Abstract
Purpose :
Growing evidence suggests that retinal shape and retinal periphery are associated with myopia development and progression, and recent studies implicate a significant role of peripheral retina in emmetropization. However, previous studies on optical coherence tomography (OCT) imaging in children are limited to central 30 degrees retinal and choroidal thickness. We evaluated retinal shape and thickness for retina and choroid up to 55 degrees eccentricity in young children.
Methods :
Radial scans (55°, 12 line) centered on the fovea in right eyes were collected with wide-field spectral domain OCT (Heidelberg) in healthy emmetropic children (n=37, ages 7.8±0.9 years) following a thorough vision exam. Images were processed in custom Matlab programs, and corrected for lateral magnification using biometric data collected for each eye (Lenstar) and a 4-surface schematic eye modified for children. Retinal and choroidal thickness were compared across eccentricities of 1, 3, 5, 8 and 12 mm, and across 4 retinal zones using one-way ANOVAs. Retinal curvature in the horizontal (RcH) and vertical meridians (RcV) were correlated with axial length (AXL) and mean corneal curvature (mean K).
Results :
Retinae were steeper in the horizontal than the vertical meridian (RcH=12.4±1.8 mm, RcV=14.7±3.8 mm, t=5.31, p<0.001). RcH became steeper with increasing AXL (r=0.38, p<0.05) and mean K (r=0.42, p=0.01), while RcV showed no such relations. There was significant effect of retinal eccentricity for both retinal (p<0.001) and choroidal (p<0.001) thickness (retina central 1 mm: 272.3±21.5 µm, choroid central 1 mm: 366.38±75.13 µm), with the choroid becoming significantly thinner in the periphery. There was significant effect of retinal zone for retinal (p<0.001) and choroidal (p<0.001) thickness, with thinnest retinae temporally and thickest nasally, while the choroid was thinnest nasally and thickest superiorly.
Conclusions :
We report asymmetries of ocular shape and retinal and choroidal thickness with wide field OCT in young children that confirm earlier studies and extend measurements to 55° eccentricity. Longer eyes, which are at greater risk of developing myopia, show steeper retinae in the horizontal, but not the vertical, meridian. The asymmetries in the horizontal and vertical meridians may have implications in eye growth and refractive development in children that we are investigating in a longitudinal study.
This is a 2021 ARVO Annual Meeting abstract.