Abstract
Purpose :
To quantify parameters of foveal development longitudinally in vivo in breastfed (BF) and formula-fed (FF) rhesus monkey infants.
Methods :
Fullterm rhesus macaque infants were breastfed and mother-reared (n=8) or nursery-reared and fed either a standard human infant formula (n=7), or a formula supplemented with carotenoids, including lutein at the level in rhesus breastmilk, and natural RRR-a-tocopherol (n=8). Retinal imaging of each infant included macular sdOCT scans (Heidelberg Spectralis) at 2, 4, 8, 16 and 24 weeks postnatal age. Retinal layers were segmented by Spectralis software with manual correction of each slice. Layer thicknesses were measured at the foveal center, and average thicknesses were determined for the central 1 mm and for the 1-2 and 2-3 mm diameter annuli. In addition, macular pigment optical density (MPOD) was measured by two-wavelength reflectometry.
Results :
. A foveal pit was present in all animals at 2 weeks, and 11 retinal layers could be resolved at all ages. In all regions, total retinal thickness was approximately 75% of adult values at 2 weeks and approached adult thickness by 24 weeks. In accord with the typical pattern of foveal maturation, thickness of the inner/outer segment layer (IS/OS) and outer nuclear/Henle layer increased progressively with age, while thickness of the inner nuclear, inner plexiform and ganglion cell layers decreased, reflecting their peripheral displacement. IS/OS thickness in all regions was greater in BF than in either FF group at 8 and 16 weeks but the groups converged by 24 weeks. Conversely, thicknesses of inner nuclear, inner plexiform and ganglion cell layers in the 1-2 mm annulus were greater in FF groups at 8-24 weeks. Thus BF infants approached an adult-like pattern at an earlier age. No differences were found between formula groups. Peak MPOD at the foveal center increased progressively from 2 to 6 months in BF but not in either FF group, and the MPOD peak and total volume were higher in BF than FF groups at 4 and 6 months.
Conclusions :
BF, mother-reared rhesus infants showed more rapid foveal development than FF, nursery-reared infants. FF infants also had low MPOD despite formula carotenoid supplementation, suggesting a possible correlation between MPOD and other measures of foveal development. This study demonstrates modulation of macaque foveal development by postnatal diet and/or rearing condition.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.