Advances in cerebral/cortical visual impairment

#Ophthalmology #optometry #pediatrics #vision #neurology #neuroscience?

“If you wish to converse with me, define your terms” – Voltaire.

Cerebral/cortical visual impairment (CVI) has become a leading cause of childhood blindness in the United States and other developed nations, yet it is poorly understood. This week, two major publications by a multidisciplinary team coordinated by The National Institutes of Health have made important progress toward better defining this disorder.

Children with CVI typically have damage to visual pathways in the brain (e.g., after prematurity, infections, hypoxic-ischemic encephalopathy, seizures, or drug exposure), and have impaired vision and/or abnormal higher-order visual processing (e.g., difficulty recognizing objects or processing motion).

Because of CVI’s multiple symptom presentations and because care of these children is typically shared among multiple clinicians, it is an often misdiagnosed or under-diagnosed, in part for lack of awareness by clinicians related to lack of standard terms to define it. Many CVI patients are diagnosed years after their first symptoms, sometimes resulting in missed management opportunities. The frustration of many families dealing with CVI is understandable.

At NIH, where I direct the National Eye Institute (NEI) , we have the largest national vision research program in the United States. We have identified many unanswered questions regarding CVI that must be addressed through research, such as lack of a standard definition, lack of evidence-based diagnostic tools and guidelines, and unclear management and rehabilitation strategies. We are addressing these gaps by partnering with two other NIH institutes (the National Institute of Neurological Disorders and Stroke (NINDS) and the Eunice Kennedy Shriver?National Institute of Child Health and Human Development (NICHD) ) to form a working group of NIH staff and CVI experts from different specialties.

These two new publications are the result of nearly two years of work through those collaborations and a major step toward an expert working definition of CVI. The group has identified five elements to help clinicians affirmatively classify CVI as: (1) a spectrum disorder, (2) involving visual dysfunction greater than expected by comorbid ocular conditions, (3) encompassing lower- and higher-order visual deficits, (4) a condition that is not a disorder of language, learning, or social communication, and (5) the result of an underlying neurologic insult of the developing brain that may go undiagnosed until later in life.

Where do we go next? Clinicians can use this definition to better understand, recognize, and refer children suspected to have CVI. Researchers will be needed to address the many gaps in knowledge. At the NEI, we are developing a participant registry to collect clinical, imaging, and other data from consenting individuals with CVI to support future retrospective or prospective research. And we are working together toward a future with better diagnosis, treatment, accommodations, and education plans for these children.

For more details, see the articles published this week in Ophthalmology [https://www.aaojournal.org/article/S0161-6420(24)00565-7/fulltext] and Pediatrics [https://publications.aap.org/pediatrics/article/doi/10.1542/peds.2024-068465/199942/].