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 vision is restricted to an area of 20 degrees or less is considered legally blind

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 channel– Low vision: Uses vision as a primary means of learning

Causes

• Causes of visual impairments: Damage or disturbances to any part of the eye’s optical, muscular or nervous system

– Refractive errors: Myopia (nearsightedness) and hyperopia (farsightedness)

– Structural impairments: Cataracts, glaucoma, nystagmus, strabismus

– Cortical visual impairments: Suspected damage to parts of brain that interpret visual information

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 – low motivation to move

– Physical Stereotypy• 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

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• Computer technological aids for reading print

– 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

– Contacts

– Small hand-held telescopes

– Magnifiers

• Print reading

– 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

86% 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 7.5% of school-age children with visual impairments attend

residential schools

Current Issues and Future Trends • Specialization of services

– Children with visual impairments are likely to receive special education services in the future in both regular and residential schools

– Greater emphasis will be placed on intervention with infants and young children and on training older students for independence

• Emerging technology and research– It is hoped that all people with visual impairments will benefit

from new technological and biomedical developments– Artificial sight may be possible in the future

• Fighting against discrimination and for self-determination– Career opportunities will likely expand as individuals with

visual impairments become more aware of their legal and human rights