ABSTRACT
One hundred newborn infants [70 preterm and term] were studied. The pupil diameter was measured by ophthalmic caliper and response to light was determined. The mean [- or + S.D.] pupil diameter in a dark environment [<10 foot candles of illumination] was 36 mm [ +/- 0.9]. The pupils did not consistently respond to 600 foot candles of light before 32 weeks postconceptual age, but responded increasingly thereafter. This progressive light response correlated significantly with postconceptual age, weight and Apgar score. Significant differences in the net miosis between infants with apgar scoring >7, those between 5-7 and those less than 4 scoring [P <0.05] were detected. The pupil diameter and net miosis also correlated with the duration of incubation and the need for admission to intensive care unit. This measurement of the pupil diameter and reaction to light may prove a mandatory part in assessment of the neonatal condition in both term and preterm newborn infants