Abstract
Purpose :
The foveal retina undergoes significant developmental changes from birth into adulthood. However, there is limited data examining cone packing, foveal pit shape and the size of the foveal avascular zone (FAZ) in children. Moreover, myopia usually develops during childhood. Therefore, evaluating retinal structure in children may provide insights into the mechanisms of ocular growth. We sought to better understand whether differences exist in overall foveal geometry in children as a function of age and refractive status.
Methods :
47 healthy children aged 6 to 15 years (mean ± SD = 11.2 ± 2.7 years) underwent a comprehensive vision exam. Optical coherence tomography macular volume scans (20° x 20°, 97 lines) were acquired (Heidelberg Spectralis) to quantify foveal pit depth, diameter, slope, and thickness using a custom MATLAB program. In a subset of children, split detector and confocal adaptive optics scanning laser ophthalmoscope (AOSLO) images of foveal capillaries and cone photoreceptors were acquired in one eye over the central 4°. The FAZ border was semi-automatically marked in AOSLO perfusion images using NeuronJ to quantify FAZ area, perimeter and circularity (n=31). Bound cone density was calculated using Mosaic Analytics at 0.2, 0.3 and 0.5 mm eccentricities (n=29). Ocular biometry was measured (Lenstar) and used in a 4-surface schematic eye that was modified for children to laterally scale retinal images.
Results :
Axial length was significantly longer in older (r2=0.39, P<.001) and more myopic eyes (r2=0.59, P<.001). Foveal pit and FAZ metrics were not related to age and were not significantly different between myopic and non-myopic children. After controlling for axial length, cone density was not correlated with age. However, cone density was significantly lower in myopic versus non-myopic children at 0.2 mm (mean ± SD = 50,019 ± 5,878 cones/mm2 vs 58,989 ± 4,822 cones/mm2, P<.001) and 0.3 mm (43,944 ± 5,547 cones/mm2 vs 48,557 ± 3,558 cones/mm2, P=.01) eccentricities, but not at 0.5 mm eccentricity (31,512 ± 4,389 cones/mm2 vs 33,037 ± 3,727 cones/mm2, P=.39).
Conclusions :
We report a comprehensive, in vivo assessment of overall foveal structure in children as young as 6 years. Results suggest that overall foveal geometry does not systematically differ with age in children. However, eyes with myopic refraction and increased axial length tend to have decreased cone density close to the fovea.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.