(Activities)

THE EYE: Process of Normal Vision

Anatomy and Physiology of the Eye

How vision takes place

Blindness and Low Vision

Types and Causes of Problems of Vision

Special Adaptations, Aids and Technology for students who are blind and with low vision

The Education of Students with Visual Disability

What to do when a blind student is mainstreamed in class (for teachers)

Success stories of children and youth who are blind or with low vision

Spinning Wheel IllusionStare at one of the 5 wheels. Whichever one you stare at will appear to suddenly stop spinning. In reality -

none of the wheels are turning at all.

Let’s see if your vision and mind works hand in hand together..

The eye is a complex part of the human body that no other organ can equal.

The sense of vision is a complex and intricate physiological system.

There are 3 elements necessary for good vision to take place. These are:A pair of healthy, intact and efficiently

functioning eyes with complete parts

A well lighted objects

A healthy brain

Five physiological/physical

systems in visions:

The Protective Structure

The Refractive Parts

The Muscles

The Retina and Optic Nerves

The Brain (where vision takes

place)

Surrounds the eye to protect it from harm.

These are:

Eye Socket – contains the eyeball; It protects the

sensitive mechanism for vision trauma together

with the bones in cheeks and forehead

Bones in the cheek and forehead

The Lacrimation System (tear ducts) – secretes

fluid/tears that clean and keep the eyes moist

Eyelids – moistens and clean the cornea through

blinking

Eyebrows and Eyelashes – catch foreign bodies that

might enter the eyes.

Bends or refract light rays so that the image of the

object focuses on the retina.

These are:

Cornea – Protects the sensitive parts of the eye; It starts

the process of vision by bending the light rays into

patterns or images

Aqueous Humour - A watery liquid that fills the front

chamber of the eye to keep the eyeball properly inflated

Pupil – It constricts or dilates to regulate the amount of

light entering the eye.

Iris

Lens – adjusts its thickness so that both near and far

objects can be brought to focus on the retina.

Vitreous Humour - a chamber filled with liquid; fills

most of the eyes interior

Functions to coordinate and balance the

movements of the eyes.

They turn, raise and lower the eyes in

response to cranial or brain nerve impulses

Retina – a multilayered sheet of nerve

tissues at the back of the eye.

Rods and Cones – light receptor cells

Rods – 130 Million for black and white vision;

responsible for night vision (or images under low

illumination)

Cones – 7 Million for color perception

Macula – most sensitive part of the eye; the

area that is vital to the exact discrimination

of the details of an image/object

Optic nerves – connected to the retina;

conducts visual images to the brain

LOCATION: at the back of the head

It is one of the four lobes of the brain that

are named for the major skull bones that

covers them

Others are: Parietal Lobe – processes body sensations

Temporal Lobe –auditory or hearing

Frontal Lobe – governs the highest functions

associated with conscious activities and intelligence

The basic function of the eye is to collect the visual stimuli

and information in the form of mechanical energy from the

environment through the psychological process –

SENSATION

The stimuli are converted to electrochemical form or nerve

impulses through the process of TRANSDUCTION.

The optic nerves conveys the nerve impulses to the occipital

lobe of the brain where PERCEPTION takes place.

3 Conditions for vision to take place:

The eyes are stimulated by light rays

The light rays are reflected from objects in the visual field

The mechanical energy is converted into nerve impulses

which the brain processes

BLINDNESS : (legal definition) it is based on measurement of

visual acuity, field of vision and peripheral vision.

Visual Acuity – the ability to clearly distinguish forms or discriminate details at a specific distance. Normal Visual Acuity is measured by reading letters, numbers and others symbols from a chart 20ft away.

The Snellen Chart is commonly used for this purpose.

Field of Vision – refers to the area that normal

eyes cover above, below and on both sides when

looking at an object or when gaziing straight

ahead. The field of normal vision covers

approximately a range of 180 degrees.

Central field of Vision – looking directly at an object

Peripheral Vision – the outer ranges of the field of vision

Tunnel Vision – results from an extremely restricted field

of vision.

Legal Blindedness – condition where visual acuity

is 20/200 in the better eye after the best possible

correction with glasses or contact lenses. The field

of vision for this person is about less than 180

degrees to an area of 20 degrees.

BLINDEDNESS - Educational Definition

Total blindness – the person is absolutely without

sight but may have light and movement perception

and travel vision.

The degree of blindness include:

Light perception (can differentiate light and

dark/day and night)

Movement perception (can detect if an object or a

person is in motion or in still position)

Travel vision (field of vision is enough to travel

safely in familliar area)

In SpEd, children who are blind are differentiated

from those who have low vision (ex. Children who

are blind are given Braille books but children with

low vision are given materials with large print)

Low vision – a level of vision that with standard

correction hinders an individual in the visual

planning and execution of tasks, but which

permits enhancements of the functional vision

through the use of optical or non-optical aids and

environmental modifications or techniques.(Corn’s

definition of Low Vision)

The inability of the eyes to function

efficiently may be traced to:

1. Errors of Refraction

2. Imbalance of the Eye Muscles

3. Diseases

4. Trauma or Accidents

After light rays enter cornea, acqueous humour and pupil and the lens fails to refract or bend the light rays to the central part of the retina.

Hyperopia (Farsightedness) – the lens fails to focus the light rays near objects on the retina. Convex lenses are used to converge the light rays on the retina.

Myopia (nearsightedness) – the eyes are abnormally long from front to back and the lens fails to refract the light rays from a distant objects on the retina. Concave lenses are used to correct myopia.

Astigmatism – the cornea which normally forms a portion of a spherical lens is deformed, the refraction of light becomes faulty and blurred vision results. Cylindrical lenses are used to correct the direction of the spherical lens.

When the muscles of both eyes do not work together in a coordinated way

Strabimus – different images are cast on each retina resulting to cross-eyedness or squinting.

Diplopia (double vision) – results when the brain cannot fuse the differences in the images cast on the retina into a single image. It can be corrected by prescription lenses, exercise, surgery.

Amblyopia – occurs when vision is suppressed in one eye and it becomes weak or useless.

Nystagmus – a condition in which there are rapid involuntary movements of the eyeball that cannot result to nausea and vomiting and dizziness. (in some cases, it is a sign of brain malfunction or inner ear problems)

Cataract – caused by the clouding of the lens which results to progressive blurring of vision and eventually blindness occurs.

It is associated with the aging process but it can occur early among persons with diabetes mellitus.

Children also can suffer from congenital cataract.

Diabetic retinopathy – occurs when diabetes mellitus interferes with the flow of blood to the retina causing it to degenerate

Corneal scar – called “pilak”, whitish substance caused by injuries and inffectionsdue to accidents and malnutrtion.

Diseases of the retina – can be congenital or present at birth.

Coloboma – a degenerative disease in which the central/peripheral areas of the retina are not completely formed resulting to impairment of the visual field, the central visual acuity and blindness.

Retinitis Pigmentosa – a hereditary condition that results in the degeneration of the retina. It can result to blindness.

Glaucoma – a condition in which there is excessive pressure in the eye.

This happen because of a certain

experience leading to injuries affecting

the eye.

Example :

Retinal Detachment

Eyes are hit or struck by a foreign objecy

Rubella – mild disease in most people. But pregnant woman who come in contact with someone with rubella(specially during the first 3 months) may have a risk of having a rubella baby.

A rubella baby can have serious problems such as permanent damage to the eyes and ears, including blindness and deafness, heart disease and brain damage.

It is responsible for 95% of deaf and blind babies.

Braille – primary means of literacy for a

blind person. It is a system of writing and

reading in which letters, words, numbers

and others are made from raised and

embossed dots.

It was invented 1830’s by Loiuse Braille, a

young blind man Frenchman who played organ

in church and use it to record church hymns

and music.

It is a complex system. It uses 6 dots that are

arranged two wide and three deep and

numbered

Blind students learned to read and write in braille by using a brailler which operates like a typewriter with 6 keys.

A portable laptop called VersaBraille II+ is also available for written work, taking notes and tests.

Braille Alphabet

Typewritter – they use it to communicate with

their teachers, classmates and friends.

Manipulative and Tactile Aids – are used in

learning mathematics, sciences and social

studies.

The Cisenaire rods – developed by Belcastro (1989);

enables the student to quickly identify by touch

The Cranner Abacus – used in teaching numerical

concepts and computing 4 basic operations

The Speech-Plus talking calculator – it talks by

voicing entries and talks aloud

Braille, Verbal or Taped instructions

Embossed relief maps and diagrams

3D models and Electronic Probes

Technological Aids

Optacon (optical to tactile converter) – small

electronic device that converts regular print into a

readable vibrating form for blind people.

The Kurzweil Personal Reader – a sophisticated

computer with an optical character recognition

(OCR) system that scans and reads via synthetic

voice typeset and other printed matter.

Assistive Technology –enables blind person to

access personal computers.

1960’s – integration of blind students in regular

classes. Blind boys and girls who have average

or better mental ability were enrolled in regular

classes at School Division Pasay City, Manila

and the Teacher Training Department of the

Philippine Normal College.

The SPED teachers teaches skills and concepts

that most children learn visually through the

remaining senses: audition, touch, olfaction,

gestation and other non-visual experiences.

Blind students learned to read and write in braille. Two brailled coded are learned:

(1) Filipino Brailled Code and (2)English Brailed Code American Edition.

The Philippine Printing House for the Blind at the Department of Education transcribes most of the materials in braille.

The Resources for the Blind Incorporated (RBI), a foreign funded NGO assist the DepEd through teacher training, preparation of instructional materials and other related projects.

Blind children receive instruction in orientation and mobility. Orientation – the ability to establish one’s position in

relation to environment through the use of the remaining senses.

Mobility – the ability to move safely and

efficiently from one point to another.

The Sped Teacher uses appropriate methods

and procedures to teach travel at home, the

school and the community.

The Sped Teacher uses manipulative and tactile

aids in teaching mathematics, science and the

other subjects in the curriculum.

Truly, an efficient Sped teacher “opens the door

to a world from which his/her student who are

blind or have low vision are more removed than

seeing children.” (Lowenfield,1973)

It’s okay to use words like “look” and “see”

when communicating with a blind person.

Introduce him/her to the other students and

encourage him/her to answer them.

Include him/her in all class activities

Extend the opportunity of being a leader to

the blind child

The same disciplinary rules that apply to the

rest of the class should apply as well to the

child with visual impairment.

Encourage him/her to move about the classroom to

get the materials or to do certain activities.

Give verbal instructions or oral cues

Provide space to accommodate his or her special

materials (ex. Braille books, tactual aids etc.)

Motivate the seeing classmates to become

interested in topics related to vision and visual

impairment

Your acceptance of the child will serve as a positive

example to their classmates

Always say who you are instead of asking him or

her to guess who you are.

The blind student may exhibit certain mannerisms

(rocking, flapping, or poking the fingers into the

eye). Consult the SPED teacher on how to deal

with such behaviors.

She has been blind since she was 4, but that didn’t stop her excelling in her academics. She has been a consistent honorstudent from 4th grade onwards. She also graduated as a Valedictorian when she was in High School. Though college may be a great risk for her, she did not made her condition as an excuse for learning. She took up Bachelors degree in English and determined to teach children who experiences the same situation as hers.

“My mission is to inspire other people, blind or sighted. I want to be of service to blind people by educating them. Hopefully that’s what God wants me to do.”

Born prematurely and after was exposed to too much oxygen caused him to be blind.

Today, he has been singing in conciertos all over the world and was also renowned in his singing skills from classical broadways to popular music.

He is also a linguist. He knew 6 languages (French, German, Italian, Spanish, Russian, and Japanese languages)

FAJARDO, Adam

GARNICA,

GREGORIO, Grachelle

GUINOCOR, Abigael

INGATAN, Stephannie T.

Professor Gesela S. Macas

SOURCE: Introduction to Special Education ( A Textbook for College Students – First Edition) by T.Inciong, Y. Quijano, Y. Capulong