Denmark Survey of Research on Child and Vision Development Steen Aalberg, F.C.O.V.D., optometrist Research on Child and Vision Vision: It’s Development in Infant and Child Development Arnold Gesell, M.D. Et al. Available through OEPF 1. Vision: ”It’s Development in Infant and • Even though this book was first Child” plus the optometric heritage published in 1949 it is still current, and 2. Latent Heliotropism referred to in much newer research. 3. Visual and General Space World • The potential risk that newer data and Problems by Preschoolers observations might be contaminated from 50+ years of socio-biological 4. Stereopsis Outweighs Gravity in the change, stresses the need for existing Control of the Eyes reference to help maintaining a picture 5. The Brain’s Sense of Movement of a natural vision development. 1
The heritage The heritage The works of D. B. Harmon, Lawrence W. Macdonald, G. N. Getman, Robert A. As I was reading the material I came by Kraskin, Furth and Wachs and many preparing this presentation, it seemed to me like these pioneers put researsch to work other pioneers are now to increasingly that wasn’t even done in their own time. extent being reconfirmed by much of the current research on almost any This part of our heritage is more current vision related field. than ever, and is cumpulsory reading if we are not to reinvent the wheel. Heliotropism • Brodsky: ”By redirecting our attention M. C. Brodsky – Br. J. Opthalmol. 2002;86;1327-1328 to the posture of our patients with congenital visual disorders, we can begin • Heliotropism - an orienting response to the sun (phototropism and phototaxis might bring additional relevant to deduce the role of vision in regulating search results) human muscle tonus” • Brodsky: ”As summarised by Duke-Elder ...the control of the movements of living organisms, both plants and animals, by light is a fundamental function of great phylogenetic age, preceding the acquirement of vision and, indeed, leading directly to its development. The association of the functions of equilibration and orientation with the visual system of higher animals is in every sense basic.” 2
• This basic concept is • For example, the torticollis that seemingly unaccounted accompanies Congenital homonymous for in respect to human hemianopia may attest to the primitive neurology. Or – at least, role of vision in establishing baseline I have not been able to muscle tone. find the term in our own • The head is turned away from the seing optometric litterature. field while fixation is maintained at the object of interest, the head turn seemingly serving no obvious compensatory function Visual and General Space World • Wibke Bein-Wierzbinskis work and Problems by Preschoolers research relates early development to the visual spatial problems often Raumlich-Konstruktive Störungen bei Grundschulkindern, Wibke Bein-Wierzbinski identified by optometrists. The (Germany, Europäische Hohcschulschriften ISBN 3-631-52288-6) references are numerous and counts • A research done on the importance of the among them Ayres, Babinski, Bender, neuro motoric body righting process for the development of fine eye movements Blythe, Gesell, Frostig, Goddard, Piaget and spatial relationship as well as ways to and research on neurology and enhance these through motor training. development, rangeing from early 1934 • Eye movement up to 2002 • Visual spatial relationships • Primitive reflexes and motor programs 3
IR eyescan before and after training Development of increasingly more program (in average 1.4 yrs) complex patterns of movement Symmetric – Asymmetric - Rotational • This study shows positive effect on Stereopsis Outweighs Gravity in almost all visual components the Control of the Eyes of the training program HubertMisslisch,1DouglasTweed,2andBernhardJ.M.Hess1 • Personal concern: TheJournalofNeuroscience,2001,Vol.21 RC126 It seems as if treatments based mainly The eyes are controlled by multiple brain om motor and reflex stimulation lacks far circuits, some phylogenetically old and behind in speed, compared to Vision some new, whose aims may conflict. Old Training incorporating general motor otolith reflexes counterroll the eyes development programs. My bet is once you when the head tilts relative to gravity. switch to visual guidance, vision will be Newer vergence mechanisms coordinate your most effective learning channel. the eyes to aid stereoptic vision. 4
Counterroll hinders stereopsis, weakly when you look into the distance but • Since this study is <humor on> ”monkey strongly when you look at near. business” we may not infer the reults directly on humans. Still we can think of this mechanism as a possible cause for reduced stereoacuity at near. • In pressence of a developmental problem in early childhood, convergence suppression of otolith reflexes might partly fail, leading to reduced stereo acuity or fragile binocularity. • Should we test binocular tolerance to head tilt?? The Brain’s Sense of Movement • ”To localize an object simply means to Alain Berthoz, ISBN 0-674-00980-0 (book) represent to oneself the movements necessary to reach it” • Alain Berthos describes how human beings perceive and control body movement, how perception and cognition • ”Two basketball teams, one team of are inherently predictive, functioning to children with normal vision and one of allow us to anticipate the consequences amblyopes(?) (both eyes) with less than of current or potential actions. 20/200 who read in Braille and do not attend normal school…” 5
• ”…This experience convinced me that ”I was watching two basketball teams, opthalmological tests examine only a one team of children with normal vision tiny fraction of of visual function and, in and one of amblyopes(?) (both eyes) any case, totally ignore perception of with less than 20/200 who read in movement…” Braille and do not attend normal school… ”I could not tell which was the handicapped team” The faster the movement, the more the second group seemed to succed…” • A baby first directs his gaze using his • ”Although millions of people wear progressive own body as reference point. He turns lenses that modify the apparant velocity of his head and eyes about the axis of his visual motion in a nonlinear matter…no test body, an egocentric frame of reference. worthy of th name examines dynamic vision, which is the most important for coordinating gestures and perceiving three-dimensional shapes, as research on the contribution of movement to perceptoion of curves shows. We are working on this question in collaboration with lens manufactures” (??Essilor France??) 6
• Once he begins to walk, he must give up the fixed reference and develop a new strategy for keeping objects steady in • At 18 months he adopts his third type space. Before 18 months he fixates a of functioning, and becomes able to landmark to which he anchors his mentally update his position in the room, progression around the room. while walking, using a mechansm of • This is probably the first sign of him mental rotation and translation. constructing object location and object relationships. • If his anchor point is hidden he reverts to egocentric strategy • Go where I’m looking”, not ”Look where Summary I’m going” • It is obvious that the early development of vision is strongly connected to that • From experiments it follows that we head of movement towards where we are looking. We • Likewise is motor development simulate out trajectory and compare the depending on vision (Heliotropism) actual with the predicted movement. • Our present challenge: Revealing the developmental roots of • ”When I direct my gaze towards a target, vision problems with the intention of I’m trying at the same time to act on that preventing and remediating them target. Movement is an integral part of perception.” 7
Lena 2001 8
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