Purpose: To detect retinal features and abnormalities on optical coherence tomography (OCT) without pupil dilation and relate these to brain injury in infants with a clinical diagnosis of hypoxic ischemic encephalopathy (HIE).
Methods: Under an institutional review board-approved protocol, we imaged eight infants without pharmacologic mydriasis, using handheld, non-contact spectral-domain (Leica Microsystems, IL) or investigational swept-source OCT at the bedside in an intensive care nursery, after birth (depending on primary clinical care team permission based on health status) and weekly until discharge. The newborn infant with HIE is neurologically unstable; therefore, pharmacologic mydriasis and stimulation with visible light for retinal examination are usually avoided. We analyzed images for retinal pathologies, central foveal thickness, and retinal nerve fiber layer (RNFL) thickness at the papillomacular bundle and compared them to historical controls and published normative data, HIE clinical assessment, and abnormalities on brain magnetic resonance imaging (MRI).
Results: On OCT, three of eight infants had bilateral multiple small macular and perimacular cystoid spaces; two of these three infants also had pronounced retinal ganglion cell layer thinning and severe brain injury on MRI and the third had bilateral paracentral acute middle maculopathy and mild brain injury on MRI. Other findings in HIE infant eyes included abnormally thin fovea and thin RNFL and markers of retinal immaturity such as the absence of sub-foveal photoreceptor development and sub-foveal fluid.
Conclusions: Bedside handheld OCT imaging within the first 2 weeks of life revealed retinal injury in infants with HIE-related brain injury. Future studies may determine the relationship between acute/subacute retinal abnormalities and brain injury severity and neurodevelopmental outcomes in HIE.
Keywords: Brain injury; HIE; Hypoxic ischemic encephalopathy; Infant; OCT; Optical coherence tomography; Paracentral acute middle maculopathy; Retina.