Characteristics of Optic Nerve Development Using Hand-Held Ultra-High Resolution Spectral Domain Optical Coherence Tomography in Premature and Full-term Neonates

Abstract

Purpose: Development of the optic nerve in the neonatal period is unclear. Previous studies based on histology and digital photographs have suggested that prematurity is associated with optic nerve hypoplasia. This is the first study to describe the development of the optic nerve in infants born prematurely in comparison to full-term infants using ultra-high resolution spectral domain hand-held OCT (HH-OCT).

Methods: A mixed cross sectional and longitudinal study design was adopted. 34 infants were recruited to the study, including 23 premature infants born at 24-30 weeks gestation and 11 full-term infants born at 37-42 weeks. Each patient underwent a full ophthalmological examination and a HH-OCT scan (Bioptigen, 2.6µm axial resolution) without sedation. The premature infants were reviewed for longitudinal follow up scans on an average of 2 separate occasions up to 46 weeks gestational age. The full-term infants were examined once within the first week of birth. The optic nerve cup, disc and depth were defined using ImageJ Software and linear mixed model analysis was performed using SPSS v20 Software.

Results: The optic cup/disc ratio demonstrated a reduction with age of examination in premature infants (p<0.001) on both cross sectional and longitudinal imaging due to decreasing cup width (p<0.05) and increasing disc width (p<0.05). The optic disc rim also showed increasing width with age of examination (p<0.001). Increasing gestational age at birth was associated with deepening of the optic cup in both premature and full-term infants. The depth of the optic cup was significantly greater in infants born at full-term as compared to premature infants (p<0.05).

Conclusions: This is the first study to analyse early optic nerve development in premature and full-term infants using HH-OCT. Our results suggest prematurity is associated with significant differences in optic nerve morphology in premature infants as compared to full-term infants.

Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 629 optic nerve • 706 retinopathy of prematurity