After reading Chapter 13, you should be able to:

• Define legally blind, functionally blind, deaf-blind, and low vision.
   
• Explain the vision process and associated vision disorders.
   
• List the most common visual impairments affecting school-age children.
   
• Summarize the historical evolution of educational services for children and youth with visual impairments.
   
• Discuss observable characteristics of vision difficulties.
   
• Describe how visual acuity is assessed.
   
• Define literacy medium and learning medium.
   
• Summarize educational services for persons with visual impairments across the life span.
   
• Explain how technology benefits individuals with visual impairments.