A common framework for ambylopic, developmental and adult forms of visual crowding

弱视、发育和成人形式视觉拥挤的通用框架

• 批准号: MR/K024817/1
• 负责人: John Greenwood
• 金额: $ 74.84万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FK024817%2F1
• 关键词: common; framework; ambylopic; developmental; adult

In our visual field, objects are typically easy to see when we look directly at them and difficult to see in the periphery (the 'edges' of our vision). This difference is not simply to do with resolution - even when a target object in the periphery is large enough to be seen in isolation, the placement of other objects in its immediate vicinity can render the target 'jumbled' and impossible to recognise. This is known as 'visual crowding'. It is crowding and not simple resolution that limits our object recognition over more than 95% of the visual field.Although crowding does not affect the centre of gaze in 'normal' vision, it becomes elevated the case of strabismic amblyopia, often known as 'lazy eye'. Amblyopia is the most common cause of visual impairment in children and affects ~3% of the population. It is defined by impaired resolution in one eye that occurs despite optical correction. In addition, the amblyopic eye is also strongly affected by crowding - even when objects are large enough to be seen in isolation, vision at the centre of gaze is highly impaired in cluttered environments. Recent research suggests that the central vision of children younger than 12 is similarly affected by crowding. That is, where adults can recognise closely spaced objects when gazing directly at them, the same is not true for children. This places a significant restriction on the vision of children and processes such as their ability to learn to read. However, we know very little about it.We have here three instances of visual crowding: in normal peripheral vision, in amblyopic eyes and in the eyes of young children. What we do not know is whether these three forms of crowding have a common underlying cause. Can we consider each in the same way, using the same theory, and thus apply the same treatments and coping strategies to overcome crowding? Our hypothesis is that crowding in all its forms represents a form of 'compulsory integration' that occurs when the brain is faced with limited resources: when the cells in our brain that process vision are insufficient in number, they pool across extended regions to compensate. The aim of this project is to compare these three forms of crowding and determine whether they fit this common framework.The research will be conducted by psychologists, neuroscientists, orthoptists and ophthalmologists, with four specific goals. First, we will determine how crowding affects the appearance of objects. That is, do cluttered scenes look the same to children in their central vision as they do to adults in the periphery? This is central to testing the predictions of the compulsory integration theory and will lead to the development of computer models that simulate vision in these circumstances. Second, we will examine whether the peripheral field in normal vision is like the central vision of those with amblyopia - are there differences between the eyes and can we reduce them in the same way that we treat amblyopia? This creates the possibility for the 'normal' periphery to become a testing ground for new treatments of amblyopia, without the need to risk the central vision of children. Third, we will examine whether crowding is a single process in vision, or a general form of integration that affects different objects separately. For instance, does crowding affect moving objects in the same way that it affects letters? This will not only test the compulsory integration hypothesis in each instance of crowding, but also has the potential to develop new, more sensitive tests for crowding. Finally, we will scan the brains of 'normal' and amblyopic adults to measure whether the variation in crowding that occurs across the visual field follows the variation in neural resources to these same parts of the visual field. This will allow a direct test of the compulsory integration hypothesis in normal and amblyopic vision.

在我们的视野中，当我们直视物体时，它们通常很容易被看到，而在外围（我们视野的“边缘”）则很难被看到。这种差异不仅仅与分辨率有关——即使在外围的目标物体足够大，可以单独看到，其他物体在其附近的位置也会使目标“混乱”，无法识别。这就是所谓的“视觉拥挤”。是拥挤而不是简单的分辨率限制了我们95%以上的视野范围内的物体识别。虽然拥挤不会影响“正常”视力的凝视中心，但在斜视性弱视（通常被称为“懒眼”）的情况下，它会升高。弱视是儿童视力受损的最常见原因，约占人口的3%。它的定义是一只眼睛的分辨率受损，尽管进行了光学矫正。此外，弱视眼也受到拥挤的强烈影响——即使物体足够大，可以单独看到，在杂乱的环境中，视线中心的视力也会受到严重损害。最近的研究表明，12岁以下儿童的中央视力也同样受到拥挤的影响。也就是说，当成年人直接盯着物体看时，他们可以识别出距离很近的物体，但对于儿童来说却不是这样。这严重限制了儿童的视力和学习阅读的能力等过程。然而，我们对它知之甚少。这里有三个视觉拥挤的例子：正常周边视觉，弱视和幼儿的眼睛。我们不知道的是，这三种形式的拥挤是否有一个共同的潜在原因。我们能不能用同样的方法，用同样的理论来考虑每一种情况，从而采用同样的治疗方法和应对策略来克服拥挤？我们的假设是，各种形式的拥挤代表了一种“强制整合”，这种整合发生在大脑面临资源有限的情况下：当我们大脑中处理视觉的细胞数量不足时，它们会聚集在扩展的区域以进行补偿。这个项目的目的是比较这三种形式的拥挤，并确定它们是否适合这个共同的框架。这项研究将由心理学家、神经科学家、骨科医生和眼科医生进行，有四个具体目标。首先，我们将确定拥挤如何影响物体的外观。也就是说，在儿童和成年人的中心视觉中，混乱的场景看起来是一样的吗？这是检验强制整合理论预测的核心，并将导致模拟这些情况下视觉的计算机模型的发展。其次，我们将检查正常视力的外围视野是否与弱视患者的中心视野相似——眼睛之间是否存在差异，我们是否可以用治疗弱视的同样方法来减少它们？这就为“正常”周边视力成为弱视新疗法的试验场创造了可能性，而无需冒着损害儿童中心视力的风险。第三，我们将研究拥挤是视觉中的单一过程，还是单独影响不同物体的综合形式。例如，拥挤是否会像影响字母一样影响移动的物体？这不仅将在每个拥挤的实例中检验强制性整合假设，而且有可能开发出新的、更敏感的拥挤测试。最后，我们将扫描“正常”和弱视成人的大脑，以测量在整个视野中发生的拥挤变化是否遵循视野相同部分的神经资源的变化。这将允许对正常视力和弱视视力的强制整合假说进行直接测试。

项目成果

Phase 2a randomised controlled feasibility trial of a new 'balanced binocular viewing' treatment for unilateral amblyopia in children age 3-8 years: trial protocol.

• DOI: 10.1136/bmjopen-2021-051423
• 发表时间: 2022-05-24
• 期刊: BMJ open
• 影响因子: 2.9
• 作者: Dahlmann-Noor AH;Greenwood JA;Skilton A;Baker D;Ludden S;Davis A;Dehbi HM;Dakin SC
• 通讯作者: Dakin SC

An exploratory study of a novel home-based binocular therapy for childhood amblyopia.

一项针对儿童弱视的新型家庭双眼疗法的探索性研究。

• 发表时间: 2014
• 期刊: Investigative Ophthalmology & Visual Science
• 影响因子: 4.4
• 作者: Bossi, M.

The orientation selectivity of face identification.

• DOI: 10.1038/srep34204
• 发表时间: 2016-09-28
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Goffaux V;Greenwood JA
• 通讯作者: Greenwood JA

Categorical information influences conscious perception: An interaction between object-substitution masking and repetition blindness.

分类信息影响意识知觉：对象替换掩蔽与重复失明之间的相互作用。

• DOI: 10.3758/s13414-016-1073-z
• 发表时间: 2016
• 期刊: Attention, perception & psychophysics
• 作者: Goodhew SC

Heritable functional architecture in human visual cortex

人类视觉皮层的可遗传功能结构

• DOI: 10.1101/2020.05.04.077545
• 发表时间: 2020
• 作者: Alvarez I