Retinal vasoconstriction in premature infants with increased arterial oxygen tensions.

Baum, J. D., and Bulpitt, C. J. (1970). Archives of Disease in Childhood, 45, 350. Retinal vasoconstriction in premature infants with increased arterial oxygen tensions. Retinal vessels of newborn and premature infants were photographed under conditions of increasing arterial oxygen tension and the changes in vessel diameter were measured. In 6 infants studied, there was a consistent pattern of vasoconstriction with rise in PaO2. The reduction in calibre could be measured, but was not detectable by viewing the retina, unless photographs taken at low and high Pao2 were viewed side by side. Frank retinal vasospasm did not occur even at a PaO2 of 250 mm. Hg. It was concluded that ophthalmoscopy did not provide an alternative to direct frequent measurement of Pao2 in premature infants receiving oxygen therapy.