Presentation on theme: "Phase III CVI: What do I do now? Part 1 Kathy Quesenberry WV CVI Mentor, Occupational Therapist May 2010."— Presentation transcript:
Phase III CVI: What do I do now? Part 1 Kathy Quesenberry WV CVI Mentor, Occupational Therapist May 2010
Phase III During phase III of CVI resolution the focus is on the resolution of the CVI characteristics. In this phase modifications in the environment are critical for success. **Position paper at APH (American Printing House for the Blind) website - Statement on Cortical Visual Impairment**
Differences in Ocular and Cortical Visual Impairment Jan and Groenveld, Childrens Hospital, Vancouver, British Columbia, Canada among the first researchers to systematically document the characteristics of children with CVI summarized the primary differences between ocular and cortical visual impairment in children According to these researchers, some of the primary differences include:
Differences in Ocular and Cortical Visual Impairment continued: Children with CVI often have a normal medical eye exam while children with ocular impairments typically have an abnormal medical eye exam. Children with ocular impairments demonstrate consistent visual functioning with a normal visual attention span. Children with CVI demonstrate variable visual functioning with a markedly short visual attention span. Coordinated eye movements are usually present in CVI and not in an ocular impairment.
Differences in Ocular and Cortical Visual Impairment continued: Children with CVI often demonstrate compulsive light gazing but rarely eye pressing. Children with ocular visual impairment seldom light gaze and often demonstrate eye pressing. Sensory nystagmus is often present when an ocular loss is congenital or early and not usually present in CVI. Color perception is usually preserved in CVI and may be absent in ocular visual impairment, depending on the disorder.
Differences in Ocular and Cortical Visual Impairment continued: Children with CVI almost always have a peripheral field loss. Children with ocular visual impairment usually do not have a field loss. Close viewing present in both types of visual impairment, but for different reasons. Children with ocular impairment use close viewing for magnification. Children with CVI use close viewing for a reduction in crowding and for magnification.
Differences in Ocular and Cortical Visual Impairment continued: Children with CVI usually do not look visually impaired (p.101), while children with ocular visual impairment appear visually impaired (e.g., eyes look abnormal). Children with ocular visual impairment may have additional neurological disabilities, while children with CVI nearly always have additional disabilities (Jan & Groenveld, 1993).
Differences in Ocular and Cortical Visual Impairment continued: Children with CVI often show a head turn when they look at or reach for an object of interest; they seem to look and then look away as they reach for the object. Children with ocular visual impairment look and reach at the same time. (Groenveld 1993) Children with CVI -foreground/background perception. Difficulty looking for objects against patterned background or objects spaced closely together. Distance viewing difficulty For children with ocular visual impairment, improved functioning is seen with enhanced visual input, but for children with CVI, enhanced input often is detrimental to the use of their vision.
Differences in Ocular and Cortical Visual Impairment continued: The functional vision assessments currently used in the field rely on the needs of children with ocular impairment and do not take into account the unique characteristics of children with CVI. Roman-Lantzy developed a functional vision assessment for children with CVI, The CVI Range (Roman-Lantzy, 2007).
The information on slides 2-7 is an excerpt from the paper Reliability of The CVI Range – A Functional Vision Assessment for Children with Cortical Visual Impairment by Dr. Sandra Newcomb, with the permission of Dr. Newcomb.
Why is this important? Noting the differences between ocular and cortical visual impairments is important because in phase 3 a person may often question if there is actually a visual impairment at all. Children in phase III may often appear to demonstrate typical visual responses; especially if you are working with younger children who are non- verbal. It should be noted a child is not born as a Phase III child. If a child has CVI at some point they have demonstrated the characteristics demonstrated in Phase I and II of resolution.
What is Phase III? When a child enters phase III of resolution they will have an overall score on the CVI Range of 7+ to 10. The characteristics typically the last to resolve in CVI, and create the greatest challenges in phase 3 of resolution, include visual field preference, visual motor, distance viewing, and complexity (target, array & complexity).
Children in phase 3 of resolution typically have difficulty with two dimensional material. They often have trouble moving through new, or less familiar environments. Distance viewing continues to create challenges, especially in more visually complex environments. A visually guided reach may still be challenging with smaller items or items against a visually complex background.