Blindness and the Brain

How Blindness Affects the Structure of the Brain

A Journey Through The Visual System

What is Visual Impairment (Blindness) and how does it affect the structure of the brain?

Visual impairment refers to the loss of part or all of a person’s eye sight. This can be due to the damage of the eye, the optical nerves, or the visual cortex of the brain, or it can occur as a result of abnormal brain development. A number of conditions are associated with visual impairment. Regardless of the cause, visual impairment can lead to changes in how the brain structure develops.

Normally, visual images enter through the eye and travel the optic nerve into the visual cortex to be processed. When damage or developmental abnormalities are present that affect the visual process, the travel of these signals through the brain is impeded.

Structural changes in the brain related to uncorrected vision impairment, such as a loss of dendrite spines and a reduction of synapses as described in Biological Psychology: An Introduction to Behavioral, Cognitive, and Clinical Neuroscience by S. Marc Breedlove and Neil V. Watson, can occur resulting in the inability to transmit signals from the eyes to the visual cortex of the brain due to breaks in or incomplete neuropathways. Firing of nerves related to visual signals would not be able to completely travel the path to the visual cortex and other areas of the brain, resulting in the inability to process images. Early preventative measures and intervention can alleviate these issues, but if left unchecked until adulthood, most damage is permanent.

Brain Bleed Leading to Vision Impairment

Cerebral Visual Impairment Society

The above link provides a wide variety of information relating to cerebral visual impairment (CVI), which is a type of visual impairment. This impairment defines CVI, what processes are involved in interpreting visual stimuli in the brain, and what behaviors are associated with CVI. Since the process of interpreting visual signals is very complex, a number of ares of the brain are responsible for interpreting these signals and problems in any area can lead to CVI. It does not have to be a problem with the eye itself, optical pathways, or the visual cortex.