Introduction
Eyes are always blamed for all sorts of defects in vision. However, potential visual defects arise due to troubles apart from the eyes. Cerebral visual impairment is one among them in which visual defect is associated with irregularities in brain functioning. If the brain segment that is concerned with reading the visual signals is hampered by any means, it can reflect potential errors in the eyesight of an individual. Visual rehabilitative therapies offer promising results in such patients.
What Is Cerebral Visual Impairment?
Cerebral visual impairment (CVI) is a visual defect, mostly encountered in younger age groups, typically babies, in which the defect is precipitated by an insult to the brain segment that is responsible for vision. It is prevailing as the ruling reason for visual disturbances among kids. CVI patients exhibit normal functioning of the eyes. The entire process within the eyes appears perfectly fine, and eye examinations can detect no troubles. It is widely known by the synonym cortical visual impairment, as the trouble is associated with the cortical portion of the brain. However, further studies proved that other adjacent areas, like subcortical and visual pathways, are also involved with the condition.
What Causes Cerebral Visual Impairment?
Trauma or impact on the brain is the paramount cause of the development of cerebral visual impairment. This trauma can be developmental, physical, infectious, and many more. Likewise, it can be an inborn condition, or else it can develop after birth as well. Once the image is captured in the lens, the optic nerves convert it into a signal (electrical impulse). These nerves then transmit the signals from the eye to the brain via the visual pathway. A specific portion of the brain receives and reads the signal, facilitating vision. All these processes happen in a fraction of a second. An impact or trauma to the specific brain area reflects in the form of visual disturbances, eventually giving rise to cerebral visual impairment. Some of the critical factors that lead to CVI include the following:
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Hypoxic Brain Injuries: Remarkable depletion in the brain's oxygen supply can potentially cause brain injuries. The brain is a critical organ that cannot afford hypoxia (deduction in oxygen). Hypoxic injury to the baby in the womb can also lead to CVI in the developing baby. These kinds of brain injuries are often the result of cerebral strokes.
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Infections: Certain infectious microbes can produce brain infections and may induce injury to the brain. Some microbes known for causing such infections include Haemophilus influenza, Herpes simplex virus, meningococci, and pneumococci.
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Hydrocephalus: A grave condition marked by a strange collection of fluid (cerebrospinal fluid) within the brain spaces, exerting undue pressure and tension on brain cells. Compressive strain boosts the pressure inside the brain (intracranial pressure), and creates trauma to the brain cells paving the way for CVI.
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Seizures: Epileptic seizures like infantile spasms seen in very young kids often invoke brain injuries, eventually resulting in CVI.
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Congenital Condition: Certain babies are born with certain defects or malformations in the brain. CVI often develops from such inborn malformations.
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Physical Trauma: Injury or impact to the brain, especially in small kids, often reflects in the form of CVI. Brain impact inflicted by intense and aggressive shaking, as in shaken baby syndrome, is reported to be associated with CVI.
What Are the Symptoms Associated With Cerebral Visual Impairment?
Symptoms of cerebral visual impairment are not restricted to visual defects. In addition, it also encompasses neurological, developmental, and behavioral issues. Some routinely encountered symptoms include:
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Deteriorated Visual Acuity: The image clarity will be remarkably compromised. The person exhibits difficulty with detailed vision.
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Impaired Cognitive Functioning: It is the cognitive functioning that enables one to interpret the vision and makes sense of it, and it also aids in keeping a visual memory.
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Proposagnosia: The person elicits trouble in identifying the faces.
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Simultanagnosia: Trouble in interpreting and understanding a visual scenario where the focus should be given to multiple objects simultaneously.
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Altered Visual Field: CVI often manifests defects and flaws in the visual field. The visual fields become more narrow, compromising the inferior and superior visions.
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Slow Visual Response: CVI often projects a remarkable lag in reacting to the visual scene.
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Compromised Contrast Sensitivity: The person experiences trouble seeing objects in dull backgrounds.
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Photophobia: High-intensity light beam produces extreme discomfort compared to dim light.
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Hemiparesis: Certain neurological troubles, like weakness and incapacitation involving one-half of the body, accompanies CVI.
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Cerebral Palsy: It is expressed as trouble in movement, posture, and other motor functions.
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Developmental Disorders: Cerebral visual impairment is often accompanied by other developmental disparities. It frequently exhibits a general lag in the intended growth and development.
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Auditory Deficit: At times, CVI patients manifest compromised hearing functions.
How Is Cerebral Visual Impairment Detected?
A thorough analysis of clinical findings, medical history, and neurological evaluation plays a significant role in the diagnosis process. Apart from that, specific tests and procedures are carried out to confirm the diagnosis of the condition and some of them include the following:
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Electroencephalogram (EEG): It aids in detecting defects in the brain’s functioning, especially in signal (impulse) transmission.
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Visual Evoked Response Test (VER): It typically detects irregularities in the part of the brain concerned with the vision (visual cortex). In this test, the response is brought about by specific visual triggers or stimuli.
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Magnetic Resonance Imaging (MRI): It provides a clear picturization of the brain injury, enhancing the diagnosis and treatment strategies.
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Computed Tomography (CT): It aids in assessing the extent of brain injury and, thereby, confirming the diagnosis.
What Are the Treatment Strategies Available for Cerebral Visual Impairment?
As CVI develops from trauma in the brain, there is no apparent cure or curative therapies. However, visual defects can be compromised by appropriate rehabilitative treatments like light reflex stimulation to facilitate image perception. Treatment therapies should be customized based on the extent of visual and other neurological deficits. In case of associated hearing loss, hearing aids are suggested to enhance auditory functions. Studies reported that occasionally the affected child shows considerable visual recovery over a longer period, even without any treatments. Researchers are trying to figure out the underlying principle for this recovery.
Conclusion
Cerebral visual impairment is an ophthalmic condition impacting visual, developmental, and neurological functions. Diverse manifestations of the condition are primarily due to the involvement of multiple systems in the body. Identifying the defects and supporting the child with appropriate rehabilitative therapies enhance their quality of life. Rehabilitative therapies are designed by taking into account each patient’s needs and impairments.
