IOP after LASIK for hyperopia.     

准分子激光原位角膜磨镶术治疗中高度远视的疗效观察

目的　观察准分子激光原位角膜磨镶术（ｅｘｃｉｍｅｒｌａｓｅｒｉｎ ｓｉｔｕ ｋｅｒａｔｏｍｉｌｅｕｓｉｓ,ＬＡＳＩＫ） 治疗中高度远视的安全性及有效性。方法　对９ 例（１７ 只眼） 高度远视患者行ＬＡＳＩＫ。术前远视度数为＋５－５０ ～＋ ９－００ Ｄ,平均为（＋ ７－１８±１－００） Ｄ。术后随访观察１２ 个月以上。结果　术中无严重并发症,术后最佳矫正视力与术前相比,未见视力下降超过１ 行以上者。术后３ 个月时,屈光度基本稳定;术后１２ 个月时,平均远视度数为（ ＋１－７７±１－５６）Ｄ,未见屈光度在０ 以下者,屈光度在０～＋ １－００ Ｄ者占５３％ （９／１７）;平均裸眼远视力为０－６０±０－１７,其中≥０－５ 者１５ 只眼（８８％ ）;平均裸眼近视力为０－９８±０－２４ ,其中≥０－５ 者１７ 只眼（１００ ％） 、≥１－０ 者１３ 只眼（７７％ ）。结论　ＬＡＳＩＫ 对于中高度远视治疗具有良好的安全性及有效性,对于治疗参数尚需作进一步调整。     

Photorefractive keratectomy for myopia and myopic astigmatism correction using the WaveLight Allegretto Wave Eye-Q excimer laser system

To analyze photorefractive keratectomy (PRK) outcomes in myopia and myopic astigmatism correction using the WaveLight Allegretto Wave Eye-Q^® excimer laser system (WaveLight Laser Technologie AG, Erlangen, Germany). 222 eyes of 151 patients underwent PRK (mean age 33.5 ± 6.8 years). Pre-operative best spectacle-corrected visual acuity (BSCVA) ranged from 0.4 to ?0.1 logMAR (mean ?0.03 ± 0.06). Mean spherical equivalent (SE) was ?3.29 ± 1.20 D. Efficacy, predictability and safety were evaluated. Minimum follow-up was 3 months. Accountability at 3 and 6 months was 100 and 54 %, respectively (median follow-up 5 months, mean 5.2 ± 2.6 months). At 3 months, mean uncorrected visual acuity (UCVA) was ?0.02 ± 0.07 logMAR, BSCVA ?0.03 ± 0.05 logMAR, efficacy index 0.98 and safety index 1.02. UCVA was ≥20/16 in 40.1 %, ≥20/20 in 86.5 % and ≥20/25 in 98.2 %. Mean SE was ?0.02 ± 0.20 D. Residual refractive error was ± 0.13 D in 81.5 %, ± 0.25 D in 88.7 % and ± 0.50 D in 97.7 %. At 6 months, outcomes were similar: mean UCVA was ?0.02 ± 0.07 logMAR, BSCVA ?0.03 ± 0.06 logMAR, efficacy index 1.00 and safety index 1.03. UCVA was ≥20/16 in 43.7 %, ≥20/20 in 86.6 % and ≥20/25 in 96.6 %. Mean SE was ?0.02 ± 0.17 D. Residual refractive error was ± 0.13 D in 86.6 %, ± 0.25 D in 93.3 % and ± 0.50 D in 98.3 %. Refractive stability was achieved at 3 months. No patient lost more than one line of BSCVA. There were no retreatments. The WaveLight Allegretto Wave Eye-Q is effective, predictable and safe in low-to-moderate myopia and myopic astigmatism PRK correction.     

Conventional vs wavefront-guided LASIK using the LADARVision4000 excimer laser

PURPOSE: To compare outcomes after LASIK surgery using the conventional LADARVision4000 laser and the wavefront-guided LADARWave CustomCornea wavefront system. METHODS: A prospective study was performed involving 140 myopic eyes receiving conventional or CustomCornea LASIK between May and October 2003. The preoperative manifest spherical equivalent refraction was limited to myopia < or = -7.00 diopters (D). The preoperative manifest cylinder was limited to < or = -2.50 D of astigmatism. Patients were evaluated for 3 months following surgery. Results evaluated were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity, manifest refraction, dilated wavefront measurements, contrast sensitivity, and patient responses to subjective questionnaires. RESULTS: For the CustomCornea eyes at 3 months, 80% (70/87) had UCVA > or = 20/20 and 95% (83/87) had UCVA > or = 20/25. For the conventional eyes at 3 months, 45% (9/20) had UCVA > or = 20/20 and 80% (16/20) had UCVA > or = 20/25. At the 3-month postoperative visit, 85% (74/87) of the CustomCornea eyes and 55% (11/20) of the conventional eyes were within +/- 0.50 D of their intended correction. At 1 and 3 months, the CustomCornea treated eyes had a statistically significant lower mean increase in higher order aberrations than conventionally treated eyes (P < .05). CONCLUSIONS: CustomCornea wavefront-guided LASIK surgery appears safe and effective and provides clinical benefits that appear to exceed those of conventional LADARVision surgery.     

Rates of epithelial ingrowth after LASIK for different excimer laser systems

PURPOSE: To investigate the incidence of epithelial ingrowth after laser in situ keratomileusis (LASIK) using the VISX 20/20B and VISX Star S3 laser systems. METHODS: A chart review of patients who had undergone LASIK between April 1999 and December 2001 was performed. Patients having known risk factors for epithelial ingrowth were excluded from the study. Both eyes of patients who were operated with both laser systems were included in a paired analysis. The first operated eyes of the remaining patients were included in an unpaired analysis. The outcomes studied were epithelial ingrowth (a region of epithelial growth under the flap that was contiguous with the flap edge and extended at least 0.7 mm in the radial direction) and epithelial ingrowth requiring treatment (extending into the pupillary zone, causing reduced vision, causing nighttime glare, or inducing any melting of the flap edge). RESULTS: In the paired study, 11 (61.1%) of 18 eyes treated with the VISX 20/20B had epithelial ingrowth, and 7 (38.9%) eyes required treatment. None of the eyes treated with the VISX Star S3 had epithelial ingrowth. In the unpaired study, 39 (37.1%) of 105 eyes treated with the VISX 20/20B were noted to have epithelial ingrowth and 14 (13.3%) eyes required treatment. None of the eyes treated with the VISX Star S3 had epithelial ingrowth. The incidence of epithelial ingrowth was significantly different for the VISX 20/20B and the VISX Star S3 in both analyses (paired: P<.001, McNemar's test; unpaired: P<.001, Fisher's exact test). CONCLUSIONS: The laser system used in LASIK is a risk factor for the development of epithelial ingrowth.     

Five-year follow-up of laser in situ keratomileusis for hyperopia using the Technolas Keracor 117C excimer laser

PURPOSE: To evaluate safety, predictability, efficiency, and long-term stability of laser in situ keratomileusis (LASIK) for spherical hyperopia. METHODS: This study was a retrospective 5-year analysis of 67 patients (125 eyes) who had LASIK for spherical hyperopia; preoperative mean manifest spherical equivalent refraction was +3.84+/-1.13 D (range +1.00 to +6.50 D) and mean astigmatism was 0.37+/-0.27 D (range 0 to 1.00 D). Preoperative spherical equivalent refraction for the low hyperopia group was +1.00 to +2.75 D; medium hyperopia group, +3.00 to +4.25 D, and high hyperopia group, +4.50 to +6.50 D. All surgeries were performed using the scanning Chiron Technolas Keracor 117C excimer laser. Uncorrected and best spectacle-corrected visual acuity, predictability, long-term stability of refraction, and complications were analyzed. RESULTS: At 5 years after hyperopic LASIK, mean spherical equivalent refraction for the low hyperopia group was +0.48D+/-0.79 D; medium hyperopia group, +1.52+/-1.45 D; high hyperopia group C, +3.39+/-1.98 D. The percentage of eyes with a spherical equivalent refraction within +/-0.50 D of emmetropia for the low hyperopia group was 63% (37 eyes); medium hyperopia group, 42% (20 eyes); high hyperopia group, 22% (4 eyes). Eyes with chronic dry eye symptoms had a mean difference in spherical equivalent refraction from target refraction of +1.43 D compared with +0.84 D for eyes without dry eye symptoms. Five eyes (4%) lost 2 lines of BSCVA at 5 years. CONCLUSION: LASIK was safe, effective, and stable for primary hyperopia between +1.00 and +3.00 D. Higher amounts of hyperopia had poor long-term stability, especially eyes with more than +4.25 D. Chronic dry eye symptoms were associated with regression over time.     

Corneal infiltrates after excimer laser photorefractive keratectomy and LASIK

PURPOSE: To determine the frequency and clinical characteristics of corneal infiltrates after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) and to evaluate the efficacy of treatment. METHODS: We retrospectively reviewed the records of 8508 eyes treated with PRK or LASIK in a university-based clinic for the correction of refractive errors for 60 days postoperatively. RESULTS: Corneal infiltrates were observed in 35 (0.8%) of 4492 PRK-operated eyes and in 4 (0.1%) of 4016 LASIK-operated eyes. The mean time of diagnosis was 5.46 days. Among the 39 eyes with infiltrates, 10 (9 PRK, 1 LASIK) had culture-verified infectious keratitis. Coagulase-negative Staphylococcus was the most frequently isolated bacterium (50%), followed by S aureus (20%), Corynebacterium xerosis (10%), Streptococcus viridans (10%), and an unidentified gram-positive coccus (10%). Final visual acuity of > or = 20/30, without correction, was achieved in 79.5% of the 39 eyes. CONCLUSIONS: Corneal infiltrates occurred in 0.8% of PRK eyes and 0.1% of LASIK eyes. Bacterial smears were positive for several eyes. In all cases, prompt treatment was responsible for good visual outcome.     

激光原位角膜磨镶术治疗中高度远视疗效观察

目的　探讨准分子激光原位角膜磨镶术 (LASIK)治疗远视的预测性、安全性及有效性。方法　应用准分子激光对13例 (19眼 )原发性远视 (+ 4 0 0D～ + 8 5 0D) ,采用LASIK进行治疗。术后平均随访 12月 ,观察手术前后视力、屈光度的变化和并发症。结果　术中无严重并发症 ,术后 3月时 ,屈光度基本稳定 ;术后 12月时 ,平均残余屈光度为 (+ 0 2 8± 0 74)D ,屈光度在 1 0 0D以内占 84 2 1% ;平均裸眼远视力为 0 68± 0 19,≥ 0 5者 (19眼 )占 10 0 % ,≥ 1 0者 (4眼 )占 2 1 0 5 % ;平均裸眼近视力为 0 99± 0 3 1,其中≥ 0 5者 19眼 (10 0 % ) ,≥ 1 0者 16眼 (84 2 1% )。结论　LASIK能有效地治疗中高度远视 ,且有良好的预测性及安全性。