690 likes | 1.76k Vues
Cortical Visual Impairment. What is it? How do we Adapt?. Defined.
E N D
Cortical Visual Impairment What is it? How do we Adapt?
Defined • According to the American Printing House, aph.org, the definition for medical purposes: Cortical visual impairment (CVI) may be defined as bilaterally diminished visual acuity caused by damage to the occipital lobes and or to the geniculostriate visual pathway. CVI is almost invariably associated with an inefficient, disturbed visual sense because of the widespread brain disturbance • According to the American Printing House, aph.org, the definition for educational purposes: Cortical visual Impairment (CVI) is a neurological disorder, which results in unique visual responses to people, educational materials, and to the environment. When students with these visual/behavioral characteristics are shown to have loss of acuity or judged by their performance to be visually impaired, they are considered to have CVI. • There are 30 areas of the brain that processes vision and 10 areas of the brain stem - In children with CVI, information must be channeled to these areas of the brain rather than the affected primary area
Prevalence • Cortical visual impairment is the leading cause of visual impairment in children in the US • Optic Nerve Hypoplasia is the second leading cause of visual impairment in children in the US • Retinopathy of Prematurity the third leading cause of visual impairment in children in the US
CVI • Can be congenital • Can be acquired • May also exist with other visual conditions such as: optic nerve atrophy, hypoplasia, dysplasia, or retinopathy of prematurity
Causes • Asphyxia • Hydrocephalus • Cytomegalovirus • Premature Birth • Metabolic disorder • PeriventricularLeukomalacia • Seizure Disorder • Brain Bleeds • Trauma • Shaken Baby Syndromes • Exposure to toxins & drugs • ETC.
Normal Eye Exam • Normal optical structure • Normal coordinated eye movements with the possible exception of the presence of eye movement that is similar to nystagmus • Normal color perception
Difficulties with Visual Novelty • Novelty: Objects that the child are not familiar with • More able to notice objects that are familiar to them Example: Toys they have played with or educational tools they have used over a period of time
Difficulties with visual Complexity and Environmental Complexity • Too much visual, auditory, and/or tactile information at one time • Low Complexity High Complexity
Complexity • Environmental complexity include classroom noise, people talking, visual clutter, etc. • Headphones, ear plugs or sock caps, project boards can be used to eliminate or lessen background noise • Drapes/sheets, project boards, carousels, may be used to limit or lessen visual clutter
Complexity • Educational materials include, worksheets, whiteboard presentations, board work, etc • Different sizes of typoscopes (reading windows) can be used to decrease the amount of visual clutter on a page
Distinct Color Prefence • Most typical color preferences are Red or Yellow (because there are more red cones in the retina than any other color)
Distinct Color Preference Speech Pathologist can wear Red Lipstick so the child’s vision will be directed toward their lips
Visual Field Deficits • Loss of vision in area(s) of sight • 90% have visual field deficits • Lesions in temporal fibers; upper field loss • Lesions in parietal fibers; lower field loss • Lesions in one hemisphere; field loss in opposite half of each eye
Non-Purposeful Gaze • Child’s eyes are focused on something/someone but it appears he is looking through it
Light Gazing Behaviors • Child likes to look at lights • The child continuously looks at ceiling fans when there is a source of light • The child will move into a sunny area or area with direct light • Note: Some children with CVI demonstrate light sensitivity particularly in the early stages of CVI
Light Gazing Child sees many service providers in a day. Take pictures of them, put them on transparency, and put them on a light box as a way of letting the child know they will be seeing them next. Starts to recognize the picture and the person are the same.
Visual Latency • Child takes time to react to something to which he is visually attending • It make take several seconds or minutes for him to “notice” and respond
Attracted to Movement • Child sees items that have a movement characteristic. The item may not actually be moving
Atypical or Absent Visual Threat Response • Child does not respond to visual threats, such as when an open hand is brought quickly toward the face
Use of Near Space and Close Looking • Brings object close to block out irrelevant background / visual clutter (the effects of figure ground)
Distance Viewing As child resolves difficulties with distant viewing, he is able to see objects further and further away
Atypical Motor Behavior • Child focuses on a person or object
Use of Computers and iPads • The computer or iPad are an excellent tool to use with children who have CVI. It provides high contrast, two dimensions and fills the child's visual fields to eliminate the effects of figure-ground • There are excellent children’s computer programs that are simple and educational that use bright colors and eliminates visual clutter. Examples: Creature Capers, Creature Cartoons, Creature Antics, Creature features, Creature Magic (from Laureate Learning Systems), Senswitcher.com • Make your own interactive books/games using Microsoft Power Point
iPad Applications • Scroll n Roll – scrolls print across the screen thus child may be able to read • Tap and See Little Bear Sees • Fluidity • See Wonderbaby.com for a list of recommended apps for visual impairment and CVI • Shapes • Baby Finger • Findit • Rattle • Touch Free • Tail Toes • Match It Up • Speak up: When children speak loud enough, colors and shapes appear • iMeba: Cause and effect
To Promote Reading • To promote reading use different fonts, colors, and sizes • Dog • Cat • Bird
Reading • Lighting • Electronic Magnification
Materials • Dollar Tree or Dollar store: tap and light up, spinner lights, beads, bows, mini strands of lights, solar toys, etc • APH.org • Bubble lights purchased at Cracker Barrel Stores when in stock or Google LED bubble gun for a variety of sources • Garage sells • Purchase materials cheaper the day after a holiday
References and Thank you • Renee Miller, CTVI at OSB • Tonya Givens, Secretary, OSB • Pam Cox, Special Education Teacher, Union Schools • Abi McClain Student, Union Schools • Miss Madge and her students, Union Schools • Students at OSB • Dr. David Lewerenze, Northeastern State University College of Optometry • Dr. Christine Roman-Lantzy