Chapter 10 Blindness and Low Vision

Definitions of Visual Impairment Legal definition of blindness The legal definition is based on visual acuity and field of vision A person whose visual acuity is 20/200 or less after the best possible correction with glasses or contact lenses is considered legally blind A person whose field of vision is restricted to an area of 20 degrees or less is considered legally blind (normal 160-170) Educational definitions of visual impairments The IDEA definition emphasizes the relationship between vision and learning Totally blind: Receives no useful information through the sense of vision Functionally blind: Learns primarily through the auditory and tactile senses Low vision: Uses vision as a primary means of learning but may supplement by using tactile and auditory input

Characteristics of Students with Visual Impairments Cognition and language Impaired or absent vision makes it difficult to see the connections between experiences Motor development and mobility Visual impairment often leads to delays and deficits in motor development Social adjustment and interaction Children with visual impairments interact less and are often delayed in social skills Many persons who have lost their sight report that the biggest difficulty socially is dealing with the attitudes and behavior of those around them

Prevalence and Causes Fewer than 2 children in 1000 have visual impairments Almost half of school age children with visual impairments also have another disability Causes of visual impairments Refractive errors (light rays): Myopia (nearsightedness) and hyperopia (farsightedness) Structural impairments (damage or poor development): Cataracts (cloudiness), glaucoma (high pressure), nystagmus (rapid back-forth movement), strabismus (both eyes cannot focus on same object) Cortical visual impairments: Suspected damage to parts of brain that interpret visual information

Educational Approaches The age of onset has implications for how children with low vision should be taught Visual impairment can be congenital (present at birth) or adventitious (acquired) Special adaptations for students who are blind Braille Tactile aids and manipulatives Technological Aids for Reading Print Opticon - Optical-to-tactile converter Kurzweil 1000 - Optical character-recognition system Hardware/software that magnifies screen images Speech recognition software Software that converts text files to synthesized speech

Special Adaptations for Students with Low Vision Functional vision Teaching a child to use the vision that she has Optical devices Glasses or Contacts Small hand-held telescopes Magnifiers Closed-circuit television Reading Print Approach magnification Lenses Large print Classroom adaptations Special lamps Desks with tilting tops Off-white writing paper Chairs with wheels

Expanded Curriculum Priorities Orientation and mobility training (O&M) Cane skills Guide dogs Sighted guides Electronic travel aids Listening skills Functional life skills Cooking Personal hygiene Shopping Financial management Transportation Recreational activities

Educational Placement Alternatives 88% of children are educated in public schools Itinerant teacher model Most students who are included in general education classrooms receive support from itinerant teacher-consultants The most important factor to the successful inclusion of students with visual impairments is the regular classroom teacher’s flexibility Other important aspects Peer acceptance and interaction Availability of support personnel Adequate access to special supplies and equipment Residential schools About 6% of school-age children with visual impairments attend residential schools