Grönqvist, H., Strand-Brodd, K., Rosander, K. (2011) ) Develoment of smooth pursuit eye movements in very prematurely born infants: 2. The low-risk subgroup. Acta Paediatrica. 100, e5-e11

The purpose was to investigate the impact of premature birth on visual tracking in a group of 37 infants, born before the 32nd gestational weeks (mean 29 + 6 weeks) and diagnosed as being without major neonatal complications. At 2 and 4 months corrected age, eye and head movements were measured when the infant tracked a moving object. The eye movements were analysed in terms of smooth pursuit and saccades. Accuracy of gaze, proportion of smooth pursuit, head movements and saccades were calculated. The results showed that between 2 and 4 months of age, all infants improved their ability to smoothly pursue a moving object. However, at both occasions, the preterm infants had less proportion of smooth pursuit than the full-term infants. The groups did not differ with respect to gaze and head movements, but the saccade frequency was higher for the very preterms in some of the conditions. It was concluded that the development of smooth pursuit in the low-risk preterm infant group was strongly delayed compared to typically developed infants. Thus, the 2 months or more extra visual experience did not have a distinguishable positive effect on visuo-motor development as expressed in smooth pursuit.