Presentation on theme: "Characteristics of CVI. Function of vision No one place in brain is responsible Organized in different places of the brain."— Presentation transcript:
Characteristics of CVI
Function of vision No one place in brain is responsible Organized in different places of the brain
FUNCTIONAL USE OF VISION: Using vision to complete an activity within daily life Not based on visual acuity Based on visual, individual and environmental characteristics.
What is CVI? CVI is a condition in which the eye works but the part of the brain which interprets the signals provided by the eye does not. This will cause the child to have difficulty using visual input he/she is receiving. CVI is not an indication of the childs cognitive ability.
Differences between Ocular and Cortical Visual Impairment CVI: child may see accurate visual image, but cant interpret it accurately Ocular: child has difficulty obtaining good visual image, but can process and interpret image accurately when enough information is present Some children have both (Levack, 1991)
Let s talk about CVI Child has difficulty using visual input he/she is receiving. CVI gets better or it gets worse. It can seem to vary from day to day. CVI is suspected when: Normal eye exam Brain injury Unique characteristics present
Presence of the unique CVI characteristics
Characteristics of CVI Early Resolution Light Gazing Visual Reflex Response (touch) Mid Resolution Color Latency Visual Novelty Visual Reflex Response (threat) Movement Later Resolution Visual Field Preference Visual Motor Complexity Target Array Complexity Distance Viewing
Light Gazing Staring at lights or light sources is often observed; may also be attentive to ceiling fans. May be difficult to redirect childs attention away from a light source. Sources of light should be positioned behind child. When lighted toys or objects are used the light should be used to accentuate or highlight the item. Toys which have light and music should not be used with children in this phase.
Light Gazing/Non Purposeful Gaze Across Ranges Range 1-2 Range 3-4 Range 5-6 Range 7-8 Range 9-10 May localize briefly but no prolonged fixations on objects or faces. Overly attentive to lights or possibly ceiling fans Less attracted to lights – can be redirected to other targets Light is no longer a distractor
Color: Items typically need to be a single color. May need to use childs preferred or favorite color. Once child is looking at a variety of single color items may need to use favorite, or preferred color, to initiate looking when child is tired or engaged in activities which may challenge other areas (i.e.: motor) at the same time.
Color Across Ranges Range 1-2 Range 3-4 Range 5-6 Range 7-8 Range 9-10 Objects viewed are generally single color Has a favorite color Objects may have 2-3 colors More colors, familiar patterns regarded No color or pattern preference
Latency In Phase I it may take the child extended periods of time to demonstrate a visual response. Child may demonstrate a delay in using vision to look at a target most of the time when a new item is presented or a new activity starts. Allow the child multiple opportunities and extended periods of time to demonstrate a visual response. Latency may decrease as the child uses his/her vision more.
Latency Across Ranges Range 1-2 Range 3-4 Range 5-6 Range 7-8 Range 9-10 Prolonged periods of visual latency Latency slightly decreases after periods of consistent viewing Latency present only when student is tired, stressed, or over stimulated Latency rarely present Latency resolved
VISUAL NOVELTY Children prefer familiar items over novel items. May ignore something that is novel. Very different from ocular impairments, in which something new will attract attention.
Visual Novelty Across Ranges Range 1-2 Range 3-4 Range 5-6 Range 7-8 Range 9-10 Only favorite or known objects solicit visual attention May tolerate novel objects if they share characteris tics of familiar ones Use of known objects to initiate looking sequence Selection of objects less restricted, requires 1- 2 sessions of warm up time Selection of objects not restricted
Visual Reflexive Responses Range 1-2 Range 3-4 Range 5-6 Range 7-8 Range 9-10 No blink in response to touch and/or visual threat Blinks in response to touch but response may be latent Blink response to touch consistently present. Visual threat response intermittently present Visual threat response consistently present (both near 90% resolved) Visual reflexes always present, resolved
MOVEMENT Objects viewed have movement or reflective property Way to jump- start visual system
Movement Movement may be needed to initiate and sustain visual attention, regardless of how brief. Objects which provide the appearance of movement can be used to initiate or sustain looking (i.e.: toys which have shiny or reflective properties such as mylar).
Movement Across Ranges Range 1-2 Range 3-4 Range 5-6 Range 7-8 Range 9-10 Objects viewed generally have movement or reflective properties More consistent localization, brief fixations on movement & reflective materials Movement continues to be an important factor to initiate visual attention Moveme nt not required for attention at near Typical responses to moving targets
Visual Fields Preference Child generally shows a field dependency or preference. They have a place where there best use of vision is noted. Child will typically use peripheral vision. May briefly try to use his/her central vision. Child often appears to be looking through people or objects.
Visual Fields Across Ranges Range 1-2 Range 3-4 Range 5-6 Range 7-8 Range 9-10 Distinct field dependency Shows visual field preference Field preferences decreasing with familiar inputs May alternate use of right and left visual fields Visual fields unrestricted
Visual Motor Visual targets need to be simple, non- complex, because it is probably too difficult at this point to use his/her vision and demonstrate a motor response (i.e.: reaching) in Phase I of resolution. In Phase I child typically does not use a visually guided reach.
Visual Motor Across Ranges Range 1-2 Range 3-4 Range 5-6 Range 7-8 Range 9-10 Look & touch occur as separate functions. Large and/or moving targets Look & touch on smaller objects that are familiar, lighted, or reflective Visually guided reach with familiar objects or favorite color Look and touch occur in rapid sequence but not always together Look and touch consistently
Complexity Remember that visual complexity not only includes what the child is looking at (visual clutter), but any form of sensory input which is occurring. In phase I items need to be presented against a solid black background. When working on a childs vision in phase I the child needs a quiet environment to work and play in.
COMPLEXITY Complexity of target/object Complexity of array Complexity of sensory environment
Complexity of Target/Object
Complexity of Array
Complexity of Sensory Environment
My Mother in Three Rivers Stadium (Chris Roman)
Complexity Across Ranges Range 1-2 Responds only in strictly controlled environments. Range 3-4 Visually fixates when environment is controlled. Range 5-6 Student tolerates low levels of familiar background noise. Regards familiar faces when voice does not compete.
Complexity (cont.) Range 7-8 Competing auditory stimuli tolerated during periods of viewing - student may now maintain visual attention on music toys. Views simple books/symbols. Smiles at/regards familiar and new faces. Range 9-10 Only the most complex visual environments affect visual response. Views books or other 2-dimensional materials. Typical visual-social responses.
DISTANCE VIEWING Often problematic for children in early phases In Phase I child typically only responds within inches of his/her face. May be result of increased complexity of visual array
Distance Viewing Across Ranges Range 1-2 Range 3-4 Range 5-6 Range 7-8 Range 9-10 Visually attends in near space only Occasional visual attention on familiar, moving or large targets at 2- 3 feet Visual attention extends beyond near space, up to 4-6 feet Visual attention extends to 10 feet with targets that produce movement Visual attention extends beyond 20 feet Demon- strates memory of visual events
Progression of Resolution Early Resolution Light gazing, blink reflex Mid Resolution c olor, latency, novelty, visual threat, movement Later Resolution Field, visual motor, complexity, distance viewing
Assessment Framework Interview Observation Direct Evaluation/Interaction with Child
CVI Range CVI can be severe, moderate, or mild Phases (I, II & III) describe broad functioning levels Number ranges (0-10 scale used in assessment) describe specific levels of functioning Phases guide intervention strategy to support best visual functioning
Ranges 0 to 10 scale 0 = no functional vision 10 = typical visual functioning Correlation with phases is approximate Phase 10 to 3.5 score Phase 23.5 to 7.5 score Phase 37.5 to 10 score
Interventions Environmental engineering Based on individual child/student characteristics Support the best vision where the child is functioning NOW Learning to use vision Remove, decrease supports to environment as progresses through to resolution of CVI characteristics
Phases Phase 1 : building stable visual function Phase 2: integrating vision with function Phase 3: resolution of CVI characteristics
Phase I Students generally require: 1. Single color objects 2. Objects of preferred color 3. Objects that produce movement or are shiny 4. Objects presented against a simple background 5. Objects that are familiar -Roman-Lantzy, 2005
Phase 2 Students generally require: 1. Reduction of information when presented in 2 dimension Use occluders or window cards to eliminate excess detail Highlight or outline critical features of symbols or pictures **Students should be at least a 7 on the CVI Range before asking them to discriminate 2-D objects** -Roman-Lantzy, 2005
Phase 3 Students generally require: For complexity visual field considerations in highly novel and/or over-stimulating environments -Orientation (verbal & physical) to the setting -Assistance from an adult or peer -Possible use of a cane In the classroom help the student think about their thinking Focus on problem solving rather than specific strategies -Roman-Lantzy, 2005
CVI in Infancy First three years are most critical for permanent changes Early identification provides best opportunity to take advantage of brain plasticity Dont wait for medical diagnosis! Parents are best reporters about their children Expect improvements
Impact of Sensory Loss on Child Development
Always remember to watch for signs of stress and fatigue!! Facial grimaces Hand and/or finger extension, opening, and tension Light gazing and avoiding looking at anything Yawning and/or falling asleep Hiccupping High pitched vocalizations
Contact Information Annette Carey, Project Director (304) , Ruth Ann King, Project Coordinator (304) , Mentors Tammy Belt Cell: (304) , Jamie McBride Cell: (540) ,
Contact Information Continued Mentors continued: Bridget Bailey Cell (304) , Kathy Quesenberry Cell (304) , Partners: Jennifer Cook Cell Tina Foster Cell (304) ,
Contact Information Continued Partners Continued: Kyle Heeter Cell Anita Nesland Cell , Amie Cook Smith Cell ,