Rare diseases and CVI explained

Learn about the CVI and rare disease connection, anecdotes from other CVI and rare disease parents, when to suspect CVI, and what to do next.

Lacey looks up at her daughter Savannah, who sits in a wheelchair in an accessible playground.

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Statistics and research about CVI and rare diseases

Cerebral/Cortical Visual Impairment (CVI) is the leading cause of childhood blindness and low vision, but less than 20% of children with CVI are diagnosed. This statistic holds true within the rare disease community, even though CVI is common in multiple rare diseases.

CVI is a lifelong brain-based visual impairment caused by damage to the visual pathways and visual processing areas in the brain. There is a high prevalence of CVI in children with genetic anomalies, epilepsy, autism, developmental delay, and cerebral palsy, and many of these conditions also co-exist with rare diseases.

Samsky sits next to his teacher in a classroom and claps.

What is a rare disease? 

A rare disease is defined as any disease affecting less than 200,000 people in the United States. 

1 in 10 people have a rare disease: 10,000+ rare diseases affect more than 30 million Americans. 

About 50 to 75% of rare diseases begin in childhood.

Up to 50% of rare diseases are still undiagnosed. Researchers continue to uncover genetic conditions, but certain rare diseases can be challenging to identify and treat because they are not well-known. Other genetic variants may fall into the undiagnosed category, which can lead to delays in getting the right care. 

As research continues to develop, more rare diseases will likely be discovered, as “an average of about 260–280 rare genetic diseases are discovered per year,” greatly increasing this prevalence number. 

“Not having a diagnosis was very scary and also a lonely journey since we didn’t have anyone else to connect with or understand what we were going through. Finding CVI Now gave us a sense of community and a place to meet others, including other undiagnosed families, who understood what it was like to have a child with CVI. I found that it gave me a place to belong, and we weren’t lonely anymore, as we had others who understood and could even guide us through this journey.” – Ali Mahady, CVI mom to Weston, who has an undiagnosed rare disease

For many families and caregivers raising kids with rare diseases, a CVI diagnosis brings community, belonging, and a path forward. 

Weston wears an Elmo shirt, white shorts, and stands at the edge of the water on a beach, looking out toward the ocean.

Why consider CVI in your rare community?

Rare diseases often involve conditions that affect the brain. Since CVI is a brain-based visual impairment, people with rare diseases can have a higher risk of it. CVI occurs with damage or interruption to the brain’s visual pathways and processing areas. Often, when we think about vision, we think about the eyes, but it’s our brains that make sense of the visual information the eyes take in and understand the world around us. 

Of the 7,000 diseases listed on the National Institute of Health’s Office of Rare Diseases site, most are neurological and of genetic origin and 90% of rare diseases have neurological effects.

Ivelina P Kioutchoukova, et al., Neurologic orphan diseases: Emerging innovations and role for genetic treatments

Like other brain-based conditions, CVI can have diverse manifestations. If a rare disease comes with a neurological condition, it’s important to consider CVI.

Does CVI exist in your rare community? 

We hear this often: “Some individuals in our rare community have a diagnosis, but it does not apply to all.”

Because CVI is so often misdiagnosed, overshadowed, or undiagnosed, we ask: Could it be that CVI is not documented in your rare community as a sign, symptom, or associated condition?

A diverse array of genetic factors influences complex neurological conditions. We know that many rare diseases have many overlapping conditions, which may include epilepsy, cerebral palsy, developmental delays, and autism, and those conditions may take precedence.

Sometimes, visual behaviors associated with CVI are first attributed to more commonly known conditions. For example, difficulty making clear and sustained eye contact is often associated with CVI. When CVI is overshadowed due to another known condition, it can delay a CVI diagnosis and critical access to learning and education.

Logan wears a zebra short and sits crossed-legged on a wooden floor.

Is CVI overlooked in my child with a rare disease?

Complex neurological conditions often involve co-existing conditions such as epilepsy, cerebral palsy, developmental delays, and autism. In the rare disease community, visual behaviors linked to Cerebral/Cortical Visual Impairment (CVI) are sometimes mistaken for symptoms of other conditions, delaying a CVI diagnosis and access to educational materials and resources. As a result, CVI may not always be recognized.

If you observe your child having visual difficulties or unexplained visual behaviors, it may be beneficial to investigate CVI further.

Your child might:

“I will never forget my daughter’s early relationship with her visual world. She was extremely attracted to light and shiny materials, and she would stare at the light and the mirror above her swing without any real intent. She would interact with materials by using her hands and listening rather than looking at the items we presented to her. Now that I am a Teacher of Students with Visual Impairments (TVI), I now realize that these were early indications that CVI should be considered, especially given my daughter’s complex neurological history.” – Lacey Smith, TVI and CVI mom to Savannah

Hazel is smiling, sitting outside in a wheelchair.

Why a CVI diagnosis can be beneficial

“The thought of getting another diagnosis, another medical condition to monitor, have appointments for, and worry about, was daunting. But, after fully understanding CVI and what the diagnosis actually meant, I realized a few things. The diagnosis gave me a community to belong to since my son was undiagnosed. It also gave me the knowledge and skill set, after really learning and understanding what CVI is, to provide my son with adaptations and modifications so that he could see things better, and ultimately, it helped him learn. The feeling of being overwhelmed with another diagnosis changed to a feeling of pure happiness watching my son see his word in an easier way for the first time.” – Ali Mahady, CVI mom to Weston

A medical diagnosis of CVI is made by a pediatric ophthalmologist, neurologist, neuro-ophthalmologist, optometrist, or clinical low-vision specialist who understands the visual behaviors of CVI. 

A CVI diagnosis can:

Find a doctor who is knowledgeable about CVI. 

Finding the beauty in raising a child with a rare disease and CVI is cherishing those small yet meaningful moments — ‘glimmers’ as they are sometimes called.

Danielle Kowalski, CVI mom to Bruce
Danielle and Bruce hug, smile and look at the camera.

Obstacles to obtaining a CVI diagnosis

Like many rare diseases, CVI is not yet well understood by many medical professionals and continues to be drastically underdiagnosed. Currently, the medical community is working towards agreed-upon diagnostic criteria. Often, families travel long distances to find a medical provider who can evaluate and diagnose CVI. Service providers and educators who work with individuals with rare diseases most likely don’t know about CVI and how to observe visual behaviors commonly seen in individuals with CVI.

For some, a CVI diagnosis may be considered only once the individual is provided with a diagnosis for their rare genetic condition and the condition has a known common association with CVI. For others, caregivers, early intervention teams, doctors, specialists, or other knowledgeable professionals may suspect CVI even before the individual has a genetic diagnosis. 

“Despite my daughter’s complex birth history, CVI was not put on our radar until around six months. We consider ourselves lucky for an early diagnosis but I often think, ‘What if I did not have good access to medical care for Savannah? Would I have attributed her visual difficulties to her hydrocephalus, another rare condition that she was diagnosed with shortly after birth? Would I have continued to seek out another genetic condition after her microarray was inconclusive?’ It was through Whole Exome Sequencing (WES) when my daughter was almost four years old that we learned she had an ultra-rare genetic condition known as Ogden Syndrome, commonly associated with CVI. It was then that we could put all supports in place to help Savannah reach her fullest potential and understand each of her conditions.” – Lacey Smith, TVI and CVI mom to Savannah

Three young girls with Ogden Syndrome lay on their backs on a carpeted floor, wearing matching blue bows.

Next steps

Rare disease patients face several diagnostic obstacles, which are not too different from those faced by CVI patients. Knowing what to ask and what to look for can help your loved one on their CVI diagnostic journey.

Does your rare disease Organization want to collaborate with US?

Check out Our Collaborators page for more information.


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