Getman, a renowned behavioural optometrist, defined vision as a learned ability to understand things that cannot be heard, touched, smelled or tasted.
He distinguished vision from sight, which, according to him, is simply a response to light and from acuity, which refers to light’s clarity. He stated that vision enables the child to interpret the world. In his pyramidal schema of learning, the foundation comprises motor learning from which vision or visual perception develops. If the foundation is solid, vision will be too, thus enabling higher-level functions.
Many have conceded the importance of visual perceptual skills in academic success, including Frostig and Horne, who believed reading would be impossible without adequate visual perception.
Problems of visual perception are noted in the following component areas. A few examples are given in each to illustrate its specific nature.
- Visual (object) discrimination refers to the ability to recognize the nature of objects. The child who experiences difficulties in this area cannot recognise shapes, sizes, colours or other dimensional aspects of objects, letters or numbers.
. - Form discrimination is defined as the ability to perceive differences among and positional aspects of objects. The child having a problem in this area is unable to distinguish between similar geometric shapes such as a square, a rectangle and a diamond, or similar letters such as /b/ and /d/ or /m/ and /n/, or words such as /pan/ and /pen/ or /the/ and /they/ or /hose/, /house/ and /horse/.
. - Foreground-background differentiation involves focusing on selected objects and screening out or ignoring the irrelevant ones. The child experiencing difficulty in this area cannot recognize an object surrounded by others. For example, the child cannot locate a ball in a picture of several toys or a word in a word-find puzzle.
. - Spatial relations relate to the ability to recognise the positioning of objects in space in relation to one another and the observer. The child with a manifest problem in this area cannot perceive the position of objects in relation to each other or themself. For example, the child is unable to place the letter /f/ in the alphabet, the number /9/ in relation to /0/ and /10/, or see each word in a sentence as a separate entity, or know in which direction objects or other children are in relation to their desk.
. - Visual closure. Also referred to as visual analysis and synthesis, this is the ability to recognise an object from a partial or limited stimulus or to form a “gestalt.” The child with difficulty in this area cannot perceive “whole-part” relationships in partially visible stimuli. Thus, the child may have problems forming a gestalt, that is, recognising objects when they are partly hidden. Similarly, even when the whole is visible, it is not recognised because the child is engrossed in its individual parts.
. - Visual sequencing refers to seeing objects in a particular sequential order. The child with difficulty in this area cannot perceive the order of stimuli in which they appear. For example, the child has problems arranging pictures of events in the sequence in which they are presented, copying the alphabet or numbers in the correct order, or seeing the order of letters in words such as /was/ and /saw/.
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Characteristically, according to Hayes, the child with visual perceptual problems (1) attends poorly to visual tasks such as silent filmstrips, artwork and copying; (2) tends to reverse, invert or rotate letters, numbers, words and forms; (3) may complain of eyes bothering them; (4) does not seem to attend to visual cues such as punctuation marks in reading or process signs in mathematics; (5) is lacking in observational skills; (6) tends to skip words or lines; (7) cannot locate information easily; (8) generally enjoys auditory tasks; and (9) is a good talker.
