It has long regarded as blind infants. Today, these theses are forgotten and experiments have even highlighted a sensitivity to light as early as the seventh month of intrauterine life. Although imperfect, the vision of the newborn is an inexhaustible source of exploration of the new world.
Early work on the vision of infants date back fifty years. Robert Fantz believed that the fascination of the babies for the new things should be regarded as a kind of silent language.
Two distinct concepts
The study of vision in infants is composed of two different concepts:
on the one hand that he perceives.
on the other hand that expresses the “eye” in the relationship of the newborn to its environment. It is the notion of “look-spell” of Ajuriaguerra.
In 1983, demonstrated by ultrasound fetal open eyes in the amniotic fluid from the sixteenth week of intrauterine life. In addition, exposure of the maternal belly to a bright, flashing light causes an acceleration of their heart rate and the agitation of their members. Seven months after its conception, the baby is already.
The newborn is able, at birth, fixation of the gaze. This tells us about the existence, in the baby of photomoteurs reflexes. The baby can follow an object on a 90 ° arc (a quarter of a circle). Moreover, he accompanied the eye pursuit of a rotation joint head, as long as the stimulus is presented at a suitable distance and be sufficiently attractive (as a result of contrast, light intensity or his movement).
After the meal, the gullet, calm baby, breathing regularly, open bright eyes for a time more and more long. There are notable differences between the children. Some babies are acute, other much more sleepy and less eye-catching look. Outside exterior elements (such as the duration of delivery, drugs, etc.), it is likely that a difference of neural maturation occurs in large part.
With regard to accommodation, the curvature of the lens is not changed with distance. The distance is fixed at birth, about 18-20 cm. At the age of 3 months, the accommodation is excellent and even greater than that of the adult. A 4 weeks, eyes follows a toy that we go for a walk before him. A 6 weeks, he follows the persons eyes moving in the room. 8 Weeks, following an object moving on more than 90 ° and at 12 weeks, it follows from one side to the other. Around 3 or 4 months, he hung gaze movements of objects by rotating the head. A 6 months, he sought to see what interested him by changing position. It is only12 months he may follow the blind a fast moving object.
The newborn sees relatively well things little remote and very contrasting. It can distinguish between two beaches to a difference of 5% light intensity that adults perceive that differences of 1-2%. Infant distinguishes the dish of the volume to 6-7 weeks and the difference between concave and convex to 10 weeks. From 4 months, infants see colors as the adult. Modern studies confirm that infants have a Visual preference for new images. It would seem that infants who will later have a delayed intellectual development already have lower selectivity Visual capabilities. Parmelee has shown that infants who showed no preference for new images have more pathological history (obstetric and post-natal complications) than those that show this preference.