Chandna Lab (SEELAB)
External CollaboratorsBinocular 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:
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 email@example.com.
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
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 firstname.lastname@example.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:
Rehabilitation Engineering Research CenterView 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
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.
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.
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
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.
Reading in mTBI
People with mTBI often complain about dificulty in reading in spite of normal results in usual eye exams.
Welcome to CVI@SKI
We are a Smith-Kettlewell Eye Research Institute sponsored,Little Learners Program, Lighthouse for the Blind, San Francisco supported information, communication research advocacy group consisting of SKI researchers, select clinicians, teachers of the visually impaired, and parents of children with cerebral visual impairment.
Calibration of Eccentric Power Refractor
Eccentric power refractors need to be calibrated for accommodation and gaze position for individual participants. Calibration however can be time consuming.
- Devashish Singh - Research Assistant
- Hoover Chan - Professional Researcher - UCSF Medical Center
- Shrika Ravichandran - Research Intern
- Silvia Veitzman - Clinical Researcher
- Eric Seemiller - Research Associate at the Indiana School of Optometry
- Nikolay Nichiporuk - Research Assistant
- Olivia Reed - Optometrist at Wright-Patterson AFB
- Saeideh Ghahghaei - Research Associate
- Spencer Harris - Clinical Research Fellow - Chandna
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.
International Higher Visual Function Question Inventory StudyThe 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.
SKERI Researchers Identify Potential Screening Questions for CVIResearchers 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 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.
UK Opthalmologist Joins Smith-Kettlewell Research StaffArvind 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.