Ocular hemodynamics following suction cup oculopression

In the study reported here the authors investigated the influence on ocular perfusion pressures of suction-cup oculopression, a procedure which permits oculopression without orbital compression. Patients over 50 years of age were examined before cataract extraction. Ulrich's method of ocular oscillodynamography was used to determine ocular perfusion pressures. A Mikuni and Yoneyama suction-cup dynamometer was applied for suction-cup oculopression. Ocular hypotonia following suction-cup oculopression was adequate and comparable to that achieved by other oculopression methods. After oculopression a significant increase in ocular perfusion pressures (retinal, ciliary, and diastolic) was found. However, ocular blood pressure remains constant after oculopression. Moreover, the increase in ocular perfusion pressure could not be explained by oculocardiac reflexes, because there was no change in systemic arterial blood pressure. It must be assumed, therefore, that the increase in ocular perfusion pressures is caused by a lowering of resistance, i.e., a drop in intraocular pressure.     

角膜切口对白内障手术后散光的影响

目的:观察沿角膜散光陡峭轴方向做透明角膜切口行白内障超声乳化联合人工晶状体植入术后散光和视力的变化。方法:根据IOL-Master检测结果选择角膜最大屈光力轴行3.0mm透明角膜切口做白内障超声乳化术42眼作为观察组(A组),常规颞上(右眼)、鼻上(左眼)3.0mm透明角膜切口白内障超声乳化术68眼作为对照组(B组)。检测术前、术后1d;1wk;1,3mo角膜散光和视力变化。结果:A组术前、术后1d;1wk;1,3mo视力分别为0.2±0.24,0.73±0.37,0.78±0.38,0.94±0.36,0.76±0.13;B组为0.17±0.2,0.82±0.3,0.84±0.2,0.77±0.26,0.8±0.36;差异无统计学意义(P>0.05)。A组术前、术后1d;1wk;1,3mo角膜散光度分别为1.01±0.10D,1.33±0.13D,1.15±0.14D,0.90±0.13D,0.89±0.12D;B组为0.95±0.13D,1.25±0.15D,1.07±0.13D,0.87±0.12D,0.82±0.11D。术后1d;1wk;1mo与术前相比散光度均无统计学意义(P>0.05)。两组术后3mo散光度与术前相比差异有统计学意义(P<0.05)。两组术后3mo裸眼视力≥0.8者分别为21眼(50%)和32眼(47%),两者相比有统计学意义(P<0.05)。结论:沿陡轴透明角膜切口白内障超声乳化联合人工晶状体植入术有助于患者视力提高及减少术后角膜散光。     

小切口超声乳化白内障摘出术后早期角膜屈光状态和中央角膜厚度对视力的影响

背景 小切口超声乳化白内障摘出联合人工晶状体（IOL）植入术是目前白内障治疗的主流术式,其术后视力的恢复受术中、术后并发症以及术后角膜屈光和中央角膜厚度（CCT）改变的影响,其中角膜屈光改变和CCT对视力波动的影响研究较少. 目的 分析小切口超声乳化白内障摘出术后早期患者的视力波动情况及其影响因素.方法 采用系列病例观察研究设计,选取2011年11月至2012年4月于复旦大学附属眼耳鼻喉科医院行2.6mm颞侧透明角膜切口超声乳化白内障摘出联合折叠型IOL植入术的年龄相关性白内障患者25例29眼,白内障手术均由同一医师完成.分别于术前1d,术后1、3、14d及术后1个月、2个月进行电脑验光和主觉验光,检查术眼裸眼视力（UCVA）和最佳矫正视力（BCVA）,用Pentacam眼前节分析系统测量CCT及角膜散光值,结果均采用矢量分析法.对术眼手术前后UCVA、BCVA、等效球镜度（SE）、角膜散光值和CCT进行比较,并分析UCVA和BCVA的影响因素. 结果 术眼术后1d平均UCVA（LogMAR）为0.52±0.06,2个月为0.64±0.07,差异有统计学意义（t=-3.051,P＜0.05）;术眼术后1d平均BCVA（LogMAR）为0.24±0.04,术后2个月为0.13±0.04,差异有统计学意义（t=-3.031,P＜0.05）.术眼术后1、14、60 d的SE差异有统计学意义（F=3.562,P=0.039）,术后1d的SE为（-1.74±0.28）D,术后14 d为（-1.99±0.27）D,差异有统计学意义（t=2.515,P＜0.05）;术眼术后2个月SE为（-1.69±0.24）D,明显低于术后14d的SE值,差异有统计学意义（=-2.987,P＜0.05）.术眼术前J0成分为（0.06±0.06）D,术后1d增加到（0.29±0.08）D,差异有统计学意义（t=-4.625,P＜0.01）;术后14 d J0成分为（0.38±0.07）D,明显高于术后1d值,差异亦有统计学意义（t=-7.858,P＜0.01）;术后2个月J0成分为（0.27±0.07）D,与术后14d比较差异有统计意义（t=-5.649,P＜0.01）.术眼手术前后CCT的差异有统计学意义（F=     

Influence of corneal astigmatism, corneal curvature and meridional differences on corneal hysteresis and corneal resistance factor

Background: This study investigated the influence of corneal astigmatism, corneal curvature and meridional differences on corneal hysteresis (CH) and the corneal resistance factor (CRF) in a group of normal Chinese persons. Methods: Ninety‐five participants were recruited and data from the eye with higher corneal astigmatism were analysed. The anterior corneal curvature was measured by corneal topography. The Goldmann‐correlated intraocular pressure (IOPg), corneal‐compensated intraocular pressure (IOPcc), CH and CRF at different meridians (default horizontal position, 10°, 20° and 30° along the superotemporal and inferonasal meridians) were obtained from an ocular response analyser. The corneal powers at these specific meridians also were calculated. Results: At the default position, the IOPg and CRF had weak correlations with corneal astigmatism, while the IOPcc and CH were not significantly correlated with corneal astigmatism. Both the IOPg and IOPcc were measured significantly higher at the default position. The CH and CRF were lower at the default position but the difference in the CRF from obliquity could not reach statistical significance. The CH was not significantly correlated with the corneal power at all meridians. The CRF correlated with the corneal power only at 30° superotemporal. Conclusion: Corneal astigmatism and head tilt did not have much effect on the measurement of CH and the CRF, both of which were lowest along the horizontal meridian. Clinically, the difference was small. The influence of corneal power on CH and the CRF was minimal.     

Influence of suture regularity on corneal astigmatism after penetrating keratoplasty

Purpose: To investigate whether suture regularity affects corneal astigmatism after keratoplasty. Methods: Twenty‐one patients undergoing penetrating keratoplasty for various corneal diseases were included in the study. The grafts were sutured in place using a single‐running Nylon 10‐0 suture, taking 24 bites. Immediately after surgery, standard calibrated images of the grafted eye were captured and stored. Using a dedicated image analysis programme, stitches and needle points were identified, and a number of suture regularity variables were calculated. Corneal topographic images were obtained before suture removal (12 months after surgery) and 3 months after suture removal (18 months after surgery). Topographic measures of astigmatism [surface regularity (SRI), surface asymmetry index (SAI) and simulated keratometric astigmatism] were calculated and correlated with the computed suture regularity variables. Results: The average stitch length was 3.04 ± 0.28 mm and the distance between the outer needle points was 2.53 ± 0.09 mm. The SRI was 1.26 ± 0.36 and the SAI was 1.59 ± 0.67 after 12 months; these decreased to 1.03 ± 0.48 and 0.92 ± 0.46 after 18 months, respectively. Corneal astigmatism was 6.38 ± 2.99 and 5.87 ± 3.13 dioptres after 12 and 18 months, respectively. Suture regularity did not affect SAI, SRI or corneal astigmatism significantly 12 months after surgery. Eighteen months after surgery (3 months after suture removal), the standard deviation on the original stitch length was found to significantly increase corneal astigmatism. In addition, the size of the counter‐clockwise angle between stitch and graft radian was correlated significantly with a lower SRI. Conclusion: The origin of corneal astigmatism after penetrating keratoplasty is multifaceted. Regular stitch length and stitch advancement on the surface appears to improve the optical quality of the graft after suture removal. Factors such as stitch depth, suture tension and variations in wound construction might also be important predictors of corneal astigmatism after penetrating keratoplasty.     

矫正角膜散光对人工晶状体计算的影响

目的:分析白内障术中矫正角膜散光对人工晶状体度数预测的影响。方法:选择老年性白内障患者35例35眼,行上方切口超声乳化联合PMMA人工晶状体植入术后角膜散光减少,测量术前和术后3mo的角膜曲率及屈光状态。比较SRKⅡ,SRK/T,HolladayⅠ公式在使用术前和术后角膜曲率值计算的绝对预测误差。结果:手术前后平均角膜曲率增加0.30±0.81D,角膜散光度数减少0.70±0.71D,都有统计学意义(P<0.05),两者的相关性为(r=-0.554,P<0.01)。SRKⅡ,SRK/T,HolladayⅠ使用术前角膜曲率计算的绝对预测误差中位数分别为0.85D,0.73D,0.78D,公式间无统计学差异(χ2=4.474,P>0.05);使用术后角膜曲率计算则分别为0.72D,0.54D,0.46D,有统计学差异(χ2=7.758,P<0.05);3代公式在两种计算方法下结果有有统计学差异(Z=-2.208,-2.273,P<0.05)。结论:矫正角膜散光会引起角膜屈光度变化,导致人工晶状体度数的预测误差增大,计算公式尤其是3代公式的准确性下降,有必要对公式进行相应调整优化。     

角膜后表面散光

眼球的散光主要包括角膜散光和眼内散光(即晶状体的散光),角膜散光由角膜前后表面散光组成.角膜后表面散光大小约0.3D,主要为逆规散光(占85％～96.1％).角膜后表面非球面性并非完全由前表面的非球面性决定,它与年龄呈负相关.随年龄增长前表面散光由顺规向逆规漂移明显;后表面散光的趋势则相反,但总体变化很小.同时角膜前后表面半径比与年龄也呈负相关.后表面散光对前表面的补偿作用随年龄增加而减小.因此,对于青年人,后表面散光减小总角膜散光;对于老年人,后表面散光则增加总角膜散光.忽略后表面散光可能会导致总角膜散光的错误估计,测量角膜后表面散光以进一步准确计算角膜总散光是白内障屈光手术临床应用的迫切需求.     

老年性白内障患者中角膜后表面散光对总角膜散光的影响

目的　研究老年性白内障患者模拟角膜曲率计散光和总角膜散光大小及轴位的差异,评价角膜后表面散光对总角膜散光的影响。方法　８０例老年性白内障患者（１０５眼,左４７眼,右５８眼）手术前行Ｐｅｎｔａｃａｍ检查,记录角膜前后表面散光,并对角膜前后表面散光行相关性分析。模拟角膜曲率计散光用屈光指数１．３３７５及角膜前表面曲率半径计算,总角膜散光由前后表面散光在角膜后表面的矢量合计,计算模拟角膜曲率计散光和总角膜散光的矢量差Ｅ→、大小差Ｅ和轴位差Ａ。结果　角膜前表面散光和后表面散光大小间无明显相关性（Ｐ＝０．９８）,后表面散光对前表面散光的平均补偿作用为５．７９％。总角膜散光及模拟角膜曲率计散光大小分别为（１．１２±０．６５）Ｄ和（１．０７±０．６４）Ｄ,差异具有统计学意义（ｔ＝－２．４０,Ｐ＝０．０２）;两者轴位分别为（６７．９３±５６．５０）°和（６８．９０±５９．６８）°,差异无统计学意义（ｔ＝－０．２７,Ｐ＝０．７９）。散光值大小及轴位差异的算术均值分别是（０．０５±０．２３）Ｄ和（－０．５７±１３．０２）°,绝对值是（０．１９±０．１５）Ｄ和（７．００±１０．９７）°。两者散光大小差别大于０．５０Ｄ或轴位差别大于１０°的有３０眼,占２８．５７％。结论　老年性白内障患者忽略角膜后表面测量可能会导致具有临床意义的角膜散光值估计的差异。     

Influence of corneal diameter on surgically induced astigmatism in small-incision cataract surgery

ObjectiveClear corneal incisions (CCI) in cataract surgery create a variable amount of surgically induced astigmatism (SIA). As refractive outcomes become increasingly important, it is necessary to understand factors that impact SIA and refractive surprises. In this study, we evaluate the effect of horizontal corneal diameter (white-to-white, WTW) on SIA in 2.2 mm small-incision cataract surgery.DesignProspective study at an academic-university-based outpatient clinic (Duke Eye Center).ParticipantsWe enrolled adults ≥18 years of age without prior corneal surgery or corneal pathology undergoing cataract surgery with a single surgeon (R.R.V.).MethodsAll surgeries were uncomplicated and performed through a manually constructed, limbal, temporal, or superotemporal 2.2 mm CCI. Enrolled participants received standard-of-care evaluations and postoperative management. SIA was calculated at the first postoperative month using the Jaffe and Clayman vector analysis equation.ResultsWe enrolled 43 subjects (55 eyes) with a mean age of 71 years with WTW corneal diameter values ranging from 11.34 to 12.99 mm obtained from Lenstar® (Haag-Streit Group, Koeniz, Switzerland). Postoperative SIA ranged from 0.072 to 1.6 D (mean 0.47 D, standard deviation 0.33 D). SIA was plotted against WTW and best fit to a linear regression model with a slope of −0.056 and an R² value of 0.006.ConclusionsIn this prospective study, WTW diameter had minimal effects on the SIA in uncomplicated small-incisional cataract surgery through a 2.2 mm temporal or superotemporal CCI with a single surgeon. Our findings suggest that corneal diameter does not play a clinically significant role in this population undergoing small-incisional cataract surgery.     

两种不同长度角膜缘切口对白内障超声乳化术后角膜前后表面散光影响的对比

背景 白内障超声乳化术中切口的不同会引起不同的角膜手术源性散光已经被众多研究所证实,影响因素包括切口的长度、位置和形态等,但关于2.2 mm、3.0mm角膜缘切口白内障超声乳化手术引起的手术源性散光,尤其是引起的角膜后表面散光变化的研究国内外鲜有报道. 目的 对比经2.2 mm、3.0mm角膜缘切口的白内障超声乳化摘出联合人工晶状体(IOL)植入术后引起的角膜前表面、角膜后表面手术源性散光( SIA)值、总的SIA值及其变化.方法 将白内障患者47例71眼分成2.2mm切口组和3.0 mm切口组2个组,分别在角膜曲率最大子午线轴位做2.2 mm、3.0 mm角膜缘切口,行白内障超声乳化摘出联合IOL植入术.术前及术后1d、1周、1个月、3个月应用Pentacam系统测量角膜前表面、角膜后表面曲率及中央角膜厚度.根据角膜前表面平坦轴和陡轴方向的曲率半径及角膜前表面所在的空气和角膜本身的屈光指数计算角膜前表面散光值,以同样的方法计算角膜后表面的散光值,根据所得的角膜前表面、角膜后表面散光值,应用矢量法得出角膜总散光.使用Jaffe/Clayman分析法分别计算2个组患者不同时间点角膜前表面、角膜后表面SIA值和总SIA值,比较术后上述各时间点2个组间及2个组内SIA值的差别.结果 术后1d、1周、1个月及3个月2.2mm切口组白内障超声乳化摘出联合IOL植入术后平均角膜前表面、角膜后表面SIA值及总SIA值均低于3.0mm切口组,不同时间点组间的总体比较差异无统计学意义(前表面:P=0.290;后表面:P=0.740;总SIA:P=0.434).2个组术后3个月平均角膜前表面、角膜后表面散光值均明显低于术后1d和术后1周的散光值,差异均有统计学意义(2.2 mm切口组:P=0.020、0.036;3.0 mm切口组:P=0.006、0.023).术后1d时2.2mm切口组和3.0mm切口组术后角膜后表面散光值分别为(0.70±0.43)D和(0.75±0.54)D,而术后1周、1个月和3个月散光值均逐渐减少,与术后1d比较差异均有统计学意义(2.2mm切口组:均P=0.001;3.0 mm切口组:P=O.028、0.044、0.032).2个组术后1周、1个月、3个月的角膜总SIA值均明显低于术后1d值,差异均有统计学意义(2.2mm切口组:P=0.015、0.002、0.002;3.0mm切口组:P=O.049、0.007、0.016).结论 2.2mm和3.0 mm角膜缘切口超声乳化白内障摘出联合IOL植入术相比,前者SIA值相对较小但差异无统计学意义.对两组各个时间点的比较发现,角膜总的SIA值和后表面SIA值变化趋势基本一致,但与角膜前表面SIA值变化趋势不完全一致.     

不同超声乳化术切口对白内障患者术后角膜散光的影响

目的：比较不同超声乳化术切口对白内障患者术后角膜散光的影响。 方法：选取我院收治的白内障患者,将患者随机分为对照组（与角膜缘相反弧形巩膜隧道切口组）和观察组（角膜上方或颞上方透明角膜切口组）。比较分析两组患者术后1 wk;1,3 mo不同时间角膜散光度的变化情况及视力的变化情况。 结果：与对照组患者相比,观察组患者术后1 wk;1,3 mo平均角膜散光度及手术源性角膜散光度均明显降低,裸眼视力及矫正视力均明显提高,差异具有统计学意义（P〈0.05）。与对照组患者相比,观察组患者手术所用时间明显缩短,差异具有统计学意义（P〈0.05）。 结论：角膜中心远处的小切口超声乳化术,能够减少患者术后散光度,促进患者术后视力提高,为进一步加强患者的临床治疗效果提供了保障。     

The effect of posterior corneal flat meridian and astigmatism amount on the total corneal astigmatism estimated from anterior corneal measurements

Background

To evaluate the effects of posterior corneal astigmatism and the absolute flat meridian difference between anterior and posterior corneal surfaces (AMD_Ant-Post) on the estimation of total corneal astigmatism using anterior corneal measurements (simulated keratometry [K]).

Methods

Ninety-nine eyes of 99 healthy participants were enrolled. Anterior, posterior, and total mean corneal power, cylinder power, flat meridian, and vector components J₀, and J₄₅ measured by a dual Scheimpflug camera were analyzed. The correlation between the posterior corneal cylinder power, AMD_Ant-Post, and the difference in the cylinder power between simulated K and total cornea (cylinder power difference_SimK-Tot) were evaluated.

Results

The cylinder power difference_SimK-Tot was positively correlated with the posterior corneal cylinder power (rho?=?0.704 and P?Ant-Post (rho?=??0.717 and P?0 was strongly associated with the posterior corneal cylinder power and the AMD_Ant-Post. When corneal J₀ had a positive value, the cylinder power of simulated K tended to be larger than the total corneal cylinder power. In comparison, the opposite trend was presented in eyes with negative anterior corneal J₀. When anterior corneal J₀ was larger than 1.0 or smaller than ?0.9, the errors from estimating the total corneal cylinder power using anterior corneal measurements tended to be larger than 0.25 D.

Conclusion

Posterior corneal astigmatism should be considered for more accurate corneal astigmatism predictions, especially in eyes with anterior corneal astigmatism greater than 2.0 D of with-the-rule astigmatism or greater than 1.8 D of against-the-rule astigmatism.