Transcript Introduction to Blindness and Low Vision

Introduction to Blindness
and Low Vision
BJ LeJeune, M.Ed., CVRT, CRC
RRTC on Blindness and Low Vision
Mississippi State University
Blindness and Low Vision
 A low incidence disability
 A social-economic as well as a physical
reality
 Age related – older persons more likely to be
visually impaired so there are often
accompanying age-related losses.
Stereotypes of Blindness
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Negative
Unable to work or care for
themselves
Incapable
To be pitied
Dependent & Needy
Punishment for sin
Worst than death
Positive
 Additional insights and
wisdom
 Super-human
 “Aren’t they just
amazing?”
Barriers to Social Acceptance
 Low self-esteem
 Learned Helplessness
 Poor Social Skills
 Transportation Issues
 Overcoming Stereotypes and Negative
Attitudes
 Unemployment/ preceived low productivity
Unemployment Data
www.afb.org/Section.asp?SectionID=15&TopicID=413&Sub)TopicID=177
 New Bureau of Labor Statistics data 9/2010
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Persons 16-64 years of age who reported
serious difficulty seeing even when wearing
glasses, 56% of them did not consider
themselves as part of the labor force.
Of the 43% who either did have a job or were
actively looking for a job, slightly over 13 %
were unemployed. The bottom line is that
approximately 38% were employed.
(Percentages slightly off due to rounding)
Braille & Employment
(http://nfb.org/legacy/bm/bm98/bm980204.htm)
 Study by Ruby Ryles (1998)
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Among blind and severely visually impaired
individuals who learned braille as an initial
reading medium there was a 44%
unemployment rate, as compared to those
who learned to read using print where there
was a 77% unemployment rate.
Interesting data related to type of employment
– unskilled (u), skilled (s) and professional (p).
Braille readers u=16%, s=23%, p=16%; Print
readers u=0, s=10%, p=13%
Barriers to Employment and
Independence (Adele Crudden)
 Transportation
 Attitudes
Employers
 Self (adjustment issues)
 Rehabilitation Counselor 36%
 Overcoming Print Barriers
 Lack of Employment Preparation and Blindness Skill
 Braille
 Assistive Technology
 Independent Living
 Work Skills
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Blindness Defined
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Definition of Legal Blindness: 20/200 or less in
the better eye with best correction, or widest diameter
of visual field subtending an angle of no greater than
20 degrees.
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Severe Visual Impairment: Between 20/70 and
20/200. At this point one is usually unable to obtain a
driver’s license.
Vision Loss Defined
 Visual Abilities: Measurable organic functions
including visual acuity, occipital lobe functions, color
and light sensitivity, and visual fields (Corn, 1983).
 Low Vision: A level of vision that is not improved by
the use of standard correction and which hinders an
individual in the visual planning and execution of
tasks, but which can be enhanced by the use of
optical and non-optical aids, environmental
adaptations and/or techniques (Corn, 1989).
Charting Vision
Snellen
Feinbloom
Terminology for Vision Loss
 OD (right eye), OS (left eye), OU (both eyes)
 1) 20/400
 2) 20/600
 3) Count Fingers (CF@_____ distance)
 4) Hand Motion Only (HMO)
 5) Light Perception Only (LPO)
 6) No Light Perception (NLP)
 7) Tunnel Vision
Functional Vision/Blindness
 Defined in reference to the overall use of
residual vision.
 The level of vision or lack of vision that is
utilized by the individual after incorporating in
the use of low vision aids, environmental
adaptations, vision enhancement techniques
and visual abilities.
 Two individuals with the same etiology, visual
acuity and field measurements may function
differently in trying to accomplish the same
task.
Factors of Functional Vision:
Visual Abilities
 Acuity
 Visual Fields
 Motility
 Brain Function and Processing
(Neurological Considerations)
 Light and Color Reception
Factors of Visual Functioning:
Environmental Factors
 Color
 Contrast
 Time
 Space
 Illumination (Glare and lighting type)
Factors for Functional Vision:
Individual Factors
 Cognition
 Sensory Development Integration
 Perception
 Psychological Make-up
 Physical Make Up
 Fatigue
 Experience
Other Issues in Functional Vision
 Night Blindness
 Depth Perception
 Double Vision
 Variability in Functioning
 Cortical Vision Impairment
 “Blurring Out”
Major Confounding Factors
 Lighting
 Color/Contrast
 Glare
 Fatigue
 Size and Magnitude
Quote of the Day
by Christian Roman
“Contrast is our friend, glare is our
enemy.”
Blindness Facts
 Blindness is considered to be a low incidence
disability.
 Approximately 2.25 per 1000 people in the U.S.
are legally blind.
 More people are blinded by definition than any
other cause.
 Blindness is a unique disability requiring
specialized services and trained professionals to
help individuals reach their maximum potential
Professional Eye Care Specialists
 Ophthalmologist – MD Diagnoses, treats, does
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surgery, refraction and manages eye disease
Optometrist – OD diagnoses, non-surgical
treatment interventions and refraction.
Optician – make lenses
Orthopist –work with ocular imbalances
Low Vision Clinician – Physican who does LV
Low Vision Therapist – vision professional who
assists a Low Vision Clinician
Severe Vision Loss and Age
 Rates for children = .02% of school age
children, or 2 in 1,000.
 Rates for Seniors = 2.5% or 250 per 1,000 in
people over 65 years of age.
Aging and Vision Loss
 Approximately 68% of those who are
legally blind are over the age of 55.
 Approximately 80% of those over 75
have some functional vision loss.
 As many as 40% of these individuals
also have hearing loss. The
combination can cause additional
functional limitations.
How many are there?
 Current estimates vary, but it is
estimated that there are
approximately 3.5 million legally
blind people in the United States.
 Some more questionable studies
estimate as high as 18 million.
Why the numbers disparity?
 Survey Questions vary
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N-Hanes (National Health and Nutrition
Examination Survey)
NHIS (National Health Interview Survey)
Census
 Questions to define vision loss are vague
(example: Do you have difficulty reading
even with glasses on?)
 Self report is unreliable
 No national registry
International Blindness Facts
 The World Health Organization (WHO)
estimates that there are between 27 and 35
million blind people in the world today.
 Approximately 42 million if you consider those
with a visual acuity of 20/200. However,
statistics are very unreliable from many
developing countries and the numbers may be
higher.
International Facts
 World Health Organization {WHO} estimates
that 80% of the world’s blindness is
preventable and/or treatable.
 The major cause of blindness in the world is
cataracts.
 Ninety percent of the world’s blind population
live in developing countries.
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Asia has approximately 20 million.
Africa has approximately 6 million
World Causes of Blindness
 Cataracts (at least 50% of world’s blindness)
 Trachoma (bilateral kerato-conjunctivitis)
 Hansen’s Disease (Leprosy)
 Onochocerciasis (River Blindness)
 Xerophthalmia (Vitamin A deficiency)
Quote of the Day
“Optimism is the faith
that leads to
achievement. Nothing
can be done without
hope and confidence.”
Helen Keller