Cortical visual impairments (CVI) are the leading cause of visual impairment in children, making up about 30-40% of those diagnosed. The prevalence of CVI is reported to be about 72 per 100,000 children (Flanagan, Jackson, & Hill, 2003). Those with CVI have damage or malformation to the part of the brain responsible for processing visual information (Rychwalski et al, 2006). Improvements in functional vision are possible through adolescence and early adulthood (Roman-Lantzy, 2007). Occupational therapists are beginning to see more children with CVI to maximize functional vision. Most functional vision assessments are geared toward children with ocular visual impairments. However, the profession lacks widely-used standardized assessments and evidence-based interventions for improving functional vision for children with cortical visual impairments. The CVI Range was developed by Christine Roman-Lantzy as an assessment protocol to direct intervention. More work needs to be done to formulate a strong body of literature to support the use of this assessment and associated intervention strategies.
Section 2: Identify Patient-Reported Needs
A literature review was performed using EBSCOhost, Medline, OVID, and PubMed databases using combinations of key search terms: cortical visual impairment, intervention, visual impairment, vision assessment, complex care, CVI Range, and child. The proposed study will be investigating children ages 0-22 years old diagnosed with a cortical visual impairment, with an associated neurological disability, and receiving treatment in a pediatric rehabilitation hospital.
Jan and colleagues in British Columbia have contributed a great amount of research in regards to visual behaviors seen in children with cortical visual impairments. Jan, Groenvald, and Sykanda (1990) measured the prevalence of light-gazing in this population. This was a study completed on all children evaluated by a visual impairment program in a 2 1/2-year period. The study started with patient caregiver report. Researchers observed patients and light-gazing was monitored by any time longer than 15 seconds where children were compulsively staring into lights. A total of 69 patients with CVI were observed. A group of 167 children with ocular visual loss were also observed. Results showed that 60% of children with CVI demonstrated some sort of light-gazing. Light-gazing was frequently involved among girls more so than boys, and among those with congenital CVI more frequently than acquired CVI, with the behavior resolving with age for both groups. Variables worth noting from this research was the role of gender, epidemiology, and age on the CVI characteristic of light-gazing.
Cohen-Maitre and Haerich (2005) investigated color and motion as means of soliciting visual attention in children with CVI. The sample consisted of eleven children between the ages of 18-72 months with a CVI diagnosis and associated Cerebral Palsy (CP). Severity of CVI in the sample of children was not stated. Data was completed for 4 boys and 5 girls, with two participants omitted from the study. All children had some sort of impairment in motor movement. The study was conducted in a small room with no windows. Children remained in their wheelchairs or stationary chairs for the study. Two monitors were placed 6.5 feet away and presented various colors on a black background. The researchers used the child’s eye gaze to monitor their ability to follow a stimulus. Stimuli remained on the screen for 10 seconds. Seven different tests were done, with 16-32 trials in each test. A child’s gaze was documented noting duration of initial look, total number, and total duration of looks at each stimulus. The results demonstrated that color and movement were both important factors in getting attention. Movement of an item was preferred over any color alone. Movement with the addition of color was the most influential stimuli for visual attention. Movement, color, and associated disabilities were all notable variables considered in this research study.
The research indicates several characteristics of CVI prevalent in children. The above articles consider light gazing, movement, and color as suggested difficulties or variables to consider when addressing visual response and function. The causes of CVI for the children discussed varied, along with their age, and level of other associated disabilities. The research available for CVI is sparse. Much of the research suggests general characteristics and trends seen amongst children with CVI, but fails to address evidence-based intervention strategies or standardized measures to use with this population. (ADD HOW LONG THE SETTING HAS BEEN USING THIS ASSESSMENT AND INTERVENTION ASSOCIATED WITH IT. ADD SOURCE FOR WHERE SOMEONE HAS USED IT WITH THE SAME POPULATION TO JUSTIFY. TALK ABOUT HOW IT HAS NOT BEEN STUDIED MUCH YET.)
Section 3: Choose Sound OT Interventions that Address Client-Reported Needs
The Bureau of Early Intervention and the New York State Department of Health developed clinical practice guidelines for the assessment and intervention of young children aged 0-3 years with vision impairments. The clinical practice guideline suggests that visual responses will be enhanced with practice. The guideline encourages therapists to ensure the child is using their vision in increasingly more advanced ways and to find the limits to the child’s visual abilities. Strategies used include environmental modification and visual stimulation. Environmental modifications to enhance visual function include variations with illumination, glare, color and contrast, size, and position. When trying to optimize functional skills and use of vision, the clinical practice guideline suggests presenting visual images or objects in isolation, pairing the visual information with another sensory cue, and being aware of the child’s specific visual preferences. The purpose of visual stimulation as a therapy technique is to provide opportunities for practice of visual skills including attention, tracking, fixation, localization, and reaching/grasping. Visual stimulation should be used to strengthen existing visual skills (New York State Department of Health Division, 2007).
McKillop et al (2006) conducted a focus group of parents and caregivers of children with CVI to determine general characteristics of each child’s CVI and helpful strategies they were using at home to address these difficulties. Data was collected from the primary caregivers and family of 17 children. Specific ages, settings, presence of other associated disabilities, and severity of CVI were not given. Reported strategies from the families included compensatory strategies, verbal or auditory cueing, reducing complexity, using favored colors, presenting items on a black background, and providing substantial rest breaks for visual fatigue.