Eye movements and vision – Tony Pansell's research group

The research group is interdisciplinary and consists of about 20 employees who divide their time between research, teaching and clinic. The group includes ophthalmologists, optometrists, orthoptists, computational linguists, psychologists, speech therapists and engineers. What unites us is the interest in increasing the understanding of how congenital and acquired diseases and damage to the eyes and the brain's visual system can be identified and how these affect different functions and abilitie

Part of the Department of Clinical Neuroscience
Tony Pansells research group Photo: Privat

The research group is located at Marianne Bernadotte Center, Eye Center of Excellence and St. Erik Eye Hospital in Solna. The research in the group ranges from experimental models of humans and animals to clinical patient research. At our laboratory, we have several different methods for eye movement measurements and eye movements are extra exciting as eye movements have something to tell us about what vision does and how the brain works.

 

The research within the group can be divided into the following thematic areas:

Pediatric ophthalmology

Acquired cerebral visual impairment

Early detection of dyslexia and neurological diseases with eye tracking

Neural mechanisms of visuo-vestibular integration 

 

In the research project tab, a couple of typical projects are presented very briefly under each theme

 

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Research Projects

Pediatric ophthalmology

The research in pediatric ophthalmology is run by associate professor Kerstin Hellgren at the Neuropediatric Department at Astrid Lindgren's Children's Hospital and professor Kristina Teär Fahnehjelm, Clinic for Children's Eye Care, Strabismus and Electrophysiology at St Erik Eye Hospital. The research focus is on describing typical visual function in cerebral visual impairment, method development for early identification of visual impairment and ocular malformation, and the effects of various treatment interventions. 

The Express study

The survival rate of extremely premature babies is constantly increasing thanks to advanced neonatal care. However, these children are at risk of developing brain injuries, visual impairment and blindness, behavioral disorders and cognitive problems. It is well known that these children require more assistance from school and that they often have learning difficulties. A better understanding for the underlying mechanism is of immense importance. The project is multidisciplinary and includes description of ocular structure and visual pathways, visual function, cognition, eye movement control, and magnetic resonance imaging (MRI) of the brain.

Children with microphthalmus and anophthalmos 

This is a multidisciplinary study on children with small eyes, so-called microphthalmus or absence of eyes, so-called anophthalmos. The study focuses on associated somatic disease states, genetic defects and visual functions. Among other things, how the children's sleep cycle and sleep quality are affected in the absence of eyes, this is because our circadian rhythm is controlled by light.

 

Acquired cerebral visual impairment

The research projects about acquired brain injuries and cerebral visual impairment are led by PhD Jan Johansson, PhD Ulrika Birkeldh, and associate professor Tony Pansell. The projects treat visual and oculomotor problems in adults with acquired brain injuries such as concussions, infections such as post-covid, stroke and more. These problems mean that daily activities such as reading, orienting oneself, maintaining balance and interacting with the environment can become exhausting or impossible with great limitations in everyday life as a result. The studies take place in close collaboration with Rehabilitation Medicine and Neurology Clinics. The research focus is on describing what happens to the brain's visual function and how visual function, cognition and quality of life can be improved through special spectacles and filter treatment as well as visual rehabilitation.

The effect of repeated concussions on visual function and retinal degeneration

In this project, we investigate how repeated concussions in contact sport affects the morphology of the retina. It is known that damage to the brain that leads to loss of nerve cells indirectly damages retinal nerve cells. With a group of ice hockey players who ended their careers due to increased symptoms during play due to repetitive concussions, we are now investigating eye movement control, visual contrast function, pupillomotor response, and measurement of the retina using Ocular Coherence Tomography (OCT). The goal is to find objective markers that are sensitive to identifying the early stages of brain injuries. The study has been expanded to include younger hockey players from Djurgården Hockey's U-16 team, following them prospectively. 

Visual disturbances after Covid-19 

The study focuses on non-hospitalized patients with long-term symptoms after Covid-19. The questions are about types of deviations and the connection between brain fatigue and the function of the brain's network. The project applies examination of visual functions, neuropsychological examination, and functional magnetic resonance imaging (fMRI) and is a collaboration with Rehabilitation Medicine at Danderyd Hospital. 

 

Early detection of dyslexia and neurological diseases with eye tracking

These research themes take place under the guidance of PhD Mattias Nilsson and PhD Gustaf Öqvist Seimyr. 

Parkinson's and Alzheimer's disease 

Research shows that eye movement and gaze behavior in people with Parkinson's and Alzheimer's disease can be affected at an early stage of the disease. We, therefore, see the potential to develop a technology that takes advantage of eye movement measurement and machine learning for early screening of this type of neurodegenerative disease.

Eye movements during children's reading development 

In this project, the reading ability of 3,000 primary school children has been examined. The focus has been on examining the extent to which early reading eye movements can say something about students' reading ability at a later stage, in this case, one year after the original eye movement measurements. The results show that already in grades 1 and 2, you can get a good indication of which students will have continued reading difficulties a year later (in grades 2 and 3), which suggests that it could be beneficial to introduce reading support when you discover reading difficulties. Unfortunately, people often wait too long to introduce systematic reading development support in school. Thus, the difficulties risk-taking hold and negatively affecting the entire schooling process. This project is part of Andrea Strandberg's doctoral project.

 

Neural mechanisms of visuo-vestibular integration 

These research themes take place under the direction of PhD Tobias Wibble. Our research on gaze-stabilizing eye movements aims to better understand how the brain adapts to different environments. A bodily movement activates the eyes via the vestibular system, which must interact with vision to ensure good visual acuity. The same structures in the brain that control these eye movements are responsible for our balance, which is why we can use the eye to measure how well-adapted an individual is when dealing with dizziness or unsteadiness. 

The research takes place in two tracks. Through basic research with the lamprey as an experimental animal, we examine the brainstem's ability to convey sensory information from the vestibular and visual senses. This is done by placing electrodes in different brain parts and measuring the activity to visual or bodily movement. We also map the anatomy through injections into cranial nerves. In this way, we have recently been able to identify the most fundamental network that controls our eyes and how information from vision and the inner ear is woven together.