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Visual Development & Age-Related Eye Disease

The clinical arm of our research team is involved in a wide array of research topics. Some of the most active areas of research are described below.

Amblyopia

Amblyopia (lazy eye) is a developmental disorder of vision in which there is reduced visual function despite full optical correction and the absence of pathology. Our work in amblyopia has the following aims: 

  • Understanding the precise nature of the amblyopic visual deficit 
  • Investigating whether subtle structural abnormalities of the eye contribute to the visual deficit in amblyopia
  • Understanding the impact of amblyopia on everyday visual function and quality of life measures. 

Cataracts

Cataracts are the leading cause of blindness in the world due to the lack of surgical facilities in low-income countries, and the leading cause of visual impairment in high-income countries such as the UK. Bradford’s School of Optometry & Vision Science has been involved in cataract research for over 25 years and was part of several multi-centre anti-cataract drug trials in partnership with Oxford and Harvard Medical Schools. Our current work has the following aims: 

  • Determining whether it is safe to prescribe new spectacles sooner than the current guidelines of 4-6 weeks 
  • Determining whether a target refraction of myopia (and not emmetropia) would be useful for some pre-surgery myopes who were used to reading without spectacles 
  • Developing professional guidelines for optometrists to best manage refractive correction changes caused by cataract surgery. 

Children’s Vision 

In addition to research into amblyopia (lazy eye) and myopia (short-sightedness) which are ocular conditions that predominantly start in childhood, we have further avenues of research regarding vision in children, and particularly children with special needs.  These include: 

  • Glasses in Classes, a Department for Education funded project which involves sharing the results of vision screening with schools and providing an extra pair of glasses to be kept at school. The school can encourage the parents of children who failed to take them for an eye exam and can encourage and monitor glasses wear. The aim is to measure the impact of these measures on educational attainment.  
  • Developing assessment tools and interventions for children with Cerebral Visual Impairment who have complex needs and visual dysfunction 
  • Providing in-school assessment for over 300 children with special needs every year, contributing to the NHS England Special Schools Eye Service national dataset 
  • Identifying those aspects of binocular visual dysfunction that may contribute to poor reading performance in children 
  • Investigating the associations between binocular motor anomalies and deficits in visual short-term memory and attention. 

Contact Lenses & Anterior Eye  

The range of contact lenses has increased over the years, leading to a greater availability for more complex refractions, and an increase in the different designs and materials available. There are also new applications for contact lenses, including myopia control and other therapeutic uses. With the growing amount of contact lens wear and new technology and materials used, assessment of their potential impact on the cornea and anterior eye is becoming increasingly important. Currently our research is looking at: 

  • Use of eye drops and staining agents in clinical practice 
  • Patient and practitioner attitudes to contact lenses and their care 
  • Assessing the performance and subjective experience of contact lens wearers in different lens designs and materials 
  • Investigating the performance of different contact lens cleaning products 

Glaucoma 

Glaucoma is one of the most common eye diseases and the leading cause of untreatable blindness worldwide. The early stages of glaucoma have no symptoms, meaning the disease can go undetected until already advanced, by which time vision is already permanently lost. Glaucoma is detected and monitored by a combination of clinical tests including eye imaging, vision measurements and measurement of the eye pressure, with no one test giving us a perfect picture of a patient’s condition.  We are interested in both the fundamental understanding of glaucoma and in developing new techniques for diagnosis and monitoring. A multi-faceted approach is used to study different aspects of glaucoma, including: 

  • Developing new ways to use the latest, state-of-the-art optical coherence tomography (OCT) imaging techniques for glaucoma assessment 
  • Developing new visual field test modalities using custom devices and computer simulation 
  • Developing improved ways to combine information from multiple clinical tests for glaucoma diagnosis and monitoring using computer modelling 
  • Psychophysically studying changes to visual processing and visual perception caused by glaucoma 
  • Using questionnaire-based studies of patient and public experiences to better understand treatment adherence . 

Myopia

The worldwide prevalence of myopia (short-sightedness) has been increasing rapidly in recent years and has reached pandemic levels in East Asia, with some places reporting myopia in 90% of the population. Predictions suggest that the worldwide prevalence of myopia will increase to 50% by 2050 at current rates, with high myopia (> 5.00D of myopia) increasing dramatically from 2.7% (163 million) to 9.8% (938 million). Higher levels of myopia are linked with greater risk of visually disabling conditions including myopic maculopathy, retinal detachment and glaucoma, so that this pandemic increase in prevalence is a major public health concern.  

This is a hugely active research area but already a range of myopia control options are available. Our research group is particularly interested in the following aspects of myopia progression and control: 

  • Investigating the environmental and genetic influences related to myopia 
  • Investigating currently available and new optical interventions for myopia management  
  • Researching new and experimental non-optical approaches to limiting myopia progression 
  • Researching the impact of the myopia burden on UK finances and NHS health objective outcomes. 

Service Evaluation and Public Health 

The model of delivery of primary eye care is evolving rapidly, and there is wide variation in provision both nationally and internationally. Our work in this area aims to evaluate and inform the development of eye care services, for example: 

  • Evaluating ways to improve uptake of primary eye care services, especially in underserved areas and populations 
  • Evaluating new and existing services to ensure safety and system-wide cost effectiveness 

Sports Vision 

Vision is hugely important for many sports and for sport refereeing. Popular sports literature suggests that two beliefs are commonly held: First, that athletes make superior use of their vision than non-athletes, and second, that vision therapy improves sporting performance. However, neither of these beliefs holds up to scientific scrutiny. Our work in sports vision has the following aims: 

  • Comparing vision and visuo-motor skills in elite and club-level sports people and in novices: Are elite sports men and women better? 
  • Establishing movement control parameters for individual sportspeople as they perform sports-specific  tasks 
  • Determining the effect of vision of referees on performance: Do referees with good vision perform better? 
  • Determining whether goggles can be safely and effectively worn by rugby players? 

Vision, Spectacles & Falls 

Falls are common in elderly people with a third of people over 65 years reporting a fall in the previous year, rising to 50% in people aged over 80. Falls can have devastating consequences, being the leading cause of accidental death in the elderly as well as causing hip and other fractures and long lies. In addition, falls are not accidents, but linked to a variety of risk factors. Although visual impairment is an important risk factor for falls, correcting visual impairment does not always reduce falls rate. For example, large changes in refractive correction have been shown to increase falls rate in older patients as some find adaptation to large changes in correction difficult, likely due to magnification changes and distortion. Our work in this area has the following aims: 

  • Modelling how both refractive correction and vision changes affect how safely we negotiate steps and stairs and alter falls risk 
  • Providing professional guidelines to optometrists to help them prevent falls in their older patients 

Mobility and falls

Locomotor strategies are planned using information acquired by intermittent visual sampling of the environment, which means the visual system is free to attend to other things. This highlights that where and when we look are key factors in our ability to safely negotiate changing terrains. It also highlights that visual impairment that results in impoverished information about the environment may lead to the adoption of unsafe locomotion strategies.

How is landing behaviour affected by visual impairment when stepping down?

To understand what, where and how different aspects of visual (and other sensory) information is used to regulate locomotion and posture in various environments and ambient conditions.

For example:

  • How correctable visual impairment such as refractive blur and cataract effects balance control and movement strategy during stair negotiation
  • How multifocal spectacle use effects gait over obstacles and/or during transition to a new level
  • How the removal of binocular vision effects movement planning and control
  • What peripheral versus central cues are used to plan and control movement

Multifocal lens wearers are twice as likely to fall as single vision lens wearers. This is likely to be because low level objects are out of focus when viewed though the intermediate or near addition part of lens.

In the UK over 2m falls each year result in hospital treatment. Of these, almost 10% of cases are linked to visual impairment, with the majority being elderly individuals 65 yrs and above. It is estimated that up to 80% of this visual impairment is correctable via refractive correction (40%) or cataract removal (37%). Although it is known that visual impairment is a risk factor for falls, little is known about how visual impairment affects postural stability and obstacle & step/stair negotiation. Even when vision is optimally corrected, the use of multifocal spectacles has been linked to increased risk of falls.