角膜塑型镜控制青少年近视效果及机制的研究进展

在近视控制方面,与传统的药物和光学疗法相比,角膜塑型镜疗效显著。通过塑形作用获取周边视网膜近视性离焦可能是角膜塑型镜控制近视进展的主要机制之一。本文就角膜塑型镜控制近视进展的循证证据、角膜塑型镜制造周边近视性离焦、角膜塑形镜的塑形作用以及临床应用中的问题和拓展进行综述。     

角膜塑形镜离焦技术在近视防控中的研究进展

近视发病率在全球范围内呈逐渐上升趋势,严重影响青少年儿童的眼部健康,引起了巨大的经济和社会效益损失。因此,近视防控工作至关重要且刻不容缓。近年来,角膜塑形镜逐渐在近视防控领域体现出其优越性。目前,角膜塑形镜控制近视发展的原理主要以视网膜远视性光学离焦学说为主,促使近视患者的远视性离焦向近视性离焦漂移从而延缓眼轴增长。其控制近视发展的效果与多种因素相关,包括离焦总量、瞳孔直径、光学区设计及镜片偏心等。角膜塑形镜的广泛使用将有效降低青少年儿童的近视发病率,本文就角膜塑形镜利用离焦技术控制近视发展的原理、离焦量和离焦环位置与近视防控效果的关系等方面进行综述,旨在阐明角膜塑形镜离焦技术在近视防控中的研究进展。     

多焦软性角膜接触镜对周边屈光度及周边角膜屈光力的影响

目的：观察配戴多焦软性角膜接触镜引起的周边屈光度及周边角膜屈光力的变化,研究二者之间的关系。方法：自身对照研究。于2020年10月1─15日在温州医科大学收集成年近视受检者18例,在配戴单焦软性角膜接触镜（简称单焦软镜）和多焦软性角膜接触镜（简称多焦软镜）状态下分别采用红外自动验光仪和角膜地形图测量周边屈光度及周边角膜屈光力。周边屈光度的测量范围为鼻颞侧30°（5°间隔）。周边屈光度与中心屈光度的差值为相对周边屈光度（RPR）。通过拟合获得鼻颞侧相对周边屈光度曲线,曲线下面积即视网膜相对周边屈光面积（ARPR）。根据高斯光学系统,计算各注视方位相应的角膜坐标,获取各位点的全角膜屈光力,并计算角膜相对周边屈光力（CRPR）和角膜ARPR。采用配对t检验比较各状态RPR和CRPR,采用 Pearson相关分析法分析视网膜ARPR与角膜ARPR的关系。结果：配戴单焦软镜时鼻侧（5°至25°）及颞侧（5°至20°）的RPR呈远视状态,配戴多焦软镜使各点RPR发生近视性漂移（均P<0.001）,除鼻侧5°、颞侧30°外。配戴多焦软镜时,鼻侧（25°～30°）及颞侧（10°～30°）CRPR与配戴单焦软镜时相比呈现出更大的正屈光力（均P<0.001）。配戴多焦软镜时,视网膜ARPR与相应的角膜ARPR呈正相关（r=0.54,P=0.031）。结论：多焦软镜使角膜周边的相对正屈光力增加,从而增加了视网膜的周边近视性离焦量。临床上,配戴多焦软镜引起的角膜屈光力变化可以在一定程度上反映视网膜离焦的变化。     

周边视网膜相对屈光度与近视进展的关系

在正视眼或者低度远视眼中,周边视网膜呈相对远视屈光状态者比周边视网膜呈相对近视屈光状态者更容易发展为近视眼.正视眼周边视网膜呈轻度相对近视屈光状态,未矫正的远视眼周边视网膜呈稍大程度的相对近视屈光状态,未矫正的近视眼周边视网膜呈轻度相对远视屈光状态或比正视眼程度轻的相对近视状态.这两种观点已经被学者广泛接受.动物实验也证明异常视觉信号不仅能引起中央视网膜屈光不正,也能改变眼球后极部眼球形态和周边视网膜相对屈光不正的类型,并且黄斑切除并不影响正视化过程.相反,周边视网膜能单独调控眼球正视化过程并能对异常视觉信号起作用进而发展为各种屈光不正.临床研究表明,矫正视网膜周边远视性离焦的框架镜片对近视眼进展能起到一定的控制作用.虽然,周边视网膜远视性离焦是否促进近视进展的确切原因还不能肯定,但目前的研究倾向于认为两者之间可能有某种关系.     

高度近视患者与中低度近视患者周边屈光度的比较研究

目的研究高度近视与中低度近视患者周边屈光度的差异。方法对45例2013年6~10月在本院眼视光学中心就诊的近视患者(-2.50~-11.50 D)进行周边屈光度测量。患者平均年龄为(28.67±7.37)岁(20~47岁)。将患者分为高度近视组(球镜>-6.00 D,26例)和中低度近视组(球镜≤-6.00 D,19例)。遮盖左眼,右眼裸眼状态下,从颞侧30°至鼻侧30°依次注视7个2.5 m远视标,用红外自动验光仪获取6个角度的周边屈光度和1个中心屈光度。周边屈光等效球镜值(Ma)减去中心屈光等效球镜值(M0)即得到相对周边屈光度(RPRE)。周边与中心散光均分解为180°轴位散光(J180)和45°轴位散光(J45)。结果高度近视组和中低度近视组的平均RPRE在颞侧视网膜差异有统计学意义(P<0.05),且随偏中心注视角度的增加而增大,高度近视组的RPRE比中低度近视组更倾向于远视性离焦,而在鼻侧视网膜差异无统计学意义(P值均>0.05)。高度近视组鼻、颞侧RPRE不对称,颞侧视网膜较鼻侧视网膜远视性离焦量大(P<0.05)。2组患者周边散光差异无统计学意义。结论高度近视颞侧远视性离焦较中低度近视更加显著,可能与高度近视患者近视持续加深相关。     

中国青少年近视患者水平视网膜相对周边屈光度和散光分量曲线类型研究

背景 视网膜相对周边屈光度(RPR)状态与近视进展的关系近年来成为研究的热点,目前尚缺乏对中国近视人群中视网膜RPR状态及散光分量的研究.因此,有必要针对中国青少年近视患者的视网膜RPR类型及散光分量进行分型研究. 目的 研究中国青少年近视患者视网膜RPR和散光分量的曲线类型.方法 选取2014年6月至2015年10月在北京大学人民医院眼科就诊的青少年近视患者301例301眼.以5°作为间隔,采用WAM-5500型开放视野红外验光仪采集从水平视野鼻侧30°至颞侧30°的周边屈光度数据.仅选取右眼数据进行分析.计算各个角度的等效球镜度(SER),用中央SER减去水平周边SER即为视网膜RPR(以离焦表示).依据视网膜RPR曲线的不同形态及鼻侧与颞侧的相对关系将视网膜RPR整理分型.采用傅里叶分解法将各个角度的散光分解为J0和J45分量,分析散光分量的曲线类型.结果 视网膜RPR曲线可分为7种类型,分别为负离焦型、颞侧正离焦鼻侧平坦型、颞侧正离焦鼻侧负离焦型、颞侧平坦鼻侧负离焦型、平坦型、颞侧负离焦鼻侧平坦型和正离焦型.散光分量Jo和J45可分为9型.中高度近视在Ⅰ型RPR(负离焦型)中的分布明显高于低度近视,差异有统计学意义(X2=26.770,P＜0.05);低度近视在Ⅲ型RPR(颞侧正离焦鼻侧负离焦型)中的分布明显高于中高度近视(X2=12.500,P＜0.05). 结论 低度近视与中高度近视的RPR曲线类型分布存在明显差异.散光绝对值在水平方向周边区域呈现鼻侧、颞侧不对称性.在视网膜鼻侧,随着注视角度的增加,其所对应的散光绝对值呈现逐渐增加的趋势(鼻侧10°除外).     

周边屈光对近视的影响

周边屈光,即周边视网膜的屈光状态,指与视轴成一定的夹角,距注视点30°以外周边视野内的屈光状态。动物及人类研究表明,周边屈光与近视存在密切关系。周边相对远视的屈光度数能影响中央近视度数,不同年龄阶段人群周边相对远视的屈光状态均呈现为近视发生的危险因素,并可能为近视眼屈光度进展的危险因素之一。周边近视离焦可能阻止眼轴增长,从而控制近视进展、促进视力恢复。我们归纳近年来周边屈光对近视的发生、发展及控制的影响,及其与眼球形态、调节、遗传的关系进行综述。     

配戴角膜塑形镜和框架眼镜对近视儿童周边屈光度影响的随机对照临床试验

背景 临床实践发现角膜塑形镜具有延缓近视及眼轴长度进展的效果,但对于角膜塑形镜配戴的相关作用机制,特别是角膜塑型术对视网膜中心和周边的离焦作用机制尚不完全清楚. 目的 观察低中度近视儿童配戴角膜塑形镜和框架眼镜6个月后周边屈光度以及相对周边屈光度(RPR)的变化.方法 采用随机对照临床试验方法,于2014年6月至2015年1月在北京同仁眼科中心招募屈光度为-0.50～-6.00 D的低中度近视儿童100例,平均年龄(11.0±1.9)岁,均纳入右眼进行研究.受试者按入组顺序编号后由SAS统计软件PROC PLAN过程语句随机均分为角膜塑形镜组和框架眼镜组,每组50例50眼,戴镜时间均为6个月.采用开放视野红外自动验光仪分别测量戴镜前后中央0°、颞侧15°和30°、鼻侧15°和30°径线的屈光度,观察并比较各组受试眼戴镜前后周边屈光度和RPR(周边屈光度与中央屈光度差值)变化趋势. 结果 角膜塑形镜组和框架眼镜组受试者戴镜前屈光度分别为(-3.35±1.31)D和(-3.01±1.15)D,差异无统计学意义(P=0.201).角膜塑形镜组受试眼戴镜前鼻侧30°、鼻侧15°、中央0°、颞侧15°和颞侧30°径线周边屈光度分别为(-2.28±1.60)、(-3.28±1.41)、(-3.40±1.23)、(-3.38±1.12)和(-2.09±1.29)D,受试眼除颞侧30°外戴镜后6个月近视度数均下降,戴镜前后鼻侧30°、鼻侧15°、中央0°、颞侧15°屈光度变化值分别为(0.29±1.67)、(0.85±1.66)、(0.92±1.76)和(0.66±1.66)D,其中鼻侧15°、中央0°、颞侧15°与戴镜前相比差异均有统计学意义(均P＜0.05).框架眼镜组受试者戴镜前鼻侧30°、鼻侧15°、颞侧15°和颞侧30°径线周边屈光度分别为(-1.88±1.30)、(-2.66±1.18)、(-2.89±1.27)和(-1.94±1.31)D,戴镜后6个月上述各径线近视度数均增加,戴镜前后变化值分别为(-0.25±0.80)、(-0.43±0.67)、(-0.32±0.64)和(-0.22±0.75)D,与戴镜前比较差异均有统计学意义(均P＜0.05).角膜塑形镜组受试者戴镜前各径线RPR均为远视性离焦状态,戴镜后6个月颞侧15°和颞侧30°RPR变为近视性离焦状态.框架眼镜组受试者戴镜前各径线RPR均为远视性离焦状态,戴镜后各径线RPR均呈远视性离焦加深状态.结论 长期配戴角膜塑形镜能够使近视儿童的周边屈光度发生远视性漂移,视网膜周边呈现相对近视性离焦,而长期配戴框架眼镜则使周边屈光度发生近视漂移,视网膜周边远视性离焦加深.角膜塑形镜配戴可能通过改变周边屈光度而达到减缓近视进展的目的.     

角膜塑形镜和周边离焦框架镜近视控制效果比较

目的:探讨周边离焦框架镜和角膜塑形镜对儿童青少年近视患者眼轴的控制效果。方法:前瞻性研究。选取2019-06/2021-06在龙岩市第二医院就诊的儿童青少年近视患者71例134眼,配戴周边离焦框架镜12mo后配戴角膜塑形镜。随访观察配戴周边离焦框架镜、角膜塑形镜3、6、12mo的眼轴增长情况。结果:纳入患者配戴周边离焦框架镜、角膜塑形镜12mo眼轴增长中位数分别为0.35、0.14mm,配戴角膜塑形镜3、6、12mo眼轴增长量均低于周边离焦框架镜(P<0.001),且眼轴增长速度明显减缓。根据配戴周边离焦框架镜12mo眼轴增长量将纳入患者分为快速进展型组(眼轴增长≥0.4mm, 29例54眼)和非快速进展型组(眼轴增长<0.4mm, 42例80眼),两组患者配戴周边离焦框架镜12mo眼轴增长量中位数分别为0.70、0.24mm,配戴角膜塑形镜12mo眼轴增长量中位数分别为0.31、0.09mm,两组患者配戴角膜塑形镜12mo眼轴增长速度分别减缓56%、63%。非快速进展型组患者配戴角膜塑形镜12mo眼轴增长量低于快速进展型组,且不随年龄和屈光度变化。快速进展型组中不同年龄、...     

调节、离焦与儿童近视关系的研究进展

近视已成为全球一个重大的问题,近年来学者们对近视的发展机制进行了大量研究。调节滞后是儿童近视发展的一个重要影响因素,近视儿童调节反应的变化性高于正视儿童,调节滞后亦重于正视儿童。周边视网膜像处于正视状态或低度远视离焦状态者相对于处于近视离焦状态者发展近视的危险性要高。本文就调节及周边离焦与近视发展关系的研究进展做一综述。     

光学离焦技术控制近视的研究进展

近视是一种常见的眼病,近年来,近视的发生率在全球范围内呈逐年上升趋势,高度近视会增加视力丧失的风险,近视的并发症可引起巨大的经济和社会效益损失。因此,实施控制近视的有效措施至关重要且迫在眉睫。人们对近视的发病机制研究表明,周围远视离焦引起眼球轴向伸长不受控制可能是近视发展的机制之一,由此引申的各种光学策略尤其是光学离焦技术控制近视日益成为近视管理主流临床实践的一部分。本文从光学离焦控制近视的原理、离焦性近视动物实验研究、不同光学离焦技术控制近视的最新临床应用等方面进行综述,总结了使用渐进多焦眼镜、周边离焦框架眼镜、多点近视离焦框架眼镜、角膜塑形镜及多焦点软性角膜接触镜控制近视的临床研究结果,拟为延缓近视进展的治疗方案设计提供新的选择。     

配戴减少周边远视离焦眼镜对近视儿童眼部参数的影响

目的：通过比较配戴减少周边远视离焦设计的框架眼镜(AMSPL)和普通球柱镜框架眼镜(SPL)对近视儿童眼部各参数的影响,确定AMSPL安全性和有效性。

方法：随机抽取2017-07/2018-02于我院眼科中心配戴AMSPL的8～14岁近视儿童50例作为AMSPL组,同样抽取年龄、近视程度及配镜时间相当的SPL配戴者资料50例作为SPL组。检查两组患者眼压、睫状肌麻痹下的屈光状态、远距水平隐斜、近距水平隐斜、AC/A等双眼协动参数。

结果：AMSPL组儿童配戴初期舒适程度略低于SPL组,主要为周边视物模糊,但1mo后两者无差异; AMSPL组屈光不正度数年平均增长-0.62±0.50D,SPL组年平均增长-0.77±0.48D(P=0.072); 对于8～10岁近视儿童AMSPL组屈光不正度数年平均增长(-0.71±0.41D)低于SPL组(-1.05±0.39D),差异具有统计学意义(t=2.164,P=0.041); AMSPL组和SPL组远距水平隐斜、近距水平隐斜、AC/A等双眼协动参数无差异(P>0.05)。

结论：配戴AMSPL能在一定程度上延缓近视发展,尤其对于低龄近视儿童(8～10岁)效果较明显。配戴AMSPL与SPL相比眼部参数无明显变化,这表明近视儿童配戴AMSPL与SPL同样安全。     

Optical changes and visual performance with orthokeratology

Orthokeratology has undergone drastic changes since first described in the early 1960s. The original orthokeratology procedure involved a series of lenses to flatten the central cornea and was plagued by variable results. The introduction of highly oxygen-permeable lens materials that can be worn overnight, corneal topography, and reverse-geometry lens designs revolutionised this procedure. Modern overnight orthokeratology causes rapid, reliable, and reversible reductions in refractive error. With modern designs, patients can wear lenses overnight, remove them in the morning, and see clearly throughout the day without the need for daytime refractive correction. Modern reverse-geometry lens designs cause central corneal flattening and mid-peripheral corneal steepening that provides clear foveal vision while simultaneously causing a myopic shift in peripheral retinal defocus. The peripheral myopic retinal defocus caused by orthokeratology is hypothesised to be responsible for reductions in myopia progression in children fitted with these lenses. This paper reviews the changes in orthokeratology lens design that led to the reverse-geometry orthokeratology lenses that are used today and the optical changes these lenses produce. The optical changes reviewed include changes in refractive error and their time course, high- and low-contrast visual acuity changes, changes in higher-order aberrations and visual quality metrics, changes in accommodation, and changes in peripheral defocus caused by orthokeratology. The use of orthokeratology for myopia control in children is also reviewed, as are hypothesised connections between orthokeratology-induced myopic peripheral defocus and slowed myopia progression in children, and safety and complications associated with lens wear. A better understanding of the ocular and optical changes that occur with orthokeratology will be beneficial to both clinicians and patients in making informed decisions regarding the utilisation of orthokeratology. Future research directions with this lens modality are also discussed.     

Practical applications to modify and control the development of ametropia

For many individuals, the developmental trend of lessening hyperopia from birth continues past emmetropia towards myopia during childhood. The global pattern for prevalence of refractive errors indicates that the prevalence of hyperopia is low; in contrast, the burden of myopia is on the rise because of rising prevalence and magnitude of myopia. This review highlights the need to lessen the global burden of myopia by intervening with the development and/or slowing the progression of myopia. Further, outcomes from human clinical trials of pharmaceutical, optical, and environmental approaches to control myopia will be summarised. Pharmaceutical treatments are effective in controlling eye growth but are associated with deleterious side effects. Optical strategies that induce myopic defocus at the retina such as peripheral defocus reducing lenses, simultaneous defocus lenses, bifocals, and orthokeratology as well as environmental influences such as increased outdoor activity show promise and provide a substantially risk-free environment in which to control eye growth.     

Optical mechanisms regulating emmetropisation and refractive errors: evidence from animal models

Our current understanding of emmetropisation and myopia development has evolved from decades of work in various animal models, including chicks, non-human primates, tree shrews, guinea pigs, and mice. Extensive research on optical, biochemical, and environmental mechanisms contributing to refractive error development in animal models has provided insights into eye growth in humans. Importantly, animal models have taught us that eye growth is locally controlled within the eye, and can be influenced by the visual environment. This review will focus on information gained from animal studies regarding the role of optical mechanisms in guiding eye growth, and how these investigations have inspired studies in humans. We will first discuss how researchers came to understand that emmetropisation is guided by visual feedback, and how this can be manipulated by form-deprivation and lens-induced defocus to induce refractive errors in animal models. We will then discuss various aspects of accommodation that have been implicated in refractive error development, including accommodative microfluctuations and accommodative lag. Next, the impact of higher order aberrations and peripheral defocus will be discussed. Lastly, recent evidence suggesting that the spectral and temporal properties of light influence eye growth, and how this might be leveraged to treat myopia in children, will be presented. Taken together, these findings from animal models have significantly advanced our knowledge about the optical mechanisms contributing to eye growth in humans, and will continue to contribute to the development of novel and effective treatment options for slowing myopia progression in children.     

Effectiveness of peripheral defocus spectacle lenses in myopia control: a Meta-analysis and systematic review

AIM: To evaluate the effectiveness of peripheral defocus spectacle lenses (PDLs) in myopia control. METHODS: Literature retrieval on PubMed, Cochrane Library, Embase, and Web of Science databases, and the search time limit was from the establishment of each database to December 29, 2021 were conducted. Change of spherical equivalent refraction (SER) and axial change (AL) were extracted from the literatures that met the inclusion criteria, and RevMan5.3 software was used for Meta-analysis. RESULTS: A total of 4 randomized controlled trials (RCTs) were included in this Meta-analysis, involving 770 myopic children. The results showed that PDLs could delay the progression of myopia in children with myopia compared with single vision spectacle lenses (SVLs; WMD=0.21 D, 95%CI: 0.01, 0.41, P=0.04). However, there was no significant difference in controlling the growth of axial length (AL) in myopic children (WMD=-0.10 mm, 95%CI: -0.21, 0.01, P=0.07). The results of the effectiveness of myopia control between the two spectacle lenses showed that PDLs were more effective in controlling the progression of myopia (OR=5.73, 95%CI: 2.58, 12.70, P<0.001) and delaying the growth of AL (OR=44.25, 95%CI: 8.84, 221.58, P<0.001) than SVLs, and the differences were statistically significant. CONCLUSION: PDLs can control the progression of myopia compared with SVLs, but cannot delay the growth of AL, and the effectiveness of PDLs in myopia control better than SVLs.     

脉络膜厚度与近视防控研究进展

近视是指外界的平行光线经过眼的屈光系统后落在视网膜黄斑中心凹前方的屈光状态。近视严重影响了青少年的健康成长,近视防控成为社会普遍关注的热点问题。研究普遍认为,近视与脉络膜变化有着密切关系,随着屈光度增加、眼轴增长,脉络膜厚度呈现逐渐变薄趋势。循证医学研究证实有效的近视防控方法(角膜塑形镜、离焦镜片、阿托品滴眼液、光照、后巩膜加固术等)均呈现出脉络膜增厚效应,提示脉络膜增厚是近视控制的保护因素。本文围绕现行的近视防控有效方法对脉络膜厚度的影响展开综述,以期为将脉络膜厚度变化作为近视防控疗效评价指标提供参考。