智慧型光斑LASIK治疗近视临床分析

目的:探讨智慧型光斑LASIK治疗近视或近视散光可预测性、稳定性、有效性及术后残留屈光度危险因素分析。方法:回顾性分析2008-10/2009-10在我中心行LASIK病例,术前最佳矫正视力(BCVA)≥0.8,随访时间>1mo,球镜<-10.00D纳入统计分析病例,共768例。按激光切削模式及屈光度分组,对术后裸眼视力,术后1,3,6mo;1a残留等效球镜,屈光回退患者术前术后数据行统计学分析。结果:10例BCVA术后未达术前;预测性:术后常规组98.0%SE<0.50D,99.2%SE<1.00D;波前组97.4%SE<0.50D,99.3%SE<1.00D;术后残留屈光度,常规组:1mo:-0.01±0.10D;3mo:-0.02±0.20D;6mo:-0.07±0·31D;1a:-0.15±0.38D。波前组:1mo:-0.01±0.08D;3mo:-0.01±0.09D;6mo:-0.03±0.15D;1a:-0.08±0.19D;视力改变,常规组:0±0.05,波前组:0.01±0.04。23例术后残留屈光度危险因素分析,术后残留球镜与年龄,术前球镜有关,术后球镜=1.355-0.034年龄+0.142术前球镜;术后残留柱镜与术前柱镜,术前中央角膜厚度有关,术后柱镜=3.489+0.238术前柱镜-0.007术前中央角膜厚度。结论:智慧型光斑LASIK预测性,稳定性,有效性均较好,波前像差引导LASIK在预测性及有效性方面更优,两种术式均有较好的稳定性;术后残留球镜危险因素:年龄、术前球镜,术后残留柱镜危险因素:术前柱镜、术前中央角膜厚度。     

准分子激光角膜原位磨镶术矫治高度近视准分子激光屈光性角膜切削术后屈光回退的临床观察

目的评价准分子激光角膜原位磨镶术（LASIK）矫治高度近视准分子激光屈光性角膜切削术（PRK）后屈光回退的疗效。方法回顾性临床研究。对PRK术后2年以上、屈光回退且屈光度稳定的患者8例14眼行LASIK,对LASIK术后术眼进行评价。患眼PRK术前屈光度为-6.25～-12.50 D,PRK术后屈光度为-1.50～-6.25 D。随访观察LASIK矫正1年后术眼的裸眼视力、最佳矫正视力、屈光度、上皮下雾状混浊（haze）形成和角膜厚度的变化。结果所有患眼术后主观症状较轻。LASIK术后1年平均球镜度数为（-0.62±0.94）D。LASIK术后0.5≤裸眼视力〈0.8者4眼,≥0.8者9眼,1眼（7.1%）最佳矫正视力下降2行。4眼术后出现不同程度的haze,包括2级haze 3眼、3级haze 1眼。应用氟米龙滴眼液1个月后,haze及屈光回退减轻;术后1年,1级haze 2眼,2级haze 2眼,3级haze 1眼。LASIK术前角膜厚度为（467±38）μm,术后为（422±21）μm。结论高度近视PRK术后屈光回退行LASIK矫治是一种可行的方法,但少数患者术后可出现haze,仍需治疗。     

PRK和LASIK治疗近视术后角膜地形图分析

目的分析准分子激光屈光性角膜切削术(photorefractive keratectomy,PRK)和准分子激光原位角膜磨镶术(laserin situ keratomileusis,LASIK)治疗近视术后角膜表面形态.方法对术前屈光度为(-3.00～-10.00)D,平均为(-608±1.21)D的患者76例(150眼)行PRK,75例(150眼)行LASIK,分为PRK和LASIK组.术后1、3、6、12个月行角膜地形图检查.结果角膜地形图形态分为平滑型、半圆型、钥匙孔型、肾型、中央岛型和不规则型.LASIK术后未见中央岛型.LASIK组平滑型明显多于PRK组(P≤0.01).两组各种类型角膜地形图所占比例的差异均有非常显著意义(P≤0 001).术后3个月,两组中各种类型所占比例基本稳定.两组角膜地形图均有逐渐变平滑的趋势.中央岛型和不规则型术后UCVA较术前BCVA下降≥2行的比例最高,平滑型最低.PRK组术后UCVA较术前BCVA下降≥2行的比例高于LASIK组(P≤0.05).结论LASIK术后角膜地形图形态较PRK规则.LASIK术后视力恢复较PRK好.     

LASIK治疗RK后屈光欠矫临床观察

目的评价准分子激光原位角膜磨削术(LASIK)治疗放射状角膜切开术(RK)术后屈光欠矫的临床效果。方法对34眼(21人)RK术后残余近视、散光患者行LASIK治疗,年龄20～38岁,残余球镜屈光度-2.00～-13.00D(-5.87D±2.65D),柱镜屈光度0～3.5D(-1.15D±0.94D)。结果术后6个月屈光稳定,裸眼视力≥术前矫正视力32眼(94.12％),所有眼屈光度在术前预期矫正±1.00D以内。1眼最佳矫正视力较术前下降l行。无角膜瓣移位、脱失、角膜混浊等并发症。结论LASIK治疗RK后屈光欠矫安全、有效、预测性好。     

LASIK术后视网膜脱离

目的 :探讨准分子激光原位角膜磨镶术 (LaserinsituKeratomileusis ,LASIK )后视网膜脱离的临床特点及治疗方法。方法 :对我院 1996年 7月至 1998年 10月的 2 836例 (5 60 9只眼 )LASIK手术后发生视网膜脱离的 6例 (6只眼 ) (A组 )和1998年 11月至 2 0 0 0年 12月行LASIK手术 2 160例 (4165只眼 )无视网膜脱离发生 (B组 )进行回顾性分析。结果 :A组 6只眼LASIK术前平均屈光度为 -8 375± 2 761D (-5 2 5～ -12 2 5D)视网膜脱离发生在LASIK术后平均 12±6 2 3个月 (3～ 2 0个月 ) ;5只眼进行巩膜环扎加外加压术 ,1只眼进行了玻璃体切除、 18%C2 F6 气体填充联合巩膜环扎术 ,6眼均一次手术成功 ,视网膜复位。LASIK术后、视网膜脱离前平均最佳矫正视力为 0 97± 0 2 3(0 6～ 1 2 ) ,脱离经治疗后平均最佳矫正视力为 0 5 8± 0 31(0 1～ 1 0 ) ,LASIK术后视网膜脱离前平均屈光度为 -0 875± 0 48D (-0 2 5～ -1 5 0D) ,治疗后为 -3 0 4± 0 62D (-2 0 0～ -3 75D)。结论 :LASIK术后视网膜脱离与近视眼本身易发生视网膜脱离有关 ,与LASIK手术无直接关系 ,常规巩膜环扎术及玻璃体切割术能有效治疗LASIK术后视网膜脱离但能增加近视度数 ,所以行LASIK手术前应使用间接眼底镜及三面镜详细检查眼底     

LASIK术后裂孔性视网膜脱离的临床分析

目的探讨准分子激光原位角膜磨镶术(Laser-assisted in situ keratomileusis,LASIK)后裂孔性视网膜脱离(Rhegmatogenous retinal detachment,RRD)的发生率、临床特点、手术方法及结果。方法回顾分析18342眼(9598例)行LASIK术后的情况,平均屈光度为-7.21D(-0.75D～-15.00D),所有患者均无角膜病等病史,术前检查包括详细的散瞳眼底检查。LASIK术后,患者平均随诊20m(4～27)月,对发生RRD的6眼之临床资料进行考察。结果本组LASIK术后RRD的发生率为0.327‰;RRD眼术前平均屈光度-9.33D(-6.25～-14.00)D,均无视网膜光凝史;RRD发生时间为术后9.25月(2～18)月;所有RRD均为自发性,经手术治疗后随诊9.3m(3～18)m,均一次复位成功(100%)。结论LASIK术后RRD的发生率低;LASIK手术和高度近视眼发生RRD间无确切的因果关联;LASIK术前应该充分注意眼底可能导致RD的病变并及时处理。     

Verisyse有晶状体眼人工晶状体植入和准分子激光原位角膜磨镶术术后视觉质量的临床研究

目的研究Verisyse有晶状体眼人工晶状体（phakic intraoeular lens，PIOL）植入和准分子激光原位角膜磨镶术（laser in situ keratomileusis．LASIK）矫正高度近视术后的视觉质量。方法收集两组高度近视患者，一组15例（26眼），近视屈光度数为-8．25～-21．00D，行有晶状体眼虹膜固定型人工晶状体（Verisyse）植入矫正；一组15例（27眼），近视屈光度数为-9．00- -16．00D，行LASIK矫正。术前行常规检查，包括视力、验光、裂隙灯、眼底等，术后1d行裂隙灯检查，术后1周测裸眼视力并行裂隙灯检查,术后3个月查视力、验光以及iTrace综合仪测量高阶像差。结果PIOL组和LASIK组有效性指数平均值分别为105.73±27.60和92.5±24.79，PIOL组高于LASIK组，但差异无统计学意义。PIOL组和LASIK组安全性指数平均值分别为121．28±32.78和105.32±32.06，PIOL组高于LASIK组，但差异无统计学意义。术后3个月,屈光度数在±1.0D范围内者PIOL组和LASIK组分别占80.8％和92.6％。术后3个月，高阶像差在4mm瞳孔下彗差（RMS-COMA）、球差（RMS-SPHERICAL）、三阶像差（RMS3）差异均有统计学意义,PIOL术后彗差比LASIK术后大,球差比LASIK术后小,但两者术后的高阶像差在4mm瞳孔下无明显差异。结论对高度和超高度近视，Vefisyse PIOL植入和LASIK均能达到预期的矫正效果，两组安全性和有效性相当、在术后3个月时，PIOL的各项视觉与屈光参数——最佳矫正视力、裸眼视力等与LASIK的效果无明显差异，甚至有些效果好于LASIK。     

Q值引导LASIK术后对比敏感度的变化

目的:对比Q值引导的LASIK与常规LASIK治疗近视术后术眼对比敏感度的变化差异。方法:选择27例近视度数在-2.50～-9.25D,散光度<-2.00D,无屈光参差的患者做LASIK,每名患者随机选择1眼行Q值引导LASIK(F-CAT组),另眼行常规LASIK(对照组)。Q引导值取术眼角膜Q20的平均值加上-0.5。术后随访1mo,比较F-CAT组和对照组的对比敏感度(contrast sensitivity,CS)的差异。结果:分别比较两组术后UCVA和残余的度数均无统计学差异。F-CAT组Q20的增加量比对照组增加量减少(P<0.05),并且术后球差增加量<对照眼(P<0.05)。两组术后各空间频率CS均无降低(P>0.05)。术后1mo,F-CAT组Q值引导眼在3c/d时对比敏感度高于对照组(P<0.05)。结论:用Q值引导的LASIK矫正近视,在提高术后CS方面比常规LASIK有优势。     

准分子激光原位角膜磨削术矫正近视术后2年疗效分析

目的　评价准分子激光原位角膜磨削术 (LASIK)治疗近视 2年的疗效。方法　 98只眼 ,近视范围 -4 0 0～-2 0 5D ,散光≤ -5 0 0D ,用Keracor 116型准分子激光治疗。结果　开始绝大部分呈过矫 ,渐向近视回退 ,6个月后基本稳定。术后 2年时 ,>-15 0 0D ,-10 0 0～ -15 0 0D ,<-10 0 0D 3组的屈光度在± 0 5D之内分别为 5 0 % ,5 2 % ,72 % ;在± 1D之内分别为 6 3 % ,6 6 % ,81%。最佳矫正视力下降不超过 2行。≥ -10 0 0D组和 <-10 0 0D组 ,术后裸眼视力≥ 0 5分别占 77% ,91% ;≥ 1 0分别占 42 % ,70 %。结论　LASIK治疗近视效果稳定 ,手术安全 ,可作为中高度近视的首选术式。     

双眼同时LASIK矫正近视性屈光参差

目的 对准分子激光原位角膜磨镶术（laser in situ keratomileusis,LASIK）矫正近视性屈光参差的疗效进行分析。方法 采用SCMD公司的可调式气动微型角膜刀和Coherent公司的Schwind Keratom-Ⅲ型准分子激光治疗仪,对两眼等效球镜度差≥-2.50D的近视性屈光参差48例,进行LASIK手术前后平均屈光度、屈光参差度数、最佳矫正视力和裸眼视力的评价。LASIK后随访6个月以上,应用标准对数视力表作视力检查,采取5分记录法。结果 术前平均等球镜度较高眼-12.66D,术后减少为-0.70D;对侧眼为-8.42D,术后减少为-0.37D。术前两眼屈光参差平均为-4.24D,术后减少为-0.26D。96眼中最佳矫正视力（BCVA）术后保持不变的52眼（54.2%）,提高1行以上的23眼（24.0%）,提高2行以上的14眼（14.6%）;有6眼减少1行（6.3%）,有1眼减少4行（1.0%）;有42眼（43.8%）术后BCVA为5.0。平均裸眼视力（NCVA）提高0.92,术后NCVA≥4.7的68眼（70.8%）。结论 LASIK治疗近视性屈光参差不仅能提高患者的最佳矫正视力和裸眼视力,解除患者对眼镜或角膜接触不能耐受的痛苦,而且对于恢复其双眼单视功能有积极意义。     

Thygeson's superficial punctate keratitis recurrence after laser in situ keratomileusis

PURPOSE: To report a case of recurrent Thygeson's superficial punctate keratitis (SPK) in a patient submitted to photorefractive keratectomy (PRK) in one eye and laser in situ keratomileusis (LASIK) in the fellow eye. DESIGN: Observational case report. METHODS: A 32-year-old woman was diagnosed with Thygeson's SPK 5 years before undergoing PRK on the right eye and LASIK on the left eye to correct -3.00 + 1.50 x 20 and -3.75 sph, respectively. RESULTS: The patient presented with recurrence of Thygeson's SPK in the left eye 10 months after the LASIK procedure and no recurrence on the right eye, which was treated with PRK. CONCLUSIONS: This case report suggests that PRK may be a better option than LASIK in patients with ocular history of Thygeson's SPK. However, no strong conclusion can be established until further studies confirm the hypothesis of a lower recurrence rate of Thygeson's SPK following PRK compared with LASIK.     

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.     

Unilateral corneal ectasia after laser in situ keratomileusis in a patient with uncomplicated photorefractive keratectomy in the fellow eye

We report a patient treated for low myopia with laser in situ keratomileusis (LASIK) in one eye and photorefractive keratectomy (PRK) in the fellow eye. Corneal ectasia developed in the LASIK-treated eye. Preoperative corneal pachymetry, topography, and attempted correction were similar in both eyes. In patients whose corneas may be predisposed to instability, PRK may be a safer alternative procedure than LASIK.     

The safety and efficacy of photorefractive keratectomy after laser in situ keratomileusis

PURPOSE: To determine the safety and efficacy of performing photorefractive keratectomy (PRK) in corneas previously treated with laser in situ keratomileusis (LASIK) surgery. METHODS: Fifteen eyes of 14 patients who had initially received LASIK for the treatment of myopia and compound myopic astigmatism were evaluated. Variables included existence of and/or type of flap complication associated with the original LASIK procedure, refractions before and after (3 and 6 months) PRK, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and the development of complications after PRK such as haze, scarring, double vision, or ghosting. RESULTS: All 15 eyes were available for analysis at 6 months. Eleven eyes had experienced flap complications during the initial LASIK procedure and 4 eyes had experienced complications in the LASIK postoperative period. Characteristics prior to performing PRK included 11 myopic and 4 hyperopic eyes. By 6 months after PRK treatment, 87% of eyes had UCVA > or = 20/40, 53% had > or = 20/25, and 40% had > or = 20/20. All eyes had BSCVA of > or = 20/30, with 73% being > or = 20/20. No eye had lost 2 lines of BSCVA and only 1 eye lost 1 line of BSCVA. Sixty percent of eyes were within 1.0 diopters (D) of emmetropia, and 40% were within 0.5 D of emmetropia. A trend towards undercorrection and surgical induction of astigmatism as confirmed by vector analysis was noted. No eye developed significant haze or scarring. CONCLUSIONS: Photorefractive keratectomy may be a safe procedure to perform in corneas previously treated with LASIK surgery. Results show good reduction of refractive error and improvement of UCVA and BSCVA. A significant undercorrection of astigmatism was attributed to surgically induced astigmatism. Further studies are necessary to determine the long-term safety and stability of outcomes.     

Photorefractive keratectomy with mitomycin C versus LASIK in custom surgeries for myopia: a bilateral prospective randomized clinical trial

PURPOSE: To compare photorefractive keratectomy (PRK) with prophylactic use of mitomycin C (MMC) and LASIK in custom surgeries for myopic astigmatism. METHODS: Eighty-eight eyes of 44 patients with a minimum estimated ablation depth of 50 microm were randomized to receive PRK with MMC 0.002% for 1 minute in one eye and LASIK in the fellow eye. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), cycloplegic refraction, slit-lamp microscopy, contrast sensitivity, specular microscopy, aberrometry, and a subjective questionnaire were evaluated. Forty-two patients completed 6-month follow-up. RESULTS: Mean spherical equivalent refraction error before surgery and mean ablation depth were -3.99+/-1.20 diopters (D) and 73.09+/-14.55 microm in LASIK eyes, and -3.85+/-1.12 D and 70.7+/-14.07 microm in PRK with MMC eyes, respectively. Uncorrected visual acuity was significantly better in PRK with MMC eyes 3 months (P=.04) and 6 months (P=.01) after surgery. Best spectacle-corrected visual acuity and spherical equivalent refraction did not differ significantly in the groups during follow-up (P>.05). Significant haze was not observed in any PRK with MMC eye. Mean higher order aberration was lower in PRK with MMC eyes postoperatively compared with LASIK eyes (P=.01). Better contrast sensitivity was observed in PRK with MMC eyes than LASIK eyes (P<.05). The endothelial cell count did not differ significantly between groups (P=.65). In terms of visual satisfaction, PRK with MMC eyes were better rated. CONCLUSIONS: Photorefractive keratectomy with MMC appears to be more effective than LASIK in custom surgery for moderate myopia. During 6-month follow-up, no toxic effects of MMC were evident. Long-term follow-up is necessary to attest its safety.     

Wound healing in rabbit corneas after photorefractive keratectomy and laser in situ keratomileusis

PURPOSE: To compare the wound-healing process in the rabbit cornea after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) with the same refractive correction. SETTING: Department of Ophthalmology, Wakayama Medical University, Wakayama, Japan. METHODS: Adult albino rabbits (N = 24) were used. One eye of each animal had PRK or LASIK with the same refractive correction. Each animal was killed after an interval of up to 6 months. The expression pattern of corneal stromal injury-related molecules with the 2 treatments were compared. Paraffin sections of the cornea were processed immunohistochemically for alpha-smooth muscle actin (alpha-SMA), collagen type IV [alpha1(IV)](2),alpha2(IV), and heat shock protein (HSP) 47 as well as other HSPs. Sections were also examined after hematoxylin and eosin or periodic acid-Schiff staining. RESULTS: Hematoxylin and eosin staining showed the central epithelium to be thick in PRK-treated corneas. The thick epithelium was restricted to the area around the corneal flap edge adhesion in LASIK-treated corneas at 3 months. Periodic acid-Schiff staining showed an absence of or interruption in the epithelial basement membrane in PRK-treated corneas for up to 6 months. Heat shock protein 47 was detected in keratocytes on day 3 but not after that in PRK-treated corneas. There was no difference in the expression of other HSPs. Alpha-smooth muscle actin was expressed in keratocytes repopulated in the central anterior cornea of PRK-treated corneas at 28 days. Keratocytes with immunoreactivity for these 2 proteins were not seen in LASIK-treated corneas. Collagen IV [alpha1(IV)](2),alpha2(IV) was not detected in either group of corneas. The central epithelium became transiently thicker in PRK-treated corneas. CONCLUSION: Keratocyte responses to laser stromal ablation were more marked in corneas treated with PRK than in those treated with LASIK.     

PRK and LASIK--their potential risk of cataractogenesis: lipid peroxidation changes in the aqueous humor and crystalline lens of rabbits

PURPOSE: There are insufficient data on the possible cataractogenic side effects of excimer laser corneal surgery. Higher malondialdehyde (MDA) levels could indicate oxidative events related to the cataractogenic process. We therefore examined MDA levels after refractive laser surgery. METHODS: Six white Russian rabbits received laser in situ keratomileusis (LASIK) (Schwind keratome) in the right eye and a 250-microm-deep microkeratome cut (Schwind microkeratome) in the left eye. Six others underwent photorefractive keratectomy (PRK) in the right eye; the left eye remained untreated. The 180 mJ/cm2 fluence applied at a rate of 10 Hz with an optical zone diameter of 5 mm in all rabbits (438 pulses) resulted in an estimated central photoablation depth of 116 microm. Two weeks later, lenses and aqueous were taken immediately after death. MDA was detected in aqueous and homogenate of lenses after reacting with thiobarbituric acid (TBA). MDA bound to TBA (MDA-TBA) was specifically analyzed by high-performance liquid chromatography (HPLC) (excitation, 525 nm; emission, 551 nm) using phosphate-buffered methanol as eluent. RESULTS: No significant laser-induced MDA alteration was found in either the aqueous or the lens. The microkeratome group, however, had two to three times higher MDA levels in the lenses than the control group (p = 0.12) or the PRK (p = 0.03) group. CONCLUSION: Elevation of MDA in the lens of the microkeratome group indicates that LASIK, but not PRK, may be a risk factor in cataractogenesis. The increased MDA levels in the LASIK group are probably caused by the microkeratome incision rather than the secondary radiation of the excimer laser. Postoperative inflammation may explain the surprising results.     

PRK术中应用低浓度丝裂霉素治疗低中度近视

目的：评价PRK术中应用低浓度(0.02g/L)丝裂霉素(PRK+LMMC)30s治疗低、中度近视眼术后疗效。

方法：选取我院接受屈光性角膜切削术(PRK)治疗的30例57眼低、中度近视患者,术中应用0.02g/L的MMC 30s,将术后6mo的随访结果与同期接受准分子激光原位角膜磨镶术(LASIK)治疗的疗效进行比较。

结果：术后6mo,PRK+LMMC治疗组等值球镜屈光度0.210D、等值球镜屈光度在±0.50D范围内的发生率71.9%、裸眼视力≥1.0者77.2%,平均最佳矫正视力1.19±0.18; LASIK治疗组等值球镜屈光度-0.017D,等值球镜屈光度在±0.50D范围内的发生率70.1%,裸眼视力≥1.0者72.7%,平均最佳矫正视力1.16±0.19,两组比较差异均无统计学意义(P>0.05)。术后6mo,PRK+LMMC治疗组没有出现超过1级的haze,所有眼最佳矫正视力均好于术前。LASIK治疗组1眼因角膜上皮植入使最佳矫正视力较术前下降3行,其余眼最佳矫正视力均好于术前。

结论：PRK术中应用0.02g/L的MMC 30s治疗低、中度近视同LASIK具有同样的视力结果,避免了LASIK瓣的并发症,不失为一个可取的手术程序。     

Laser in situ keratomileusis and photorefractive keratectomy for residual refractive error after phakic intraocular lens implantation

PURPOSE: To determine the visual and refractive outcome of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) in eyes with prior posterior chamber phakic intraocular lens implantation for high myopia. METHODS: We studied a series of 37 consecutive eyes of 31 patients who underwent LASIK or PRK for residual refractive error following collamer posterior chamber intraocular lens (IOL) (Staar Surgical Implantable Contact Lens) implantation into a phakic eye. Twenty-eight eyes had LASIK and nine eyes had PRK. Mean follow-up was 8.1 +/- 4.7 months after laser ablation (range, 3 to 18 mo). RESULTS: The preoperative mean spherical equivalent refraction prior to phakic posterior chamber IOL implantation was -17.74 +/- 4.89 D (range, -9.75 to -28.00 D). Following phakic IOL implantation and prior to LASIK or PRK, mean spherical equivalent refraction was -2.56 +/- 2.34 D (range, -0.25 to -8.75 D). One month following LASIK or PRK, mean spherical equivalent refraction was -0.24 +/- 0.52 D (range, -1.50 to +1.50 D), 3 months following LASIK or PRK, mean spherical equivalent refraction was -0.19 +/- 0.50 D (range, -1.50 to +1.00 D). The refraction was within +/-1.00 D of emmetropia in 36 eyes (97.2%) and within +/-0.50 D in 31 eyes (83.7%). Three eyes developed anterior subcapsular opacities several weeks after laser ablation, one eye developed macular hemorrhage 4 weeks after laser ablation, and one eye had corticosteroid induced ocular hypertension. CONCLUSIONS: LASIK or PRK can be used to treat the residual refractive error following posterior chamber phakic IOL implantation.     

Ablation centration after active eye-tracker-assisted photorefractive keratectomy and laser in situ keratomileusis

PURPOSE: To evaluate the ablation centration after active eye-tracker-assisted photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) and to investigate the effect of surgery, patient, and surgeon on the centration. SETTING: Department of Ophthalmology, China Medical College Hospital, Taichung, Taiwan, Republic of China. METHODS: This retrospective study comprised 177 eyes of 101 patients: 16 eyes had PRK and 161, LASIK. All laser treatments were performed with the aid of an eye tracker. The amount of decentration was analyzed by corneal topography. The factors influencing centration were divided into surgery related (PRK/LASIK), patient related (low/high myopia and effect of learning), and surgeon related (learning curve). RESULTS: The mean decentration was 0.33 mm in PRK eyes and 0.35 mm in LASIK eyes. For the surgery-related factor, there was no significant difference between the PRK and LASIK eyes. For the patient-related factors, centration was better in the second eye (effect of learning) and decentration was more severe in eyes with high myopia (low/high myopia). For the surgeon-related factor, there was no significant difference between eyes that had the first 50 LASIK procedures and those that had the last 50 procedures. CONCLUSIONS: An eye tracker, which makes the laser beam follow the eye's movements, helps to avoid severe decentration. This study showed, however, that an active eye-tracking system alone cannot ensure good centration. Patient cooperation and fixation are important.