Retinal Vasoconstriction in Premature Infants with Increased Arterial Oxygen Tensions

Abstract

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 P_ao₂. The reduction in calibre could be measured, but was not detectable by viewing the retina, unless photographs taken at low and high P_ao₂ were viewed side by side. Frank retinal vasospasm did not occur even at a P_ao₂ of 250 mm. Hg. It was concluded that ophthalmoscopy did not provide an alternative to direct frequent measurement of P_ao₂ in premature infants receiving oxygen therapy.