Researchers recently aimed to correlate 29 systemic health factors with retinal nerve fiber layer (RNFL) thickness in 83 preterm infants at 36 weeks postmenstrual age (PMA) using OCT.
They found that 12 factors were significantly associated with RNFL thickness, including birth weight, birth weight percentile, gestational age, infant weight at imaging and growth velocity. A second analysis showed that low infant weight at time of OCT imaging and the presence of sepsis or necrotizing enterocolitis (NEC) were independently associated with thinner RNFL.
“These findings, together with our recently reported association between birth weight and RNFL thickness, suggest that poor intrauterine and postnatal growth, as well as sepsis/NEC, may adversely affect optic nerve development in preterm infants, corresponding with previous reports of impaired long-term neurodevelopment in these infants,” the authors concluded in their study.
Previous studies found a higher systemic level of interleukin-6 was associated with thinner RNFL in obese children, which is one of the possible mechanisms to explain the thinner RNFL. This is the same for adults that have systemic lupus erythematosus without ophthalmological manifestations who had significantly thinner RNFL than healthy individuals.
“These clinical studies further suggest a link between systemic inflammation and RNFL thickness,” the authors explained. “Another possible explanation for the association between
sepsis/NEC and RNFL thickness is that sepsis/NEC may damage brain regions covering the visual track (via ischemia, infection or inflammation), which may, in turn, cause retrograde trans-synaptic degeneration of retinal ganglion cells, resulting in thinner RNFL.”
To their knowledge, the authors say, this study is the first to demonstrate a significant association between sepsis/NEC and RNFL thickness in preterm infants while in the NICU, “suggesting that OCT-measured RNFL thickness may offer a potential noninvasive biomarker to assess the negative impact of sepsis/NEC on the central nervous system in preterm infants during their critical postnatal weeks before reaching term equivalent age.”
Shen LL, Mangalesh S, Michalak SM, et al. Associations between systemic health and retinal nerve fibre layer thickness in preterm infants at 36 weeks postmenstrual age. Br J Ophthalmol. July 30, 2021. [Epub ahead of print].