It was long considered the newborn as blind. Today these theories are forgotten and experiments have even shown a sensitivity to light from the seventh month of intrauterine life. While not perfect, the vision of the newborn is an endless source of exploration of the New World.
The first work on the vision of newborns date from the fifties. Robert Fantz thought the fascination baby new things should be considered as a kind of silent language.
Two distinct concepts
The study of vision in the newborn brings together two different concepts:
Frstly what he perceives on the other hand it expresses the “look” in the relationship of the newborn to its environment. This is the concept of “look-spell” Ajuriaguerra.
In 1983, it was demonstrated by ultrasound that the fetus open their eyes in the amniotic fluid from the sixteenth week of intrauterine life. In addition, exposure to bright womb and flashing light causes accelerated heart rate and agitation of their members. Seven months after its conception, the baby already seen.
The early stages of vision The baby is able to birth, fixing the gaze. It informs us about the existence in the baby, photomoteurs reflexes. The newborn can track an object through an arc of 90 ° (a quarter circle). He also accompanies the eye tracking joint rotation of the head, provided the stimulus to be presented at a suitable distance and is sufficiently attractive (because of its contrast to its light intensity or movement).
After the meal, the newborn sated, quiet, breathing regularly, opens bright eyes for a time longer and longer. There are significant differences between children. Some babies are alive, others much more sleepy and less eye-catching look. Apart from external factors (such as length of labor, medication, etc.), it is likely that neural maturation difference intervenes largely.
Regarding accommodation, the curvature of the lens is not changed depending on the distance. The distance seems fixed at birth, around 18-20 cm. At the age of 3 months, the accommodation is excellent and superior to that of the adult. At 4 weeks, his eyes follow a toy that walks before him. At 6 weeks, his eyes follow people on the move in the room. At 8 weeks, there follows a moving object over 90 ° and 12 weeks, following the one side to the other. To 3 or 4 months it hangs gaze moving objects by rotating the head. At 6 months, he looks to see what interests by changing positions. It is only from 12 months it can follow the gaze a fast moving object.
The newborn sees relatively well the contrasting and somewhat distant things. There are two ranges of light intensity difference of 5%, while the adult perceives differences of 1 to 2%. The infant distinguishes flat volume around 6-7 weeks and the difference between concave and convex to 10 weeks. From 4 months, babies see colors as adults
Modern studies confirm that infants have a visual preference for new images. It seems that infants will eventually delayed intellectual development has already inferior visual selectivity capabilities. Parmelee has shown that infants who show no preference for new images have more medical history (obstetric complications and postnatal) that those who show this preference.