老视理论及治疗进展

老视是一种常见的眼部退行性病变，表面为年龄相关性调节力下降，它影响到每一个老年人。随着全新的Schachar调节理论的提出以及传统理论的发展，近年来出现多种老视治疗方法。目前除了通过各框架眼镜和接触镜来矫正老视，还可以应用手术方法如前睫状区巩膜切开术（ACS）以及巩膜扩张（SRP）来恢复调节能力。采用人工晶状体植入形成单眼视，多焦点人工晶状体，可调节型人工晶状体，LASIK手术也都是可行的老视治疗措施。本总结了目前有关老视的各种机制和治疗方法。     

老视矫治手术治疗最新进展

老视是一种年龄相关的生理性老化现象.老视手术治疗已逐渐成为屈光手术最终需要面对的挑战.目前,其手术矫治包括眼外(施于角膜或巩膜)和眼内(晶状体置换或施于晶状体本身)两大策略,如角膜准分子激光手术、热传导成形术、飞秒激光基质内环形切开术、角膜植入物手术、各种多焦人工晶状体植入术、可调节人工晶状体植入术、晶状体软化术、巩膜扩张术等.各种手术方法均存在自身的优势和不足.本文就目前现有和近期即将问世的老视治疗方法及其被关注的问题作一综述.     

手术治疗老视的研究进展

手术治疗老视尚处于初步阶段,传导性角膜热成形术(ConductiveKeratoplasty,CK)和准分子激光原位角膜磨削术(LASIK)多焦点切削(multifocalablation)等技术是新出现的治疗方式。多焦点人工晶状体或可调节人工晶状体植入术也为弥补老视调节不足提供了新的手段,对于重建调节的巩膜老视手术的研究也在不断深入。     

老视矫正的多样化研究进展

配戴框架凸透镜是矫正老视的主要方式，如单光眼镜、双光眼镜、渐变多焦镜及其他新兴衍射镜片。屈光性手术也为矫正老视提供了新的途径，可分为角膜屈光性手术、晶状体摘除联合可调节型人工晶状体（IOL）植人手术以及巩膜屈光性手术。角膜屈光性手术通过改变角膜的屈光力而改变眼球的屈光状态，包括激光角膜手术和角膜层间植人物手术两类。晶状体摘除联合人工晶状体植人术的关键在于可调节型人工晶状体的研发，现有的单焦调节型及多焦调节型人工晶状体优点是减少眩光或光晕，获得较好的夜间视觉，临床效果仍需进一步研究。巩膜屈光性手术通过增加晶状体赤道部与睫状肌的距离治疗老视，包括睫状体前巩膜切开术、激光老视逆转术和巩膜扩张术。老视矫正逐渐向多样化发展，为不同需求的老视者提供了更多的选择。     

老视手术治疗最新进展

老视是一种进行性的与年龄相关的眼调节能力下降。本文就近年来治疗老视的常用手术方式,包括巩膜扩张术、多焦点人工晶状体植入术、LASIK老视矫正术、传导性角膜热成形术及其临床疗效、并发症等做一综述,为临床治疗老视提供参考依据。     

人工晶状体矫正老视的临床应用

老视是一种随年龄增长出现的眼调节功能逐渐下降的生理现象。全球人口老龄化日益加剧, 目前有近1/4人口受到老视的影响。晶状体手术可以矫正老视, 包含有晶状体眼人工晶状体植入术和晶状体置换术。本文对各种矫正老视的人工晶状体, 如单焦点、多焦点、景深延长型、可调节等人工晶状体的临床应用及进展进行汇总分析, 以期为临床矫正老视提供参考。     

老视手术治疗最新进展

老视是一种进行性的与年龄相关的眼调节能力下降。本就近年来治疗老视的常用手术方式，包括巩膜扩张术、多焦点人工晶状体植入术、LASIK老视矫正术、传导性角膜热成形术及其临床疗效、并发症等做一综述，为临床治疗老视提供参考依据。     

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。     

老视矫正手术方法的现状和发展趋势

老视是因年龄相关性调节幅度的下降使得近阅读渐渐困难的一种生理老化现象。现阶段老视矫正的主流方式是配戴单焦框架眼镜、双焦框架眼镜和渐变多焦点眼镜。目前所有针对老视的手术方法都未能带来持久的真正生理意义上的调节改善,本文就目前各种老视矫正手术方法（包括单眼视方法的、施于角膜的、施于巩膜的与施于晶状体的）的现状与发展趋势做一综述。     

调节机制和老视的研究

本文综述了有关调节和老视机制的各种观点 ,主要归纳为Tescherning ,Helmholtz,Schachar提出的三种假说。重点介绍了Schachar调节理论的提出 ,所使用的各种临床和基础研究论证方法 ,以及近年来不支持这一新理论的研究情况。同时还介绍了关于巩膜扩张手术治疗老视的正反两方面的意见     

老視理論及治療進展

老視是一種常見的眼部退行性病燮,表現為年齡相關性調節力下降,它影響到每一個老年人.隨着全新的Schachar調節理論的提出以及傳統理論的發展,近年來出現了多種老視治瘵方法.目前除了通過各種框架眼鏡和接觸鏡來矯正老視,還可以應用手術方法如前睫狀區鞏膜切開術(ACS)以及鞏膜擴張(SRP)來恢復調節能力.采用人工晶狀體植入形成單眼視,多焦黠人工晶狀體,可調節型人工晶狀體,LASIK手術也都是可行的老視治瘵措施.本文總結了目前有關老視的各種機制和治瘵方法.     

Lens Refilling

Cataract surgery has developed into a very safe and highly reproducible procedure but the ultimate goal to also restore physiological accommodation has not yet been achieved. A variety of accommodative intraocular lenses (IOLs) and surgical techniques have been suggested to cure presbyopia but all showed only poor accommodative effects by objective measurements. Complete lens refilling with flexible polymers might be an interesting alternative. Recent investigations on accommodation and presbyopia have given support to the lens refilling method. After development of suitable surgical techniques and filling materials only secondary cataract formation and the unsolved intraoperative control of refraction restrict the clinical use of this technique.     

Dynamic aberrometry during accommodation of phakic eyes and eyes with potentially accommodative intraocular lenses

Since the introduction of potentially accommodative intraocular lenses (IOLs), it was hard to perform an objective evaluation of the accommodative amplitude in pseudophakic eyes. Laser interferometric measurements were performed to evaluate anterior chamber depth changes, which provides information on the functionality of potentially accommodative IOLs. By means of wavefront analysis, the dynamic behaviour of potentially accommodative IOLs can be determined. All measurements in this study were performed using a Hartmann-Shack aberrometer at a frequency of 7 Hz. Six to 8 weeks after implantation of potentially accommodative IOLs (CrystaLens AT-45, C&C Vision, 1CU, Humanoptics), 43 eyes were investigated using this dynamic wavefront analysis. Patients focussed at a distance target for 10 s, followed by focussing at a near target for 10 s and then again at a distance target for a further 10 s. During these 30 s, a total of 200 single measurements were performed. The same measurements were also conducted in healthy eyes of young persons as well as in eyes after implantation of standard IOLs for comparative purposes. The dynamic course of changes in low-order aberrations (defocus, astigmatism) as well as high-order (e.g., fourth-order spherical aberration) were analysed. Dynamic wavefront analysis allowed objective and observer-independent measurement of changes in accommodation in phakic and pseudophakic eyes. Dynamic aberrometry is capable of objectively quantifying the effect of any surgical option for the treatment of presbyopia. We recommend use of this technology in addition to the common psychophysical examinations to attain objective information on the efficacy of the treatment modality used.     

New intraocular lens technology

PURPOSE: To review the current status of phakic intraocular lenses (IOLs), intraocular treatment of presbyopia, and IOLs that filter some blue light. DESIGN: Review of current information on the subject from numerous sources. METHODS: Medline search and Internet search engines on the topics of phakic IOLs, presbyopia or multifocal IOLs, and blue light and macular degeneration. RESULTS: An iris fixated phakic IOLs is now approved in the United States (US). There are concerns for corneal endothelial stability and late dislocation. Other approaches include anterior chamber fixation with concerns of corneal endothelial stability and pupil elongation, and posterior chamber fixation with concerns of cataract formation, IOL dislocation, and pigment dispersion. Intraocular treatment of presbyopia includes monovision, multifocal, and accommodative IOLs. Which approach is superior today is still not clear. There are IOLs designed to block some blue light to potentially lessen the risk of age-related macular degeneration (ARMD). While there is presumptive evidence of this, no definitive study shows such a correlation. Color perception issues are unlikely to be a problem. While decreased scotopic vision has been proposed, there is no study that proves this is an issue of clinical significance. CONCLUSIONS: The IOL field is dynamic with many new choices. Phakic IOLs and treatment of presbyopia will be an increasingly important part of ophthalmology; however, there are important unresolved issues. With better evidence that blue light is an important variable in ARMD, such an approach could rapidly become the standard.     

Comparison of the behavior of natural and refilled porcine lenses in a robotic lens stretcher

The mechanism by which the eye dynamically changes focal distance (accommodation), and the mechanism by which this ability is lost with age (presbyopia), are still contested. Due to inherent confounding factors in vivo, in vitro measurements have been undertaken using a robotic lens stretcher to examine these mechanisms as well as the efficacy of lens refilling - a proposed treatment for presbyopia. Dynamic forces, anterior and posterior curvatures, and lens thickness are all correlated for young natural and refilled porcine lenses. Comparisons are made to lenses refilled with a homogeneous polymer system. The amplitude of accommodation of the young porcine lens is very small such that it may be a suitable model for presbyopia. The behavior of refilled lenses was highly dependent on the refill volume. The volume could be tuned to maximize accommodative amplitude in the refilled lens.     

The IOL horizon: accommodative intraocular lenses.

BACKGROUND: For more than half a century, intraocular lenses have been used effectively to correct vision after cataract extraction. New developments in intraocular lens design have led to the creation of lenses that may have a significant role in the restoration of accommodation as well. PURPOSE: Accommodative lens technology is constantly evolving. Many different lens designs are currently under development. It is important for optometrists to be familiar with this technology and the various lenses being developed, as accommodative intraocular lenses stand to become the mainstay for cataract surgery, as well as for the surgical treatment of presbyopia. METHOD: The literature is reviewed in order to summarize the developments in accommodative lens technology.     

Akkommodation und Presbyopie

There are two basic approaches for the surgical correction of presbyopia: increasing depth of focus (e.g. by means of multifocal laser abrasion of the cornea), Or restoring accommodation in the sense of a dynamic change in ocular refraction (accommodative intraocular lenses, scleral expansion). Pseudoaccommodative procedures are able to achieve satisfactory near vision, albeit at the price of lower performance in the intermediate range and decreased image quality. The restoration of accommodation remains problematic, partly because the mechanism of accommodation and the development of presbyopia are still not fully understood. Some surgical procedures are based on concepts, the validity of which is not confirmed or which even contradict experimental evidence. Thus, it is necessary to assess the results and presumed mechanisms critically and objectively.     

Accommodation and presbyopia : part 2: surgical procedures for the correction of presbyopia

There are two basic approaches for the surgical correction of presbyopia: increasing depth of focus (e.g. by means of multifocal laser abrasion of the cornea), Or restoring accommodation in the sense of a dynamic change in ocular refraction (accommodative intraocular lenses, scleral expansion). Pseudoaccommodative procedures are able to achieve satisfactory near vision, albeit at the price of lower performance in the intermediate range and decreased image quality. The restoration of accommodation remains problematic, partly because the mechanism of accommodation and the development of presbyopia are still not fully understood. Some surgical procedures are based on concepts, the validity of which is not confirmed or which even contradict experimental evidence. Thus, it is necessary to assess the results and presumed mechanisms critically and objectively.     

可调节人工晶状体的研究进展

在白内障手术后老视问题的各种解决方法中,可调节人工晶状体(accommodating intraocular lenses,IOL)能够提供不戴镜的近、中、远视力,这些IOLs利用焦点的移动来进行调节。本文通过对其设计原理、发展历程、选择依据、材质比较、临床研究等多方面探讨,全面分析可调节人工晶状体,并对其未来发展进行展望。     

Accommodative intraocular lenses: current status

PURPOSE OF REVIEW: The possibility of using a monofocal IOL with accommodative ability allows refractive cataract surgery with a clearly decreased potential of photic phenomena. Three IOLs of different designs and materials have demonstrated accommodative ability, but the degree of accommodative amplitude has been reported to different extents and variabilities. The plate-haptic CrystaLens has a hinged design that might permit forward movement of the optic as a result of pressure changes in the vitreous cavity. The 1CU has modified haptics that bend in the bag as the lens capsule contracts, which are supposed to cause anterior displacement of the lens optic. With the dual-optic one-piece Synchrony, springlike haptics separate a high-plus anterior lens from a posterior minus lens. With accommodative effort, the capsular bag expands and the springs express kinetic energy, which might allow the optics to separate as the anterior lens moves forward. RECENT FINDINGS: This article seeks to clarify and distinguish the concepts of true accommodation and pseudo accommodation. Current designs of accommodative IOLs are supposed to work by the focus-shift principle to allow true pseudophakic accommodation. Studies that biometrically assessed optic shift found no or only low amplitudes of forward movement. The amount of forward movement, if present, was highly variable between patients. To date, most studies present psychophysical data for the proof of concept, which alone seems insufficient. Capsule bag performance and posterior capsule opacification with accommodative IOLs seem worse than those with standard intraocular lenses. SUMMARY: The potential clinical benefits of accommodative IOL technology for both cataract patients and refractive patients may place accommodative IOLs in a competitive position with multifocal IOL technology.