a cartoon rendering of an eyeball and a brain holding hands

Chandna Lab (SEELAB)

                                                                    External Collaborators

Binocular vision, Strabismus, Amblyopia, Cerebral Visual Impairment

Our laboratory investigates mechanisms of normal and abnormal vision and ocular motility in children and adults with special emphasis on cerebral visual impairment, acquired brain injury, strabismus and amblyopia. Our aim is to improve detection, diagnosis, treatment, and outcomes in childhood eye disease through rigorous scientific research.

There is a strong emphasis on translational research. We investigate globaly common eye diseases in children and in adults associated with long-term visual loss and morbidity with high socioeconomic costs and impacts. 

What is CVI?

Cerebral (sometimes known as Cortical) Visual Impairment is an overarching term covering a wide range of visual and perceptual visual impairments resulting from injury or dysfunction of visual pathways. While CVI can be caused by a wide variety of factors, most common is a lack of oxygen to the brain shortly before, during, or shortly after birth. CVI can be difficult to diagnose, as the eye itself may have average to near average vision. Children with CVI tend to have vision that improves over time, as their neuro pathways are elastic and can create alternate pathways to process the information perceived by the eye itself. Early diagnosis for CVI can be especially helpful as it speeds family support and professional intervention, allowing children to take advantage of learning environments that suit their needs and expand their capacity to process visual information.  


In the SEELAB, we use visual electrophysiology/EEG methods and with eyetrackers and infrared photorefractor we measure eye movements and accommodation simultaneously.


EEG Stimuli Video: 




Current projects:

Our projects involve remote telephone/video interviews and, in our physical laboratory we use non-invasive, quantitative methods, including: low-channel and high-density EEG steady-state visual evoked potentials (SSVEP); eye tracking and photorefraction in correlation with clinical findings: 

  • Cerebral Visual Impairment (CVI): Exploring three levels visual function deficits (HVFDs) in children with mild to moderate CVI
  • Amblyopia and/or Strabismus : Studying mechanisms of visual function loss and recovery in amblyopia and strabismus
  • Strabismus: Studying mechanisms of vergence and accommodation in strabismus and other clinical conditions (CVI, TBI)
  • Eye Dominance: Role ocular dominance, sensory and motor, in oculomotor stability.
  • Reading studies wih simultaneous messures of oculomotor control and accommodaton..
  • Monocular Visual Loss: Comparing monocular and binocular sensory and motor functions
  • Assessment and Intervention: Developing applications for visual assessment and training in babies and young children.

If you are interested in being a participant in our work or want to know more about our research, either remotely via Zoom or in person in our lab, please get in touch with us at seelab@ski.org.

We are especially interested in the following eye conditions:

  • Cerebral Visual Impairment and Brain-Based disorders of visually guided behavior
  • Traumatic Brain Injury and other causes of Acquired Brain Injury
  • Strabismus (misaligned eyes) since childhood
  • Anismetropia (a significant difference in eyeglass prescription between the two eyes) since childhood
  • Amblyopia (poor vision in one or both eyes since childhood often associated with strabismus and anisometropia) 
  • Cataract in childhood 
  • Loss of one eye in childhood

CVI@SKI. A CVI Discussion Group for Parents and Children with CVI

A group for parents of children and children with Cerebral/Cortical Visual Impairment (CVI) supported by clinicians, researchers and teachers of the visually impaired.

The purpose of this group is to provide a centralized space for individuals -- including family members, researchers, doctors, educators, and more -- to discuss topics related to CVI. We specifically hope to create a safe environment in which we can achieve the following:

  1. Parents will be able to discuss the challenges they face with their children with CVI. We aim to provide a forum for parents to share their own experiences while learning from other parents. 

  2. Older children will be able to discuss their own experiences living with CVI. They may contribute their own strategies for tackling shared difficulties, or choose to elicit advice from their peers. 

  3. Everyone will gain access to reliable and understandable information regarding CVI. We will also invite experts to share their knowledge.

  4. Researchers will provide updates on recent developments in the field of CVI. 

Group meetings will be held every 6 weeks via a secure online platform sponsored by Smith Kettlewell Eye Research Institute (SKERI), San Francisco and hosted by the Chandna SeeLab at SKERI. We expect meetings to last for approximately 1 hour. The next meeting will take place in April 2023 (exact date/time TBD). 

If you are interested in joining our discussion group, or if you would like to learn more about CVI@SKI:


Adults with CVI Group

This group is sponsored by the SeeLab at The Smith-Kettlewell Eye Research Institute and is comprised of adults with CVI, clinicians, vision scientists, and teachers with extensive experience in CVI. The main goals of this group are to provide a supportive space for adults with CVI to share their experieces while advocating for them, learn more about brain-based visual impairments, and introduce current research. If you are interested in joining, please contact Dr. Arvind Chandna, at arvind@ski.org, with your name and e-mail adress. This group is only available for SK Staff at this time, not external participants.


Higher Vision Function Question Inventory (HVFQI) Study:

The HVFQI is a screening question inventory for parents with children between the ages of 4 and 18 years old with a diagnosis or suspected diagnosis of cerebral visual impairment (CVI) to analyze their brain based vision impairments. The web-based app has 59 questions and is useful to assess the spectrum of visually guided behaviors in children who have good visual acuities and higher visual function deficits. We hope to be able to make a significant difference to the assessment of children with cerebral visual impairment once this international, remote study is complete.





Some of our published papers:


Journal Articles
Chandna, A., Badler, J. B., Singh, D., Watamaniuk, S. N. J., & Heinen, S. J.. (2021). A covered eye fails to follow an object moving in depth. Scientific Reports, 11. http://doi.org/https://doi.org/10.1038/s41598-021-90371-8
Chandna, A., Nichiporuk, N., Nicholas, S., Kumar, R., & Norcia, A. M.. (2021). Motion Processing Deficits in Children With Cerebral Visual Impairment and Good Visual Acuity. Investigative Ophthalmology Vision Science , 62(14), 1-17. http://doi.org/https://doi.org/10.1167/iovs.62.14.12
Saeed, M., Raza, S., Goyal, S., Cleary, G., Newman, W., & Chandna, A.. (2013). Presentation of Suspected Pediatric Uveitis. Seminars In Ophthalmology, 29. http://doi.org/10.3109/08820538.2013.810288
Other Publications
  • Collage of RERC staff mebers and RERC projects

    Rehabilitation Engineering Research Center

    The Center's research goal is to develop and apply new scientific knowledge and practical, cost-effective devices to better understand and address the real-world problems of blind, visually impaired, and deaf-blind consumers

    View Center
  • Visual Functions in CVI Application

    Cerebral Visual Impairment (CVI): An in-depth study of visual functioning in everyday life

    The purpose of this research study is to learn about how cerebral visual impairment affects everyday visually guided behaviours and determine interventions to treat the difficulties. This study is conducted remotely through telephone or video link and also in person at the laboratory.

    Read More
  • Communication, Information, Information, Advocacy

    CVI@SKI: CVI Discussion Group for Parents and Children with CVI

    A group for parents of children and children with Cerebral Visual Impairment (CVI) supported by clinicians, researchers and teachers of the visually impaired.

    Read More
  • Illlustration of cover test

    Eye Movements and Accommodation Patterns in Strabismus

    Strabismus misaligned eyes is a common developmental condition in young children that can lead to amblyopia or poor vision and other forms of low vision. This project looks at the eye movements in relation to accommodation or focusing power in these patients to determine predictors of strabismus and outcome of treatment, with the goal of improving early detection, intervention and treatment.

    Read More
  • Active

    Investigating Reading in Individuals with Cerebral Visual Impairment (CVI)

    In this project, we aim to understand (i) how CVI affects reading, (ii) how current rehabilitation techniques or assistive technologies help improve reading in CVI and (iii) what more can be done to assist those individuals with CVI

    Read More
  • Vernier sweep schematic

    Patterns of Visual Deficits in Amblyopia

    Background Amblyopia means blunted sight in the Greek language and is a term clinicians use to describe decreased vision usually in one eye most commonly due to a focusing error (refractive error in one eye, very different from other eye - anisometropia) and/or a misalignment between the two eyes (strabismus or squint). Amblyopia is sometimes called “lazy eye”. This is different than being just near or far sighted which is a refractive error usually similar and in both eyes developing at any age and vision improves instantly on prescribing and wearing spectacles to correct the error.

    Read More
  • Active

    Reading in mTBI

    People with mTBI often complain about dificulty in reading in spite of normal results in usual eye exams.

    Read More
  • SKERI RERC logo

    SKERI Receives Rehabilitation Engineering Research Center (RERC) grant on...

    Smith-Kettlewell is proud to announce the newly awarded Rehabilitation Engineering Research Center (RERC) grant on Blindness and Low Vision. This is a five-year grant from the National Institute on Disability, Independent Living, and Rehabilitation Research, establishing Smith-Kettlewell as a center promoting the independence and well-being of people with visual impairments through research and development to improve the understanding of, and provide solutions for, challenges facing the blind and low-vision community.
  • seelab logo

    International Higher Visual Function Question Inventory Study

    The Higher Visual Function Question Inventory (HVFQI), created and validated by Dr. Arvind Chandna, researchers in the SEELAB, and Alder Hey Children's Hospital is a growing international study that is attracting participants all over the world, including Canada, Scotland, and the United Kingdom. This study is being done completely remote, with interviews being held through virtual meetings. It is being made available in numerous languages and even accommodating a text to speech option. This study is approved by our Institution Review Board (ethical approval) at Smith-Kettlewell Eye Research Institute.
  • SEELAB Logo: anthropomorphized brain and eyeball icons holding hands

    SKERI Researchers Identify Potential Screening Questions for CVI

    Researchers at the SEELAB and collaborators at Alder Hey Children’s Hospital have validated the Higher Visual Function Question Inventory (HVFQI) an assessment tool for vision difficulties in everyday life in children with Cerebral Visual Impairment (CVI) and identified 11 of the fifty-one questions (the Top-11) that were highly sensitive in detecting these visual difficulties
  • Dr. Arvind Chandna

    Dr. Arvind Chandna Receives the PMC Department of Ophthalmology Residency...

    Arvind Chandna, M.D., Senior Clinician Scientist at Smith Kettlewell Eye Research Institute was selected as a recipient of a CPMC Department of Ophthalmology Residency Teaching Award for 2020. This award was presented to him at the Barkan Research Symposium on Saturday, June 13, 2020, via Zoom.
  • Photo of Arvind Chandna

    UK Opthalmologist Joins Smith-Kettlewell Research Staff

    Arvind Chandna, MD, joined The Smith-Kettlewell Eye Research Institute in San Francisco on November 1, 2015, as a Senior Clinicial Researcher in pediatric ophthalmology and strabismus.