Characteristics of Normal Foveal Development in Infants and Young Children as Imaged Using Hand-Held Optical Coherence Tomography

Abstract

Purpose: To characterise the time course of normal foveal development in vivo in full term infants and children using hand-held high resolution spectral domain optical coherence tomography (HH-SDOCT).

Methods: 256 children with a mean age of 2.2 years (range 0-6.9 years) and 39 older children and adults with a mean age of 15 years (range 7.1-27 years) were recruited. Each participant had a full ophthalmological examination and HH-SDOCT scans. The OCT scans were segmented using a customised macro in ImageJ. The thickness and angle of each retinal layer at the fovea and parafovea were quantified and correlated with log gestational age (logGA) and visual acuity (VA).

Results: The central macular thickness (CMT) increases linearly with logGA by 85% between birth and three years of age, after which it plateaus. This relationship is described by: CMT (µm) = 61log(GA-1) + 111. In the parafovea, there is a more gradual 20% increase in retinal thickness over the same time period. The foveal outer segment (OS) and inner segment (IS) of the photoreceptors and the outer nuclear layer (ONL) also follow a linear pattern, with a 330%, 24% and 55% increase in thickness respectively, between birth and eighteen months of age, after which they plateau. In the parafovea, this increase is more gradual with the OS (76%), IS (12%) and ONL (15%). The foveal outer plexiform (OPL), inner nuclear (INL), inner plexiform (IPL) and ganglion cell layers (GCL) decrease in thickness with GA. Interestingly, the parafoveal thickness of the retinal nerve fibre layer (RNFL), GC complex (GCL and IPL) initially decrease in thickness until two years of age, followed by a gradual increase. The age adjusted CMT, ONL and IS are significant predictors of VA, with r ² = 0.739 and p = 0.000 for CMT and r² = 0.748 and p= 0.000 for the ONL and IS. The age adjusted angle between the fovea and the upper border of the ONL at 1000 µm is also a significant predictor of VA, with r ² = 0.777 (p = 0.001) and 0.765 (p = 0.045) for the temporal and nasal angles respectively.

Conclusions: We have characterised the time course of normal foveal development in infants and young children using the HH-SDOCT and several predictors of visual acuity have been identified. This is important as the HH-SDOCT will play an increasingly prominent diagnostic and prognostic role in children with retinal pathology.

Keywords: 698 retinal development • 757 visual development: infancy and childhood • 585 macula/fovea