视觉认知与近视

大脑接收的外界信息80％以上来源于视觉,视觉系统与脑的许多高级功能密切相关.大量的视觉信息从视网膜开始向大脑传递,最终产生感觉和认知.近视作为一种屈光异常状态,将会影响视觉信息的获得,并影响大脑对外部信息的分析及处理,从而影响个体对环境的适应.目前视觉行为学方法是研究视觉认知功能的工具,通过行为学方法可观察动物的识别能力、空间记忆力等方面的功能.研究近视与视觉认知的关系可加深对近视发生机制及其所产生影响的了解,为深入研究近视提供新的思路.     

视感知觉训练对间歇性外斜视患者术后双眼视觉重建的研究进展

间歇性外斜视(IXT)是一种发病率高、斜视角度多变、双眼视觉功能不同程度受损的眼科常见疾病。双眼视觉功能缺损与视觉皮层的改变有关,IXT涉及包括双眼融合相关皮质区域在内的多个脑区的功能改变,部分IXT患者在矫正眼位后,大脑皮层的异常改变依然存在,双眼视觉的恢复仍然困难。针对这些问题,视感知觉训练逐渐应用到IXT患者术后双眼视觉功能的重建中,视感知觉训练从大脑层面修复视觉皮质,通过不断刺激视觉中枢,提高大脑视皮层处理信息的能力,进而修复视觉中枢功能,使患者获得良好的双眼视觉功能,稳定眼位,减少复发。本文就IXT患者双眼视觉损伤机制以及视感知觉训练在IXT治疗中的作用做一综述。希冀为视感知觉训练重建IXT患者术后双眼视觉功能、降低复发率提供更多证据。     

运动员视觉保健

视觉作为在人类多种感观认识功能中占主导地位的感知方式，对体育竞技中的各类感觉运动性活动具有举足轻重的作用。运动视觉的医疗职能包括：①预防和治疗体育和竞技运动中造成的眼部损伤。②评估和矫正某些影响协调性运动机能的视功能异常。③针对体育运动的环境性因素展开专业性的角膜接触镜业务，并对一些对眼动、视力和应急状态具有特殊要求的竞技项目提供帮助。④基于视觉和环境等因素的考虑，向专业运动员提供特制的眼部保护装置和助视仪器。⑤评估与某些竞技运动项目密切相关的视觉功能及技巧。⑥通过对运动员的视功能强化训练进而提高其运动成绩。⑦向运动员、教练员或整个团队提供有助于提高运动成绩的视觉功能及技巧的咨询。人们一直都很关注视觉功能与运动成绩之间的联系，许多专家与临床医生都试图寻求与特定的运动技能相关的特殊视觉技巧，进而建立精确的方法予以评估。运动员具有比非运动员更好的视觉功能，而与一般的运动员比较，顸尖水平的运动员往往从优异的视觉功能中获益更大。不同的视觉功能对于帮助运动员取得优秀成绩的作用在运动项目中是有所差异的。运动视觉专家必须区分出哪些视功能是与运动相关的关键性的视功能，并用最恰当的方法对其进行评估。不同的运动项目，对视觉功能的要求也常常不同。运动员的验光矫正包括运动或娱乐过程中配戴特制的框架眼镜及角膜接触镜。在决定最佳处方的同时，应考虑最适合的镜片种类、镜框设计、染色特征和应考虑的安全防护因素。基于运动和环境需要的角膜接触镜染色工艺是目前正在研究和发展中的高新技术，其产品即将面世，在运动或娱乐场所的不同光照环境下能够减少眩光，提高视觉舒适性，增强视功能。运动型太阳眼镜光学性能的改善和上述染色型角膜接触镜的发展，将为运动员们减少眩光提供了可能的解决方法。为运动员们提供视觉保健时，首先应予考虑的问题是减少在训练和比赛中的眼部损伤。通常在采用了这些眼保措施后，绝大多数损伤是可以避免的。运动员所接收的视觉信息的质量和各种感观接收器提供的大量反馈信息是影响其赛场表现的关键因素。技巧性动作的熟练程度和运动员以往的经验对于运动系统(肌肉)运行的有效性和效率的影响是不可估量的。有天赋的运动员能够稳定而持久地在赛场发挥出色，而且似乎一点都不费力。通过筛选出对运动影响显著的视功能并加以强化训练，进而提高运动员成绩已成为可能。专业人士已经设计出多种视功能训练方案以改善视觉技巧和与视觉相关的运动技巧，并提高视觉信息传递过程中的效率。眼科保健工作者可以采用很多方法来帮助运动员尽量发挥其潜能。通过分析与运动员从事的运动最相关的视功能，可以指导眼科保健工作者选择最适合的矫正模式，如最佳的配戴设计、染色、角膜接触镜参数以及保护方案等。当眼保健工作者选择视觉训练来矫正功能不足或强化与运动相关的视功能时，需要和运动员进行交流，使其积极配舍。结果表明，不但是那些顸尖的运动员能从我们的医疗服务中获益，而且各种人群因为接受训练进而改善了视功能并提高了自身的生活质量。     

重视与体育运动有关的视觉科学研究

体育运动与视觉功能关系密切,不同的体育项目对视觉功能的要求不同.大部分体育项目对视觉的需求都是综合性的,即不仅需要敏锐的视力、立体视、色觉、视野等静态视觉,还需要快速的眼球运动、调节辐辏等动态视觉.优秀运动员必须具备良好的视觉功能,而相关的视觉功能训练可望提高运动成绩.我们应重视并开展体育运动与视觉科学的研究.     

视觉重塑在视觉损伤中的原理及应用进展

中重度视觉损伤会严重影响患者的生活质量,但目前又缺乏有效的治疗手段。近年来,有研究结果表明,视觉损伤后大脑会自发通过皮质重塑调节自身结构与功能,这提示通过视觉重塑恢复视觉具有现实可能性。对视觉损伤人群进行微视野生物反馈训练、非侵入性脑刺激及丰富环境等疗法可能促进视觉重塑。然而,视觉功能重塑的原理尚不明确,由此展开的应用仍有诸多限制。本文中笔者就视觉重塑的原理以及应用进展进行综述,以期为视觉损伤提供新的治疗思路。     

基于认知学习理论的儿童视觉功能训练读物研究

传统儿童读物的对象往往是正常儿童,而对视觉功能有缺陷的弱视儿童并不合适。设计一种能让弱视儿童在完善双眼视功能的同时提高其学习能力的读物,是眼科学也是学习科学中的一个研究方向。为此,从认知学习理论和弱视儿童心理特点出发,结合视觉功能训练原理,设计一种适合弱视儿童的双眼视觉功能训练读物。将该读物应用于临床,经1mo的训练数据表明,该读物一定程度上提高了其双眼视觉功能和学习能力,为弱视儿童完善双眼视功能和提高学习能力提供了一种切实有效的途径。     

视觉-运动整合理论模型及其临床应用

对环境中的物体和事件的认知即知觉视觉是视觉的一个重要功能,然而视觉的进化最初不是提供对世界本身的感知,而是为生物提供作出不同运动时的末梢感官控制运动视觉。随着视觉与认知神经科学的发展,对视觉-运动之间关系的研究逐渐系统化,形成了视觉-运动整合的理论模型。本文综述了视觉-运动整合的理论模型及其与临床相关病种的关系,并针对视觉-运动整合理论模型的临床应用展开讨论。     

视觉信息加工的神经机制

外界信息的80%是经视觉系统传人大脑,视觉系统与脑的许多高级功能密切相关,对视觉信息加工机制的研究成为神经科学、认知科学的热门课题.随着脑科学的发展,视觉信息加工机制的研究进入一个崭新阶段.就视觉通道、等级加工、功能特异化、选择性注意、视皮层细胞的同步振荡等进行综述.     

脑卒中后的视觉障碍及康复

视觉障碍是脑卒中的常见并发症,可表现为视感觉障碍、视运动障碍和视知觉障碍,影响患者的视觉感受和生活质量,并可阻碍全身整体康复进程。视感觉障碍包括视力下降和视野缺损,配镜和助视器有助于改善视力,视野缺损的康复手段包括替代性治疗、补偿性训练及恢复性治疗;视运动障碍包括斜视和眼球运动障碍,治疗方法包括眼球运动训练、棱镜、遮盖、药物及斜视矫正手术等;视知觉障碍最常见的是视觉忽略,治疗方法包括针刺及其他康复手段。对视觉障碍的有效治疗和康复,为脑卒中患者的全身康复提供了良好的视觉条件。（国际眼科纵览,2022, 46：370-377）     

功能性磁共振成像在人类视觉皮层定位的应用

功能性磁共振成像作为一种非侵入性、空间分辨率高且可精确定位大脑功能活动区域的技术,在哺乳动物尤其是猕猴和人类的视觉系统研究中得到了广泛应用,并取得了许多成果.本文综述了人类大脑功能性磁共振信号的测量原理、方法和定位,介绍了视觉皮层的功能分区,包括已得到普遍承认的11个视觉相关区域,其可能的组织形式是依据共同的离心性分布特点将它们分成数个簇,在一个簇内的各分区有相似的视觉功能.     

Vision and self‐reported mobility performance in patients with low vision

Background: As vision plays a significant role in mobility performance, it is usual to refer low vision patients, particularly those who complain of mobility difficulties, for orientation and mobility (O&M) training to help them maintain safe independent travel. Our study aimed to determine whether there was a relationship between measures of vision and self‐reported mobility, and the applicability of a patient‐based mobility assessment in patients with heterogeneous causes of visual loss. Method: We assessed the high and low contrast visual acuity, visual field and scanning ability of 30 patients with low vision. A validated mobility questionnaire was used to assess the participants’ perceived visual ability for independent mobility. Results: Vision was significantly correlated with self‐reported mobility performance, however, visual field was a significant predictor accounting for 56.5 per cent of the variance. The instrument was well constructed with valid content and high reliability scores. Conclusions: Self‐reported mobility performance together with measures of vision could be used as a guide to refer patients for O&M training. The patient‐based assessment instrument was valid to measure perceived visual ability for independent mobility in patients with heterogeneous causes of visual loss.     

Experimental study of visual training effects in shooting initiation

Introduction : The present study was conducted to investigate the influence of specific visual training in shooting initiation performance. Methods : Seventy-one first-year university students were divided randomly into two groups. The experimental group followed a nine-session shooting training program that included technical, physical and psychological components, along with specific visual exercises. The control group followed the same program with one difference: this group received theoretical lectures on psychological training techniques instead of doing visual exercises. Pre- and post-test results were obtained for shooting, concentration, saccades and visual acuity. Results : Statistical analysis indicated significant gains in the four mentioned variables for the experimental group. The control group also showed significant differences in the three first variables but no significant improvement in visual acuity. No significant differences in shooting performance were observed between groups. Conclusions : The effect of vision training on sports initiation performance is still not clear. It cannot be assumed that the improvement is transferable to the performance of precision shooting at the stage of sports initiation.     

A Survey of Drivers Vision in Victoria

ABSTRACT A survey was conducted of presenting patients to optometric practices who held drivers licences. It was found that 12.3% failed the visual acuity standard (6/12) with their habitual vision; however, only 1.2% could not attain the standard with their best corrected vision. Of those who failed the standard but could be corrected to better than the standard 21.3% refused to accept the correction or the change in correction. It is argued that voluntary controls do not maintain the visual standard of a driving population and that more stringent licensing procedures should be adopted.     

屈光参差性弱视儿童双眼视觉状态

目的：分析屈光参差性弱视儿童的屈光状态、矫正视力情况及其与双眼视觉功能的关系。方法：横断面研究。收集2015年11月至2016年9月就诊于北京9家医院（分布于8个区县）的屈光参差性弱视儿童患者106例（106眼），年龄（6.2±5.4）岁。根据屈光参差危险因素将所有患者分为远视性屈光参差组（67例）、近视性屈光参差组（5例）、散光性屈光参差组（12例）、远视合并散光性屈光参差组（20例）及近视合并散光性屈光参差组（2例）。对所有患者行裸眼视力（UCVA）、矫正视力（BCVA）、屈光状态、远近立体视等检查。采用Pearson相关性分析双眼屈光参差的差值程度与高度屈光不正眼UCVA、BCVA及双眼视觉间的相关性，并分析双眼矫正视力差值程度与双眼视觉的相关性。采用单因素方差分析比较5组高度屈光不正眼BCVA及远近立体视情况。结果：屈光参差的差值程度与高度屈光不正眼UCVA和BCVA、远立体视、近立体视（即随机点立体视，包括立体视锐度、交叉立体视、非交叉立体视）均呈负相关（均P<0.05）；双眼矫正视力差值与远立体视、近立体视均呈负相关（均P<0.05）。5组间在高度屈光不正眼BCVA、远立体视、近立体视方面总体差异均有统计学意义（F=6.221、5.271、3.622、3.647、3.464，P<0.05），进一步两两比较显示高度屈光不正眼BCVA在近视性屈光参差组最好，然后依次为远视性屈光参差组、散光性屈光参差组、近视合并散光性屈光参差组以及远视合并散光性屈光参差组，组间差异均有统计学意义（均P<0.05）；远立体视在远视性屈光参差组最好，然后依次为近视性屈光参差组、散光性屈光参差组，组间差异均有统计学意义（均P<0.05），但远视合并散光性屈光参差组与近视合并散光性屈光参差组的远立体视差异无统计学意义；近立体视在近视性屈光参差组最好，然后依次为远视性屈光参差组、散光性屈光参差组、远视合并散光性屈光参差组以及近视合并散光性屈光参差组，组间差异均有统计学意义（均P<0.05）。结论：屈光参差性弱视儿童的屈光参差程度与视力、立体视功能相关，且立体视功能和双眼矫正视力差值也有相关性。不同类型屈光参差儿童立体视损害有所差异。     

Vision Impairment and Driving

Driving is the primary mode of travel in many countries. It facilitates the performance of routine daily activities and is thus integral with the concept of quality of life. Vision is inarguably a fundamental component of safe driving. Drivers with certain eye conditions reduce their driving exposure and restrict their driving to the safest times, yet there is preliminary evidence that some eye conditions increase the risk of crashes. Visual acuity is only weakly related to crash involvement, whereas peripheral vision appears to play a more critical role. Color vision deficiency by itself is not a threat to safe driving. Based on the current literature, it is unclear whether other types of visual sensory impairment have a significant impact on driving safety and performance. Tests of visual attention and processing speed show great promise as methods of identifying high-risk drivers. There is a serious need for well-designed studies in key practical areas, such as the safety of low-vision drivers who use bioptic telescopes, the impact of monocular vision impairment on safety, and the effectiveness of vision rescreening policies after initial licensure. For ophthalmologists to guide patients about driving fitness, valid and reliable assessment tools must be developed and made widely available.     

The Role of Low Vision Rehabilitation in Neuro-ophthalmic Disease

Neuro-ophthalmic disease can cause a wide array of visual impairments. Management should include neuro-ophthalmic examination, patient education regarding visual prognosis, and evaluation of visual function. Often, low vision examination and rehabilitation are useful adjuncts to the neuro-ophthalmic evaluation. Components of a low vision examination pertaining to neuro-ophthalmology are discussed. Specific low vision management strategies are reviewed for patients with visual acuity loss, visual field loss, decreased contrast sensitivity, and ocular motor disturbances caused by neuro-ophthalmic disease.     

Vision Rehabilitation and Charles Bonnet Syndrome

Purpose: To evaluate the prevalence of visual hallucinations in Charles Bonnet Syndrome (CBS) among patients at a Low Vision Clinic. To determine whether Low Vision Rehabilitation (LVR) intervention results in a decrease of these visual hallucinations. Methods: We surveyed 50 consecutive new patients in a low vision clinic to determine whether they had experienced visual hallucinations consistent with CBS. All patients were: questioned about the presence of visual hallucinations; given an educational handout that described CBS and reassured them of the benign nature of these hallucinations; and administered Folstein's Mini Mental Status Examination (MMSE). During their low vision examination, all patients received low vision aids to improve their visual function. At follow-up patients who had symptoms of CBS were administered a second survey to evaluate whether they had experienced any change in the frequency of their visual hallucinations. Results: Of the 50 patients surveyed, 12 of 50 (24%) had visual hallucinations typical of CBS. 6 of these 12 patients (50%) had daily recurring hallucinations. At mean follow-up of 34.9 +/?30 days, a second survey was administered to 11 of the 12 patients diagnosed with CBS. One patient was lost to follow-up. Three of the 11 patients (27.3%) experienced a decrease in the frequency of their hallucinations by 43.33% +/?30.55%. Eight of 11 patients (72.7%) did not note a change in their symptoms. Conclusions: It is important to include direct questions regarding visual hallucinations in the case history of a low vision examination. LVR may decrease the frequency of CBS hallucinations in some patients. Rehabilitation strategies should include low vision devices that allow for improved visual function and patient education to provide needed reassurance.     

Vision and falls

Book reviewed in this article: Falls occur in about one third of older people living independently in the community every year. This can lead to significant physical, psychological and financial costs to the individual and the community. While the risk factors for falls in older people are multi‐factorial, poor vision is considered to be an important contributing factor. The aim of this review is to evaluate current research linking impaired visual function with falls and to review current intervention strategies for the prevention of falls in older individuals. The evidence from the current literature indicates that impairment of visual functions, such as visual acuity, contrast sensitivity, visual fields and depth perception, is associated with an increased risk of falls. Recent studies have also demonstrated that falls can be reduced following cataract surgery as a visual intervention. Optometrists need to be aware of these associations and through appropriate treatment, referral and/or education, they can play a major role in optimising visual function in older people, as part of a multidisciplinary approach to falls prevention.