Halos y lentes intraoculares multifocales: origen e interpretación

ObjectiveTo present the theoretical and experimental characterization of the halo in multifocal intraocular lenses (MIOL).MethodThe origin of the halo in a MIOL is the overlaying of 2 or more images. Using geometrical optics, it can be demonstrated that the diameter of each halo depends on the addition of the lens (ΔP), the base power (P^d), and the diameter of the IOL that contributes to the «non-focused» focus. In the image plane that corresponds to the distance focus, the halo diameter (δH^d) is given by: δH^d = d^pn ΔP/P^d, where d^pn is the diameter of the IOL that contributes to the near focus. Analogously, in the near image plane the halo diameter (δHⁿ) is: δHⁿ = d^pd ΔP/P^d, where d^pd is the diameter of the IOL that contributes to the distance focus. Patients perceive halos when they see bright objects over a relatively dark background. In vitro, the halo can be characterized by analyzing the intensity profile of the image of a pinhole that is focused by each of the foci of a MIOL.Results and conclusionsA comparison has been made between the halos induced by different MIOL of the same base power (20D) in an optical bench. As predicted by theory, the larger the addition of the MIOL, the larger the halo diameter. For large pupils and with MIOL with similar aspheric designs and addition (SN6AD3 vs ZMA00), the apodized MIOL has a smaller halo diameter than a non-apodized one in distance vision, while in near vision the size is very similar, but the relative intensity is higher in the apodized MIOL. When comparing lenses with the same diffractive design, but with different spherical-aspheric base design (SN60D3 vs SN6AD3), the halo in distance vision of the spherical MIOL is larger, while in near vision the spherical IOL induces a smaller halo, but with higher intensity due to the spherical aberration of the distance focus in the near image. In the case of a trifocal-diffractive IOL (AT LISA 839MP) the most noticeable characteristic is the double-halo formation due to the 2 non-focused powers.     

比较两种人工晶状体矫正老视效果的临床研究

目的比较非对称区域折射型多焦点人工晶状体(IOL)与衍射型三焦点IOL治疗年龄相关性白内障的疗效。 方法回顾性研究。收集2016年11月至2018年6月于成都爱尔眼科医院白内障中心行超声乳化白内障吸除联合IOL植入术57例(57只眼)患者的病历资料。其中,男性28例(28只眼),女性29例(29只眼);年龄50~76岁,平均年龄(63.3±5.5)岁。按照植入IOL的类型将患者分为区域折射组和衍射三焦组。检查并记录两组患者术前与术后3个月的术眼屈光度、裸眼远距离视力(UDVA)、裸眼中距离视力(UIVA)、裸眼近距离视力(UNVA)、最佳矫正远视力(BCDVA)、客观散射指数(OSI)、调制传递函数截止空间频率(MTF cutoff)、斯特列尔比值(SR)以及对比度视力。根据中文版VF-14视功能指数量表对上述指标进行评分,并对患者进行问卷调查。两组患者患眼的眼轴长度、角膜散光、术前UDVA、术前BCDVA、术后OSI、MTF cutoff、SR及中文版VF-14视功能指数量表评分等指标采用均数±标准差表示,并以独立样本t检验进行比较。UDVA、UIVA、UNVA、BCDVA及对比度视力采用中位数和四分位数间距表示。采用Mann-Whitney U检验,比较两组患者术后3个月术眼的UDVA、UIVA、UNVA、BCDVA以及对比度视力。 结果区域折射组和衍射三焦组患者的术后球镜屈光度分别为-0.75 D~+0.50 D和-0.50 D~+1.00 D。两组患者球镜屈光度位于-0.50 D~+0.50 D区间者占比的比较,差异无统计学意义(χ²＝0.000,P>0.05)。两组患者术后柱镜屈光度分别为0.00 D~-0.75 D和0.00 D~-1.00 D。两组患者柱镜屈光度位于-0.75 D~-1.00 D者占比的比较,差异无统计学意义(χ²＝0.459,P>0.05)。区域折射组患者术后的UDVA、UIVA、UNVA及BCDVA分别为0.10(0.00,0.10)、0.20(0.20,0.20)、0.20(0.10,0.20)及0.00(0.00,0.10);衍射三焦组患者术后分别为0.05(0.00,0.10)、0.20(0.10,0.20)、0.10(0.10,0.20)及0.00(0.00,0.05)。经Mann-Whitney U检验,两组患者术后UDVA、UNVA和BCDVA的比较,差异无统计学意义(Z＝-0.169,-1.265,-1.410;P>0.05);UIVA的比较,差异有统计学意义(Z＝-2.708,P<0.05)。区域折射组患者术后的OSI、MTF cutoff及SR分别为(1.9±0.7)、(24.755±7.751)c/deg和(0.126±0.029);衍射三焦组患者术后分别为(1.6±0.7)、(35.813±9.984)c/deg和(0.195±0.083)。经t检验,两组患者MTF cutoff和SR的比较,差异有统计学意义(t＝-5.419,-4.822;P<0.05);OSI的比较,差异无统计学意义(t＝1.959,P>0.05)。区域折射组患者术后在100%、20%和9%对比度下的对比度视力分别为0.70(0.60,0.90)、0.50(0.40,0.60)和0.30 (0.20,0.30);衍射三焦组分别为1.20(0.95,1.50)、0.70(0.60,0.90)和0.50(0.30,0.70)。经Mann-Whitney U检验,两组患者对比度视力的比较,差异有统计学意义(Z＝-4.882,-4.829,-3.676;P<0.05)。区域折射组与衍射三焦组的中文版VF-14视功能指数量表评分分别为(94.39±4.74)分与(96.86±3.63)分,两者比较的差异无统计学意义(t＝-0.075,P>0.05)。区域折射组与衍射三焦组眩光的发生率分别为10.7%与6.9%。两组近脱镜率和眩光发生率的比较,差异无统计学意义(χ²＝0.181,0.002;P>0.05)。区域折射组与衍射三焦组轻度光晕的发生率分别为3.57%与27.59%,差异有统计学意义(χ²＝4.505,P<0.05)。 结论两种老视矫正型IOL均能为年龄相关性白内障患者提供较好的全程视力,术后患眼屈光度可预测性好,而衍射型三焦点IOL客观视网膜成像质量的评估方面较区域折射型多焦点IOL略好。     

老视矫治的研究进展

老视是一种与年龄相关、因调节能力下降而引起的渐进性视近困难，目前发生机制尚不明确，但矫正方法很多，包括配镜、角膜手术、巩膜手术、晶状体手术和药物治疗，也是屈光手术矫正近视、远视、散光取得良好效果后需要突破的重点；但各种方法均以增加屈光力为目的，并不能真正逆转老视的发生。就老视治疗的方法和集中关注的问题进行综述。     

A geometric model of ocular accommodation

An exoteric geometric mechanics model of ocular accommodation is detailed to elucidate the main ideas of various ongoing modeling efforts. The present study derives solutions for the stretched state of the ocular lens as it might appear during accommodation by using simple geometric arguments and a volume constraint, rather than the more mathematically intensive theory of elasticity. Results show that geometric shapes similar to the lens will deform in a similar fashion. This implies that, while the true lens geometry is somewhat more complex, it should also follow these qualitative behaviors.     

老视渐进镜临床验配的实践与体会

近年来,随着眼科视光学的不断创新,各种新技术、新方法不断用于临床实践。在配镜领域,自渐进多焦镜问世以来,由于它的方便美观和具有良好的视觉效果,在老视人群中的普及率逐年提高,为广大老视患者带来福音。从问诊、验光与处方、镜架的选择、配镜参数、镜片制作、配镜指导和投诉分析等临床实践方面进行分析,体会老视渐进镜验配经验,以飨读者。     

飞秒激光INTRACOR技术矫正老视

目的 评价飞秒激光INTRACOR技术治疗老视的安全性、有效性和可预测性.方法 回顾性病例研究.老视患者28例(28眼),选取非主导眼采用TPV520F飞秒激光系统INTRACOR技术进行老视矫正,检测手术前后的裸眼远、近视力,屈光度,眼压,角膜内皮计数,角膜地形图,对比敏感度,眩光敏感度及患者术后主观感受.术后随访6个月.采用配对t检验或配对Wilcoxon秩和检验.结果 所有手术均顺利,术后6个月裸眼远视力中位数为0.0(0.2～-0.1)[术前为0.0(0.2～-0.1)]logMAR,两者差异无统计学意义;术后6个月裸眼近视力中位数为0.25(0.4～0.0)[术前为0.5(1.0～0.3)]logMAR,较术前平均提高(6.25±1.74)行,差异有统计学意义(t=18.66,P＜0.01).术后6个月球镜度中位数为-0.25(-0.75～0.25)D,柱镜度中位数为0.0(-0.75～0.25)D,等效球镜中位数为-0.37(-0.75～0.25)D,术前分别为+0.5(-0.25～1.0)D、0.0(-0.5～0.0)D、+0.25(-0.12～0.75)D,手术前后球镜和等效球镜度差异有统计学意义(Z=-4.50、-4.57,P＜0.01),柱镜度差异无统计学意义,术眼屈光度轻度近视漂移.眼内压、角膜内皮计数及对比敏感度眩光敏感度手术前后比较差异均无统计学意义,术后6个月采用生活质量调查表进行量化评价得分为89±14,满意度高.结论 INTRACOR飞秒技术治疗老视术后能显著提高患者近视力,对远视无明显影响,有较好的安全性和有效性.     

老视客观检查法的探索和应用

目的 探索一种可用于临床客观检查、简便可行的老视检查装置,并评价此种装置在老视测定中的应用价值.方法 自制分光同时视验光镜架,对60例45～65岁的老视患者进行老视检查,每位患者皆分别采用经验法、规范验光方法[移近法测调节幅度、试验性近附加=工作距离（用屈光度表示）-1/2调节幅度、正负相对调节进行精细调整]、分光同时视检影法进行检查,记录每种方法测量所需时间及配镜度数,就3种测量方法所测得的结果与最终处方的符合程度、验配的速度作比较分析.结果 45～54岁患者检查结果：（1）经验法、规范验光方法及分光同时视检影法所得的配镜度数无明显差异（P ＞0.05）;规范验光方法与分光检影法一致性较好,临床上可接受.（2）分光同时视检影法所消耗的时间介于规范验光方法和经验法之间,差异有统计学意义（P＜0.05）.55～65岁患者检查结果：（1）经验法、规范验光方法及分光同时视检影法所得的配镜度数两两比较差异均有统计学意义（均P＜0.01）;分光检影法一致性较其余两者好,临床上可接受.（2）分光同时视检影法所消耗的时间介于规范验光方法和经验法之间,差异有统计学意义（P＜0.01）.结论 分光同时视检影法是一种可靠而又简便可行的老视患者ADD客观检查装置;对于45～65岁年龄段患者,相对于经验法和规范验光方法,分光同时视检影法更具优越性.     

Short term responses to soft contact lens corrections for presbyopia

Eleven subjects were each fitted with five different soft contact lens corrections for presbyopia. The correction types were distance contact lenses with lookover spectacles, concentric bifocals, monovi-sion, modified monovision and progressive bifocal contact lenses. Subjects were asked to rate each contact lens correction in terms of distance, intermediate, near and peripheral vision, confidence when walking and climbing stairs, eye-hand co-ordination, performance on work tasks, vision difficulties in bright and dim ambient illumination and the correction most preferred for daily wear. There were few significant differences between ratings for the different corrections. Monovision, modified monovision and the concentric bifocal corrections were the preferred options for daily wear.