国人近视屈光手术人群角膜前表面非球性参数的调查

目的调查我国近视屈光手术人群的角膜前表面非球性参数(Q值)的分布及与其他相关参数的关系。方法180例近视患者的右眼分为低、中、高近视程度三组,每组60例,性别及年龄匹配。进行角膜地形图、综合验光、角膜中央厚度及其他屈光手术常规术前检查。进行Q值和各参数之间的相关分析。结果总体Q值均数为-0.142±0.151,男性为-0.126±0.14,女性为-0.156±0.16,差异无统计学意义。Q值与屈光不正度数间呈正相关(P=0.015);三组间Q值的差异有统计学意义(F=4.574,P=0.012),低度组和中、高度近视眼组间的差异有统计学意义(P=0.009,P=0.01);中、高度近视眼组间差异无统计学意义(P=0.951)。Q值与平均角膜曲率呈负相关(P=0.031);Q值与角膜直径及角膜中央厚度无相关性(P=0.482,P=0.799)。结论适宜屈光手术近视人群的Q值呈正态分布,大部分人群的角膜曲率由中央到周边逐渐变平。Q值与屈光不正程度、角膜中央曲率相关,而与性别、角膜中央厚度、角膜直径之间无相关。     

准分子激光角膜屈光手术后角膜非球面性和角膜像差的变化

目的探讨准分子激光角膜屈光手术后角膜非球面性和角膜像差改变的影响因素。方法回顾性分析2005年7月至2006年6月行准分子激光角膜屈光手术（LASIK,LASEK）49例（94眼）术前和术后的临床资料。统计手术前后角膜非球面性和角膜像差值,分析不同术式对其的影响。结果（1）近视术前角膜非球面性Q值为-0．32±0．11,角膜球差为（0．51±0．19）μm,呈正态分布。（2）屈光手术后角膜球差值增加4．37倍（P〈0．01）,球差改变与等效球镜改变（r=0．520,P〈0．01）和Q值改变相关（r=0．792,P〈0．01）。（3）角膜非球面性由prolate（Q〈0）变为oblate（Q〉0）（P〈0．01）,其变化和等效球镜改变相关（r=0．578,P〈0．01）。（4）术后LASEK组Q值,角膜球差及其变化值均小于LASIK组（P〈0．01）。结论激光本身以及角膜生物力学变化和伤口愈合导致角膜形态变化,从而改变角膜的非球面性,引起术后角膜像差增大。     

角膜屈光手术后角膜形态及生物力学的研究现状

随着科学技术的提高、手术方式的改进,角膜屈光手术成为治疗近视的主要方式.角膜屈光手术后角膜形态及生物力学的变化对于尽早发现术后相关并发症及术后长期稳定性具有重要意义,不同的术式及术后不同的恢复阶段角膜表面非球面参数及生物力学指标的变化存在一定差异,明确其变化的原因及机制可对临床研究提供一定的参考.     

江西近视手术人群角膜前表面非球性参数调查分析

目的 调查江西近视激光手术人群角膜前表面非球性参数(Q值)的分布特征,并分析Q值与其他参数如屈光度、角膜平均曲率、角膜散光、像差、年龄等凶素的关系.方法 应用Orhscan- Ⅱ角膜 地形图仪(Bausch & Lomb)K＆Q计算软件获得411例近视患者822只眼角膜6mm分析区域的Q值和K值,使用Zywave波前像差仪获取完全的像差分布图像.按性别不同分为男性组(188例376只眼)和女性组(223例446只眼).按照近视程度不同分为轻、中、高度三组.按年龄分为Ⅰ组(17～25岁)、Ⅱ组(26～34岁)、Ⅲ组(35～44岁)三组.并对性别间、不同程度近视、不同年龄组间Q值的差别,总体Q值的分布及与其他参数如屈光度、角膜平均曲率、角膜散光、像差、年龄等因素的相关性进行统计学分析.结果 411例822只近视眼角膜Q值呈正态分布,总体Q值平均为-0.148±0.120,男性为-0.130±0.128,女性为-0.163±0.110,男女间差异有统计学意义(t=4.069,P<0.01).不同程度近视组间角膜Q值差异无统计学意义(F=1.434,r=0.239,P>0.05),Q值与近视屈光不正度数间无明显相关;不同年龄组间Q值的差异有统计学意义(F=4.567,P<0.05),26～ 34岁和35～44岁组间角膜Q值差异有统计学意义(P<0.01);Q值与平均角膜曲率、角膜散光、高阶像差(RMSh)和水平彗差(C8)间均有统计学的相关性,尤其与球差(C12)间存在显著负相关,但与其他参数如总体像差(RMSg)、垂直彗差(C7)、角膜直径、角膜厚度、眼压、年龄之间无明显统计学相关性.结论 适宜激光手术的江西近视人群Q值呈正态分布,大部分人群的角膜曲率由中央到周边逐渐变平.角膜Q值与近视程度无关,个体间变异较大.Q值与平均角膜曲率、角膜散光、高阶像差(RMSh)和水平彗差(C8)相关,Q值和球差之间存在密切相关.性别间角膜Q值有统计学差异性,不同年龄组间的角膜Q值有统计学差异性.     

江西近视手术人群角膜前表面非球性参数调查分析

Objective To assess the distribution features of Q-value of corneal anterior surface in Jiangxi myopia population for laser refractive surgery and to investigate the relationship between Q-value and other related parameters, such as spherical equivalent (SE), corneal curvature, cornea astigmatism, wavefront data and age. Methods The K&Q calculator of Orbsean- Ⅱ anterior segment system was used to obtain the Q-value of 6 mm optical zone in 411 cases (822 eyes) .There were 188 male subjects (376 eyes) and 223 female subjects (446 eyes). Accnrding to SE, subjects were divided into three groups including low myopia, moderate myopia and high myopia. According to different age, subjects were divided into three groups including group Ⅰ (age from 17 to 25), group Ⅱ (age from 26 to 34) and group Ⅲ (age from 35 to 44). Statistical analysis was used to comprehend the distribution characters of Q-value and its relations with SE, corneal curvature, cornea astigmatism, wavefront data and age. Results The Q-value of 822 eyes (411 cases) distributed as positive normal distribution, the average of Q- value was -0.148± 0.120 (range from -0.73 to 0.56) and -0.130± 0.128for male subjects and -0.163± 0.110 for female ones with statistically significant difference in Q-value in different genders (t=4.069, P <0.01). A significant difference was observed in Q-value among 17-25 years, 26-34 years and 35-44 years groups (F =4.567, P <0.05) as well as between 26-34 years group and 35-44 years group (P =0.004). However, there was no significant difference found between different myopic groups (F =1.434, P >0.05). The Q-value shown significantly negative relationship with C12, the Q-value show poor relationship with cornea curvature, cornea astigmatism, RMSh and C8. But the Q-value was not related with SE, RMSg, C7, cornea thickness, ocular pressure and age. Conclusions In Jiangxi myopia population for refractive surgery corneal curvature of majority population become flatter from center to periphery (Q<0), minority become steeper from center to periphery (Q>0). The Q-value of corneal anterior surface is independent from myopic SE. The Q-value show poor relationship with cornea curvature, cornea astigmatism, RMSh and C8, C12 is the most important related factor of Q-value. The Q-value is significantly greater in males than in females. A significant difference is observed in Q-value between 26-34 years and 35-44 years group.     

江西近视手术人群角膜前表面非球性参数调查分析

Objective To assess the distribution features of Q-value of corneal anterior surface in Jiangxi myopia population for laser refractive surgery and to investigate the relationship between Q-value and other related parameters, such as spherical equivalent (SE), corneal curvature, cornea astigmatism, wavefront data and age. Methods The K&Q calculator of Orbsean- Ⅱ anterior segment system was used to obtain the Q-value of 6 mm optical zone in 411 cases (822 eyes) .There were 188 male subjects (376 eyes) and 223 female subjects (446 eyes). Accnrding to SE, subjects were divided into three groups including low myopia, moderate myopia and high myopia. According to different age, subjects were divided into three groups including group Ⅰ (age from 17 to 25), group Ⅱ (age from 26 to 34) and group Ⅲ (age from 35 to 44). Statistical analysis was used to comprehend the distribution characters of Q-value and its relations with SE, corneal curvature, cornea astigmatism, wavefront data and age. Results The Q-value of 822 eyes (411 cases) distributed as positive normal distribution, the average of Q- value was -0.148± 0.120 (range from -0.73 to 0.56) and -0.130± 0.128for male subjects and -0.163± 0.110 for female ones with statistically significant difference in Q-value in different genders (t=4.069, P <0.01). A significant difference was observed in Q-value among 17-25 years, 26-34 years and 35-44 years groups (F =4.567, P <0.05) as well as between 26-34 years group and 35-44 years group (P =0.004). However, there was no significant difference found between different myopic groups (F =1.434, P >0.05). The Q-value shown significantly negative relationship with C12, the Q-value show poor relationship with cornea curvature, cornea astigmatism, RMSh and C8. But the Q-value was not related with SE, RMSg, C7, cornea thickness, ocular pressure and age. Conclusions In Jiangxi myopia population for refractive surgery corneal curvature of majority population become flatter from center to periphery (Q<0), minority become steeper from center to periphery (Q>0). The Q-value of corneal anterior surface is independent from myopic SE. The Q-value show poor relationship with cornea curvature, cornea astigmatism, RMSh and C8, C12 is the most important related factor of Q-value. The Q-value is significantly greater in males than in females. A significant difference is observed in Q-value between 26-34 years and 35-44 years group.     

近视眼准分子激光原位角膜磨镶术后角膜非球面性的改变

目的 研究近视眼准分子激光原位磨镶术（laser in situ keratomileusis，LASIK）后角膜非球面性的改变。方法 对93例近视眼患者（148眼）LASIK术后进行回顾性分析．用Orbscan-Ⅱ角膜地形图仪测量角膜在LASIK术前和术后非球面参数Q值、角膜曲率simk值（K）、切削的偏心值。分析Q值、角膜曲率改变（△K），△Q与预期矫正值（SE）、AK之间的相关性，以及术后。值与偏心量之间的相关性。结果 角膜形状从术前扁长型（Q〈0）到术后为扁圆型（Q〉0）；角膜曲率变平；AQ与SE、AK之间存在相关性（分别为r=0．771，P〈0．01和r=0．783，P〈0．01），但术后Q值与偏心量之间无相关性（r=0．068，P〉0．05）。结论 近视患者LASIK术后角膜非球面参数Q明显增大，变化量与预期矫正值、曲率变化量相关。     

正视眼与近视眼角膜前表面非球面性的分析

目的探讨我国正视眼与近视眼中青年人群的角膜前表面非球性参数(Q值)的分布及其与屈光度的关系。方法随机选择18～44岁行准分子激光角膜屈光手术的低、中、高度近视及正视眼患者,各组均取40例(80眼)。应用AstraMax三维角膜综合检查站行角膜地形图检查,记录Q值,并进行统计学分析。结果正视眼Q值均数为-0.1028±0.0712;近视眼总体Q值均数为-0.1600±0.1700,呈正态分布;近视眼Q值与屈光度之间存在线性相关关系(F=9.6665,P=0.0021);正视眼与近视眼Q值总体差异有统计学意义(t=19.7241,P<0.001);高度近视组和低度、中度组间的差异均有统计学意义(q=4.0037,P<0.05;q=3.1218,P<0.05);低度、中度近视眼组间差异无统计学意义(q=0.8818,P>0.05)。结论我国近视人群的Q值呈正态分布,大部分人群角膜为长椭球形。Q值与屈光不正程度相关。近视眼角膜前表面形态较正视眼更趋于长椭圆非球面形。     

近视眼角膜前表面的非球面性

目的应用Orbscan-Ⅱ角膜地形图仪研究近视眼角膜前表面的非球面特性。方法对正视和近视成人共156例249眼行角膜地形图检查及主觉验光。按照等效球镜分成正视组（-0．25～＋0．50D）、低度近视组（-0.37～-3．00D）、中度近视组（-3.12～-6.00D）和高度近视组（〉-6．00D）。对所得角膜地形图参数中角膜非球面参数（Q值）进行方差分析。结果样本总体Q值平均为-0．23±0.13（-0．69～0．00），组间Q值差异有统计学意义（P〈0．01），但在近视的三组之间Q值差异无统计学意义（P〉0．05）。结论角膜形态为扁长椭圆形，从中央到周边逐渐平坦；近视性屈光不正可导致角膜非球面性的改变。     

Q值引导的个体化准分子激光原位角膜磨镶术后角膜地形图分析

目的 分析Q值引导的个体化准分子激光原位角膜磨镶术后角膜地形图的动态变化.方法 将94例188只眼接受准分子激光原位角膜磨镶术治疗的近视患者分为两组,47例94只眼行非球面个体化切削作为Ⅰ组;另47例94只眼行标准切削作为Ⅱ组,采用Orbscan Ⅱ角膜地形图仪随访6个月.结果 术后各时间点切削区形态、平均偏中心距离和SimK的变化,两组比较差异无统计学意义(P>0.05),各时间点Q值差异两组比较有统计学意义(P<0.05),非球面切削组的Q值明显低于标准切削组,两组术后平均角膜厚度和切削深度的差异有统计学意义(P<0.05).结论 Q值引导的个体化准分子激光原位角膜磨镶术治疗近视具有较高的有效性、安全性和稳定性,且比标准切削更有助于维持角膜的非球面性.角膜地形图为分析评估手术效果提供了客观依据.     

Interchangeability of corneal curvature and asphericity measurements provided by three different devices

AIM: To evaluate the interchangeability of keratometric and asphericity measurements provided by three measurement systems based on different optical principles. METHODS: A total of 40 eyes of 40 patients with a mean age of 34.1y were included. In all cases, a corneal curvature analysis was performed with IOL-Master (IOLM), iDesign 2 (ID2), and Sirius systems (SIR). Differences between instruments for flattest (K1) and steepest (K2) keratometric readings, as well as for magnitude and axis of corneal astigmatism were analyzed. Likewise, differences in asphericity (Q) between SIR and ID2 were also evaluated. RESULTS: Mean differences between devices for K1 were 0.20±0.21 (P<0.001), -0.12±0.36 (P=0.046) and -0.32±0.36 D (P<0.001) for the comparisons IOLM-SIR, IOLM-ID2 and SIR-ID2, respectively. The ranges of agreement for these comparisons between instruments were 0.41, 0.70, and 0.70 D. For K2, mean differences were 0.31±0.33 (P<0.001), -0.08±0.43 (P=0.265) and -0.39±0.38 D (P<0.001), with ranges of agreement of 0.65, 0.84, and 0.74 D. Concerning magnitude of astigmatism, ranges of agreement were in the limit of clinical relevance (0.49 D, P=0.011; 0.55 D, P=0.386; 0.43 D, P=0.05). In contrast, ranges of agreement were clinically relevant for astigmatic axis (26.68o, 33.83o and 18.37o, P≥0.121) and for Q between SIR and ID2 (0.16, P<0.001). CONCLUSION: The keratometric corneal power, astigmatic axis and asphericity measurements provide by the three systems evaluated cannot be considered as interchangeable, whereas measurements of corneal astigmatism obtained with SIR and ID2 can be considered as interchangeable for clinical purposes.     

The asphericity, curvature and tilt of the human cornea measured using a videokeratoscope

The EyeSys videokeratoscope (VK) measurements of the principal corneal meridians of 98 subjects already analysed by Douthwaite et al. [Ophthal. Physiol. Opt. (1999)19:467-474] were re-analysed in order to revise the assessment of asphericity, to derive information on corneal tilt and to assess the degree to which the corneal section approximates to that of a conic section. The range of normality for the revised p-value (asphericity) was from 0.57 to 0.97 for the near horizontal and from 0.56 to 1.08 in the near vertical principal meridians. The approximate corneal tilt angles ranged from -3.95 to +8.13 degrees in the horizontal and from -8.99 to +9.33 degrees in the vertical meridian. A tilted conicoidal surface will display a linear relationship (r = 1) when a scatterplot is drawn of the perpendicular distance squared vs radius squared, after first averaging the two semimeridian results for each VK ring. Analysing the results from the human cornea in the same way allows an assessment of the degree to which the corneal section approximates to that of the conic section.     

LASIK手术对角膜前后表面非球面性的早期影响

目的探讨准分子激光原位角膜磨镶术（LASIK）对近视患者角膜前后表面不同范围内非球面性的早期影响。方法对54例（107眼）近视及近视散光患者行常规LASIK,使用Pentacam眼前节分析系统对患者角膜前后表面6、7、8、9mm等不同直径的平均Q值进行测量,研究术前术后Q值的变化规律及各相应范围内Q值的变化特点,并分析其与其他变量之间的相关性。结果术前角膜前后表面形态随着角膜直径取值范围的增大,Q值负向增大,呈椭球形的特点,前后表面Q值有一定的相关性,且越近周边越显著,Q值与屈光度间无相关性,角膜后表面7、8、9mm直径下的Q值与角膜厚度呈负相关。术后1个月,4个直径范围内角膜前后表面的Q值均往正向变化,除后表面9mm区域Q值变化与术前比较差异无统计学意义外（t=-1．495,P=0．138）,其余前后表面各范同Q值与术前比较差异均有统计学意义（P〈0．05）,切削区内增加最显著。术后角膜前表面△Q与切削深度及剩余基质床厚度均呈正相关（P〈o．05）,而后表面△Q则与两参数无明显相关（P〉0．05）。结论角膜前后表面越靠近周边区域Q值越负,呈椭球形特点;LASIK不仅改变了角膜前表面的非球面特性,对角膜后表面的形态也产生了一定影响,使后表面发生了扁球形改变。     

不同引导方法LASIK术后角膜非球面性改变及临床分析

目的：探讨不同引导方式LASIK术后角膜非球面性改变及临床分析。 方法：48例95眼行LASIK手术,其中45眼接受Q值引导LASIK,50眼接受非Q值引导的LASIK。术后1,3,6mo分别检查视力（visual acuity,VA）、屈光状态、角膜K值、Q值、球差、对比敏感度(contrast sensitivity function, CSF)等,并行统计分析。 结果：两组术后3,6mo在视力和有效指数方面无差异;术后3mo屈光状态在±0.50D范围Q值组和非Q值组分别为95%和90%,术后6mo,±0.50D两组分别为97%和98%;术后1,3和6mo Q值组CSF均较术前提高,差异有统计学意义（P<0.05）,而非Q值组术前术后差异无统计学意义。Q值组和非Q值组术后1,3和6mo的平均Q值分别为0.50±0.33和0.81±0.51、0.50±0.35和0.80±0.48、0.50±0.34和0.80±0.47,与术前比较差异均有统计学意义。Q值组和非Q值组术后6mo球差较术前平均增加分别为4倍和8.5倍;⊿Q与预矫屈光度高度正相关,与患者年龄、性别、术前角膜K值、Q值、球差无相关性;定量关系非Q值组为y= 0.18e^0.32x ,R²=0.72,Q值组为y=0.04x²-0.19x+0.54,R²=0.75。 结论：非球面引导的LASIK可以有效地减少近视屈光手术对角膜非球面性的影响,从而减少术后球差的增加,有利于术后视觉质量的提高。预计的目标Q值与实际的Q值之间存在较大差异。"     

正常眼角膜Q值检测分析

目的:研究正常眼角膜Q值及其分布特点。方法:采用Allegrettowavetopolayzer角膜地形图仪检测20例39眼正常眼角膜地形图,计算角膜Q值,并作统计学分析。结果:正常眼39眼角膜平均Q值为-0.28±0.09;水平方向Q值为-0.29±0.09,垂直方向为-0.28±0.12,水平和垂直方向Q值差异无显著性意义(t=-0.482,P=0.631);右眼Q值为-0.28±0.08,左眼为-0.27±0.02,双眼Q值差异无显著性意义(t=-0.512,P=0.612)。结论:正常眼角膜多呈中央屈力高而周边屈力低的长椭圆体,其正常眼角膜Q值基本呈正态分布。     

Pentacam眼前节测量分析系统对青壮年近视患者角膜前、后表面Q值的测量和分析

目的探讨青壮年近视患者角膜前、后表面不同范围非球面性参数Q值的分布及它与其他参数间的关系。方法使用Pentacam眼前节测量与分析系统检测203例（406眼）等效球镜（spherical equivalent,SE）为-1．00～11.38D的18—36岁青壮年近视患者,获取角膜前、后表面Q值、角膜像差、角膜表面散光△K值。结果角膜前表面Q20、Q25、Q30、Q35、Q40分别为-0．14±0．15、-0．20±O．11、-0．24±0．09、-0．30±0．23、-031±0．23。角膜后表面Q20、Q25、Q30、Q35、Q40分别为0．48±0．32、0．27±0．25、0．09±0．20、-0．05±0．18、-0．20±0．17。角膜前表面Q30与球镜、柱镜、SE之间呈正相关（r值分别为0．11、0．19、0．15）,与角膜前表面散光△K、z40、RMSh呈正相关（r值分别为0-31、O．64、0．56）;角膜后表面Q30与角膜后表面z40、RMSh、RMSg呈正相关（r值分别为0．82、0．59、0．24）。性别、年龄、配戴角膜接触镜对Q值无显著影响。双眼Q值呈-致性。结论大多数青壮年近视患者角膜前表面为长椭圆形（prolate）,前、后表面的Q值均随着测定范围的扩大变得越来越小。角膜Q值受许多因素的影响。     

近视眼角膜前、后表面不同范围非球面性及其与角膜球差的关系

目的 探讨拟行准分子激光角膜屈光手术的近视患者角膜前、后表面不同范围非球面性(Q值)及其与角膜球差的关系.方法 横断面研究.选取拟行角膜屈光手术的近视及近视散光患者116例(116眼),年龄18～45岁,球镜度- 1.25～-10.75 D,柱镜度0.00～-3.50 D.应用Pentacam眼前节分析系统对角膜前、后表面6、7、8、9 mm直径下的Q值及角膜球差进行测量.采用Pearson直线相关分析角膜前、后表面Q值与球差及其他参数的相关性、以及角膜前、后表面Q值的相关性,采用直线回归分析建立角膜前、后表面相应范围Q值与球差的回归方程 结果 在6～9 mm取值范围下,角膜前表面Q值分别为-0.24±0.09 、-0.29±0.09、-0.33±0.09和－0.39±0.10;后表面Q值分别为-0.12-0.12、-0.21±0.11 、-0.30±0.10和-0.38±0.10.前表面Q值较后表面Q值偏向负值方向,6～8 mm前后表面差异有统计学意义(t=- 10.35、-6.68、-3.46,P＜0.01).6～9 mm取值范围下角膜前、后表面Q值均呈正相关(r=0.30、0.37、0.40、0.42,P＜0.01).0值与球差存在明显的相关性,在6mm角膜直径下,前表面回归方程为SA=0.663Q+0.415,后表面回归方程为SA=0.159Q-0.177,前表面Q值为-0.60时,球差接近零.6～9 mm取值范围下,前表面Q值与与柱镜度均呈正相关(r=0.28、0.27、0.25、0.22,P＜0.05).后表面7～9 mm范围内的Q值与角膜厚度呈负相关(r=-0.18、-0.21、-0.24,P＜0.05)Q值与年龄、性别、眼别无相关 结论 近视眼角膜前、后表面均呈长椭圆形,前表面较后表面的长椭圆形特点更显著.Q值与球差存在正相关关系,Q值越负,球差越小.     

不同群体角膜前表面非球性系数测量结果分析

目的:分别测量近视眼及白内障两组患者角膜前表面非球性系数(Q值),探讨可能的相关因素。方法:近视眼患者240例,按屈光度分为高、中、低三组,性别比例基本匹配,年龄为18~32岁,随机选择其中48例配戴角膜接触镜的患者分别测量摘镜后第1,15d的Q值;白内障患者123例,年龄42~80岁。常规进行角膜地形图、综合验光、角膜中央厚度等检查,对各项检查结果进行分析。结果:近视眼组其Q值范围为-0.62~-0.04,平均为-0.296;白内障组其Q值范围为-0.67~-0.01,平均为-0.232,白内障患者的Q值低于近视眼患者的Q值,差异有统计学意义(P=0.00);近视眼的Q值女性高于男性,差异有统计学意义(P=0.00);Q值与屈光度相关性分析显示无明显相关,高、中、低三组间差异没有统计学意义;近视眼组同一个体左右眼Q值、隐形眼镜脱镜后第1,15dQ值分布线性关系显著,但差异均无统计学意义。结论:Q值是表示角膜最平坦子午线角膜变陡或变平的程度表面形状系数。近视眼及白内障患者两个群体角膜Q值均呈正态分布,两组数值分布差异有统计学意义;Q值与角膜曲率、屈光度、角膜厚度无明显相关,配戴角膜接触镜对Q值的测量结果无影响。