准分子激光手术矫正老视的研究进展

准分子激光手术是一种简单、安全、有效的矫正老视的方法,并有可能提供个体化的切削以提高老视患者的视觉质量.本文就老视的机制及治疗、准分子激光手术矫正老视的理论进展、手术方式、切削模式及效果评价进行综述.     

Monovision与老视矫正手术

Monovision(MV)矫正是一种成熟的矫正老视的方法,近10 a来,老视矫正手术逐渐开展,一些准分子激光角膜屈光手术(PRK、LASIK等)、激光角膜热成形术和传导式角膜成形术、人工晶状体植入术也采用MV矫正方法治疗老视,取得很好的效果,本文就MV矫正在这些老视矫正手术中的应用进行综述.     

激光手术矫正老视的应用和研究进展

尽管老视矫正方法日趋繁多,但手术矫正老视仍是屈光领域一个重大难题.近年来激光手术矫正老视逐渐得到重视.主要包括作用于角膜的激光老视手术如准分子激光原位角膜磨镶术、飞秒激光角膜基质内老视矫正术、激光角膜热成形术、角膜层间镜片植入术,以及作用于晶状体的飞秒激光晶状体老视矫正手术等.本文对激光矫正老视的临床应用和最新研究进展进行综述.     

老视的角膜矫正手术

老视是随着年龄增长、调节能力丧失出现视近物困难的一种生理现象,发病机制尚不明确。人口老龄化使老视人口及老视矫正的需求逐渐增多,老视的手术矫正方法正成为眼科医师关注的热点。随着技术和材料的不断发展,出现了多样化的老视矫正手术,包括经角膜老视矫正手术、晶状体老视矫正手术和巩膜老视矫正手术。尽管还没有一种完美的老视矫正手术能真正恢复眼的调节功能,现有的手术已取得一些临床效果。现对老视的角膜手术矫正方法做一综述。     

Q值与准分子激光角膜屈光手术

目前角膜非球面性参数Q值得到越来越多的眼科学者的关注,Q值已成为准分子激光角膜屈光手术不可忽视的重要参数。Q值的调整有助于减少球差的引入,同时Q值还在老视矫正手术中得到应用。现就Q值的相关研究以及在准分子激光角膜屈光手术中的应用作一综述。     

应用Monovision矫正老视的研究进展

Monovision矫正方法常用于老视和老视前期患者,即一眼矫正看远,另一眼矫正看近,其机制是双眼间的模糊抑制,MV可应用于单焦点角膜接触镜,并且还可应用于人工晶状体植入术和PRK,LASIK等激光屈光手术中,以及目前最新的非激光手术—传导性角膜成形术。本文就MV矫正的机制、对双眼视力功能的影响以及研究进展作一综述。     

影响老视眼视觉质量的关键因素

老视是与年龄相关的进行性眼调节力下降,老视的矫正不仅重视视力,而且要注重视觉质量。研究影响老视眼视觉质量的关键因素有利于寻求矫正老视的有效手段,达到提高视觉质量的目的。本文就人眼视觉质量的评价、非手术因素、人工晶状体植入、传导性角膜成形术及准分子激光手术等对老视眼视觉质量的影响进行综述。     

激光老视逆转术初步临床疗效及其机理探讨

目的 观察激光老视逆转术（LAPR）的初步临床效果，并探讨其矫正老视的机制。方法 用PR-270激光老视治疗仪对四名老视患者行单眼激光老视逆转术（LAPR），观察手术前后的远近视力、调节幅度、屈光、眼压等改变，评价手术效果，探讨该手术矫正老视的机制。结果 术后术眼近视力及调节幅度明显提高，术后一年时调节幅度平均增加1．8D，短期对侧眼视力及调节幅度也有轻微的提高，但是3个月后很快回退。术后短期内远视力有轻度改变，术后半年基本恢复了原有的视力。早期术后屈光改变主要表现在散光和球镜的转化，但一年时基本恢复到初始状态。术后1周眼压轻度降低，一个月后基本恢复到术前的水平。术后没有发生明显的眼部并发症。结论 激光老视逆转术（LAPR）术式简单、安全性高、术后回退率低，是一种有效的老视矫正术。它矫正老视的机理主要是通过增加巩膜的弹性、扩大睫状环的空间来加强睫状肌的调节作用。     

准分子激光角膜屈光手术矫治老视新进展

老视是指随年龄增长眼调节能力下降导致视近困难, 多在40岁以后出现症状。老视的矫治包括重建调节和改善症状两种, 前者目前仍难以实现, 而后者主要为配戴凸透镜。随着越来越多的患者有摆脱框架眼镜的愿望, 手术矫治的方法逐渐得到推广应用。准分子激光角膜屈光手术是手术矫治老视的常用方法之一, 本文在介绍该手术矫治老视理论机制的基础上, 回顾近期文献综述应用不同算法进行手术的新进展。     

老视及其矫正

老视是一种生理现象，不论屈光状态如何，每个人均会发生老视。随着人类社会的老龄化，老视的矫正问题成为我们日益严峻的挑战。本文拟就有关老视的调节机制及近年来一些矫正方法的原理、手术方式、临床应用结果作一综述。     

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.     

The mechanism of presbyopia

Accommodation in humans refers to the ability of the lens to change shape in order to bring near objects into focus. Accommodative loss begins during childhood, with symptomatic presbyopia, or presbyopia that affects one's day to day activities, striking during midlife. While symptomatic presbyopia has traditionally been treated with reading glasses or contact lenses, a number of surgical interventions and devices are being actively developed in an attempt to restore at least some level of accommodation. This is occurring at a time when the underlying cause of presbyopia remains unknown, and even the mechanism of accommodation is occasionally debated. While Helmholtz' theory regarding the mechanism of accommodation is generally accepted with regard to broad issues, additional details continue to emerge. Age-related changes in anterior segment structures associated with accommodation have been documented, often through in vitro and/or rhesus monkey studies. A review of these findings suggests that presbyopia develops very differently in humans compared to non-human primates. Focusing on non-invasive in vivo human imaging technologies, including Scheimpflug photography and high-resolution magnetic resonance imaging (MRI), the data suggest that the human uveal tract acts as a unit in response to age-related increasing lens thickness and strongly implicates lifelong lens growth as the causal factor in the development of presbyopia.     

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.     

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 1: physiology of accommodation and development of presbyopia

Accommodation is a dynamic change in the dioptric power of the eye. According to the widely accepted and experimentally confirmed theory of Helmholtz, it is achieved by release of zonular tension with contraction of the ciliary muscle and consecutive modelling of the shape of the crystalline lens by the elastic lens capsule. The ability to accommodate is gradually lost with age (presbyopia). Because of difficulties in examining the accommodative apparatus in vivo, many theories, in part contradictory, about the mechanism of accommodation and the origin of presbyopia have been developed. In recent years experimental studies have greatly increased the knowledge about the acommodative apparatus and suggest a multifactorial aetiology of presbyopia. A better understanding of the physiology of accommodation and presbyopia can contribute to the development of effective treatments.     

老视理论及治疗进展

老视是一种常见的眼部退行性病变,表现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,近年来出现了多种老视治疗方法。目前除了通过各种框架眼镜和接角镜来矫正老视,还可以应用手术方法如前睫状区巩膜切开样(AGS)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。本文总结了目前有关老视的各种机制和治疗方法。     

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.     

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.     

Cause and treatment of presbyopia with a method for increasing the amplitude of accommodation.

To understand the mechanism and cause of accommodation and presbyopia, the sclera in the region of the ciliary body of presbyopic patients was expanded. The amplitude of accommodation was increased in all presbyopic patients. A unique hypothesis of accommodation based on increased zonular tension is presented, which when applied clinically, results in a treatment for presbyopia.     

Akkommodation und Presbyopie

Accommodation is a dynamic change in the dioptric power of the eye. According to the widely accepted and experimentally confirmed theory of Helmholtz, it is achieved by release of zonular tension with contraction of the ciliary muscle and consecutive modelling of the shape of the crystalline lens by the elastic lens capsule. The ability to accommodate is gradually lost with age (presbyopia). Because of difficulties in examining the accommodative apparatus in vivo, many theories, in part contradictory, about the mechanism of accommodation and the origin of presbyopia have been developed. In recent years experimental studies have greatly increased the knowledge about the acommodative apparatus and suggest a multifactorial aetiology of presbyopia. A better understanding of the physiology of accommodation and presbyopia can contribute to the development of effective treatments.