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.     

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.     

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。     

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。     

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.     

飞秒激光晶状体老视手术的研究进展

由年龄增长所致的生理性眼调节下降引起、以视近困难为主要表现的屈光状态称为老视.老视的发生是多因性的,但晶状体年龄相关性硬化、弹性和变形能力下降以及调节力丧失是其主要致病机制.飞秒激光晶状体老视手术是近年来老视研究领域中出现的全新术式,其主要利用飞秒激光的光致分解作用按预设深度和形状在晶状体内进行微切开,从而制作出可滑动光爆破平面来治疗老视,整个手术过程在恢复自身晶状体弹性和变形能力的基础上,真正实现了眼的动态调节和连续聚焦功能,甚至逆转了年龄相关性的调节潜力丧失,为老视的治疗开辟了新的思路.在国外通过相关基础和临床试验,其矫治效果、有效性和安全性已得到初步验证,目前该技术尚处于研究阶段,仍面临很多问题,但它的出现革新了传统的老视治疗理念,相信其在老视手术中具有广阔的应用前景.本文就飞秒激光晶状体老视手术的理论依据、实验研究、效果评价及存在的问题等进行综述.     

老视的治疗研究现状

老视是一种自然性老化现象,其发生机制目前虽有所了解,但尚不完全清楚.文中就目前国内外对老视的发生机制及治疗方法包括非手术、手术的有关研究现状进行了综述,并认为惟有完全明确调节和老视的机制,才有可能产生新的逆转老视的有效方法.     

角膜热成形术治疗老视新进展

老视是正常人随年龄增加而生理性退化在眼部的表现,一般人40岁后就会出现老视现象,眼调节功能开始衰退,导致近距离用眼视力模糊不清、重影.50岁以后无一不受老视的困扰.随着人们生活水平提高,对延长工作、生活质量的要求,视光学有关的眼调节机制与老视的理论和矫正手术研究课题,正在成为世界范围内的研究热点.可以预料随着近视眼矫正手术的成熟发展后,倍受瞩目的屈光手术就是老视眼的矫正术.     

老视矫正型人工晶状体原理及临床应用新进展

白内障手术已从简单的复明手术发展成为更具挑战的屈光手术,手术需求者希望通过手术提高视力并摘掉眼镜,单焦点人工晶状体虽能解决患者视远问题却无法解决脱镜问题,由此老视矫正型人工晶状体应运而生.在双焦点人工晶状体的基础上,目前市场上新产生的几款老视矫正型人工晶状体成为了热门.本文将综述目前临床应用广泛的几款老视矫正型人工晶状体的设计原理及临床应用效果.     

准分子激光矫正老视的研究进展

老视是一种随着年龄增长而调节力逐渐下降的自然现象。 目前老视的机制尚未完全阐明,因此多种手术方法用于改善老视眼的调节。其中准分子激光手术成为矫正老视一种重要方法,而且其安全性及有效性不断进步。本文就老视的发生机制、治疗方法以及准分子激光矫正老视的手术方式和切削模式进行综述。     

Functional presbyopia in a rural Kenyan population: the unmet presbyopic need

Background: Presbyopia is the most common reason for requiring spectacles in low‐income regions, although the unmet need for presbyopic spectacles in these regions is very high. The aim of this study was to estimate the prevalence of presbyopia, and the functional impairment and spectacle use among persons with presbyopia in a rural Kenyan population. Methods: A cross‐sectional study was carried out in the Rift Valley, Kenya. Clusters were selected through probability‐proportionate to size sampling, and people aged ≥50 years within the clusters were identified through compact segment sampling. Within the context of this survey, 130 eligible participants were selected for interview and underwent near‐vision testing. Functional presbyopia was defined as requiring at least +1.00 dioptre in order to read the N8 optotype at a distance of 40 cm in the participant's usual visual state. Participants were corrected to the nearest 0.25 dioptre in order to see N8. Unmet and met presbyopic need, and presbyopic correction coverage were calculated. Results: Functional presbyopia was found in 111 participants (85.4%). Mean age was lower in those with presbyopia (64.1 years vs. 71.5 years, P = 0.004). Increasing degree of addition required to see N8 was significantly associated with increased difficulty with reading (P = 0.04), sewing (P = 0.03), recognizing small objects (P = 0.02) and harvesting grains (P = 0.05). Among participants with functional presbyopia, 5.4% wore reading glasses and 25.2% had prior contact with an eye care professional. The unmet presbyopic need was 80.0%, met presbyopic need was 5.4% and presbyopic correction coverage was 6.3%. Cost was cited as the main barrier to spectacle use in 62% of participants with presbyopia. Conclusion: In low‐income regions, there is a high prevalence of uncorrected presbyopia, which is associated with near‐vision functional impairment. Provision of spectacles for near vision remains a priority in low‐income regions.     

Change in the accommodative force on the lens of the human eye with age

The aim of the study was to determine the age-dependence of the accommodative force on the lens in order to make it clear whether the causes of presbyopia are due to lenticular or extralenticular changes. A finite element model of the lens of an 11-, 29- and 45-year-old human eye was constructed to represent the fully accommodated state. Subsequently, the force that was needed to mould the lens into its unaccommodated state was calculated. The force on the lens appeared to be preserved with age, with only a slight increase to a value of approximately 0.06N. In conclusion, the preservation of the net force delivered by the extralenticular ciliary body indicates that the causes of presbyopia must be ascribed to lenticular changes.     

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。     

Prevalence of presbyopia in a semi-urban population of southwest,Nigeria: a community-based survey

Uncorrected presbyopia is a major cause of poor near vision in the developing countries. To determine the prevalence and demographic characteristics of presbyopia among adult populations (40 years and above) in a sub-urban population, southwest Nigeria, a population-based cross-sectional study was carried out from April to May 2014. A multi-stage sampling method was used to select eligible respondents. All participants had distance visual acuity assessment done and participants with visual acuity of less than 6/6 were refracted. Near vision was then assessed at 40 cm with distance correction in place if required. Information on near vision was obtained from the participants using interviewer administered questionnaires. Data collected were analysed using SPSS version 22. A total of 440 subjects aged 40 years and above were studied. Prevalence of presbyopia was 75 % and was significantly associated with increasing age. There was higher prevalence of presbyopia among females than males (76.3 % vs. 73.5 %), though not statistically significant. Also prevalence of presbyopia was not significantly associated with educational and occupational status in the study. This study demonstrated a high prevalence of presbyopia. There is need for improved awareness on presbyopia screening and available correction in the local government.     

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.     

老视矫正手术的临床应用与展望

随着人们对生活质量的需求提高,老视问题越来越受到关注。像屈光不正矫正手术一样,老视的激光矫正治疗无论是设备开发还是临床手术的应用都逐年增多,如角膜的激光、角膜板层间镶嵌、角膜热重塑、巩膜气化等。但是老视又与屈光不正（近视、远视和散光）不同,到了一定年龄屈光度会相对稳定,而老视则与年龄有紧密的相关性。目前老视人群庞大,因此有许多人期待着安全、有效、可预测性强、远中近视力都能兼顾的老视矫治手术。     

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.     

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。