Visual Acuity
Visual acuity refers to how well one sees and to a measurement of the ability to clearly discriminate symbols at a given distance (Buktenica, 1958, and Barage, 1970). Most visual acuity tests require the child to distinguish and identify stimuli at 20 feet by 5 years. If he is able to accomplish the task, the child has perfect (20/20) vision. Legal blindness is 20/200 vision or worse in the better eye with the best refracted correction. That is, the legally blind child may see at 20 feet what the normally sighted sees at 200 feet. Partially sighted children have a visual acuity no better than 20/70. Vaughan and Asbury (1974) present the following progressing of visual acuity in children.
| Age | Visual Acuity |
| 2 months | 20/400 |
| 6 months | 20/200 |
| 1 year | 20/100 |
| 2 years | 20/60 |
| 3 years | 20/30 |
| 4-5 years | 20/20 |
Near Vision
Reaches and grasps: observe accuracy of child’s reach and grasp. Use seven lotto cards: car, plane, doll, chair, shoe, ice cream cone, spoon. Ask the child to name each card at a near distance. If the child calls the pictures something other than what it is, accept the label, if she uses it consistently, you may tell the child the label if the is unfamiliar with it.
Shifts gaze: Hold two objects 6" apart. Attract her attention to one and then the other. Observe the speed and response behavior.
Distance Vision: use a tape measure to find 15 feet. At the 15’ distance again show the pictures to the child. She needs /50 vision to pass at this distance. Test both eyes simultaneously. Observe whether the child squints or attempts to move forward to backwards.
If he is able to name the cards at a close distance but not at the mark, move slowly toward the child in 5 foot intervals until he can see the picture and record the sources.
Visual Perception and Color Perception
Use color cubes – 7 colors; two of each color; ask child to match seven sets of two (all colors). Use beads of several sizes and string. Ask child to string them. Use pencil and paper and nine capital block letters: L, H, T, R O, U, A, V. Ask child to trace the letters with pencil. Watch for postural changes and wandering eye-hand movements. Use lock and key and ask child to insert key. Use shape sorter to ask child to insert three shapes.
| Yes | No | |
| Color cubes | ||
| String beads | ||
| Capital letters | ||
| Lock and key | ||
| Shape sorter or form board | ||
| TOTAL |
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How to use the score: more than two numbers in more than two categories should signal the caring parent or professional to seek further evaluation. Observable antidotal information should be recorded and used in supplementing categorical yeses and nos.
Fixates on 4” object-record no. of seconds (use red ball) At 12-18 inches; at 10 feet
Focuses with two eyes (binocularly) (use closed book)
Blinks at shadow of hand over eyes
Pupils constrict and dilate (use flashlight)
Tracks horizontally (use flashlight)
Tracks vertically (use flashlight)
Tracks circularly (figure-eight)
Light reflects on pupil at 12” (muscle balance –use flashlight)
Names (pins)(pellets)
- 3 objects very small (1”) at 5 ft.
- 3 objects kitchen utensil size at 5’ and 10’
- 3 objects clothing size 20-30’
TOTAL
The teacher should prepare the testing situation so that is is in a familiar setting—one with which the child has had experience and can feel comfortable and relaxed. As the teacher displays the materials on a low table or desk, questioning of the child can begin. ASK QUESTIONS which establish interest in the child and his vision:
Do you wear glasses?
Does anyone in your family?
What kind of lights do you like?
Very bright or do they hurt your eyes?
Can you see the animals across the room?
What’s blue and round sitting over there?
IF A CHILD WEARS GLASSES. TEST HIM/HER WITH GLASSES ON
Supplies
Lotto cards of objects
Miniatures set of objects: car, plane, doll, chair, knife, fork, spoon
Miniature set of animals and/or people
3 balls of graduated sizes: tennis ball and smaller
Pie tin
doll 5" high
Flashlight(s)
Slinky toy
Flint sparkler
Wind-up toys
Color cubes
Closed book
Pellets or sugar pills
Finger puppets
Color beads and string
White paper
Black marking pencil
Lock and key
Shape sorter or form board
| Mobility and Reflexive Reactions | Yes | No |
| Runs backwards, forwards, to each side | ||
| Moves legs and arms in alternation pattern (reciprocal) | ||
| Orients peripherally by turning head left and right | ||
| Climbs over obstacles; kicks, jumps, without falling |
Check off what child can do
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X | X | X | X | ||||
| Walks backwards | Uses tools, screws, unscrews | Tolerance for separation | Sense of time | |||||
| Circles | X | Directed aggression | Sex modeling | Three words phrases | ||||
| Holds hands | Curious | Control of sphincters | Demands – short “I” – you code | |||||
| Pedals | Creative | Determination | Temporal awareness | |||||
| Makes crisscrosses | Classification/property | Adds parts | ||||||
| Recall – memory improves |
Visual Assessment for Parents and Teachers of Young Children
Why Screen 2-5 Year Olds
Functional screening for potential visual problems is an integral part of educating young children. From birth, a child’s vision needs to be carefully observed by caring teachers and parents. The structural elements of vision need to be evaluated. They are
a) reflexive reactions;
b) mobility;
c) muscle balance and eye movements;
d)visual acuity: near and distance vision, and
e) visual perception (Langley and Dubose, 1978)
Some forms of ocular impairment occur in young children in the absence of other handicapping condition. Nystagmus (jerking of the eyes), strabismus (muscle imbalance), amblyopia (lazy eye), and estropia (crossed eyes) are among common dysfunctions occurring in the normal population that are amenable to correction.
Conditions such as optic atrophy, cortical blindness, or rentrolentalfibroplasia are most often identified at birth or in early infancy, and require specific early sensory – stimulation training in order to optimize existing vision.
The purpose of vision screening is to:
a) identify levels of functional vision,
b) refer any observed problem for further professional evaluation, and
c) enhance the child’s ability to use existing levels of vision.
Observe the Child at Play
Gearhart and Weishahn (1976) provide a list of characteristics and behaviors that may signal the presence of a visual problem in a preschool-age child:
Visual Behavior
| Observable Signs | Yes | No | ||
| Red eyelids | ||||
| Crusts on lids among lashes | ||||
| Recurring sties or swollen lids | ||||
| Watery eyes or discharge | ||||
| Reddened or water eyes | ||||
| Crossed eyes or eyes that do not appear to be straight | ||||
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| Eyes that move excessively | ||||
| Drooping Eyelids | ||||
| TOTAL |
| Yes | No | ||
| Pushes, pokes eyes | |||
| Shakes head from side to side | |||
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| Holds objects and flicks or twirls | |||
| Waves hands in front of eyes | |||
| TOTAL |
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Set-up for screening – Antidotal information
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