PRK、LASIK术后非接触眼压测量值的准确性

目的 :评估准分子激光屈光性角膜切削术 (PRK)和准分子激光原位角膜磨镶术 (LASIK)后非接触眼压 (NCT)测量值的准确性。方法 :对 5 5例 (10 9只眼 )行PRK和 5 7例(113只眼 )行LASIK的近视患者进行回顾性分析 ,手术前、后采用非接触眼压计测量患者的眼压 ,并测量角膜厚度和角膜曲率 ,进行统计学分析。术后随访时间 >1年 ,停用激素至少半年以上。结果 :PRK和LASIK术后NCT测量值都低于术前 ,分别下降 (3.6 7± 1.6 5 )mmHg和 (5 .11± 1.5 1)mmHg ,差异有非常显著意义 (P <0 .0 0 1)。PRK和LASIK术前眼压测量值与角膜厚度均呈高度正相关 (P <0 .0 0 1) ;术后眼压测量值的降低与角膜厚度的减少高度正相关 (P <0 .0 5 ) ,其回归方程分别为 ^Y(手术前、后眼压差 ,mmHg) =1.36 1+0 .0 38X(手术前、后角膜厚度差 ,μm)和 ^Y =1.95 4 +0 .0 4 0X ;眼压测量下降值和角膜曲率的降低无关。结论 :PRK和LASIK术后眼压测量值均低于术前 ,角膜厚度是导致手术后眼压测量值减少的主要因素 ,且眼压测量值随角膜厚度的减少而下降。在临床工作中 ,应避免术后类固醇性青光眼因眼压测量值的下降而被漏诊。     

准分子激光原位角膜磨镶术后眼压与角膜厚度及角膜屈光力的相关性

目的 :研究准分子激光原位角膜磨镶术后非接触式眼压计 (NCT)测量值的改变情况 ,以及其与术中角膜切削厚度及术后角膜屈光力改变值之间的相关性。方法 :随机选择接受LASIK手术的近视患者 1 77例 337眼 ,对术前、术后 1个月NCT测量值及角膜屈光力分别作配对t检验 ,并对术后眼压改变值与术中角膜切削厚度及术后角膜屈光力改变值分别作相关性分析 ,计算回归方程。结果 :①术后 1个月NCT测量值、角膜屈光力明显低于术前 ,差异有显著性 (P <0 .0 0 0 1 )。②术后眼压下降值 (Y)与术中角膜切削厚度 (X_1)呈正相关 (r =0 .2 4 1 ,P <0 .0 0 0 1 ,Y =2 .571 + 0 .0 2 5×X1)。③术后眼压下降值 (Y)与角膜屈光力下降值 (X2 )呈正相关(r =0 .2 6 1 ,P <0 .0 0 0 1 ,Y =2 .94 7+ 0 .2 85×X2 )。结论 :LASIK术后NCT测量值低于实际值 ,眼压下降与角膜厚度变薄及角膜屈光力下降有关。为避免LASIK术后青光眼的漏诊 ,应对NCT测量值进行矫正。     

动态轮廓眼压计与非接触式眼压计的比较

目的探讨中央角膜厚度和角膜曲率对轮廓动态眼压计以及非接触式眼压计眼压测量结果的影响。方法接受准分子激光原位角膜磨镶术(LASIK)的近视患者27例(54只眼),分别于术前和术后第4周使用非接触式眼压计(NCT)和动态轮廓眼压计(DCT)进行眼压测量。多元线性相关分析研究NCT、DCT测量值和角膜曲率及角膜中央厚度(CCT)之间的相关性。结果LASIK术后NCT测量值降低,而DCT测量值和术前比较差异则无统计学意义。角膜曲率、CCT和NCT读数呈线性相关,而与DCT读数无关。结论DCT测量眼压不受角膜曲率和中央角膜厚度影响,因此更适合于正常眼以及曾经接受角膜屈光手术眼的眼压测量。     

LASIK术眼角膜厚度与眼压及屈光度相关性研究

目的研究接受LASIK手术的近视人群的角膜厚度与屈光度及眼压高低之间的关系。方法选择接受LASIK手术的近视连续病例136例268眼手术前后进行屈光检查、角膜地形图检查及非接触眼压测量,记录角膜激光切削厚度,对获得的数据进行统计学分析。结果该人群中央角膜厚度为(541.47±33.61)μm。眼压值为(15.35±2.73)mmHg(1 mmHg=0.133kPa),角膜激光切削厚度为(96.15±2.71)μm,术后1周眼压测量较术前降低(5.75±0.22)mmHg。统计结果:1、中央角膜厚度与眼压呈正的直线相关(r=0.4415,P<0.001),回归方程:Y(中央角膜厚度,μm)=456.76 5.52X(眼压,mmHg)。2、术后眼压值减低与角膜激光切削厚度呈正的直线相关(r=0.346,P<0.001)。回归方程:Y(眼压降低值,mmHg)=3.028 0.0283 X(角膜激光切削厚度,μm)。结论近视眼中央角膜厚度与眼压以及角膜激光切削厚度与术后眼压降低值呈正的直线相关关系。     

高度近视LASIK术后眼压值的变化

目的 探讨LASIK治疗高度近视术后眼压变化与角膜切削量的关系.方法 427例高度近视患者按屈光度分成A组(-6.0D至-10.00D)和B组(-10.0至-21.0D),施行LASIK术前后用非接触眼压计(NCT)测量眼压,并分析其与角膜切削量的关系.结果 两组眼压术后明显下降.A组为12.21±3.22 mmHg;B组为10.48±2.76mmHg(P＜0.001).角膜切削量占术前角膜中央厚度A组为12.4～18.9 %;B组为19.0～34.7 %(P＜0.01).结论 LASIK治疗高度近视术后NCT眼压值下降与角膜中央厚度变薄和抗压强度减弱有关.     

Diaton眼压计测量准分子激光原位角膜磨镶术后眼压

目的:通过与非接触式眼压计(non-contact tonometer,NCT)的比较,评价Diaton眼压计(DT)在准分子激光原位角膜磨镶术(laser in situkeratomileusis,LASIK)前后眼压测量中的应用价值。方法:在LASIK术前及术后1mo,分别使用NCT和DT测量患者眼压,使用SPSS13.0统计软件对所得结果进行统计学分析。结果:术后1mo时,NCT眼压测量值较术前下降(5.76±2.31)mmHg,DT眼压测量值则无显著差异(t=0.70,P=0.487);NCT与DT读数测量值差值与术中切削量呈正相关,与术后中央角膜厚度呈负相关。结论:Diaton测量眼压不受角膜厚度的影响,因此更适用于LASIK术后患者的眼压测量。     

角膜厚度和角膜曲率对LASIK术后眼压测量值的影响

目的探讨准分子激光原位角膜磨镶术（LASIK）后角膜厚度和角膜曲率对眼压测量值的影响。方法150例（285眼）近视行LASIK并随访1年，对手术前后的角膜厚度、角膜曲率及眼压进行统计学分析。结果LASIK术后3、6、12个月的角膜厚度、角膜曲率及眼压测量值均较术前明显下降（P〈0．01）。术前及术后3、6、12个月的眼压测量值与角膜厚度、角膜曲率呈正相关。结论LASIK术后眼压测量值低于术前，眼压测量值与角膜厚度和角膜曲率均呈正相关，角膜厚度和角膜曲率是眼压测量值的影响因素。     

PRK和LASIK对非接触眼压计测量值的影响

目的 :研究PRK和LASIK手术前后非接触眼压计 (NCT)测量值的改变及其与切削深度的相关性。方法 :对不同屈光度患者 673只眼 (PRK 3 2 5眼、LASIK 3 48眼 )术前、术后 3、 6、 12个月的眼压、角膜厚度及切削深度 ,应用统计学方法检验 ,并对眼压改变值与术中角膜切削深度作相关性分析。结果 :术后角膜厚度随屈光度增加而变薄 ,LASIK组大于PRK组 :NCT测量值均明显低于术前 ,差异有显著性 (P <0 0 5 ) ,但LASIK组与PRK组差异无显著性。术后一年眼压下降值与术中角膜切削深度存在统计学上的相关性 :PRK组r =0 2 85 6,LASIK组r =0 2 5 3 8。结论 :PRK和LASIK术后NCT测量结果下降 ,角膜变薄是其主要原因。     

PRK术后2年眼压临床分析

目的;探讨PRK术后2年的眼压变化情况及其相关影响因素。方法：应用非接触式眼压计（NCT）对接受PRK手术的121只术眼进行了2年的跟踪观察,术前按术前屈光度分为3组,I组：－6．0D以下;Ⅱ组：－6．25D－－9．0D;Ⅲ组：－9．25D以上。并对术眼不同阶段NCT测量值进行多元分析。结果：各PRK术后NCT眼压测量值均较术前明显降低,具有显著性差异;并且切削厚度与眼压差存在显著相关性;术后眼压发生有规律性变化与术后常规应用激素类药物有关。结论：PRK后NCT眼压测量值低于术前并发生有规律性变化,术后眼压与角膜厚度、角膜切削厚度、角膜前表面曲率改变及拂炎眼液的用药时间、次数有关,并且测量值受NCT工作原理的影响。     

准分子激光角膜切削术后2年眼压临床分析

目的：探讨PRK术后2年的眼压变化情况其相关影响因素。方法：应用非接触式眼压计（NCT）对接受PRK手术的121只术眼进行了2年的跟踪观察。术眼按术前屈光度分为3组,Ⅰ组：－6．00D以下;Ⅱ组：－6．25D－－9．00D;Ⅲ组：－9．25D以上,并对术眼不同阶段NC测量值进行多元分析。结果：各组PRK术后NCT眼压测量值均较术前明显降低,具有显著性差异,并且切削厚度与眼压差存在显著相关性,术后眼压发生有规律性变化与术后常规应用激素类药物有关。结论：PRK后NCT眼压测量值 低于术前并发生有规律性变化,术后眼压与角膜厚度,角膜切削厚度,角膜前表面曲率改变及拂炎眼液的用药时间,次数有关,并且测量值受NCT工作原理的影响。     

影响准分子激光屈光性角膜切削术后眼压的因素

目的分析影响准分子激光屈光性角膜切削术（ｅｘｃｉｍｅｒｌａｓｅｒｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ,ＰＲＫ）术后眼压的因素。方法采用非接触式眼压计（ｎｏｎｃｏｎｔａｃｔｔｏｎｏｍｅｔｒｙ,ＮＣＴ）测量眼压,对ＰＲＫ前、后随访半年以上８６例（１５０只眼）患者眼压差与角膜切削厚度、术前术后角膜曲率差之间进行多元回归分析。结果术前眼压明显高于ＰＲＫ术后１周、３及６个月的眼压,差异有非常显著性（ｔ检验,Ｐ＜０．０１）,与术后１个月时眼压比差异无显著性（Ｐ＞０．０５）。术后１个月时的眼压高于术后其他时间眼压（Ｐ＜０．０１）。ＰＲＫ后眼压降低与角膜厚度减少及角膜前表面曲率的降低有关（ｒ＝０．３６１,Ｐ＜０．０１;ｒ＝０．１８８,Ｐ＜０．０５）,建立二元回归方程如下：Ｙ＝－０．０５９－０．０３８Ｘ１＋０．００９Ｘ２。Ｙ：术前术后眼压差（ｋＰａ）,Ｘ１：术前术后角膜曲率差（Ｄ）,Ｘ２：角膜切削厚度（μｍ）。结论ＰＲＫ后ＮＣＴ测量眼压低于术前,术后眼压与氟甲脱氧泼尼松龙（ｆｌｕｏｒｏｍｅｔｈｏｌｏｎｅ）的用药次数和时间、角膜切削厚度、角膜曲率有关。     

准分子激光屈光性角膜切削术后眼压测量值的变化

目的：探讨影响准分子激光屈光性角膜切削术（laser photorefractive keratectomy,PRK)后眼压测量值变化的因素。方法：对209例（364只眼）近视患者行PRK,手术前、后采用Goldemann压平式眼压计测量患者的眼压,并测量角膜厚度和角膜曲率,进行量角膜厚度和角膜曲率,进行统计学分析。术后随访时间＞1年。结果：术后6个月和12个月术眼的眼压测量值低于术前,差异有非常显著意义（P＜0．001）,术后12个月的眼压测量值低于术后6个月,差异有非常显著意义（P＜0．001）,术后12个月的眼压测量值低于术后6个月,差异有非常显著意义（P＜0．001）。术后眼压测量值的降低与角膜厚度的减少和角膜曲率的降低均呈高度正相关（P＜0．01）,其二元回归方程为Y（手术前、后眼压差,mmHg）＝1．156＋0．022X1（手术前、后角膜厚度差,μm)＋0．052X2（手术前、后角膜曲率差,D）。结论：PRK术后眼压测量值低于术前;角膜厚度和角膜曲率是导致手术前、后眼压测量值变化的因素。     

Effect of corneal curvature and corneal thickness on the assessment of intraocular pressure using noncontact tonometry in patients after myopic LASIK surgery

PURPOSE: To evaluate the effect of corneal curvature and corneal thickness on the assessment of intraocular pressure (IOP) using noncontact tonometry (NCT) in patients after myopic LASIK surgery. METHODS: All patients who had myopic LASIK in a university-based eye clinic between February 2002 and May 2002 were retrospectively analyzed. Preoperative NCT was compared with postoperative NCT, postoperative corneal thickness, and postoperative corneal curvature. RESULTS: The difference between the mean preoperative NCT (15.46 +/- 2.50 mm Hg) and postoperative NCT (6.30 +/- 1.57 mm Hg) was significant (9.16 +/- 1.96 mm Hg, P < 0.010). Preoperative NCT significantly correlated with postoperative NCT (P < 0.001), postoperative corneal thickness (P = 0.006), and postoperative anterior corneal curvature (P < 0.010). CONCLUSIONS: Both corneal thickness and anterior corneal curvature affect IOP assessment in patients with myopic LASIK. Although correction formulas can be used to estimate the actual IOP, alternative methods should be investigated to assess IOP independent of corneal thickness and curvature.     

A correction formula for the real intraocular pressure after LASIK for the correction of myopic astigmatism

PURPOSE: To create a correction formula to determine the real intraocular pressure (IOP) after LASIK considering the altered corneal thickness, corneal curvature, and corneal stability. METHODS: This prospective clinical trial comprised 101 eyes of 59 patients (34 women and 25 men) that underwent LASIK with a mean preoperative spherical equivalent refraction of -6.3 +/- 2.17 diopters (D) (-3.0 to -11.5 D). Mean patient age was 32 +/- 9 years. Preoperatively and 6 months postoperatively, IOP (by Goldmann applanation tonometry), keratometry (by topography), and central corneal thickness (CCT) (by ultrasound pachymetry) were evaluated. These parameters were measured in all patients between 8 and 11 o'clock in the morning. RESULTS: Due to the LASIK procedure, IOP was reduced from 16.5 +/- 2.1 mmHg (range: 12 to 22 mmHg) to 12.9 +/- 1.9 mmHg (range: 8 to 16 mmHg). Multiple linear regression analysis of the IOP values before and after LASIK showed a significant correlation between the measured IOP and CCT and keratometry values (R2=0.631; P<.001). After LASIK, the biomechanical bending strength of the cornea is reduced by the cut so that the measured IOP must be additionally corrected by 0.75 mmHg. An equation containing all three changes is given: IOP (real) = IOP (measured) + (540-CCT)/71 + (43-K-value)/2.7 + 0.75 mmHg. CONCLUSIONS: Intraocular pressure measurements after LASIK for the correction of myopia are inaccurate as a consequence of changes in CCT, corneal curvature, and corneal flap stability. After LASIK, the measured IOP should be corrected to avoid false low IOP applanation readings.     

LASIK对非接触眼压计测量的影响

目的 分析近视眼LASIK手术后用非接触眼压计测量眼压降低的原因.方法 660只眼接受过LASIK手术的近视眼入选本研究.对其术前和术后3月的眼压(IOP)、中央角膜厚度(CCT)和角膜屈光度(CRP)资料用SPSS 13.0做统计学分析.术前和术后的同项计量资料做配对t检验,眼压对中央角膜厚度和角膜屈光度做相关性分析,中度线性相关者(r≥0.4,P<0.001)建立直线回归方程.结果 LASIK术后660只眼IOP平均下降(5.01±2.23)mmHg(t=57.736P=0.000),CCT平均减少(69.4±26.12)μm(t=68.255 P=0.000),CRP平均减少(4.37±1.72)D(t=65.140P=0.000).术前IOP对CRP和CCT的直线回归方程为:Y(IOP)=3.119-0.204X1(CRP)+0.040X2(CCT),R2=0.251,剩余标准差(Sy·x)=2.215.术后IOP对CRP和CCT的回归方程为:Y(IOP)=1.981-0.017X1(CRP)+0.021X2(CCT),R2=0.277,(Sy·x)=1.474.CCT每减少21μm,IOP下降1 mmHg.结论 近视眼LASIK术后NTC测量眼压下降的主要原因是角膜减薄所致.     

Applanation tonometry in "normal" patients and patients after LASIK

BACKGROUND: Until now it was thought that morphological parameters of the eye such as corneal thickness, corneal curvature and axial length do not affect tonometry results. However, the aim of this study was to find out whether there actually is an influence of these parameters on applanation tonometry. PATIENTS AND METHOD: In this prospective study we examined 125 eyes of 125 normal patients with a corneal thickness of 568.8 +/- 43.79 microm, a corneal curvature of 7.72 +/- 0.27 mm and an axial length of 23.62 +/- 2.05 mm. Before performing a phacoemulsification, the anterior chamber was temporarily punctured. With a closed system the intraocular pressure (IOP) was manometrically set at 20, 35 and 50 mmHg using an H (2)O column. The IOP was then measured with a Perkins tonometer. With these patients we compared 102 eyes that had undergone LASIK due to a myopia of 6.3 +/- 2.17 D. Before and 6 months after surgery, IOD, k-values and central corneal thickness of these patients were measured. RESULTS: At all set pressure levels there was a highly significant correlation of measured IOP and corneal thickness. At all set pressure levels the measured IOP significantly depended on corneal thickness (r(2) = 0.78 - 0.83). After LASIK, IOP was reduced from 16.5 +/- 2.1 to 12.9 +/- 1.9 mmHg. There was a significant correlation between IOP and corneal curvature as well as corneal thickness (r(2) = 0.631; P < 0.001). The biomechanical characteristics of the cornea are changed so that the measured IOP has to be corrected by an additional 0.75 mmHg. CONCLUSION: Since corneal thickness does affect Goldmann applanation tonometry we recommend to use the "Dresden Correction Table" (Tab. ) to achieve the real IOP. Pressure measurements after LASIK are inaccurate because of a change in corneal biomechanics, corneal thickness and curvature and they should be corrected as follows: IOP (real) = IOP (measured) + (540 - CCT)/71 + (43 - K-value)/2.7 + 0.75 mmHg.     

LASIK对非接触型眼压计测量眼压的影响

目的：分析准分子激光原位角膜磨镶术（ｌａｓｅｒ ｉｎ ｓｉｔｕ ｋｅｒａｔｏｍｉｌｅｕｓｉｓ,ＬＡＳＩＫ）治疗近视眼术后眼压的影响因素。方法：采用ＬＡＳＩＫ治疗２１４只近视眼。用非接触式眼压计测量术前、术后的眼压。对眼压与术前、术后各因素进行相关分析和多元逐步回归分析。结果：ＬＡＳＩＫ术后１月的眼压明显低于术前,差异具有显著性意义（ｓｔｕｄｅｎｔ ｔ检验,Ｐ〈０．０００１）。ＬＳＡＩＫ术后眼压的降     

角膜中央厚度和曲率对非接触式眼压计测量值的影响

目的研究角膜中央厚度、曲率对非接触式眼压计(NCT)测量值的影响.方法测量PRK或LASIK术前102例(204眼)患者的角膜中央厚度、角膜曲率、眼压,并将测量结果进行相关及回归统计学处理.结果角膜中央厚度与NCT测量值的相关系数r=0.4846,P＜0.001,有高度统计学意义;角膜曲率与NCT测量值的相关系数r=0.0687,P＞0.05,无统计学意义.结论角膜中央厚度与NCT测量值呈正相关,角膜曲率与NCT测量值之间无相关关系.     

Changes in intraocular pressure after laser in situ keratomileusis for myopia,hyperopia, and astigmatism

PURPOSE: Reports have shown that photorefractive keratectomy changes intraocular pressure (IOP) in myopic eyes by changing the thickness and curvature of the cornea. Changes in intraocular pressure after laser in situ keratomileusis (LASIK) for hyperopia led the authors to evaluate IOP after LASIK for various refractive errors. METHODS: The measurement of intraocular pressure with a Goldman applanometer in the central cornea was evaluated before and 3 months after LASIK in 100 eyes of 55 patients with various refractive errors. Corneal thickness (pachymetry) and corneal topography were evaluated. RESULTS: After LASIK, a significant decrease of intraocular pressure was observed in most eyes: mean 11.9 +/- 3.2 mmHg before and 9.8 +/- 2.6 mmHg at 3 months after surgery (P < .001). Mean decrease in IOP was 2.75 +/- 3.3 mmHg (P < .0001) for myopic eyes, 2.28 +/- 2.43 mmHg (P < .001) for hyperopic eyes, and 1.47 +/- 2.5 mmHg (P < .0012) for astigmatic eyes. IOP reduction was not significantly correlated to the amount of ablation (r = 0.05) or to corneal thickness. CONCLUSION: Intraocular pressure decreased in myopic, hyperopic, and astigmatic eyes after LASIK. The reduction was not correlated to the amount of tissue removed or to flattening or steepening of the central cornea.