Health and Community Services
Hearing & Vision Screening Program
VISION
Experts agree that at least 80% of what a sighted person learns is through vision. Schools, television, and movies all use this knowledge effectively to present ideas to their audiences.
Vision is most commonly described in terms of an acuity measure, or the best a person can see. 20/20 is considered normal vision; while 20/50 prohibits driving in Michigan without special aids, 20/70 is called a visual handicap, and when a person sees 20/200 or worse in his or her better eye with the best possible correction on that eye, that person is considered to be “legally blind.” A person can see with uncorrectable 20/200 vision, but often too little is recognized to be very helpful.
Relative sizes of objects seen with specific acuities are illustrated by these “E's”:
E
20/20 |
E
20/50 |
E
20/70 |
E
20/200 |
Vision can be hampered in a number of ways. Refractive errors can create distortions.
Nearsightedness
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Farsightedness
 |
Astigmatism
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Muscle balance problems, or crossed eyes, can prevent the two eyes from lining up to see the same thing. When they work together to produce one image, this is called binocular vision.
Binocular vision lets us judge the size and distance of an object from simple observation. This is known as depth perception, an important factor for good mobility.
In a young child when there is a great difference between the images “seen” by each eye, binocular vision will not result. An adult may see two images, or double vision, but a child who is learning to use vision will begin to see only the better image. This can develop into a condition known as Amblyopia - where both eyes are healthy but the brain uses only the information from the good eye and the other becomes “nonfunctional.”
Amblyopia diminishes the person's ability to see binocularly, and it virtually reduces the vision to that of the one good eye. As a child grows older with this condition, it becomes extremely difficult to train the poorer eye to “see” within a normal range.
Along with refractive errors and muscle balance problems, injuries and various other physical conditions such as cataracts, glaucoma and detached retinas can create difficulty in seeing. Symptoms of vision difficulty may include:
Appearance
- Crossed eyes
- Red eyes
- Watering eyes
- Crusty eyelids
- Frequent styes
- Cloudiness in or around pupil
Behavior
- Holds body rigid while looking at distant objects
- Thrusts head forward or backward while looking at distant objects
- Avoids close work
- Has short attention span
- Turns head to use only one eye
- Tilts head to one side
- Places head close to book or desk when reading or writing
- Blinks excessively
- Rubs eyes often, frowns or loses place, especially when reading
- Squints
- Closes or covers one eye
Complaints
- Headaches
- Nausea or dizziness
- Burning or itching of eyes
- See blur when looking up from close work
- Sees objects double
- Undue sensitivity to light
Treatment for visual problems may include:
- Prescription for glasses or contact lenses
- Surgery for severe muscle imbalance, cataracts, or severe glaucoma
- Medication for infections, allergies, glaucoma, and other conditions
- Educational assistance for the visually impaired and legally blind (i.e. visual aids, special classes, schools)
Vision Developmental Milestones
| Child's Age |
Expected Behavior |
Expected Completion* |
| Birth to |
Pupils react identically to light changes
Blinks at sudden light or object moving toward face
Looks at people (faces) and objects momentarily or longer |
Birth |
| 1 to 2 months |
Stares at people or objects
Responds to people's faces
Eyes follow a moving person or near object
Seeks lighted areas |
2 months |
| 2 to 3 months |
Inspects own hands
Eyes follow an object 180 degrees
Demands light for vision |
3 months |
| 3 to 4 months |
Eyes move in active inspection of body,
people, toys, surroundings
Looks at objects placed in hand (beginning eye-hand coordination)
Inspects own hands |
4 months |
| 4 to 5 months |
Smiles in response to familiar adult
Reaches for objects at least 1 foot away
Notices small food objects at least 1 foot away |
5 months |
| 5 to 6 months |
Eyes move together all the time
Brings objects to mouth, looks at them, then looks into space
Smiles at or pats mirror image |
6 months |
| 6 to 8 months |
Picks up or touches small objects with “raking” motion
Searches for hidden objects
Shows color preference for reds and yellows
Looks for dropped toys |
8 months |
| 8 to 10 months |
Notices details of an object such as
facial features on a doll, holes in a pegboard, geometric shapes
Reaches for string |
10 months |
| 10 to 12 months |
Understands and accomplishes vision
related motor tasks such as stacking
blocks, puffing pegs into round holes,
crawling, standing, walking |
12 months |
| 1 to 2 years |
Identifies geometric forms by placing
blocks in appropriately shaped holes
Shows interest in pictures
Scribbles on paper |
2 years |
| 2 to 3 years |
Finds object that move out of sight
without following its path
Recalls visual images
Puts together six-piece puzzles or matches
objects out of six pairs of items |
3 years |
| 3 to 4 years |
Copies geometric figures
Reading readiness present - responds to vision/speech-sound coordination activities like the television programs Sesame Street and Electric Company |
4 years |
| 4 to 5 years |
Recognizes names or colors |
5 years |
| 5 to 6 years |
Tells the difference in color shades
Depth perception fully developed
Vision approaches adult's |
6 years |
| If a child cannot perform at least two of the age-level tasks by the expected completion age, that child should be taken to an eye specialist for examination. |
Infant Warning Signs of Visual Problems:
- Visually unresponsive
- Holds things very close to see them
- Bumps into large objects
- Cannot pick up small objects with accuracy
- Favors one eye when looking at objects
- One or both eyes turn in or out for noticeable periods of time
- Squints or closes one eye frequently
Who Are The Specialists?
Specialists are people who are educated or trained to perform many specialized services for the visually impaired.
Physician: A medical doctor licensed to practice medicine in the United States.
Ophthalmologist: A medical doctor trained in diagnosis and treatment of defects and diseases of the eye.
Optometrist: A professional trained in vision disorders, evaluation for visual aids, and visual habilitation.
Optician: A professional who grinds lenses, fits them into frames to the wearer's needs.
Orthoptist: A professional who plans exercise programs for the development or restoration of normal teamwork of the eyes (binocular vision).
Visual Handicap Educator: An educator who is trained in techniques designed to increase a visually impaired individual's social adaptation skills, including learning and mobility skills.
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