Purpose
Evaluate effects of prematurity on early optic nerve (ON) development and potential utility of ON parameters as indicators of central nervous system (CNS) development and pathology.
Design
Prospective cross-sectional and longitudinal study.
Participants and Controls
Forty-four preterm infants undergoing retinopathy of prematurity (ROP) screening and fifty-two term infants.
Methods
We analyzed optic nerves from portable handheld spectral domain optical coherence tomography (SDOCT) images (Bioptigen Inc., Research Triangle Park, NC) of 44 preterm and 52 term infants. The highest quality ON scan from either eye was selected for quantitative analysis. Longitudinal analysis was performed at both 31–36 and 37–42 weeks postmenstrual age (PMA). Preterm ON parameters were also assessed for correlation with indicators of cognitive, language and motor development, and CNS pathology.
Main Outcome Measures
Vertical cup diameter (vCupDiam), disc diameter (vDiscDiam), cup-to-disc ratio (vC:D), cup depth, and indicators of neuro-cognitive development and CNS pathology.
Results
At 37–42 weeks PMA, preterm infants had larger vCupDiam and vC:D than term infants (908 vs. 700 μm, p<0.001; 0.68 vs. 0.53 μm, p<0.001), while cup depth and vDiscDiam were not significantly different. Longitudinal changes (n=26 preterm eyes, mean interval 4.7 weeks) in vDiscDiam and in vC:D were an increase of 74 μm (p=0.008) and decrease of 0.05 (p=0.015), respectively. In preterm infants (n=44), periventricular leukomalacia was associated with larger vCupDiam (1084 vs. 828 μm, p=0.005) and vC:D (0.85 vs. 0.63, p<0.001), post-hemorrhagic hydrocephalus was associated with shallower cup (331 vs. 456 μm, p=0.030), and clinical magnetic resonance imaging (MRI) was associated with larger vC:D (0.73 vs. 0.64, p=0.023). In 23 preterm infants with Bayley Scales of Infant Development scores, larger vC:D was associated with lower cognitive scores (p=0.049).
Conclusions
This is the first analysis of ON parameters in premature infants using SDOCT. It demonstrated that by age of “term birth,” vCupDiam and vC:D are larger in preterm infants who were screened for ROP than in term infants. In this prospective pilot study, ON parameters in these preterm infants appear to weakly associate with CNS pathology and future cognitive development. Future prospective studies with larger numbers are necessary before further conclusions can be made.