Definition

Cortical visual impairment (CVI), also known as cerebral visual impairment, is a leading cause of vision impairment in children under five. CVI is caused by damage to the brain's visual processing without any direct damage to the eye itself. It typically results from brain injuries related to birth complications. Effective CVI treatment requires a coordinated approach involving ophthalmologists, neurologists, and rehabilitation specialists.

A profile report on CVI cases at Dr M. Djamil Padang Hospital in West Sumatra from 2012–2015 indicated that congenital causes were more prevalent than acquired ones, with about 57% of patients under one year old. Acquired CVI causes included infections such as meningitis and encephalitis, while congenital causes encompassed conditions like intracranial bleeding, seizures, hypoxia, and prenatal infections.

Causes

CVI stems from direct brain damage, which several factors can trigger:

• Hypoxia: Low oxygen levels in the brain lead to cell death in regions responsible for visual processing. Hypoxia can affect different brain areas depending on whether the baby is premature or full-term, and it can occur either prenatally or during delivery.
• Meningitis: Meningitis, particularly from Haemophilus influenzae, is a frequent CVI cause. It impacts the occipital cortex, which processes visual information. Other agents, including pneumococcus, meningococcus, and the herpes simplex virus, can also damage this area. Vision issues from meningitis often develop after the infection has subsided.
• Hydrocephalus: This condition elevates pressure on the optic nerve, leading to optic atrophy and, potentially, CVI. However, swift hydrocephalus management can mitigate CVI risks.
• Trauma: Head trauma, often seen in cases of shaken baby syndrome, can cause CVI. Symptoms may include headache, drowsiness, confusion, vomiting, and seizures.
• Epilepsy: Epilepsy is associated with CVI, though the underlying mechanism remains unclear. Anti-epileptic drugs may also contribute to CVI development.

CVI can also affect adults following head injuries or strokes, a condition known as acquired CVI. The symptoms of brain damage in adults typically differ from those seen in pediatric CVI cases.

Risk Factor

• Hypoxia (low oxygen in the brain)
• Infections of the central nervous system
• Hydrocephalus
• Birth-related trauma
• Epilepsy
• Hypoglycemia
• Hemodialysis
• Maternal drug use during pregnancy
• Metabolic disorders
• Congenital malformations of the central nervous system
• Cardiac arrest
• Complications from cardiac surgery

Symptoms

Children with cortical visual impairment (CVI) may experience various vision difficulties, which can range from moderate to severe. Common issues for children with CVI include challenges in:

• Responding to visual stimuli directly in front of them
• Seeing movement, such as in a movie
• Recognizing faces and identifying objects
• Distinguishing objects within cluttered surroundings
• Reaching for items while looking directly at them
• Understanding or making sense of what they see

Other symptoms associated with CVI may include:

• Delayed responses to visual cues
• Ability to see stationary objects more easily than moving ones
• Preference for objects within their peripheral vision
• Attraction to bright light sources like lamps or sunlight, although some may avoid light exposure

Additionally, children with CVI may experience:

• Developmental delays
• Cerebral palsy, a condition affecting movement
• Epilepsy
• Hearing loss or impairment

Diagnosis

Doctors will begin by assessing the child’s visual acuity, and asking about any previous health issues such as seizures, high fevers, or altered consciousness related to meningitis. Eye exams may check for astigmatism, hyperopia, and strabismus. A visual field test may also be conducted to determine any specific areas of vision loss.

Additional diagnostic tests might include:

• Visual Evoked Response (VER): Assesses the visual pathway system.
• Electroencephalography (EEG): Records brain waves to detect any signs of epilepsy.

Imaging tests such as CT scans and MRIs may be used to identify potential brain abnormalities.

Management

Mild cases of CVI may resolve within a few months, though the exact mechanism remains unclear, and some experts consider it a sign of delayed visual maturity. In severe cases, CVI might not be fully treatable. Treatment may include therapies for amblyopia and strabismus to reduce symptoms.

Rehabilitation plays a critical role in managing CVI, focusing on the psychosocial needs of both the child and family. Visual stimulation therapy, such as light reflex exercises in a dark room, can help develop visual skills. For instance, children may practice observing distinct shapes like circles or stars for one minute, repeated up to 30 times a day. Given that CVI often affects both visual and motor functions, children generally benefit from coordinated, personalized therapy sessions.

For Parents

Supporting a child with visual impairment involves attention to both the child’s needs and parental well-being. Key steps include:

• Educate yourself: Learn about CVI, its treatment, and available rehabilitation options.
• Build a support system: Connect with other parents facing similar challenges.
• Take care of your health: Prevent stress and burnout.
• Nurture relationships: Maintain connections with your partner and family.
• Consult with specialists such as eye doctors, pediatricians, and rehabilitation professionals to optimize your child’s vision.
• Update school staff on your child’s needs to ensure proper support.
• Regularly check on your child’s progress and well-being in school settings.

Complications

CVI can lead to various levels of visual impairment, including, in some cases, permanent blindness.

Prevention

Routine eye exams are essential for all, particularly for those with a family history of eye conditions. Children should have eye examinations as infants, at 6 months, at 3 years, before starting school, and regularly after age 5. To prevent CVI, mothers should seek to prevent infections during pregnancy, and children should receive appropriate vaccinations to guard against illnesses such as meningitis.

When to see a doctor?

You should consult a doctor if your child exhibits any of the symptoms mentioned above, has crossed eyes, frequently rubs or closes one or both eyes, avoids bright environments, struggles with visual tracking, or has symptoms like dizziness, headaches, or vomiting.

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