Chapter 6
What Intervention Methods Improve Visual Efficiency?
Use the tools in the Barraga Visual Efficiency Evaluation (BVEE) to make an inventory of the important tasks in your student’s typical day. Rate the degree of efficiency of your student’s performance. If the rating is low, determine whether or not the performance level is adversely affected by the way your student is using, or not using, his functional vision. Prioritize the tasks where performance can be improved by accommodating learning media and environments or by instructing visual skills that are developmentally appropriate, and/or by providing strategies for dealing with perceptual deficits.
Intervention method
Once you have a list of specific tasks targeted for intervention, use the tools in the BVEE to choose the best intervention method for each task. The BVEE is a modified version of the Hall and Bailey model. Lueck (formerly Hall) (2004) describes five intervention methods:
- Instruction to encourage vision skills and use
- Instruction in the selection and use of visual environmental adaptation [and learning media accommodation]—modifying elements in the environment to facilitate the use of vision—for example, using black, fiber-tip pens on white paper for writing
- Instruction in the selection and use of sensory substitutions—learning to use other senses in place of vision—for example, putting braille labels on medicine bottles or using a finger to identify when a glass of cold water is nearly full
- Instruction in the application of assistive devices to maximize vision use—for example, using a pocket magnifier to read labels in a grocery store
- Instruction in using and integrating information from all sensory systems—for example, teaching a student to begin a visual search for the door to the school cafeteria when the smell of food and sound of children reach a certain level of intensity
(Lueck, 2004, p. 259)
All of the above intervention methods, except sensory substitution, increase visual efficiency. The BVEE is based primarily on method number one—instruction to encourage vision skills and their use. Lueck breaks this method down into three areas:
- Visual environmental management instruction (e.g., placing an infant in a play area that encourages the child to use his or her vision in many ways)
- Visual skills instruction (e.g., teaching a person who has an acquired visual field loss to scan efficiently for street signs visually)
- Visually dependent task instruction (e.g., teaching an individual to search visually for a high-contrast coat hook that is large enough to be seen, rather than searching for it tactilely)
(2004, p. 259)
Keeping in mind that the BVEP is for students with ocular impairments who have a minimum of 3-year-old level cognitive skills, the tools provided in the BVEE ask you to choose one of the three methods for each priority task identified during evaluation.
- Accommodation of environments and learning media provides visual accommodations that encourage the use of vision. If this method is chosen, after accommodations are in place, no direct teaching of visual skills will occur. The TVI will observe activities to ensure that accommodations are effective and to adjust them when necessary. As accommodations increase visual efficiency, intensity may be gradually reduced. For example, a student who participates in a cooking activity may initially need contrast enhanced markers on a measuring cup. As the object becomes more familiar, smaller markers might be used. Eventually, they might be removed.
- Instruction of visual skills provides experiences that encourage the development and use of visual skills. To the extent possible, this instruction will take place within the priority tasks identified during evaluation. Information about effective instruction is provided in chapter 8. Tools to provide instruction are provided in the BVEP Instruction book.
- Instruction of strategies that compensate for perceptual deficits improve task performance for some students. Strategies should be taught and applied in the tasks in which deficits were assessed. For example, a student who has figure-ground deficits and cannot isolate a single feature in a picture in his science book can be taught to use a cut-out window to isolate parts of the picture for sequential inspection.
In regard to all of the above, prescribed low vision devices should be used. The BVEP Instruction book does not include materials for low vision device instruction, but interventions in the Instruction book should be used after or, when necessary, in coordination with instruction for use of prescribed low vision devices.
Resources for low vision device instruction
- “Compensatory Instruction for Academically Oriented Students With Visual Impairments” (Topor, Lueck & Smith, 2004) in Functional Vision: A Practitioner’s Guide to Evaluation and Intervention (Lueck, 2004)
- “Instruction in the Use of Optical Devices for Children and Youths” (Bell Coy & Anderson, 2010) in Foundations of Low Vision: Clinical and Functional Perspectives (2nd ed.) (Corn & Erin, 2010)
- Envision I: Vision Enhancement Program Using Distance Devices (Hotta & Kitchel, 2002)
- Envision II: Vision Enhancement Program Using Near Magnification Devices (Kitchel & Scott, 2002)