Cortical Visual Impairment

Definition:

Cortical visual impairment is a neurological deficiency that originates from damage to the brain and not the eyes. It may be a temporary or a permanent condition caused by impaired nerve transmission to the visual center of the brain. This impairment makes it difficult  to comprehend,  process and  interpret visual input.

The degree of neurological damage depends on the time of occurrence as well as the location and extent of the damage.

There are two types of cortical visual impairments:

Congenital: the baby is born with brain damage. Visual center deficiency is part of this damage.

Acquired: due to injury – most cases are reversible and can be resolved.

 

Causes:

There are several causes to cortical visual impairment (CVI), but the most common is reduced blood supply to the brain (Hypoxia, Ischemia).

Additional causes: accumulation of fluid in the brain, epilepsy, meningitis, trauma, brain hemorrhage.

 

Characteristics:

  • Eyes look normal
  • Inconsistency of visual functions
  • Tendency to look at objects using peripheralvision and not the central area of the visual field
  • Due to distance vision difficulty, there is a tendency to bring objects closer to the eyes in order to isolate them from their surroundings. This action facilitates processing of visual inputs.
  • Obsessive staring at lights
  • Children with CVI are usually able to identify colors
  • Difficulty with eye-hand coordination
  • Difficulty isolating a figure from its surroundings, causing lack of proper interpretation, inability to notice details and difficulty with eye-hand coordination while preforming motoric
  • Some children look briefly at an object and then turn their head while reaching for it
  • A lack of utilizing vision spontaneously to explore the surroundings
  • Delayed eye reaction to visual stimulus
  • Preference of a certain visual field
  • Preference of big and clear objects or toys
  • Sometimes there is an impaired reflex reaction to a threatening movement and to a touch on the nose bridge
  • Difficulty to integrate sight and hearing

 

Prognosis of cortical blindness varies greatly. After treatment focusing on functional vision and thanks to general progression in several aspects of development, a significant improvement of functional vision may be achieved in many cases.

 

How we may assist a child with cortical visual impairment:

The main goals of the treatment are to maximize the use of sight remnants, improve functional vision and teach the child how to use vision to explore his surroundings. When the child’s functional vision gets better, his ability to focus on a stimulus improves as well.

  • In order to improve the child’s reactions, his surroundings should contain only a small number of stimulations
  • Controlled exposure to stimulations
  • Exposure to stimulation while conveying simple, regular and anticipated information
  • Creating color contrast
  • Using familiar objects from the child’s everyday life
  • Usage of the same object repeatedly in order to enhance the child’s sense of confidence
  • Working for short periods, a few minutes at a time
  • Allowing long period of observation that will enable the child to react to what he sees
  • Vestibular activity (moving, swinging, playing with a ball and walking) enhances visual capacity. Therefore, it’s advisable to perform some kind of motoric activity before visual stimulation treatment
Font Resize
Contrast