OVERVIEW
Blindness is the inability to see anything,
including light.
If you’re partially blind, you have limited vision.
Complete blindness means you can’t see at all.
The current politically correct terms for blindness
include visually handicapped and visually
challenged.
CLASSIFICATION
The International Classification of Diseases 11 (2018)
classifies vision impairment into two groups, distance and
near presenting vision impairment.
Distance vision impairment:
Mild – presenting visual acuity worse than 6/12
Moderate – presenting visual acuity worse than 6/18
Severe – presenting visual acuity worse than 6/60
Blindness – presenting visual acuity worse than 3/60
Near vision impairment:
Presenting near visual acuity worse than N6 or M.08 with
existing correction..
DEFINITION
Blindness: Loss of useful sight.
Blindness can be temporary or permanent damage to any
portion of the eye, the optic nerve, or the area of the brain
responsible for vision can lead to blindness.
WHAT IS LEGAL BLINDNESS?
Legal blindness is referred to as condition when
despite treatment such as surgery, a person is
unable to see properly.
To be more specific, a person who is legally blind
can see at 20 feet what a normal person can see at
200 feet.
EPIDEMIOLOGY
Blindness and vision impairment affect at least 2.2
billion people around the world.
Of those, 1 billion have a preventable vision impairment
or one that has yet to be addressed.
Globally, the leading causes of vision impairment
are uncorrected refractive errors and cataracts.
The majority of people with vision impairment are
over the age of 50 years.
WHO’S AT RISK FOR BLINDNESS?
people with eye diseases, such as macular
degeneration and glaucoma
people with diabetes
people who have a stroke
people undergoing eye surgery
people who work with or near sharp objects or toxic
chemicals
premature babies
WHAT CAUSES BLINDNESS?
Glaucoma refers to different eye conditions that can damage
your optic nerve, which carries visual information from your
eyes to your brain.
Macular degeneration destroys the part of your eye that
enables you to see details. It usually affects older adults.
Cataracts cause cloudy vision. They’re more common in
older people.
A lazy eye can make it difficult to see details. It may lead to
vision loss.
Optic neuritis is inflammation that can cause temporary or
permanent vision loss.
ACCORDING TO WHO
Globally, the leading causes of vision
impairment are:
uncorrected refractive errors
cataract
age-related macular degeneration
glaucoma
diabetic retinopathy
corneal opacity
trachoma.
WHAT CAUSES BLINDNESS?
Retinitis pigmentosa refers to damage of the retina. It
leads to blindness only in rare cases.
Tumors that affect the retina or optic nerve can also
cause blindness.
Diabetes : With diabetes, vision may be blurred, there
may be shadows or missing areas of vision, and difficulty
seeing at night
Blindness is a potential complication if you
have diabetes or have a stroke. Other common causes of
blindness include:
birth defects
eye injuries
complications from eye surgery
WHAT CAUSES BLINDNESS?
Total blindness (no light perception) is often due to:
Severe trauma or injury
Complete retinal detachment
End-stage glaucoma
End stage diabetic retinopathy
Severe internal eye infection (endophthalmitis)
Vascular occlusion (stroke in the eye)
WHAT ARE THE SYMPTOMS OF BLINDNESS?
If you’re completely blind, you see nothing. If you’re
partially blind, you might experience the following
symptoms:
cloudy vision
an inability to see shapes
seeing only shadows
poor night vision
tunnel vision
HOW IS BLINDNESS DIAGNOSED?
A thorough eye exam by an optometrist will help
determine the cause of blindness or partial loss of vision.
Doctor will administer a series of tests that measure:
the clarity of vision
the function of eye muscles
how pupils react to light
They’ll examine the general health of eyes using a slit
lamp.
HOW IS BLINDNESS TREATED?
In some cases of vision impairment, one or more of the
following may help restore vision:
eyeglasses
contact lenses
surgery
medication
If you experience partial blindness that can’t be corrected,
doctor will provide guidance on how to function with limited
vision.
For example, you can use a magnifying glass to read,
increase the text size on your computer, and use audio
clocks and audiobooks.
HOW IS BLINDNESS TREATED?
Complete blindness requires approaching life in a new way
and learning new skills.
For example, you may need to learn how to:
read Braille
use a guide dog
organize your home so you can easily find things and stay
safe
fold money in distinct ways to distinguish bill amounts
You can also consider getting some adaptive products, like
a specialized smartphone, color identifier, and accessible
cookware.
There’s even adaptive sporting equipment, like sensory
soccer balls.
HOW CAN BLINDNESS BE PREVENTED?
To detect eye diseases and help prevent vision loss, get regular
eye examinations.
If you receive a diagnosis of certain eye conditions, such as
glaucoma, treatment with medication can help prevent
blindness.
To help prevent vision loss, the American Optometric
Association recommends that have child’s eyes examined:
at 6 months of age
at 3 years of age
every year between 6 and 17 years old
If you notice symptoms of vision loss between routine visits,
make an appointment with their eye doctor immediately.