Optic disc measurements in full term infants

Background: The objectives of this study were to measure optic disc size in full term infants and to determine whether this value is influenced by sex or birth weight. Methods: Retinal images from a cohort of full term infants admitted to a tertiary perinatal centre were obtained using a retinal camera. Optic disc size was measured by carefully delineating the outline with a cursor using image analysis software. MEDLINE was then systematically searched to compare the data with other published articles. Results: 35 images of left and right eyes from 35 infants were assessed. An image from one eye per patient was then chosen for analysis. The following results were found: mean birth weight 3050±706 g; mean gestation 38.9±1.4 weeks. Mean optic disc area was 1.26±0.23 mm²; mean vertical diameter was 1.37±0.15 mm; and mean horizontal diameter was 1.14±0.12 mm. The vertical diameter of the optic disc was significantly longer than the horizontal diameter (p<0.0001). Conclusion: Birth weight and sex did not influence the size of the optic disc in term infants. There were no differences in optic disc measurements between male and female infants and between low birth weight and normal birth weight infants.